BIOECOLOGY AND MANAGEMENT OF Helopeltis antonii SIGNORET (HEMIPTERA : MIRIDAE) ON CASHEW IN COASTAL KARNATAKA MANJA NAIK, C.

Transcription

1 BIOECOLOGY AND MANAGEMENT OF Helopeltis antonii SIGNORET (HEMIPTERA : MIRIDAE) ON CASHEW IN COASTAL KARNATAKA MANJA NAIK, C. DEPARTMENT OF AGRICULTURAL ENTOMOLOGY UNIVERSITY OF AGRICULTURAL SCIENCES, BANGALORE COLLEGE OF AGRICULTURE G.K.V.K., BANGALORE 2010

2 BIOECOLOGY AND MANAGEMENT OF Helopeltis antonii SIGNORET (HEMIPTERA : MIRIDAE) ON CASHEW IN COASTAL KARNATAKA Thesis submitted to the University of Agricultural Sciences, Bangalore in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY In AGRICULTURAL ENTOMOLOGY By MANJA NAIK, C. DEPARTMENT OF AGRICULTURAL ENTOMOLOGY UNIVERSITY OF AGRICULTURAL SCIENCES, BANGALORE COLLEGE OF AGRICULTURE, G.K.V.K., BANGALORE

3 Affectionately Dedicated to My Beloved Wife Smt.Jyothilakshmi,S. and Children Mast.Chandu and Darshu

4 DEPARTMENT OF AGRICULTURAL ENTOMOLOGY UNIVERSITY OF AGRICULTURAL SCIENCES, BANGALORE CERTIFICATE This is to certify that the thesis entitled BIOECOLOGY AND MANAGEMENT OF Helopeltis antonii SIGNORET (HEMIPTERA : MIRIDAE) ON CASHEW IN COASTAL KARNATAKA submitted by Mr. MANJA NAIK, C. for the degree of DOCTOR OF PHILOSOPHY in AGRICULTURAL ENTOMOLOGY of the University of Agricultural Sciences, Bangalore is a record of research work done by him during the period of his study in this University under my guidance and supervision and the thesis has not previously formed the basis for the award of any degree, diploma, associateship, fellowship or other similar titles. Bangalore February, 2010 (A.K.CHAKRAVARTHY) APPROVED By: Chairman: (A.K.CHAKRAVARHTY) Members : 1. (C.T. ASHOK KUMAR) 2. (D.P. KUMAR) 3. (M.GOPINATH RAO) 4. (S.K. GHOSH)

5 ACKNOWLEDGEMENT I express my deep sense of gratitude and heartfelt respect to my beloved teacher Dr. A. K. Chakravarthy, Professor, Department of Agricultural Entomology, College of Agriculture, G. K. V. K., Bangalore and Chairman of my advisory committee, for his most valuable guidance, keen interest, critical review, constant supervision and encouragement during the period of investigation and preparation of this thesis. I express my sincere gratitude and indebtedness to Dr. C. T. Ashokkumar, Professor, Department of Agricultural Entomology, College of Agriculture, GKVK, Bangalore and member of my Advisory Committee for his thought provoking, inspiring and valuable guidance and encouragement in execution of the research work and critical processing of the manuscript. I am highly indebted to the members of my Advisory Committee, Dr. D. P. Kumar, Professor and Head, Division of Horticulture, College of Agriculture, G. K. V. K., Bangalore. Dr. M. Gopinath Rao, Professor, Department of Agricultural Statistics, College of Agriculture, G. K. V. K. Bangalore and Dr. S. K. Ghosh, Senior Scientist, B. C. R. L. PCI, Bangalore, for their valuable suggestions during the course of investigation and preparation of the manuscript. I am thankful to Dr. N.G. Kumar, Professor and Head, Department of Agricultural Entomology, G. K. V. K., Bangalore, for the facilities extended during my course work and the investigations.

6 I express my sincere gratitude and indebtedness to Dr. C. A. Virakthamath, Professor (Emeritus), Department of Agricultural Entomology, College of Agriculture, GKVK, Bangalore for identification of TMB insect specimens as the only species Helopeltis antonii Signoret infesting cashew in different cashew growing regions of Karnataka. I also thank Prof. (Rtd.) Mustak Ali, Department of Agricultural Entomology, College of Agriculture, G. K. V. K., Bangalore, for the identification of ant fauna existing in different cashew ecosystems of Karnataka and his valuable suggestions and encouragement during the period of investigation. I express my heartfelt thanks to Dr. D. Sundararaju, Principal Scientist, (Entomology) NRCC, Puttur, for his thought provoking inspiring and valuable suggestions during my course of investigations. I greatly acknowledge the help rendered by the Scientists of NRCC, Puttur, during the course of investigations. I also thank Dr. M. N. Narasimha Reddy, Horticulturist and Head, Dr. K. M. Rjanna, Horticulturist, AICRP on Cashew, ARS, Chintamani, for their valuable suggestions and encouragement during my service at the scheme and at the period of investigations. I take this opportunity to express my heartfelt thanks to Sri. Usman, A, CDPO, Udupi. Mr. M. Manjunath, BBMP, Bangalore, for their sincere help to me and my family members during my study period.

7 I whole heartedly thank my friends particularly, Dr.G. G. Jayasinghe, Mr. B.K. Shivanna, Dr. M. Thippaiah, Dr. Chinnamadegowda, Mr. A. N. Reddy, Mr. Kengegowda, Mr. Basavaraj Naik, Dr. L. krishna Naik, Dr. Lakshman Reddy, Mr. Ramappa patil, Mr. Chandrappa, Mr. Prasanna, Mr. Doddabasappa, Mr. Yathis, Smt. Kempamma and others who are the source of inspiration throughout my studies. I am greatly indebted to Dr. M. Swamy, Professor and Scheme Head and Dr. M. Chandrappa, Soybean Agronomist, AICRP on Soybean, GKVK, Bangalore for their encouragement and help rendered during the preparation of manuscript. No words are enough to express the sacrifice by my beloved wife Mrs. Jyothilakshmi, S. during my course work at GKVK, Bangalore. I am highly indebted to her and my children Master. Darshu and Chandu. It gives me an immense pleasure to express my sincere heartfelt thanks to the Associate Director of Research, and other colleagues of ZARS, Brahmavar, for their help and encouragement during my service at the station and the facilities provided during the course of investigations. I deeply acknowledge the University of Agricultural Sciences, GKVK, Bangalore, for granting me the Deputation and Part time facilities for prosecuting my Ph.D degree programme. Any omission in this brief acknowledgement does not mean lack of gratitude Bangalore (MANJA NAIK, C.) 2010

8 Bioecology and Management of Helopeltis antonii Signoret (Hemiptera : Miridae) on Cashew in Coastal Karnataka Manja Naik, C Chakravarthy, A. K. PAK 5005 Major Advisor ABSTRACT Investigations on the Bio-ecology and management of Helopletis antonii Signoret (Hemiptera : Miridae) on cashew in coastal Karnataka, were conducted during 2006 to The tea mosquito bug infesting cashew in coastal and maidan Karnataka was identified as Helopeltis antonii Signoret. There was no co-existence of other species of Helopeltis in these regions. The gravid female preferred to oviposit on the young shoots, inflorescence stalk and developing cashew nuts. Mean incubation period ranged between 7.20 to 7.80 days in laboratory. The least developmental period of 25.0 days (egg to adult) was recorded in October-November and longer duration of days in December January. Sex ratio female to male was 1.0 : TMB completed twelve generations in a year. Variance to mean ratio higher than 1 indicated the aggregation distribution, coinciding with the emergence of new flush, panicle and nut and fruit developmental period. Variance to mean values nearing to 1 projected the random distribution of the bugs on cashew trees. TMB egg parasitoid Telenomus sp. recorded and per cent parasitisation from the host eggs collected in Brahmavar and Pethri cashew plantations. Cashew varieties Ullal-1, V.R.I-3, V-7, 9/25-Neeleshwar, 1/40-Palaparamba, 2/97-Kottarakara and Priyadarshini were found promising against TMB. The cashew trees fully colonized by O.smaragdina exhibited the least per cent damage and during in coastal and maidan Karnataka, respectively. The fecundity of TMB released on host plant treated with λ- cyhalothrin (0.005%), carbaryl (0.10%), monocrotophos (0.05%) and endosulfan (0.05%) was least 1.04, 1.12, 0.82 and 1.09 respectively, on 0 DAT. Pruned cashew trees attracted more number of adult bugs 9.63 / tree and it was least 3.0 adult/ tree on unpruned trees. Sequential sprays of monocrotophos (0.05) + λ-cyhalothrin (0.005) + carbaryl (0.10) at new flush, panicle and nut and fruit developmental stages were found effective and recorded higher nut yield of kg / ha and C : B ratio of 1 : Department of Agricultural Entomology College of Agriculture, GKVK, Bangalore (A.K. CHAKRAVARTHY) (Major Advisor)

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10 CONTENTS CHAPTER TITLE PAGE No. I INTRODUCTION 1 II REVIEW OF LITERATURE 4 III MATERIAL AND METHODS 33 IV EXPERIMENTAL RESULTS 44 V DISCUSSION 89 VI SUMMARY 101 VII REFERENCES 105 VIII APPENDIX 124

11 LIST OF TABLES TABLE TITLE PAGE No. 1 Occurrence of Helopeltis antonii on cashew in coastal and maidan Karnataka 2 Fecundity of H. antonii on cashew in laboratory (October March) Duration of H. antonii nymphal instars in laboratory (Days) (October March) 54 4 Morphometric parameters of H. antonii life stages in laboratory (October March) 55 5 Biology of H. antonii on cashew in laboratory (October March) 56 6 Fecundity of H. antonii on cashew in field (October March ) 57 7 Duration of H. antonii nymphal instars in field (days) (October March) 58 8 Biology of H. antonii on cashew in field (October March) 9 Morphometric parameters of H. antonii life stages in field (October March) Distribution pattern of H.antonii in relation to cashew phenology Taylor s Power Law and Iwao s patchiness regression for seasonal dispersion of H. antonii 65

12 12 Per cent egg parasitisation of TMB by Telenomus sp. in field, Ant fauna of different cashew ecosystems in Karnataka Predation of H. antonii by green ant Screening of cashew varieties against TMB in coastal Karnataka Biochemical constituents of cashew varieties Population of H.antonii on pruned and unpruned cashew trees Efficacy of botanicals and insecticides against H. antonii in laboratory, and Effect of biopesticides and insecticides on H.antonii in laboratory Efficacy of botanicals and insecticides against TMB in field, Efficacy of bio-pesticides and insecticides against H.antonii in field, Effect of botanicals and insecticides against TMB in field (pooled) Cashew nut yield (kg/ha) in different treatments, Cost: Benefit ratio for the treatments evaluated against TMB in field 88

13 LIST OF FIGURES FIGURES TITLE BETWEEN PAGES 1 Duration of nymphal instars Total life cycle of H. antonii in laboratory Field biology of H.antonii Parasitisation of TMB eggs by Telenomus sp Predation of H.antonii on cashew by green ants Number of adult bugs/ pruned and unpruned trees Cashew nut yield in diefferent treatments ( ) Cost: Benefit ratio in different treatments

14 LIST OF PLATES FIGURES TITLE BETWEEN PAGES 1 Tea mosquito bug Helopeltis antonii Signoret TMB egg TMB nymph Egg parasitoid Telenomus sp Predatory ant O.smaragdina nest O.smaragdina on cashew tree Adult TMB infesting new flush New flush damaged by TMB Healthy panicle Panicle damaged by TMB Healthy cashew nuts Cashew nuts damaged by TMB 79-80

15 INTRODUCTION

16 I. INTRODUCTION Cashew (Anacardium occidentale L.) a native of Eastern Brazil was introduced in to India by the Portuguese nearly five centuries ago. The first introduction of cashew in India was made in Goa from where it spread to other parts of the country. In the beginning, it was mainly considered as a crop for afforestation and soil binding to check erosion. The nuts, apple and other byproducts of this crop are of commercial importance. Though its commercial exploitation began from the early 60 s, marginal lands and denuded forests were the areas set apart for the plantation development. Because of its adaptive ability in a wide range of agro climatic conditions it has become a crop of high economy and attained the status of an export oriented commodity bringing considerable foreign exchange to the country. India has a creditable record of attaining good amount of foreign exchange by way of export of cashew kernels. Among the agri-horticultural commodities getting exported from India, cashew ranks the second position. During , India exported Million Tonnes of cashew kernels valued at Rs.2,28,890 lakhs. India is the largest area holder of this crop. Cultivation of cashew in India confines mainly to the peninsular areas. It is grown in Kerala, Karnataka, Goa and Maharashtra along the West Coast and Tamil Nadu, Andhra Pradesh, Orissa and West Bengal along the east coast. To a limited extent it is being cultivated in Chattisgarh, North Eastern States (Assam, Manipur, Tripura, Meghalaya and Nagaland) and Andaman and Nicobar Islands. Now cashew occupies an area of 8.68 lakh ha in the country during with a production of 6.65 lakh MT. Of these, 2.00 lakh ha of the plantations developed from the beginning of VIIIth Plan alone have been with superior clones of high yielding varieties. Among the various production constraints identified, the insect pests form one of the major limiting factors causing a crop loss of 30 to 40 per cent

17 (Satapathy, 1993). More than 60 species of insects attack the crop during its different stages of growth. These pests include sap-sucking bugs, leaf-chewing caterpillars, beetles, aphids, scales, thrips and also mites that can cause considerable damage to the tree and the crop by bringing about the death of the floral-flushing shoots, the early abortion of young nuts and loss of yield. Among these the tea mosquito bug Helopeltis antonii Signoret alone has potential to cause 40 to 50 per cent yield loss in cashew yield (Anonymous, 1999). The adults and nymphs of the species feed on tender shoots and floral branches, as well as on the developing nuts and apples, by piercing and sucking the sap. Helopeltis spp. population increase during the rainy season, reaching a maximum at the end of the rainy season and the beginning of the dry season coinciding with the emergence of a new flush, panicles and nut and fruit development. Mirid bugs of genus Helopeltis are serious pests of various cultivated plants in the Old World tropics. The damaging effects of these insects on tea plants in India was documented over a century ago by Peal (1873) and Wood-Mason (1884). It was in these early accounts that the common names tea bug and tea mosquito were established. Since the late 1800s over 100 species of plants have been reported as hosts for Helopeltis spp. including a number of major commercial crops such as black pepper, cashew, cinchona, cocoa and tea. Of the 40 recognised species of Helopeltis, 26 are restricted to Africa and 14 are distributed in Oriental Australasian regions (Stonedahl, 1991; Stonedahl et al., 1995). At present, chemical control measures are recommended for management of H.antonii on cashew (Sundararaju et al., 1993). Since there is potential restriction in USA and EEC countries in importation of cashew kernels containing pesticides, developing integrated pest management practices embracing bio-agents, botanicals and new chemical molecules is required.

18 None of the varieties is resistant to the pest although some of the accessions show low incidence of the tea mosquito bug (Ambika et al., 1979). Further, the pest population density and intensity of incidence varies from tree to tree, some being heavily infested and some are practically free from infestation (Pillai, 1980; Pillai et al., 1984). Even though more than 15 species of general predators and an egg parasitoid of the pest have been identified, none of these have been utilized commercially for the management of tea mosquito bug. However, information on predator-prey interactions and sustainable management practices is lacking. In view of the growing need for the improvement in the yield of cashew and that cashew tea mosquito bug is one of the factors reducing the cashew yield, the present investigation was undertaken with the following objectives. 1. To conduct a survey of cashew plantations in Southern Karnataka to find species of Helopeltis on cashew. 2. To study the bio-ecological attributes of Helopeltis antonii on cashew. 3. To monitor and determine population dispersion and infestation pattern of Helopeltis antonii in relation to phenology of cashew tree. 4. To develop sustainable management practices embracing, biopesticides and new molecules for Helopeltis antonii on cashew.

19 REVIEW OF LITERATURE

20 II. REVIEW OF LITERATURE The literature pertaining to tea mosquito bug Helopeltis spp. relating to the present investigation has been reviewed and presented below. 2.1 To conduct a survey of cashew plantations in Southern Karnataka to find species of Helopeltis on cashew Classification of Helopeltis spp. The group of bugs, commonly referred as mirids, belongs to the family Miridae, in the true bug order Heteroptera (Superorder Hemiptera). Mirids typically suck the juice of meristematic plant tissue, a resource these small plant bugs have luxuriantly exploited to become the largest of all Heteropteran families (Southwood and Leston, 1959: Slater and Baranocoski, 1978). However, as competitors of aphids and other phloem feeding homopterans, many mirids occasionally or solely prey on these insects. About one third to one half of all heteropterans are mirids. Although fewer than 7,000 species were listed in the world miridae sp catalog (Carvalho, ), many more have been described since 1950 bringing the total to 10,000 or more. The mirid species in the world may reach 20,000 (Henry and Lattin, 1987). Latest classification is by Carvalho ( ) who recognised six subfamilies viz., Bryocorinae, Phylinae, Orthotylinae, Mirinae, Cylapinae and Deraecorinae. Schuh (1986) proposed a phylogenetic scheme for the subfamilies of Miridae and also presented an analysis relationship for the subfamily Bryocorinae. According to Carvalho ( ), more than 250 mirine genera were described by Of these, Lygus contained the greatest number of species, about 300 sub families in the largest subfamily Mirinae, Bryocorinae consists of two tribes viz., Monaloniini and Odoniielini.

21 Signoret (1858) erected the genus Helopeltis under tribe Monaloniini to receive an insect found on the tea by Antonie Dohrn in Srilanka and described it as H. antonii sp. nov. Subsequently for Helopeltis spp. a wide range of information on new species, biology, host range, pest status, control and other aspects have been compiled in various reviews and research papers (Mann, 1907; Entwistle, 1972; Devasahayam and Nair, 1986; Satapathy, 1993; Sundararaju and Bakthavatsalam, 1994) Distribution of Helopeltis spp. The genus has palaeotropical distribution extending from West Africa to New Guinea and Northern Australia. Of the 41 recognised species, 26 were restricted to Africa (Schmitz, 1968 and 1988) and 15 were prevalent in Asia and Pacific region (Stonedahl et al. 1995). Stonedahl (1991) recognised two subgenera; Afropeltis subgen. nov. (type species Eucerocoris westwoodi White) including all African species of the genus and Helopeltis sensu stricto, containing the Oriental and Australasian species which included one non-existing species, H. podagricus (Costa). Most important species of Helopeltis causing economic damage to crops in Oriental and Australasian region are H.antonii, H.bakeri Poppius, H.bradyi, H.cinchonae Mann, H.clavifer (Walker), H.pernicialis S.M. and H. theivora (Stonedahl, 1991; Stonedahl et al., 1995). The economically important species of Helopeltis occurring in Africa are H. anacardii Miller (Miller, 1954), H. bergrothi Reut., H.lalandei (Carayon), H.schoutedeni Reut. (= sanguineus Popp.) and H. westwoodi (White) (Cadou, 1994) Early records of Helopeltis spp. Plant bugs of the genus Helopeltis are serious pests of various cultivated plants in the old world tropics. In Indonesia (Java), the first record of symptoms

22 that could almost certainly be attributed to attack of Helopeltis was on cocoa in 1841 (Giesberger, 1983) and on tea Roest (rust) disease in 1847 (Shaw, 1928). Zehntner (1903) reported that H. antonii and H. theivora were involved in the damage of cocoa. Later studies indicated that H.antonii and H. bradyi were infesting cocoa especially in Indonesia (Java) (Stonedahl, 1991). In Srilanka, though H.antonii was known to cause mosquito blight on tea, its first recorded damage was on cocoa in 1863 by (Entwistle, 1972). In India, H. theivora was documented over a centuary ago on tea by Peal (1873) and Wood- Mason (1884). In south India, its outbreak on tea was reported around 1920 (Rao, 1970). Subsequently, the occurrence of H. antonii on Persian neem and other forest plants (Fletcher, 1914), neem (Rao, 1915), cashew (Ayyar, 1932), guava (Rao, 1915; Puttarudriah, 1952) and on cocoa (Abraham and Padmanaban, 1967) was reported. In India, H.antonii is observed in all the cashew growing tracts namely Maharashtra, Goa, Karnataka and Kerala in west coast (Pillai, et.al. 1976); maidan parts of Karnataka (Thirumalaraju et al., 1991) and along the coast in Tamilnadu (Ballard, 1921; Rau, 1937); Andhra Pradesh (Rao and Srinivasan, 1984), Orissa (Jena et al., 1985), West Bengal (Ghosh and Chatterjii, 1987) and Bihar (Abraham, 1958). In Tamil Nadu three species of Helopeltis viz. H.antoni, H.bradyi and H. theivora were recorded. Among these H.antonii was found to be the dominant species throughout Tamil Nadu and neem was found to be the main host for H.antonii (Sundararaju, 1996). H.antonii is the most serious pest of commercially grown cashew in India with crop losses sometimes reaching per cent (Devasahayam and Nair, 1986).

23 Sundararaju (1996) observed H. bradyi coexisting with H. antonii on cashew in Westrn Ghats of Tamil Nadu. Tea mosquito bug, Helopeltis antonii Signoret is the most destructive pest of cashew in all cashew growing regions of India (Abraham, 1958). H. antonii is considered to be the most serious pest of cashew in South India (Ayyar, 1942) To study the bio-ecological attributes of Helopeltis antonii on cashew Mass culture and biology of H.antonii Mass culture techniques The mass culture techniques for H. clavifer and H.antonii on cocoa and cashew have been reported by Smith (1973), Sundararaju and John (1992) and Satapathy (1993) Biology of H.antonii The eggs of Helopeltis spp are white, ovoelongate and laterally compressed apically 1.0 to 1.31 mm long (Miller, 1941, Satapathy, 1993). Two unequal extrachorionic processes (a long ventral one and a shorter dorsal one) arise from the anterior end of the egg, these usually are mm in length. The eggs were embedded in plant tissue, singly or in small groups, usually with operculum and extrachorionic processes exposed. The extrachorionic process was called respiratory horn. Aeropyles or air tubes that opened on the apical region of the horn provided a direct root for the exchange of gases between the ambient air and the intrachorionic air. The intrachorionic air formed a continuous layer that was held between vertical structures about 0.7 M long that separated a thin inner sheet of chorion from the main body of the shell wall (Hinton, 1962).

24 Oviposition Ovipositional site preferences among the species depends on host plant. H. theivora preferred the pods of cocoa, but would occasionally oviposit on young shoots (Miller, 1941). On tea, this species preferred new shoots and rarely the petioles and midribs of leaves (Mann, 1902; Das, 1984). H. antonii laid its eggs primarily on the young cashew shoots, inflorescence, stalks and sometimes on the petioles and ventral midribs of leaves, either singly or in groups of 2-6 (Devasahayam and Nair, 1986). Lever (1949) observed that both H. bradyi and H. cinchonae selected young shoots of tea for oviposition. The egg production and ovarial development depended considerably on environmental conditions. If conditions were poor, no mature eggs were formed and oviposition stopped for a longer or shorter period. When conditions became favourable again, many eggs could be laid in short time. This abrupt interruption and resumption in oviposition might explain the erratic nature of the pest problem, showing sudden outbreaks and suddenly declining attacks. Lowest incubation period of five days in June- August and longest incubation period of 27 days in January in H. Theivora were observed (Das, 1984). Depending on the season, the incubation period for H.antonii and H.bradyi varied between 5-12 days and 7-16 days, respectively. Helopeltis sp. had five nymphal instars varying in size, colour and the development of certain body parts viz. antennae, wings and description and illustration of the nymphal instars were provided by Ambika and Abraham (1979) and Satapathy (1993) for H.antonii. The rate of development was affected by climatic factors especially temperature (Betrem 1953; Sundararaju and John, 1992) as well as the quality of food source (Awang et al., 1998). Least developmental period (egg to adult) around days had been observed in three species (H.antonii, H.bradyi and H.theivora).

25 Adult longevity and fecundity also varied, depending on rearing condition Tan (1974) reported a mean longevity of 30 days for H. theivora reared on cocoa pods in West Malaysia. The same species was reported to have mean longevity of only six days, when reared on shoots. Longevity records for H.antonii reared on terminal shoots of cashew seedlings and cashew trees were in the range of days (Wang et al., 1998). The life cycle of H.antonii was 24 days and during its life stage it moulted 5 times (Atmadja, 2003). Relative multiplication of H. antonii was studied on its three main host plants. The net reproductive rate indicating the total female birth was 65.63, and 22.17, the population increased with an infinitesimal rate of , and and finite rate of 1,134, 1.09 and female per day and a generation was completed in 33.35, and days on neem, guava and cashew, respectively. The stable age distribution (%) of eggs, nymphs and adults on these three hosts, ranged from , and , respectively (Sundararaju and Sundarababu, 1999). Biology of H.antonii was studied under both laboratory and field conditions. Morphometric studies, indicated 5 nymphal instars in the development of H.antonii. The mean duration of the developmental period of males and females were 26.9 and 28.2 days, respectively. Female predominate in the natural population with a sex ratio of 1: The mean duration of mating was 1h and 15 minutes and resulted in a fecundity of eggs with an oviposition period of 6 days, under C and % RH (Wijetunge et.al., 2003). 2.3 To monitor and determine population dispersion and infestation pattern of Helopeltis antonii in relation to phenology of cashew tree Seasonal abundance and extent of damage by Helopeltis spp.

26 Helopeltis spp. exhibited a more or less continuous cycle of generations, through out the year (Das, 1984) observed that in the tea growing regions of North- East India, H.theivora reached the peak from June to September with population levels gradually declining in November as weather cooled down. Few adults were found on the tea plants during winter months, but their numbers increased again in March as nymphs from over-wintering eggs began attaining maturity (Mann, 1902; Das 1984). Dejong (1935) suggested that changes in the tea plants during wet season favoured the insect reproduction. But high winds with low humidity were limiting factors to the development of Helopeltis in Eastern Sumatra, where the insects developed in well protected fairly dense shade. In South India, the seasonal prevalence of the pest largely depended on weather factors and tea mosquito was generally considered a wet weather pest during South West and North East monsoon, the insect being intolerant to very dry conditions (Shaw, 1928; Rau, 1940: Muraleedharan, 1992). In Malawi, Smee (1928) found a measure of correlation between outbreaks of H. bergrothi on tea and seasons of many rainy days particularly in November and February. In peninsular India, the build up of population of H.antonii on cashew in October November synchronized with emergence of new foliage, following the cessation of the monsoon rains. It reached peak in January-February, when cashew trees were in full bloom, the insects remaining active on the plants until the onset of the monsoon rains in June (Raja Pakse and Jeevratnam, 1983); Pillai et al., 1984; Sundararaju, 1984; Devasahayam, 1985; Satapathy, 1993). Senguttavan and Baskaran (1993) observed negative relationship between rainfall and incidence of H.antonii. In East Africa, the main growth of cashew tree began after the end of the rains in May with the production of first vegetative and later of flowering shoots towards the end of the rains, population increased rapidly from July to October- November, coinciding with fruiting season. From December

27 to June, there was no population on older trees but population was observed in young trees even up to April because of continuous flushing (Swaine, 1959). In China (Guangdong), the population of H. fasciaticollis on cashew increased from August or September and reached the peak during April and May of the following year. By June - July, the population naturally decreased to its lowest point except for the peak period, the spatial distribution pattern of the infestation by the pest during the whole infesting period was of the aggregation type. The curve of the infestation, growth index indicated that, the pest population increased very slowly in the early stages of population establishment (before January) (Pan et al., 1991). In Australia, occurrence of adult population of H. Pernicialis, was observed on cashew throughout the year, including both the humid (Oct-March) and dry (April-Sept) seasons, nymphs were present in population at all times except February. The capacity of the bug to cause economic damage was the greatest during the dry season, because of its ability to directly damage both nuts and flowers at the same time. Observations revealed a very patchy distribution pattern with sever localized damage (Stonedahl et al. 1995). In Java, Helopeltis population on cocoa was the lowest in the second half of the dry season and the beginning of the rainy season. During the rainy season (September-April) there was a steady increase in numbers with a maximum in March April. Once rains stopped, the number declined again, hot and humid weather condition, with sufficient sunshine and intermittent hot, too heavy rainfall were optimum conditions for Helopeltis. Once the rains commenced after dry season, there was a rapid build up. This may be attributed to existence of Helopeltis individuals that survived until the feeding opportunities improved. Such packets were found in gullies, hollows and border of streams, where soil moisture and humidity were suitable for the development of lush vegetation of shrubs and

28 herbs, including alternative host plants. From such pockets, Helopeltis got distributed over entire cocoa plantations after the beginning of the rains (Geisberger, 1983). But, in guava, no correlation was observed between the incidence of the pest and weather factors (Gopalan and Perumal, 1973). Population build up of H. antonii commenced in January and reached the peak in the second fortnight of February, synchronizing with peak flowering and fruit set. Activity of H. antonii was favoured by abiotic factors viz. temperature, relative humidity and sunshine hour, where as rainfall adversely affected its activity (Mohapatra and Satapathy, 1999). The seasonal abundance and extent of damage by tea mosquito bug on different aged cashew trees during , to on three and years old trees in October to April. The damage was in the range of very low to severe up to five years of age and subsequently fluctuated between very low to moderate and moderate to sever. Severity of damage up to grade 4 by absolute estimate was observed in the months of January, where as, on year old trees, the population in the range of per leader shoot by relative estimate was observed in December to February and again it was the lowest in March to May, with a range of 0.02 to 0.14 per leader shoot. In severe infestation, yield reduction up to 83 per cent than previous year was observed. Comparison of weather parameters and population dynamics of TMB, only minimum temperature has shown consistently negative relationship. The population growth of TMB indicated, independent relationship of weather factors (Sundararaju, 2005). Tea mosquito bug is active from December to April. The intensity of this pest is moderate and is responsible for drying up of inflorescence and consequent, reduction in yield (Anuj, et al., 1996). In cashew the activity of tea mosquito bug is restricted to tender flushes only (Sundararaju and Sundarababu, 2000).

29 Ahmed et al. (1992) developed a population model for H. theivora in Bangladesh, based on data of seasonal abundance. The model simulated the population dynamics of the pest throughout the season and output of the model indicated that the population density of eggs, nymphs and adults was low during the early part of season and increased rapidly to a peak in September, declined slightly in October and quickly in November to become very low from December to March. This seasonal pattern appeared to be due to high fecundity and short development time during June to October Monitoring and determination of Population H.antonii is the most serious pest of commercially grown cashew in India, with crop losses, sometimes reaching per cent. The nymphs and adults fed on the leaves and stems of new shoots, panicles and developing nuts. In severe infestation, the young shoots and panicles dried up (blossom blight) giving the infested tree a scorched appearance. Successive attacks on new growth resulted in stunting or death of the tree. Damage to immature nuts caused them to shrivel, while older nuts developed a blistered or scabby appearance. A resinous substance exuded from the feeding punctures on the shoots and exudate dried up and hardened. The gummy exudation was more, around punctures on relatively harder tissues on the shoots (Devasahayam and Nair, 1986). In a field trial in Karnataka, Sathiamma (1977) found that panicles (48.4%) and fruits (32.%) sustained higher levels of attack than young shoots (14%). Nymphs caged on young shoots made an average of 114 feeding lesions per day (range ) while female made an average of 97 (16-238) and made 25 (11-59). Occurrence of H. thievora on cashew had been mentioned by Abraham and Nair (1981) from Kerala. Similar type of damage on cashew by H.anacardii and H.begrothi has been reported from Tangangilea (Swaine, 1959).

30 Siswanto et al. (2008) distribution analysis using various indices of dispersion and regression models was applied to evaluate the dispersion of H.antonii in cashew plantation. The result showed that variance to mean ratio (S 2 X ), χ 2, Lioyds mean crowding, Green s coefficient of dispersion and Taylor s power law indicated aggregated distribution when population is high during flushingflowering seasons of cashew plants and it indicated regular or random distribution when the population is low during post-flowering seasons. The aggregated distribution on cashew plants indicated that there is preferency to food sources of the plants and an individual behaviour to aggregate. The distribution of the pest was found to be aggregated and population dynamics was not influenced by weather factors. Population and damage did not differ significantly in the four quadrants of trees, North, South, East and West. Each nymph/adult during its life time damaged (S.E) shoots. The sample sizes recommended for assessing its population for control survey and life table studies is 52 leader shoots per tree and in each case a total of trees are required (Sundararaju et al.,1998) Population dynamics Swaine (1959) observed the absence of H. anacardii Miller, during the rainy season and its abundance during the flushing season (July- November) after the monsoon in Tanganyika. The insect was scarce on older trees, from December until June, but was readily found on young trees in December- April as these were putting on a considerable amount of new and succulent growth during this period in addition to the main growth after June. The population build up of TMB commenced from October synchronizing with the emergence of new flushes after the cessation of rains. The pest population reached a peak, during the blossom period in January. It was totally absent on the

31 trees during the monsoon period (June to September). Highly significant negative correlation was observed, between meteorological factors like rainfall, relative humidity and minimum temperature and the pest population, while there was positive correlation between pest population (adults and immature stages) and percentage of infested shoots and panicles (Pillai and Abraham, 1974). Rai (1981) noticed the occurrence of the pest, between November and April with a peak incidence during January to February at Ullal (Karnataka). In Goa, the pest remained very active for a prolonged period of four months from November to February, with its period of activity extending a month on either sides. Significantly more number of insects were recorded in samples of morning hours than other times. During sunny hours, adults rested on underside of cashew leaves and nuts to avoid direct sunlight. They also observed that other than rainfall, which caused about 35 to 45 per cent nymphal mortality and 25 per cent egg mortality, the wind, sunshine, relative humidity and temperature also had slight or indirect effect on TMB population (Anon., 1981). The field activity of the TMB on cashew was noticed between October to May, but the fastest build up of the pest was observed in January and February, when the host plant provided adequate succulent plant parts (Jeevarathnam and Rajapakse, 1983). Build up of the pest population commenced from October - November synchronizing with the emergence of new flush, reaching a peak in January when the crop was in full bloom and persisted in the field till May. However, the pest was absent during the monsoon from June to September (Pillai, 1980; Pillai et al., 1984). Sundararaju (1984) recorded the occurrence of the TMB between December and June with a peak incidence lasting for a month, during February. In China population of H. fasciaticollis started building up in August and September and its plumage took place before January and there after the growth

32 starts declining. The population build up commences from February and reaches peak during April and May (Pan et al., 1991). Thirumalaraju et al. (1991) found that the incidence of H. antonii on cashew commenced from second fortnight of June on young plants and reached a maximum level (46.3%) in the first fortnight of January on old trees. Subsequently, the population declined and no incidence was noticed in the first fortnight of June. The crop phenology and meteorological factors influenced the incidence of TMB in young cashew plantation, commencing from second fortnight of July and reaches a peak of 94.8 per cent shoot damage in second fortnight of December. In older cashew plantations the peak incidence was noticed during January when the shoot and panicle damage was 42.8 and 19.2 per cent, respectively with a record of 18.4 bugs/ 30 laterals. The extent of new flush formation, exhibited highly significant and positive correlation with TMB incidence (r = 0.82) and its population (r = 0.74) on young cashew grove and as well as with shoot (r = 0.73) and panicle infestation (r = 0.63) besides population (0.56) on older cashew groves. In general, the mean maximum and minimum temperature, relative humidity and rainfall exhibited significant negative correlation with shoot and panicle damage on the population of TMB. In contrast, bright sunshine hours showed positive and highly significant with all these attributes (Satapathy, 1993). Survey of forest cashew plantations carried out for insects at weekly intervals during and seasons in India, revealed that H. antonii was active from December to April with moderate intensity and it was responsible for inflorescence drying (Anuj et al., 1996). Significant correlation between infestation, severity and time indicates that the severity of the damage has progressed steadily through the season. Correlation between severity and flushing

33 stage of the crop indicates that the progress of the severity corresponds to the progress of the flushes (Wijetunge et al., 2003). Tea mosquito bug incidence on cashew starts with onset of flushing in October -November. The pest population gradually increases during January at the time of blooming. There is highly significant negative correlation between the bug population and meteorological factors, like rainfall, humidity and minimum temperature. Cloudy and humid weather prevailing during flowering season enhances their, feeding activity (Thomas et al.,1997). A minimum temperature between 15 and 20 o C, cloudiness and relatively dry weather may be optimum for triggering pest population of TMB, this coincides with flushing and flowering of cashew (Rao and Thirumalaraju, 2002). The population dynamics of H.antonii was studied in Maharashtra, India from to Infestation was observed every fortnight, on trees that were unsprayed throughout the experimental period. The H.antonii was observed on sporadic vegetative flush in June-July and The major out break was observed in November, coinciding with emergence of panicles, reaching the peak in December. The minimum temperature was negatively correlated with pest incidence. The build-up of pest population commenced with the emergence of new flush, during October after the cessation of monsoon shower. The pest remained in the field until January (Godse et.al. 2005) Pattern of infestation Both the adults and nymphs pierce and suck the sap from tender branches, shoots, panicles, developing nuts and fruits resulting in drying up of the vegetative and reproductive parts of the tree. The damage symptoms of H. antonii on cashew is manifested as drying of tender shoots and inflorescence (Abraham, 1958) and also fruit drop (Pillai et al., 1976).

34 2.3.5 Nature and extent of damage TMB damage the plant since planting of seedling. The parts of the plant destroyed are the leaf, young leaf, bud, young stem and branch as well as flower, fruit and seed (Atmadja, 2003). Extent of damage caused to different hosts by the TMB was influenced by a multitude of factors, major among them being ecological conditions of different agro climatic zones and age and growth stage of the crop. Trees with more than 25 years old and those established from seedling progeny were less prone to infestation compared to young trees established by vegetative propagation (Anonymous, 1981). Ghosh and Chatterjee (1987) recorded maximum damage (49.5%) to cashew shoots during November and inflorescence damage of 73 to 79 per cent during December to February under West Bengal conditions. The pest accounted for 4 to 21 percent shoot and 2 to 40 per cent panicle damage. The per cent damage of 25 and 15 was observed on new shoots and tender nuts on cashew, respectively (Abraham, 1958; 1959). 2.4 To develop sustainable management practices embracing, biopesticides and new molecules for Helopeltis antonii on cashew. Prior to the development and extensive use of organic insecticides, little could be done to control out breaks of Helopeltis spp. especially on tea and cocoa. Only some sort of cultural, mechanical and biological control using ants were practiced with limited success (Geisberger, 1983) Parasitoids a. Egg parasitoids.

35 In China (CIBC, 1983), per cent of H. bergrothi eggs and in India up to 45.5 per cent eggs of H.antonii (Sundararaju, 1993 and Sundararaju, 2003) were parasitized by Telenomus sp. (Scelionidae). Lever (1949) and Ibrahim (1989) recorded 36 and 11.2 per cent of egg parasitism by Erythmelus helopeltidis Gah. in the case of H. cinchonae and H. theivora, respectively. b. Nymphal parasitoid The nymphal parasitoid, Leiophron spp. (Hymenoptera: Braconidae) appeared to be most promising (CIBC, 1983), but the existence of hyper parasitoids limited their potentiality, in biological control, especially due to Stictopisthus javensis Ferriere (Hymenoptera: Ichneumonidae) on H. bradyi (Geisberger, 1983) and Stictopisthus sp on H. bergrothi (Kirkpatirck, 1941). c. Predators Predators of Helopeltis include mantids, spiders and ants. Most of the predators had not shown any definite association with mirids (CIBC, 1983). Only one attempt to use predators for biological control against H. bradyi and H. cinchonae in Casmeron had been recorded. In 1940, five species of reduvid predators, were introduced from lowlands viz., Eugorus plagiatus Burm., Rhinocoris marginells Thub., Sycanus leucomesus Thub., Syncanus leucomesus Wlk., Isyndus heros F. and Cosmolestes picticops Stal. The last three became established. Three other species, Endochus cameronicus, Isyndus sp and Euagorus sp. which were already known to attack Helopeltis in highlands were also bred and released. However, the effect of these predators on the pest was not known (Rao et al., 1971). A great deal of work has been done on the role of ants, in controlling or deterring mirids on cocoa and elaborate measures had been taken, to encourage certain species in cocoa growing areas (Entwistle, 1972). Collingwood (1977)

36 discussed this in detail and concluded that the activities of ants normally have only a marginal effect on mirid population. But recent studies have shown encouraging results by increasing the activities of Dolichoderus thoracicus (Smith) and Oecophylla smaragdina Fabicius, the infestation of Helopeltis spp. could be reduced (Chong, 1987: Graham, 1991: Chin et al. 1988). The predaceous workers of O. smaragdina feeds on live insect H. antonii serious pest of Anacardium occidentale L. (Rosy and Narendran., 1985). Green ant O. smaragdina was dominant Predator in cashew plantations. It significantly reduced the number of the four most important species of insect pests, Helopeltis pernicialis Stonedahl, on cashew trees and trees with higher numbers of O. smaragdina produced higher quality nuts, than trees with fewer numbers of O. smaragdina (Peng et al. 1995). In a scoring method, about O. smaragdina on a cocoa tree can protect it effectively Helopeltis theobromae Miller (Hemiptera: Miridae). The relatively greater efficiency of O.smaragdina as a biological control agent is associated with its actively dispersive predatory behaviour, in contrast to the localized concentration of Dolichoderus thoracicus (Smith) workers at sites such as cocoa pods, where it tends honey dew producing Homoptera and where it acts largely by deterring H. theobromae (Way and Khoo, 1991). The predatory ant, Crematogaster wroughtnii Forel was able to feed on 10 first or second instar nymphs of TMB/day (Ambika and Abraham, 1979) and the adults or 18 to 20 nymphs of TMB/day (Anonymous, 1982). The parasitoid, Telenomous sp. parasitized 1.8 to 45.5 per cent TMB eggs (Sundararaju, 1993) and were considered predominant parasitoid of H.antonii. The red ant O. smaragdina and the praying mantid observed to prey on H.antonii in the field (Wijetunga et al., 2003).

37 Natural enemies of H.antonii recorded in India and neighbouring countries Sl.No Natural enemy Place of report Author/s. I Predators i Ants 1 Crematogaster wroughtnii India: Kerala Ambika and Foorek Abraham (1979) 2 Oecophylla sp. Srilanka Jeevaratnam and Rajapakse (1981) 3 Componotus compressus India : Karnataka Satapathy (1993) II Birds Java Roepke (1916) III Mantids Roepke (1916) 1 Unidentified Java Roepke (1916) 2 Heirodula coarctata Westw India : Karnataka Satapathy (1993) IV Reduviids India : Karnataka Satapathy (1993) 1 Almene sp India : Goa Sundararaju (1984) 2 Endochus cingalensis Stoal India : Goa Sundararaju (1984) 3 E.inornatus Stoal India : Goa Anonymous (1982) 4 Irantha armipes Stoal India : Goa Sundararaju (1984) 5 Oeamus typicus Distant India : Goa Sundararaju (1984) 6 Sphendanolestes minuschulus India : Goa Sundararaju (1984) 7 S.signatus Distant India : Goa Sundararaju (1984) 8 Sycanus collaris Fabicis India : Goa Sundararaju (1984) 9 Irantha sp India : Karnataka Satapathy (1993) 10 Cydnocoris gilvus Burmester India : Karnataka Satapathy (1993) 11 Cydnocoris sp. India : Karnataka Satapathy (1993) V Spiders 1 Hyllus sp India : Goa Sundararaju (1984)

38 2 Matidia sp India : Karnataka Devasahayam and Nair (1986) 3 Phidippus patch India : Karnataka Devasahayam and Nair (1986) 4 Argeope aeomula India : Karnataka Satapathy (1993) 5 Oxypoes sehireta India : Karnataka Devasahayam and Nair (1986) 11 Argeope sp India : Karnataka Satapathy (1993) 5 Marpisa decorata Tikadar India : Karnataka Satapathy (1993) 6 Marpissa sp. India : Karnataka Satapathy (1993) 7 Neoscona laglaizei (Simon) India : Karnataka Satapathy (1993) 8 Neoscona sp India : Karnataka Satapathy (199) 9 Oxyopes shaoeta Tikadar India : Karnataka Satapathy (1993) 10 Oxyopes ratnae Tikadar India : Karnataka Satapathy (1993) 12 Oxyopes sp. India : Karnataka Satapathy (1993) Microbial control Pathogenecity of the fungus Aspergillus tamarii Kita against all 5 nymphal instars of the TMB was tested through contact inoculation method and spraying of aqueous spore suspension method. In the formers method mortality of the TMB, infested a first to fifth instar stages were 61.2, 80.5, 77.6, 91.4 and 90.6 and the mortality of the pest in corresponding instars in the latter method were 46.7, 56.7, 53.3, 46.7 and 43.3 respectively. Maximum mortality of the nymphs was recorded within 3-5 days of infection. The possibility of managing the TMB on cashew through A.tamarii is foreseen through the above investigation (Satapathy and Devaraj, 1996).

39 2.4.3 Screening of cashew varieties for resistance Of the 74 germplasm accessions of cashew screened under field conditions, VTH-153 (H-3-17, Anakayam) was the least susceptible (Sathiamma, 1979). In a scoring technique with 0-4 scale had been used to screen 11 promising accessions under artificial infestation, accession No.665 (F 1 hybrid of BLA-139 and E 2-1 was the least susceptible (Ambika et.al.,1979). Accession No.BLA 39-4 recorded the least damage out of 17 types observed (Ghosh and Chatterjee, 1987). Hiremath (1991) screened cashew germplasms at Ullal (Coastal Karnataka) and observed 51 genotypes as promising. Out of them, thirty four accessions mainly released, pre-released and tolerant types identified in germplasm and in endemic areas were screened. Only two accessions (G-11/6 and VTH-153/1) were moderately susceptible and all the other accessions were highly susceptible (Sundararaju and John, 1993). The damage caused by Helopeltis was related to flushing pattern, in the field, early flowering types suffer more damage than the late flowering ones. Caging Helopeltis in the laboratory or confining them in a large polydome simulating a field like environment did not produce consistant results. However, clone AZA 2, known to be less attacked by Helopeltis under field conditions, retained this character in the laboratory. Furthermore, half sib progenies of AZA 2 under polydome showed the same results. Knowledge of flushing habit is important, particularly when selecting cashew clones for reaction to Helopeltis attack.( Uthiah et al., 1989 and 1994). Sathiamma (1984) reported that significant differences were observed between accessions in respect of damage and pest population. The damage and pest population were high on VTH-15 (51% and 105.5no/100 panicles) and low on VTH-153 (3.7% and 3.2no/panicle). Of the 17 types, BLA-39-4 and TN-16 gave

40 maximum yield with the least susceptibility to TMB attack (10.22kg/tree and 6% damage). The highest susceptible level against the TMB was noticed in the types NLR-2/1 and H-3-17 (0.26kg/tree and 52% damage) which gave minimum yield. Annapoorna and Nagaraj (1988) observed that TMB induced chemical changes in cashew. The infestation of succulent tissues resulted in decreased sugar content. In the case of panicles, significant decrease in sugar content due to infestation was observed only in least susceptible accessions. The total phenol and O-dihydroxy phenol contents of tender shoots in the least susceptible accessions were significantly higher as compared to that of highly susceptible accessions. The reaction of 91 indigenous and nine exotic cashew genotypes for the damage of H.antonii at Agricultural Research Station, Ullal, Karnataka during Based on the damage score by using standard deviation to categorize the genotypes in to promising, susceptible and highly susceptible types. Among the promising genotypes, the damage score varied from 10 to 100 and yield ranged from 0.3 to kg/tree during 1984 and during 1985 it varied from 13 to 100 with an yield range from 1.77 to 14.1kg/tree. The promising Brazil exotic type yielded a maximum of 6.42kg/tree. The promising genotypes, Ullal cashew 1 (8/46 Taliparamba-Kerala), 8/8 Karebali- Karnataka (12.82kg/tree) and 9/25 Nileshwar- Kerala (10.35 kg/tree) could be selected for general cultivation and 8/8 Karebali- Karnataka (10 and 13 damage score) and 2/97 Kottarakara-Kerala (17 and 18 damage score) with a yield of 7.11kg/tree and 3.86 kg/tree respectively could be used for further breeding programme (Hiremath, 1991) The air layers of 35 promising indigenous and exotic cashew types planted during 1985 at Regional Research Station, Brahmavar, Karnataka, were evaluated for TMB infestation during two years ( ; ). The type 9178 produced maximum number of shoots during both the years (687 in and in ) where as it was least in Vengurla Hybrid-5 in (142-3)

41 and in type 2/97 in (62.5). the number of shoots damaged by the pest ranged from 18.6 in type 2/77 to in type 7/108 in In , the lowest and the highest shoot damage was and in type 7/108 and 3/67 (Utthaiah et al., 1994). Helopeltis bug damage tender shoots and panicles of cashew and leads to poor canopy structure and to yield reduction. When 3 screening methods were used, they all identified significantly different tolerant and susceptible clones. The damage in relative to the flushing patterns in field, the early types suffer more damage than late one. Caging Helopeltis in the laboratory or confining Helopeltis in a large polydome with a field like environment, did not produce consistent results. A knowledge of flushing habit is important, when doing clonal assessments (Millanzi, 1997). A total of 75 cashew accessions were screened consisting of released varieties, promising accessions and tolerant accessions located in hotspot area. The germplasm and progeny were screened during , under laboratory through cage screening techniques, in order to confirm genetic basis of resistance.the results revealed that all accessions were found to be susceptible. However, a single susceptible accessions (Goa-11/6) when evaluated during under unprotected field conditions in a large trial, the severity of infestation was restricted up to 5 years and subsequently the infestation declined to a low level. It also recorded a mean yield of 7.2 kg/tree and 6.2 kg/tree on seventh and eighth year respectively (Sundararaju, 1999). Thiramalaraju et al (2004) reported that the mean per cent damage and pest population per tree were lowest for ME-4/4 (13.54 and 8.18) and 1/64 Madhuranthakam (13.71 and 7.90) and highest for Vengurla-1 (51.18 and 20.28) and Bapatla-5 (48.52 and 18.33). The varieties Vengurla-1 and Baptla-5 were susceptible, Chintamani-1 and Goa-1/1 were moderately susceptible and E-4/4 and

42 1/64 Madhuranthakam were the least susceptible for H.antonii under maidan parts of Karnataka Biochemical analysis The four biochemical constituents namely, starch, sugar, phenol and orthodihydroxy phenol, estimated from tender twigs of cashew differed significantly among the ten varieties tested. However, higher quantities of phenol, OD phenol, starch and low sugar content was noticed in most of the less susceptible cashew types, as compared to susceptible types. This indicates that the biochemical components are not entirely responsible for the degree of susceptibility of cashew types to TMB infestation. However, comparatively high phenol and OD phenol along with low sugar content in the hybrids H-3-17, H-856 and other contributed for their tolerance (Bindu and Beevi, 2002). Biochemical changes in tender shoots and leaves of cashew during infestation, by tea mosquito bug have been studied. Infestation of cashew for 24 h by TMB results in decreased sugar, and carotenoid contents. Total phenol, orthodyhydroxy phenols and leaching of electrolytes tend to increase after 24 h of infestation by TMB. Activity of superoxide dismutase decreased while activity nitrate reductase increased after 24 h of infestation of TMB. Studies during shorter period of infestation have revealed that the biochemical changes are manifested early as 6 h after infestation by TMB (Nagaraja et al., 1994) Effect of botanicals The ecofriendly plant extracts particularly pongamia (2%) and callophyllum (2%) resulted in 70 and 62 per cent mortality of H.antonii. The extracts found to have growth inhibitory activity on the nymphs. Aqueous seed kernel extracts of Pongamia and callophyllum and leaves of vitex, parthenium, tridex and lantana induced morphogenetic effect on nymphs of H.antonii

43 (Satapathy, 1993). Sequential sprays of botanical and chemical insecticide for the management of H.antonii on guava at Tamil Nadu found that malathion 0.1%, calophyllum inophyllum oil 2% and pongamia oil 2% sprayed twice at the pea stage of fruits followed by another spray after 15 days, effectively reduced the pest population and corky growth on the fruits (Ragumoorthy and Arumugam, 1996). Radhakrishna (2000) tested neem based plant protection products like Achook and Rashshak were much efficient in controlling TMB. The use of neem based products will ensure safety in application as well as avoid residual toxicity and hence appreciated by farmers. The efficacy of various plant extracts and commercial formulations was evaluated against tea mosquito bug Helopeltis antonii Sig. infesting cashew (Anacardium occidentale L.) under laboratory evaluations, carbaryl induced 43.5 per cent mortality within 12 hours and had the least damage grade of 0.89 after 8 hr after treatment. The other eleven candidate botanicals recorded mortality, ranging from 10.2 to 36.7 per cent, which were significantly lesser than carbaryl. Damage grade exceeded 2.25 for all botanicals evaluated. Monocrotophos caused feeding deterrence up to 7 days after treatment, while that of botanicals could not deter pest damage. Field evaluation were conducted for 3 commercial neem formulations viz., Godrej Achook, limanool and nimbicidine (all at 10% concentration) with carbaryl as check. Damage grade after 30 days after treatment indicated an increase in pest damage, with the exception of carbaryl (0.1%) which resulted in 14.3 per cent reduction in mean percentage of attacked shoots and 7.9 per cent reduction in damage score. These results indicate the necessity of judicious pesticidal intervention with proper time scheduling for managing incidence and damage by H.antonii on cashew (Raviprasad et al. 2002). Senguttavan (1998) tested botanical pesticide neem seed kernel extract at 5 per cent was found to be equally as effective as the standard spray schedule

44 (endosulfan 0.05%, monocrotophos 0.05% and carbaryl 0.1%) during flushing, fruit and flowering respectively. Among the plant products and synthetic insecticides evaluated against H.antonii, the insecticides had no ovicidal effect, but showed maximum residual action against first instar nymphs, except for endosulfan, and quinalphos. However, cyhalothrin followed by carbaryl and monocrotophos exhibited the highest residual action for 7 days and showed the least oviposition on treated shoots (Sundararaju, 2004) Chemical control Preparations such as kerosene emulsion, pyrethrum lime, lime sulphur, nicotine sulphur sprays and dust and derris powders were also used but usually with poor to moderate results (Betrem, 1950; Fernando and Manickavasagar, 1956). Of the modern insecticides, DDT was the first to be widely used to combat infestation of Helopeltis spp. Lever (1949) recommended three dustings with DDT at 10 days intervals to control H. bradyi in the Cameron highlands. For control of H.antonii on cashew, two sprayings of DDT at 15 days interval were better than other insecticides including systemic insecticides (Damodaran and Nair, 1969). In cotton, in the earlier years, DDT, Chlordane, toxaphene and HCH were in use for control of H.schoutedeni. Subsequently with use of synthetic pyrethroids and organo phosphorus compounds, control of H.schoutedeni on cotton was quite remarkable (Cadou, 1994). As the use of DDT fell off in the 1970s gamma HCH or lindane became established as the standard chemical treatment in West Africa, Malaysia and New Guinea (Smith, 1984; Stonedahl, 1991), but problems with resistance were noted (Chong, 1987; Ho, 1994). As an alternative to gamma HCH, endosulfan was widely used to control H.antonii on cashew (Devasahayam and Nair, 1986) and H. theivora on tea and

45 cocoa (Das, 1984; Chowdhary, 1993 and Ho, 1994). Other chemicals like carbaryl, monocrotophos, phosalone, dimethoate and dichlovos had been recommended for control of H.antonii on cashew (Sundararaju, 1984; Samiayyan et al., 1989; Sundararaju et al., 1993). The insecticides particularly carbaryl (0.10%) and monocrotophos (0.05%) are the most effective insecticides against H.antonii on cashew and guava, endosulfan is commonly recommended against H.theivora on tea. Neam based formulations were found to be ineffective against H.antonii (Sundararaju and Sundarababu, 1999). Control of H.antonii using synthetic insecticide was proven effective. However, it caused a negative impact, so that generally, it is applied as last alternative. The IPM strategies viz., mechanical, physical, technical, cultural and biological methods have not applied optimally. However, the management of TMB using natural enemies is safe to the environment and has a good prospect in IPM since, it is being provided naturally (Atmadja, 2003). Bhat and Raviprasd (2007) reported that the insecticide fenpropathrin was effective at low concentration of 0.02 per cent during all the three years and the performance was on par with the recommended insecticides, such as λ- cyhalothrin (0.003%). The damage ratings in phalada III CI and spray oil (1 & 2%) were higher than recommended insecticide. There was no reduction in the population of predatory mirids and total number of predatory mirid and total number of predators in the trees treated with fenpropathrin at both at 0.02 and 0.03 per cent concentration. The efficacy of insecticides viz. chlorpyriphos (0.05%), triazophos (0.01%) and Profenophos (0.05%) were studied against cashew tea mosquito bug in comparison with recommended spray schedule. Triazophos (0.01%) and profenophos (0.05%) were observed to be equally effective to that of spray schedule. However, profenophos was equal in cost wise with recommended spray

46 schedule (Godse and Bhole, 2003). Three applications is essentially required, for effective control of tea mosquito bug on cashew. Monocrotophos (0.05%) or Phosalone ( (0.07%) were observed as equally effective pesticides for controlling TMB. The flowering and fruit initiation stages of crop growth are most critical in tea mosquito management (Godse et.al., 2002). Naik et al. (2006) reported the efficacy of solid and EC formulations of insecticides for the control of H.antonii on cashew (cv.ullal-1). Among the formulations evaluated, carbaryl 50 WP (0.10%) was the most effective as it recorded the lowest average per cent damage (6.20) and the highest nut yield (7.40 quintal/ha), followed by the spray formulation of endosulfan 35 EC (0.05%). The other solid formulations were also effective in the reduction of the population of H.antonii. Carbaryl (0.10), monocrotophos (0.05) and endosulfan (0.05) were the most effective against TMB (Thirumalaraju, et al., 1997). Population of H.antonii between insecticides viz. chloropyriphos (0.05%) triazophos (0.01%) and profenophos (0.05%) were studied against cashew tea mosquito bug in comparison with recommended spray schedule. Triazophos (0.01%) and profenophos (0.05%) were equally effective to that of spray schedule. However, profenophos was equal in cost wise with recommended spray schedule (Godse and Bhole 2003) Effective insecticides recommended for the management of H.antonii Sl.No. Name of the molecule Conc. (%) Test location Reference/s 1. Endosulfan 0.05 Kasargod (Kerala) Numbiar et al., 1973; Pillai et al Endosulfan 0.05 Tamil Nadu Arjunan and Ramaiah, 1982

47 3. Endosulfan Carbaryl Trichur (Kerala) Nair and Abraham, 1984 Phosphamidon 0.03 Quinalphos Phosphamidon 0.05 Trichur Nair and Abraham, Carbaryl (Kerala) 5. Endosulfan Monocrotophos Quinalphos Phosalone Goa Sundararaju, Endosulfan 0.05 Kasrgod Singh and Pillai, 1984 Quinolphos 0.05 (Kerala) Formathion 0.05 Diazinon Methyl parathion Fenthion Carbaryl Vridhachalam (Tamil Nadu) Samiayyan Palniswamy, 1984 and 8. Permethrin 0.01 Vengurla Godse et al Cypermethrin (Maharashtra)

48 Decamethrin Carbaryl Monocrotophos 0.05 Chintamani Thirumalaraju et al., 1997 Endosulfan 0.05 (Karnataka) Carbaryl 0.01 Among the above tested molecules the endosulfan (0.05%) was promising and recommended for most of the cashew growing regions. The menace was effectively managed with two rounds of sprays coinciding with emergence of new flush and panicle initiation and fruit set (Pillai et al., 1976; Arjunan and Ramaiah, 1982). Spraying of crop with three rounds of spray coinciding with emergence of new flush (September-October), inflorescence, (November-December) and fruit setting (December-January) are recommended for Kerala regions to manage the pest (Abraham and Nair 1981)

49 MATERIAL AND METHODS

50 III. MATERIAL AND METHODS To study the Bio-ecology and Management of Helopeltis antonii (Hemiptera : Miridae) on cashew in Coastal Karnataka, laboratory and field experiments were conducted at the Zonal Agricultural Research Station, Brahmavar, ( N latitude and E longitude) and survey at Agricultural Research Station, Chintamani (13 0 N latitude and E longitude) from Materials used and the techniques employed during the course of investigations for conducting each experiment are presented in this chapter. 3.1 To conduct a survey of cashew plantations in Southern Karnataka to find species of Helopeltis on cashew Survey on Helopeltis species To arrive at a general perception regarding the species richness and occurrence of mirid bug, collections were made in the coastal districts of Dakshina Kannada and Udupi. Three taluks in each district and five locations in each taluk of the two districts were selected for sampling. Sampling was made between September, 2006 and August The surveys were taken up during the peak period of pest attack (October- February). Adult bugs were collected from cashew trees in coastal Karnataka and Chintamani cashew plantations to ascertain the species complex Tea mosquito bug collection The tea mosquito bug is a delicate and fragile insect. It was collected using an aspirator. Mirids collected were transferred to killing tube containing ethyl acetate. Dead mirids were taken out of the tube and kept in screw vial containing tissue paper along with data labels and brought to the laboratory for further processing. The specimens after killing were glued singly on triangular

51 paper points. Prior to mounting, the pointed end of each paper was slightly bent using forceps to facilitate gluing the point on to the right side of the thorax to facilitate for the identification of the specimens Identification and abundance of Helopeltis species Species confirmation Distants (1904 and 1910) and Signoret (1858) classification was used for the identification of specimens collected during the study. Specimens were identified by the taxonomist at the Department of Agricultural Entomology, UAS, GKVK, Bangalore The species complex and abundance of the species were determined based on their dominance in the zone. During the survey, observations were recorded on the per cent damage caused by Helopeltis species on cashew trees synchronizing with the emergence of new flush, panicle initiation and nut and fruit development. The length of the I st antennal segment and posterior width of the pronotum were measured. The female genitalia was dissected and examined in glycerine, following maceration in warm 10 per cent potassium hydroxide solution. It was stained in acid fuchsine in order to facilitate the inspection of membranous regions of the genital chamber. Observations were made on the position of sclerotized rings encircling the genital chamber as separate or fused posteriorly and the conclusions were drawn based on the key developed by Stonedahl (1991). 3.2 To study the bio-ecological attributes of Helopeltis antonii on cashew. The detailed biology of H. antonii was studied under laboratory from October to February and Mass rearing techniques for tea mosquito bug Helopeltis antonii The mass rearing techniques adopted by Sundararaju and John (1992), Smith (1973) and Satapathy (1993) were adopted for rearing the Tea Mosquito

52 Bug. Cashew twigs were used as feeding material. The tender shoots and seedlings of cashew were supplied continuously for feeding and development of TMB. The mother culture of Helopeltis was established from the field collected adults which were released into the round plastic bins (25 X 21 cm) containing cashew twigs of cm long with few leaves. The cut end of the twigs were kept immersed in water in small injection vials (5 ml).the twigs were held firmly by plugging cotton to the mouth of the bottle. The mouth of the bin covered with muslin cloth was held tightly by the rubber bands. The twigs were replaced every day with fresh twigs as food. Ten bins with one pair of adult bugs in each bin were maintained to observe mating and oviposition. The gravid females were allowed to lay eggs on potted cashew seedlings enclosed in perforated tubular transparent polyester film (175 mm) cage (30 X 7.5 cm). The caging was done to prevent nymphal movements Rearing of nymphs The newly hatched nymphs were allowed to feed on the fresh cashew tender succulent cut shoots. The cut end of the shoots was kept moistened with wet absorbent cotton wrapped in piece of polythene sheet in nymphal rearing cage. Windows were provided on two sides of the cage with muslin cloth sleeve in order to facilitate the removal of adults after final moulting. On the other two sides windows were covered with transparent polyester film (175 mm) Oviposition The ovipositional behaviour of tea mosquito bug was studied in laboratory. Newly emerged adults were separated on the first day itself and reared in the adult rearing cage. Top of the cage was permanently closed with muslin cloth using an adhesive. Every day, two glass vials containing two tender shoots each were provided as food and ovipositional substrate. Ten pairs of adults were allowed to

53 mate in rearing cages. The mated pairs were separated and allowed to oviposit 1 pair per cage) in the oviposition cage Fecundity and duration of different stages Data on fecundity, incubation period, duration of different nymphal instars, their linear measurements and total nymphal period were recorded. The body length and breadth, antennal length and rostrum length of each instar was measured under microscope using an ocular and stage micrometers. Adult longevity were recorded by placing laboratory reared pairs of adults (male and female) in rearing jars provided with tender shoots as food, total life cycle in days and the sex ratio of the adults were recorded following the procedure by Sundararaju and John, (1992) Field biology The bio-ecology of H. antonii was studied on cashew plants during October March and The adult TMB 1 pair per cage were enclosed on 2-3 years aged seedlings, in a tubular muslin-cloth bags to avoid further oviposition by field population. They were observed for incubation and the number of eggs laid by the individual gravid female at 24 h intervals. Observations on number of eggs laid, incubation period, duration of different instars and their linear measurements, total nymphal duration, antennal length and rostrum length of each instar, adult longevity, total life cycle in days and the sex ratio of the adults were recorded Host plants Helopeltis species was observed on a number of host plants in the coastal and Chintamani. The primary and secondary host plants attacked by the tea mosquito bugs were recorded in these cashew growing regions of Karnataka. 3.3 To monitor and determine population dispersion and infestation pattern of Helopeltis antonii in relation to phenology of cashew tree.

54 3.3.1 Dispersion of H. antonii The studies on distribution pattern of H. antonii on cashew trees were carried out during two consecutive cropping seasons (September 2006 to March-2008) at Zonal Agricultural Research Station, Brahmavar. Fifty cashew trees of age years old with a plant spacing of 7.5 x 7.5 m were observed for the number of H.antonii adults, eggs and nymphs on each tree at fortnightly interval on the lower canopy of the plant to about 2.5 m height. To evaluate the dispersion of H. antonii among the cashew trees within observation area different techniques were used. The simplest method is the variance to mean ratio, S 2 X (Southwood, 1978) were initially calculated. Lloyds patchiness index was calculated from X*= X patchiness for each sampling occasion (Lloyd s 1967). Patchiness value of <1 considered as a regular dispersion, value equal to 1 as random dispersion and >1 an aggregated dispersion. Green s index, was calculated using the C x = (S 2 X )-1)/ X -1) (Green, 1966). C x < 0 considered as regular dispersion, C x 0 a random dispersion, and C x > 0 an aggregated dispersion. A chi-square was performed as χ 2 = (S 2 X ) (N-1) (Southwood, 1978). Dispersion of H. antonii among cashew trees based on plant phenology were carried out using Taylor s power law (Taylor, 1961) and Iwao s patchiness regressions (Iwao, 1968). Taylor s power law was estimated from the regression model, log S 2 = log a + b log X, where parameter b is the gradient/slope of the regression. The population was considered an aggregated when b > 1, random when b =1 and regular when b < 1. Iwao s patchiness regression was related to mean crowding, X*=[X + (S 2 X)-1] to X by X* = a+bx. Intercept [a] was an index of basic contagion and the slope [b] had the same interpretation as b from Taylor s power law. 3.4 To develop sustainable management practices embracing, biopesticides and new molecules for Helopeltis antonii on cashew.

55 The experiments were conducted to evaluate the effectiveness of biopesticides and new molecules against H. antonii on cashew variety V Interaction between natural enemies and pest population The occurrence of different natural enemies of H.antonii were observed during and at Brahmavara, Pethri village and Chintamani cashew plantations Parasitoids The seasonal activity of the predominant egg endoparasitoid Telenomus sp. on TMB in West Coast of Karnataka was investigated using field surveys and observations during September 2006 to August Data were collected from two study sites at Brahmavar and in Pethri village cashew plantations. The cashew plant parts (shoot, petioles, midrib and panicles) containing eggs of H. antonii were collected at monthly interval and counted under zoom stereomicroscope. They were treated in carbendazim 0.1% solution for 10 minutes. After the treatment, samples were dried to remove the dampness of carbendazim solution and placed in a plastic container (250 ml) completely wrapped with a black paper (Geisberger, 1983) to record the emergence of parasitoids and the per cent egg parasitization was calculated Predatory ants Different species of predatory ants associated with cashew plantation and their effect on H. antonii were collected over 20 locations in west coast and at Chintamani. Two surveys each in sprayed and non sprayed plantations were made in October-February, and to determine spatial distribution of H. antonii and the abundance of predatory ants. The ants specimens collected during the survey were identified by the taxonomist at the Department of Agricultural Entomology, UAS, GKVK, Bangalore. Abundance and effectiveness of ant species were determined on the basis of their predominance and predating on

56 TMB on cashew in different regions of Karnataka. The data on the colonisation by the predominant predatory ant percent damage and yield kg/tree were recorded. Indices for assessing abundance of Oecophylla smaragdina based on quick examination of an individual cashew tree (Way and Khoo, 1991) + (Few) Less than workers in tree no trails very few or no attended Homoptera, no nests ++ (Moderate number) O.smaragdina (Common) O. smaragdina usually some distinct trails on tree trunk or canopy but rarely on ground (Abundant) about O.smaragdina well defined trails in canopy and occasionally on trunk and along ground (Very abundant) > 1000 O.smaragdina or with strong trails inter connecting all or virtually all trees across their canopies and or along ground Screening cashew varieties against TMB The varieties maintained at the Agricultural Research Station Ullal, were observed for their reaction to TMB. Five trees in each variety were selected for observation. One square meter area in each of the four directions (North, South, East and West) was labelled and observations were recorded on total number of new shoots/panicles and the number of damaged shoots/panicles at fortnightly intervals.

57 Scoring of damage Score Description 0 No lesion/ streak 1 Up to 3 necrotic lesion/streak, general vigor of shoot/panicle not affected coalesing/non-coalesing lesion/streaks 3 Above 6 coalesing/non-coalesing lesion/ streaks 4 Lesions/streaks confluent /complete drying of the affected shoot/panicle Biochemical basis of resistance and tolerance The phenotypic reaction of the cashew varieties against TMB were observed. The promising and susceptible varieties were analysed for the different biochemicals to study their role against TMB Plant materials New shoots of the selected varieties were collected from the trees and were washed with distilled water, oven dried at 40 0 C for 48 hours and then ground into fine powder using pestle and mortar. One hundred milligram of dried shoot/panicle was powdered and the powder of each variety was boiled for 30 min in 25ml of 80 per cent ethyl alcohol (V/v) on hot water both. Supernatant was decanted into another flask and the residue was again re-extracted with small quantity of alcohol. After complete evaporation, the porcelain dishes were taken out and a little quantity of distilled water was added in to each dish and stirred. These were subjected to centrifugation for 30 minutes at 3200 rpm. Cation exchange resin was added for each tube and mixture was stirred 3 to 4 times at every 20minutes and later kept in refrigerator for 12-14hr. The supernatant liquid was decanted and 0.2 N ammonia (about 10-15ml) was added to cation resin in

58 each tube and shaken well before keeping in refrigerator. Later it was removed from refrigerator and anion resin was added and stirred 2 to 4 times at an interval of 25 minutes and again kept in refrigerator for hr Starch The left over residue after alcohol extraction was oven dried for 90 minutes at 60 0 C. For each of the sample 10 ml of perchloric acid was added and was shaken well for few min. The volume was made up to 25 ml by adding distilled water and kept for 20 min. The aliquot was used for estimation of starch by following the method of Clegg (1956). The quantity of starch was expressed as mg/100 mg of the sample on oven dry basis Total soluble amino acids The supernatant solution from cation resin containing 0.2 N ammonia was decanted and evaporated by keeping on hot water both. The residue in dish was rinsed with few drops of distilled water and the volume was made up to 1ml. This was subjected to centrifugation for 25 minutes at 10,000 rpm. The supernatant aliquot was used for estimation of total soluble amino acids and expressed in mg/100 mg of sample (Yapinlee and Tunekajtakashi., 1966) Total sugars The supernatant liquid from the anion resin was kept on hot water both for complete evaporation and dishes were rinsed with few drops of distilled water and the volume was made up to 1ml. These were subjected to centrifugation for 30 minutes at 10,000 rpm. The decanted liquids after centrifugation was used for estimation of total sugars following the procedure given by Dubios et al. (1951) and was expressed as mg/100 mg of sample Total phenols The residue of 0.2 N Ammonia cation resin was mixed with 6 N formic acid and stirred 3-4 times for 25 minutes. The supernatant liquid was decanted and

59 evaporated on hot water both. Distilled water was added to evaporated dishes and rinsed and the volume was made up to 1 ml. This was centrifuged for 25 min at 10,000 rpm and the supernatant solution was used for estimation of phenols (Swain and Hills 1959), total phenols were expressed as mg/100 mg of the sample Ortho-dihydroxy phenols Aliquot for estimation of phenols was also used for the estimation of Orthodihydroxy phenols (Mahadeva, 1966). The quantities were expressed as mg/100 mg of sample Artificial infestation Studies on development of artificial infestation was carried out on the 25 matured cashew trees which were pruned for removal of overlapping branches in the cashew plantation of Brahmavar during The mirid population counts were recorded on the regenerative shoots of 25 pruned trees at weekly intervals as were the stages of the pest present over two seasons to determine the threshold level of bug population for imposition of the treatments Bioefficacy of biopesticides and insecticides The effectiveness of biopesticdes and insecticides were evaluated both in laboratory and field. In field, three sprays were given in sequence at the time of new flush, panicle emergence and nut and fruit developmental stages. Treatments were replicated thrice in a Randomized Block Design and the particulars of the treatments are as below.

60 Treatment Ml/lt. (%) Pongamia oil - Pongamia oil - Pongamia oil 2% - 2% - 2% PSKE - PSKE - PSKE 2% - 2% - 2% Neem oil - Neem oil - Neem oil 5% - 5% - 5% NSKE - NSKE - NSKE 2% - 2% - 2% Beauveria bassiana - B. bassiana - B. bassiana 2ml - 2ml - 2ml Monocrotphos - λ-cyhalotrin - carbaryl 0.05% % % PSKE - λ-cyhalotrin - carbaryl 2% % % B. bassiana - λ-cyhalotrin - carbaryl 2ml % % NSKE - λ-cyhalotrin - carbaryl 2% % % Monocrotophos - endosulfan - carbaryl 0.05% % % Control PSKE : Pongamia Seed Kernel Extract NSKE : Neem Seed Kernel Extract Statistical analysis The data recorded were added to calculate arithmetic mean and standard deviation (S.D). Simple t test was adopted for comparison of two treatment means. Observations on dispersion of TMB was analysed by method of the variance to mean ratio, S 2 X (Southwood, 1978).

61 EXPERIMENTAL RESULTS

62 IV. EXPERIMENTAL RESULTS The results of experiments conducted on i) to conduct a survey of cashew plantations in Southern Karnataka to find species of H. on cashew ii To study the bio-ecological attributes of Helopeltis antonii on cashew iii) to monitor and determine population dispersion and infestation pattern of H. antonii in relation to phenology of cashew tree iv) to develop sustainable management practices embracing, biopesticides and new molecules for Helopeltis antonii on cashew are presented in this chapter. 4.1 To conduct a survey of cashew plantations in Southern Karnataka to find species of Helopeltis on cashew Identification of tea mosquito bug The insect specimens of tea mosquito bug collected on cashew both in coastal Karnataka and Chintamani were identified as Helopeltis antonii Signoret. This was the only species found infesting cashew and there was no co-existence of other species of Helopeltis during the investigation (Table1) Nature and extent of damage by H.antonii on cashew Nature of damage The nymphs and adults suck the sap from tender shoots, panicles and developing apple and nuts. Frequent sucking of the shoots result in the exudation of gum from the damaged tissues which slowly hardens on exposure. In severe infestation, the young shoots and panicles dry up, giving the infested tree a scorched appearance. Successive attacks on new growth resulted in stunting or death of the tree. Damage to immature nuts caused them to shrivel while older nuts developed a brightened scabby appearance. The cells near the feeding

63 Plate 1 Tea mosquito bug Helopeltis antonii Signoret

64 Table 1 Occurrence of Helopeltis antonii on cashew in coastal and maidan Karnataka Agro climatic zone District Taluk Location TMB (X ) Per cent damage Intensity of damage Period Dakshina Kannada N latitude and E longitude Coastal Karnataka D.K Mangalore Konaje to 25 M October- February Muduperar to 25 M October - February Yadapadavu to 50 S October - February Kairapalli to 25 M October - February Ullal to 25 M October - February Coastal Karnataka D.K Puttur Darbe to 25 M October-February Mundur to 25 M October - February Norimogaru to 50 S October - February Punchappady to 50 S October - February Savanur to 50 S October - February Coastal Karnataka D.K Sulia Bellare to 25 M October - February Kalanja to 50 S October - February Devchalla to 25 M October - February Guthigar to 25 M October - February Kodiyala to 25 M October - February

65 Contd. Udupi N latitude and E longitude Coastal Karnataka Udupi Udupi Brahmavar to 50 M October - February Cherkadi to 25 M October - February Bantakal 1.05 < 10 L October - February Kalyanpur to 25 M October - February Pethri 1.03 < 10 L October - February Coastal Karnataka Udupi Kundapura Korgi to 25 M October - February Devalkunda to 50 S October - February Jennalane to 50 S October - February Udupi Gujjadi to 50 S October - February Gundmi to 50 S October - February Coastal Karnataka Udupi Karkala Belvai to 50 S October - February Mudabidri to 25 M October - February Hebri to 50 S October - February Karkala to 50 S October - February Someshwar to 25 S October - February Chikkaballapura13 0 N latitude and E longitude Maidan part Chikkaballapura Chintamani ARS to 40 S October February ND = No damage: X = No./20 panicles: L = Low (less than 10% tree damaged) M = Moderate (11-25% tree damaged): S = Severe (26-50% tree damaged)

66 puncture die and turn dark producing the typical dark spots on infested plant parts. The adult caused feeding lesions per day on young shoots Extent of damage During the survey (October-February), extent of damage in different cashew plantations were recorded as low to severe. The mean adult and nymphal population of 1.03 to10.28/ 20 laterals were observed. The damage was categorized as low (less than 10% tree damaged), moderate (11-25% tree damaged) and severe (26-50% tree damaged) 4.2 To study the bio-ecological attributes of Helopeltis antonii on cashew. The bioecological attributes of Helopeltis antonii was studied on cashew both in laboratory and field during October-March and Eggs The freshly deposited eggs were creamy white, ovo-elongate and laterally compressed, apically, mm long. Two unequal respiratory horns arise from the anterior end of the egg, these usually are mm long. The eggs are embedded in plant tissue in 2 rows of 3 each, usually with operculum and respiratory horns exposed. H. antonii preferred to oviposit on the young shoots, inflorescence stalk and developing nuts of cashew, sometimes the bugs accept the petioles and ventral midribs of leaves Incubation period The incubation period lasted for 7.20 to 7.80 days (Table 2) during the study period. Two to three days after egg laying a brownish band appeared on the upper half of the fertilized egg. When the eggs were ready to hatch, they changed initially to dull brown and later to dark brown. The nymphs made a hole in the chorion and pushed its head out. The unfertilized eggs were white and there was no change in the colour, but the eggs gradually shriveled.

67 Table 2 Fecundity of H. antonii on cashew in laboratory (October March) Sl. No. Number of eggs / female / day (Mean of 5 generations) 2 nd 3 rd 4 th 5 th 6 th 7 th 8 th 9 th 10 th 11 th Total Incubation period (days) Per cent (Range) Hatching (Mean) Total Average

68 4.2.3 Nymphs The newly emerged nymphs crawl out of the egg through the anterior end. TMB Nnymphs under go 5 nymphal instars First instar nymph Newly emerged nymph was light orange in colour, abdomen dull light orange, head, antennae, legs dull light orange, with suffusion brown abdomen with 2 parallel rows of bristles running along the mid dorsal line and with one deep brown wart each on lateral margins of the abdominal segments. The thorax lacking a scuttellar horn and wing pad, length of the nymph ranged from 1.32 to 1.61 mm and the average length of the nymph was 1.42 ± 0.09 mm (Table 4). During October March the mean duration of first instar nymph was 2.20 to 2.40 days. (Table3). The first instar nymphs were active and move briskly on tender shoots and inflorescence and suck the sap resulting in water soaked lesions Second instar nymph The nymph increased in its size and showed the remarkable change in the body color. The head, antennae, legs, thorax and abdomen are deep orange in color. The nymph measured the mean length of 2.21 ± 0.5 mm in length and 0.35 ± 0.02 mm across the thorax. The mean duration of the second instar nymph was 2.30 to 2.80 days Third instar nymph The body colour was light brownish during third instar and measured mm in length and mm width. The duration of third instar lasted for 2.40 to 2.65 days. The nymph at this stage possess scutellar horn in the form of a clubbed structure and the wings were rudiment and prominent.

69 Fourth instar nymph Long deep brown, wing pads prominent and not overlapping, seuttllar horn well developed at this stage of the nymph. The mean body length and breadth was and mm, respectively. The instar lasted for 2.50 to 3.40 days during October March. The nymphs rest on the leaf bunch and suck sap from the succulent leaves or petiole Fifth instar nymph Sexes are distinguishable at this stage based on external genitalia and size variations. Thorax reddish purple, both sexes deep brownish, the antennae and the appendages being more deeply coloured than abdomen. The crescentic whitish dorsal patch and the ventral abdominal colouration attain a deeper hue as the development progresses to the fifth instar. Wing pads overlap on scuttellar horn, well developed tarsi two segmented. Fifth instar nymph resembles adult and suck, the sap from tender leaves, petioles and developing nuts and fruits, resulting into drying of the tender shoots and panicles. The nymph measured mm in length and mm in width. The mean duration of fifth instar nymph was 2.40 to 2.60 days with an average of 2.30 to 2.60 days during October February. The mean rostrum and antennal length in first to fifth instar nymph was mm, to mm and mm to mm, respectively (Table 4) Total nymphal period In laboratory, the mean nymphal period of the tea mosquito bug H. antonii was and days during October to February and the life cycle from egg to adult emergence occupied to days during different months (Table 5).

70 Plate 2 TMB egg Plate 3 TMB nymph

71 4.2.4 Adult The newly emerged adults were light brownish with transparent wings, which turned dark brown. The dorsum of thorax was reddish and the tergum of abdomen turned dull white. The scuttellar horn was reddish brown in both the sexes and it was erect, tapering and funnel shaped. The abdomen consists of eight segments. In female, a white patch is present on the fifth abdominal segment. The ovipositor of the female was located on the ventral portion of sixth abdominal segment. The antenna as in the nymphs was four segmented with hairs. The dorsum of the abdominal segment was deep orange. The hemielytra overlapped as in a typical Hemiptera and covered the entire abdomen with distal end showing a triangular brownish black colouration. The femur had irregular deep brownish patches while the entire tibia was brownish black. The longevity of adult was 7.10 to 8.70 days during October to March (Table 5) Total life cycle H. antonii completed one life cycle (egg to adult) in 25.50, 26.75, 30.40, and days during October- November, November-December, December-January, January-February and February-March, respectively (Table 5) Sex differentiation Sexes were easily discernible at the adult stage based on the presence of white patch on the sternal region of fifth abdominal segment. The female adult bugs were longer mm than male mm. The mean sex ratio (female to male) was 1: 0.80 (Table 4) Copulation and oviposition Copulation occurred two days after emergence, the male and female bugs were copulated in an end to end posture. The copulation lasted from 60 minutes to 2.0 hours. The gravid female bugs inserted eggs into the epidermal tender shoots, petioles of tender leaves and inflorescence axes.

72 4.2.8 Fecundity The female bugs started depositing the eggs 3 days after emergence. Considerable variations existed in the egg laying by each female which ranged from 28 to 43 eggs per female with an average of 37.6 eggs per bug (Table 2). The preoviposition and oviposition periods lasted for 2-3 and 3-5 days, respectively Number of generations The number of generations was studied in laboratory. The pest completed twelve generations in a year Feeding and nature of damage The fifth instar nymphs inflicted relatively greater damage. These congregate on tender shoots, leaf petioles and secondary veins of leaves close to the midrib and feed. When large populations were confined on small twigs feeding takes place all over the laminae of tender foliage causing dense necrotic lesions all over. On the leaves nearly truncate water soaked lesions develop around the feeding puncture and the tissues eventually dry up leaving brownish black noncoalescing necrotic patches. Similar foliage symptoms were observed under field conditions during August-September just after the flush emergence. On the shoots, elongate streaks and brownish patches develop on either sides of the feeding puncture and these regions dry up eventually. A resinous substance exudes from the feeding puncture on the shoots and the exudate dries up and hardens on exposure to air. The gummy exudation is more around punctures on relatively hardened tissues on the shoots. On the inflorescence, feeding is usually restricted to the main axis around the nodes. Necrotic lesions due to insect feeding are more concentrated around apical nodes. The tissues and the feeding puncture dry up. The insects also feed on the secondary floral branches causing irregular elongate shiny, rusty brown

73 lesions, but these lesions do not show gummy exudates. The immature nuts and apples develop the characteristic scabby spots Biology under field Tea mosquito bug on cashew under field conditions from October-2006 March and completed one cycle of generation in 30 days and 12 generations in a year. TMB inserted its eggs into tender epidermal tissues of shoots, leaf midribs and petioles of cashew. Eggs were laid singly or in small batches of 2 to 4. Two to three days after egg laying, a brownish band appeared on the upper half of the fertilized egg, when the eggs were ready to hatch they changed from dull brown to dark brown. The nymph made a hole in the chorion and pushed its head out. The unfertilized eggs were white and there was no color change. The fecundity ranged between 26 and 36 eggs per female with an average of eggs in October to March. Incubation period lasted for 5.80 to 7.80 days with the mean egg hatching ranging from to per cent (Table 6). Detailed description of the different nymphal instars are given in the biology under laboratory conditions. TMB completed five nymphal instars (Table 7). The nymphal duration was days in October-March with an average of to days. The adult survived for 6-12 days (Table 8). The life history of tea mosquito bug ranged from 21 to 32 days. Mean life cycle of was recorded during October November and longer duration of days in January-February. The morphometrical measurements of different life stages are given in the table 9. Sexes were easily discernible at the adult stage based on the presence of white patch on the sternal region of fifth abdominal segment. Female bugs were longer than males. Sex ratio of female to male was 1 : 0.62 to 1 : 0.80 under field conditions. Morphometry of different instars were presented in table 8. The TMB feeding and breeding on alternate host plants viz., guava, blackpepper, tamarind and neem was observed during study period.

74 Table 3 Duration of H. antonii nymphal instars in laboratory (Days) (October March) Instars I II III IV V Total (Days) Months Range Mean Range Mean Range Mean Range Mean Range Mean Range Mean October -November November-December December-January January-February February -March

75 Table 4 Morphometric parameters of H. antonii life stages in laboratory (October March) Instar Body length (mm) Body width (mm) Rostrum length (mm) Antennal length (mm) Range Mean ± SD Range Mean ± SD Range Mean ± SD Range Mean± SD 1 st ± ± ± ± nd ± ± ± ± rd ± ± ± ± th ± ± ± ± th ± ± ± ± 0.21 Male ± ± ± ± 0.07 Female ± ± ± ± 0.04

76 Table 5 Biology of H. antonii on cashew in laboratory (October March) Months Incubation period (days) Nymphal emergence (%) Nymphal duration (days) Adult longevity (days) Total life cycle (days) Range Mean Range Mean Range Mean Range Mean Range Mean October November :0.70 November - December :0.62 December - January :0.80 January February :0.75 February March :0.65 Sex ratio F:M

77 Table 6 Fecundity of H. antonii on cashew in field (October March ) Sl. No. Number of eggs / female / days after emergence 2 nd 3 rd 4 th 5 th 6 th 7 th 8 th 9 th 10 th 11 th Total Incubation period (days) Per cent egg hatching (Range) Total Mean Mean (%)

78 Table 7 Duration of H. antonii nymphal instars in field (days) (October March) Instars I II III IV V Total Months Range Mean Range Mean Range Mean Range Mean Range Mean Range Mean October-November November- December December -January January -February February -March

79 Table 8 Biology of H. antonii on cashew in field (October March) Months Incubation period (days) (%) nymph emerged out Nymphal duration (days) Adult longevity (days) Total life cycle (days) Range Mean Range Mean Range Mean Range Mean Range Mean October November : 0.70 November - December : 0.62 December - January : 0.80 January February : 0.80 February March : 0.73 Sex ratio F:M

80 Table 9 Morphometric parameters of H. antonii life stages in field (October March) Stages Body length (mm) Body width (mm) Rostrum length (mm) Antennal length (mm) Range Mean ± SD Range Mean ± SD Range Mean ± SD Range Mean± SD 1 st ± ± ± ± nd ± ± ± ± rd ± ± ± ± th ± ± ± ± th ± ± ± ± 0.08 Male ± ± ± ± 0.07 Female ± ± ± ± 0.30

81 4.3 To monitor and determine population dispersion and infestation pattern of Helopeltis antonii in relation to phenology of cashew tree. The population of TMB was monitored during flushing, panicle emergence and nut and fruit developmental stage and during non flushing period. Various distribution indices for H.antonii on cashew during the season and also off season were adopted and the data is presented in Table10. The data recorded during the investigations revealed that in majority of the observations, the variance to mean ratio was higher than one. This indicated the aggregated distribution of TMB among the cashew trees in the plantations observed. On the contrary, in two observations, variance to mean values were close to 1 suggesting the random distribution of the bug on cashew trees. During non flushing period from first fortnight of April to second fortnight of September, the population of H.antonii on trees of years old age were zero and the values of variance to mean ratio were nil. In majority of aggregated distribution, most of the observations were recorded. The tea mosquito population recorded in two observations were approximately one indicating the random distribution of the bug on cashew trees. In most of the observations similar values of means and variance were observed. Hence, X*/ X =1. However, X*/ X <1 indicated the absence of H.antonii population. Greens coefficient (C x ) values showed aggregated distribution of TMB among cashew trees (C x > 0). Whereas five observations (C x < 0) indicated regular distribution and two observations indicated random distribution (C x = 0). Taylors power law based on cashew plant phenology projected significant relationship between (S 2 ) and ( X ) of the H.antonii population. Slope values were significantly greater than 1 during sprouting and nut developmental stage (b= 1.82 and 1.76 with R 2 = 1.01 and 0.97 for sprouting to nut and fruit developmental stage during and , respectively, indicating aggregated

82 Table 10 Distribution pattern of H.antonii in relation to cashew phenology Date X S 2 S 2 / X χ 2 X* X*/ X C x

83 Cont Note : X = Mean; S 2 = Variance; S 2 / X = Variance to mean ratio χ 2 = Calculate chi-square; X* = Lloyd s mean crowding; X*/ X = Lloyd s patchiness mean crowding; Cx = Green s index.

84 distribution of TMB in cashew plantation. The population during off-season (April-August) was low, gradient value were below 1, (b = 0.98 and 0.88) for 2007 and 2008, respectively) proves regular distribution of TMB. Highly significant relationship between (Table 11) mean crowding and density of H.antonii was observed in Iwao s patchiness regression for cashew phenology during the season (September to March) indicated regular distribution of H.antonii. Its gradient values were below 1 (b= 0.04 and 0.07 and R 2 = 0.82 and 0.58) during sprouting to fruit developmental stage in and , respectively. Whereas b= 0.03 and 0.07 with R 2 = 0.93 and 0.73 for off-season. The above observation for two consecutive cropping seasons and the pooled data on population dispersion of TMB in cashew plantation proved the regular distribution of the pest To develop sustainable management practices embracing biopesticides and new molecules for Helopeltis antonii on cashew. The biopesticides and new molecules were evaluated against tea mosquito bug H. antonii under field and controlled conditions during for two seasons. Experiments were carried out at the Zonal Agricultural Research Station, Brahmavar, in a Randomized Block Design and treatments were replicated thrice on ten years old cashew trees of variety V TMB egg parasitoid Activity of the egg endoparasitoid, Telenomus sp. was recorded on the tea mosquito eggs and the data is presented in Table 12. Maximum egg parasitisation of and per cent were recoded during on the TMB eggs collected from Brahmavar and Pethri cashew plantations, respectively, least per cent parasitisation of 1.01 and 0.82 were observed in May, egg parasitisation was zero in July-August. During maximum per cent parasitisation of in Brahmavar and in Pethri were recorded, again the activity of the parasitoid

85 Table 11 Taylor s Power Law and Iwao s patchiness regression for seasonal dispersion of H. antonii Taylor s Power Law Iwao s patchiness regression Phenophase Period Sprouting Nut and September March fruit development Intercept Slope r 2 p Intercept Slope p log (a) (b) log (a) (b) < < r 2 Post flowering April August < < Sprouting Nut and fruit development September March < < Post flowering April August < < Pooled < <

86 Plate 4 Egg parasitoid Telenomus sp.

87 was nil during the low population intensity of H.antonii. Mean per cent parastistation for two seasons proved that Telenomus sp. was the only and predominant egg parasitoid on TMB Predatory ants on TMB The abundance of different ant species foraging on cashew trees was observed at 20 locations of coastal Karnataka and Chintamani (Table 13). In coastal Karnataka, the ground ant species Diacamma rogasum Loguill and Camponotus compresus Fabricius were observed to be less abundant and nesting on the cashew tree was low to negligible. The arboreal species Oecophylla smaragdina Fabricius was observed at all the locations surveyed. In non sprayed plantations, O.smaragdina population was abundant and occupied the entire cashew tree canopy. The other species of ants were absent on the trees colonized with O. smaragdina. It has well defined colonies that it defends aggressively against other ant species. The tree colonized by O. smaragdina were interconnected with well defined trails of worker ants invariably using aerial connections, where the canopies were overlapped and they trail on the ground where canopies were not over lapping. The incompatibility of O. smaragdina and the other ants was confirmed by their spatial separation at the edge of their territory. In maidan part 8 ant species foraging in cashew ecosystem were observed. O. smaragdina was abundant and nesting on the cashew tree branches was recorded. The other species of ants were not competing with the predominant species, O. smaragdina and other species were found foraging at the edge of the canopy. O. smaragdina makes nests by spinning silk between leaves with moderate sized, densely spaced cashew leaves, five to six medium sized nests were recorded per densely populated tree. Each nest consisting of leaflet with the underside silked over or several spun together overlapping leaflets.

88 The other species of ants Diacamma rugosum Loguill and Crematogaster wroughtonii (Forel) appear to nest in any suitable site, whether arboreal or on the ground. Ground nests some times occur abundantly in thick layer of cashew leaves and in the close layer of cashew leaves and in the close to the trunks of cashew trees, such nests were observed on borders of plantation near bunds and roads (Table 21). The activity of ants on cashew trees sprayed with insecticides was very low and few or none of the ants were observed on such trees. It was abundant (++++) to very abundant (+++++) in non sprayed plantations. Among the different ant species recorded in cashew plantations O.smaragdina appeared to be predominant arboreal ant in cashew plantations in both the situations studied. Predatory ant, O.smaragdina workers captured the insect prey and carried by operating singly or in groups. In the study sites the distribution of ant species indicated that single species of O.smaragdina occupied eighty per cent of the cashew plantation observed and was found to be very abundant ( ) (> 1000 workers occupying a tree canopy of 15 m radius). Cashew trees fully colonized by the predatory ant O.smaragdina exhibited the least per cent damage and during in coastal and maidan Karnataka, respectively (Table 14). Per cent damage on the trees partly colonized with O.smaragdina were in coastal and in maidan part. The unsprayed cashew trees with no ant recorded maximum per cent damage and in Brahmavar and Chintamani respectively, during the survey. Higher nut yield of 3.70 and 2.43 kg /tree was recorded in the trees fully colonized with O.smaragdina in coastal and maidan Karnataka, respectively. Based on the results obtained it was observed that O.smaragdina appeared as predominantly predatory ant on H.antonii in cashew growing regions of Karnataka. Its role as a key predator is of potential significance in keeping the TMB population under check leading to increased yield. Manipulating ant fauna in

89 Plate 5 Predatory ant O.smaragdina nest Plate 6 O.smaragdina on cashew tree

90 favor of O.smaragdina in an integrated pest management plays a greater role in biological control Screening of varieties The cashew varieties were screened for their reaction to tea mosquito bug H. antonii (Table 15). The least population of TMB ( /m 2 ) with the damage grade of 0.30 on shoot and 0.15 on panicle were recorded on the variety Ullal 1. Variety Ullal-2 was on par with Ullal-1 in their reaction to TMB ( bugs/m 2 ) and damage grade were 0.40 and 0.21 on shoot and panicle, respectively. Maximum population of bugs ( /m 2 ) with damage grade of 3.50 on shoot and 2.73 on panicle were recorded on the variety V-4 was found to be highly susceptible to TMB. Cashew varieties screened against TMB were grouped as promising, susceptible and highly susceptible based on their reaction to TMB damage. The varieties Ullal-1, V.R.I-3, V-7, 9/25-Neeleshwar, 1/40-Palaparamba, 2/97- Kottarakara and Priyadarshini were found promising against TMB incidence. The entries 8/103-Gubbi, V-1, BLA-39-A, UN-50, V-5, 9/72-Orchard, Local (puttur), 3/111-Gubbi and 3/108-Gubbi were found to be susceptible based on the damage grade on shoot and panicle. The high damage grade recorded in entries viz., 7/108-Gubbi, 9/10- Permanur, V-4, Propaagation, Nairobi, BPP-1, 9/66-Chirala and 4/64- Madhuranthakam were highly susceptible to TMB. The damage grade recorded in these entries were more than 3 grade points. Significant differences were observed between entries in respect of damage and pest population Biochemical constituents and reaction of cashew varieties The highly susceptible, susceptible and the promising varieties were selected for their biochemical constituents and their reaction against H.antonii (Table16). The total phenolic content ranged between 0.30 mg/100mg and

91 Table 12 Per cent egg parasitisation of TMB by Telenomus sp. in field, Mean ( ) Month Location Location Location Brahmavar Pethri Brahmavar Pethri Brahmavar Pethri January February March April May June July August September October November December

92 Table 13 Ant fauna of different cashew ecosystems in Karnataka Sl. No. Location Coastal /maidan part Sub family Arboreal /ground Abundance Sprayed/ unsprayed 1 Mundur Diacamma rugosum Loguill Ponerinae Ground + sprayed 2 Ullal Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 3 Konaje Oecophylla smarigdina (Fabricius) Formicinae Arboreal non sprayed 4 Brahmavar Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 5 Pethri Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 6 Korgi Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 7 Gujjadi Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 8 Hebri Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 9 Someshwar a Oecophylla smarigdina (Fabricius) Formicinae Arboreal non sprayed b Diacamma rugosum Loguill Ponerinae Ground + non sprayed c Camponotus compresus (Fabricius) Formicinae Ground + non sprayed d Crematogaster wroughtonii (Forel) Myrmicinae Arboreal + non sprayed 10 Belvai Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 11 Bantakal a Oecophylla smarigdina (Fabricius) Formicinae Arboreal non sprayed

93 Contnd.. b Diacamma rugosum (Loguill) Ponerinae Ground + non sprayed c Camponotus compresus (Fabricius) Formicinae Ground + non sprayed 12 Cherkadi Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 13 Kalanja Camponotus compresus (Fabricius) Formicinae Ground + sprayed 14 Guthiger Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 15 Savanur Diacamma rogasum (LeGuills) Ponirinae Ground + sprayed 16 Bellare Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed 17 Kairapalli Camponotus compresus (Fabricius) Formicidae Ground + sprayed 18 Yadapadavu Oecophylla smaragdina (Fabricius) Formicinae Arboreal + sprayed 19 Cherkadi Oecophylla smarigdina (Fabricius) Formicinae Arboreal + sprayed Crematogaster wroughtonii (Forel) Myrmicinae Arboreal + Sprayed 20 ARS Chintamani (maidan) Oecophylla smarigdina (Fabricius) Formicinae Arboreal ++++ non sprayed Crematogaster wroughtonii (Forel) Myrmicinae Arboreal + non sprayed Crematogaster sp. Myrmicinae Arboreal + non sprayed Crematogaster rothnyi (Mayer) Myrmicinae + non sprayed + : (Few) Less than about O. smaragdina workers: + + : (Moderate number) at least O. smaragdina workers : (Common) About O. smaragdina workers: : (Abundant) about O.smaragdina workers : (Very abundant) > about 1000 O.smaragdina workers

94 Table 14 Predation of H. antonii by green ant Zone Sprayed/ non sprayed Colonisation of O. smaragdina No. of trees observed Per cent damage Nut yield (kg/ tree) plantation Coastal Sprayed None Karnataka Non-sprayed None Non-sprayed Part Non-sprayed Full Maidan Sprayed None Karnataka Non-sprayed None Non-sprayed Part Non-sprayed Full

95 Table 15 Screening of cashew varieties against TMB in coastal Karnataka Sl. Accessions/variety No. adult /m 2 of canopy Damage grade (0-4) No. Shoot Panicle Shoot Panicle 1 Local (Puttur) Priyanka Propagation /69 Ichapur /103 Gubbi NAIROBI /98 Kottarakara /91 Kottarakar V.R.I /72 Orchard Vengurla BPP /25 Neeleshwar /40 Palaparamba /111 Gubbi Vengurla /66 CHIRALA Goa-11/ /64- Madhuranthakam BLA-39-A /108-Gubbi /10-Permanur /10-Gubbi UN Ullal Ullal /97-Kottarakar V Vengurla

96 0.81mg/100mg of sample. The variety V-4 recorded the least total phenolic content of 0.30 mg/100mg, whereas it was 0.81 mg/100mg in Ullal-1 and it was on par with the variety Priyanka and significantly different over V-4. The orthodihydroxy phenol was least (0.12 mg/100mg) in V-4 and it was significantly high in Ullal-1. The quantum of starch was high in the highly susceptible variety V-4 (18.70 mg/100mg) and it was on par with the variety Propagation (17.20 mg/100mg). However, the starch content was significantly low in accession Ullal- 1 (7.38).Total sugar content was high in the variety propagation (3.16 mg/100mg), was on par with V-4 (3.15 mg/100mg) and it was low in other varieties/ accessions analysed for total sugar. The nitrogenous compound particularly amino acids constituent ranged between 0.01 and mg/100mg) in different varieties analysed for its presence. TMB population and damage grade on the varieties with high total sugar, starch and amino acids and low total phenols and ortho-dihydroxy phenol was high in the variety Propagation and V and 3.03 mg/100mg, respectively. Population and damage grade were significantly low on the varieties with low starch, total sugar and high phenol. The nut yield ranged between 2.97 and 6.14 kg/ tree in different susceptible and the promising varieties. The maximum yield of 6.14 kg/tree was recorded on Ullal-1, it was on par with the variety Priyanka. The highly susceptible varieties V-4 and Propagation recorded low yield of 3.03 and 2.97 kg/tree, respectively. Based on biochemical constituents it was found that the varieties with high total starch, sugar and amino acids are susceptible for pest incidence. On the contrary, the cashew genotypes with low starch, total sugar, high amino acid, high total phenol and ortho-dihydroxy phenols are capable of sustaining to the greater extent against TMB incidence and yields better Artificial infestation Infestation of H. antonii on cashew tree was observed during September October, synchronizing with the emergence of new flush, panicle initiation and nut

97 Table 16 Biochemical constituents of cashew varieties Varieties Total phenol (mg/100mg) O.D phenol (mg/100mg) Total sugar (mg/100mg) Starch (mg/100mg) Total amino acids (mg/ 100mg) TMB adult (no/m 2 ) Damage grade Nut yield (Kg/tree) Ullal Propagation V Priyanka /72-Orchard /103-Gubbi CV (%) CD (0.05)

98 and fruit developmental stage. The population of tea mosquito bug was 9.63 and 3.0 per tree on pruned and unpruned trees respectively, during September-October. Population reached peak during January-February (19.78) on pruned trees and 9.60 on unpruned trees. It started declining from March-April and observed on the young plant in smaller numbers during off-season. The profuse and prolonged flush produced by the pruned trees acts as a trap for the assessment of the population of TMB in cashew plantations (Table 17) Efficacy of biopesticides and insecticides in laboratory Residual effect of insecticides and botanicals in laboratory against TMB during revealed that the adult tea mosquito bug released on the treatments of λ-cyhalothrin (0.005%), carbaryl (0.10%), monocrotophos (0.05%) and endosulfan (0.05%) laid 1.04, 1.12, 0.82 and 1.09 eggs on zero DAT (Table18). Adults did not survive 3 DAT on these treated plants. Plant products viz. pongamia oil (2%), PSKE (2%), neem oil (5%), NSKE (2%) and the microbial pesticide B. basiana recorded high fecundity ranging from 1.60 to 2.26 eggs / female at zero DAT. Among the botanicals, neem oil (5%) recorded maximum number of eggs (1.94/female) on 0 DAT, fecundity was observed up to 5 DAT in plant products treatments. The eggs laid on plant products treated plants were on par with the control (1.99) and it was significantly higher over chemical insecticides. Per cent egg hatching was maximum (73.45) in neem oil (5%) and it was on par with the control (75.58%). It is evident from the table that the plant products have no ovicidal effect on TMB eggs. Per cent damage by the first instar nymph was maximum (18.56) in neem oil (5%) and it was least in chemical insecticidal treatments. It is evident from the studies that since neem is also the alternate host for the TMB, the pest is able to digest the active ingredient Azadirectin present in the neem oil. The effect of the molecules evaluated during projected a

99 similar trend (Table18). Mean effect of biopesticides and new molecules during are presented in table Effect of biopesticides and insecticides in field During the per cent damage on new flush at 10 DAT ranged between 5.68 and Monocrotophos (0.05%) treated trees registered significantly least per cent damage (5.68) (Table-20). Maximum per cent damage was recorded on the entomopathogen B.bassiana alone treated trees (21.30). Among the botanicals, PSKE (2%) was significantly superior over neem products in suppressing the pest. At flushing stage the residual effect of monocrotophos was observed up to 30 days after spray and recorded the least per cent damage (13.60) followed by the botanical PSKE (15.78). Though the entomopathogen B.bassiana failed to establish under field conditions, it proved effective in suppressing the population over untreated check. The per cent damage in the botanical neem oil (5%) and NSKE (2%) were and 22.65, respectively and were significantly inferior to monocrotophos and superior over untreated check (28.60). Panicle infestation ranged between and per cent in the treated trees, whereas it was on the untreated check at 10 DAT. The least per cent damage (15.91) recorded in endosulfan (0.05%) was significantly superior to the botanicals pongamia oil (19.90), PSKE (18.14), neem oil (26.49) and NSKE (24.57). The fungal entomopathogen B. bassiana recorded higher per cent infestation (27.08). However, the new molecule λ-cyhalothrin (15.95) was on par with endosulfan (15.91). All the treatments included in the study were statistically superior over untreated check. On the panicle, λ-cyhalothrin (0.005%) and endosulfan (0.05%) at 20 DAT were found to be on par at each other in their efficacy in bringing down the

100 Plate 7 Adult TMB infesting new flush Plate 8 New flush damaged by TMB

101 population and recorded and per cent damage, respectively. They were significantly different over the remaining treatments and the control. The maximum damage of per cent was recorded in control at 30 DAT on panicle. Monocrotphos (0.05%) at new flush and λ-cyhalothrin (0.005%) on panicle proved their effectiveness by registering significantly least per cent panicle damage and 18.03, respectively. The first spray monocrotphos (0.05%) during new flush and λ-cyhalothrin (0.005%) on the panicle were on par with the recommended spray monocrotophos (0.05%) and endosulfan (0.05%) at the respective stages. The combination was significantly superior over B. bassiana 2 ml - λ-cyhalothrin (0.005%) and - carbaryl (0.10%). Botanicals and the microbial pesticides applied alone were not found effective in suppressing the pest. During nut and fruit developmental stage the third spray carbaryl (0.10%) in sequential spray of monocrotophos (0.05%) + λ- cyhalothrin (0.005%) recorded the least per cent damage (5.36) at 10 DAT and it was on par with the recommended sprays moncrotophos (0.05%) - endosulfan (0.05%) - carbaryl (0.10%), followed by the PSKE (2%) - λ-cyhalothrin (0.005%) - carbaryl (0.10%). The undamaged nuts appeared spotless and more healthy during 30 days after treatment at nut developmental stage. Control recorded nut damage as high as per cent, pongamia oil (2%), neem oil (5%), NSKE (2%) and B.bassiana (2ml) were statistically inferior to the spray schedule and superior over control. Botanicals, viz. pongamia oil, neem oil, NSKE and B.bassiana alone do not have much scope in tea mosquito management. On the contrary, the botanical PSKE (2%) was found effective in combating the pest, when it was treated alone and in sequence with insecticides. Monocrotophos (0.05%) - λ-cyhalothrin (0.005%) - carbaryl (0.10%) complemented each other for the suppression of TMB on cashew.

102 Plate 9 Healthy panicle Plate 10 Panicle damaged by TMB

103 Results on efficacy of insecticides and boiopesticides evaluated against TMB in are presented in table-21. From the data it is evident that spraying with monocrotophos (0.05%) at flushing recorded the least per cent damage (12.10) as against per cent in control at 30 DAT. Among the botanicals, PSKE (2%) again proved its effectiveness in managing the pest. At 30 days after second spray on panicle monocrotophos (0.05%) λ - cyhalothrin (0.005%) in sequence recorded significantly the least per cent infestation (12.98) and remained statistically on par with monocrotophos (0.05%) - endosulfan (0.05%) and PSKE (2%) - λ-cyhalothrin (0.005%) at new flush and the panicle initiation. The other treatments botanicals and microbial pesticide B. bassiana treated alone and in sequence with the chemical insecticides were found less effective in the management of the economically important pest, TMB on cashew. The effectiveness of botanicals and insecticides at 30 days after third spray at fruiting stage registered the least mean per cent damage on the trees treated with carbaryl (0.10%) in sequence with monocrotophos (0.05%) - λ-cyhalothrin (0.005%) followed by the sequential recommended spray schedule of monocrotophos (0.05%) - endosulfan (0.05%) - carbaryl (0.10%), the botanical PSKE (2%) - λ-cyhalothrin (0.005%) - carbaryl (0.10%) and NSKE (2%) - λ- cyhalothrin (0.005%) - carbaryl (0.10%). However, pongamia oil (2%), PSKE (2%) neem oil (5%) and NSKE (2%) and the microbial pesticide B.bassiana evaluated alone proved less effective in comparison with the inorganic insecticides in combating the menace and was effective over untreated check. Sequential spray of monocrotophos (0.05%) - λ-cyhalothrin (0.005%) - carbaryl (0.10%) at flushing, panicle and fruiting stages were found to be effective in the management of the pest TMB. The mean effect of the sequential spray schedule of monocrotophos (0.05%) - λ-cyhalothrin (0.005%) - carbaryl (0.10%) was

104 Plate 11 Healthy cashew nuts Plate 12 Cashew nuts damaged by TMB