Entomology ABSTRACT INTRODUCTION MATERIALS AND METHODS. D. Samoedi. Indonesian Sugar Research Institute, Pasuruan, Indonesia

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1 Entomology MPACT OF MASS LBERATON OF DATRAEOPHAGA STRlATALlS TOWNS ON THE POPULATON AND NTENSTY OF NFESTATON OF THE SUGARCANE MOTH BORER, CHLO AURlClLlUS DUDG N CENTRAL JAVA D. Samoed ndonesan Sugar Research nsttute, Pasuruan, ndonesa Key words: Datraeophaga stratals Towns, sugar cane moth borer, Chlo aurclus Dudg, mpact of paraste lberaton ABSTRACT The mpact of mass lberaton of an establshed larval paraste, Datraeophaga stratals Towns (Dptera, Tachndae) on the sugar cane moth borer, Chlo aurclus (Lepdoptera, Pyraldae), was studed durng the 1985/86 and 1986/87 crops at Srag Sugar Plantatons, Central Java. The ntal mass lberatons of the tachnd paraste were made) from September to December t was confrmed that the paraste was well establshed and that t effectvely controlled the sugar cane moth borer. Comparson of feld survey data before and after paraste lberaton showed decreases n both the populaton of the moth borer and the percentage ntensty of nfestaton. Ths was accompaned by an ncrease n the numbers of paraste pupara as well as percentage of larval parastsm. These results suggest that the control of C aurclus by Dstratals has been successful. NTRODUCTON ntensve feld surveys of the sugar cane moth borer durng the 1973/1974 crop revealed that Chlo aurclus Dudg (Lepdoptera, Pyraldae) was the most mportant pest.of sugar cane at Srag Sugar Plantatons, Central Java (Samoed and Wroatmodo7). There were relatvely few Csaccharphagus Boj found n ths area. An average of 32% jont nfestaton was recorded at harvest and loss of sugar due to the borer was estmated to be at least 1.68 t/ha (Mathes et ap, Wroatmodo8). Feld surveys also detected the presence of low numbers of two larval parastes, Apanteles flavpes Cam and Campyloneurus spp, and a pupal paraste, Xanthopmpla stemmator Thunb. The other n- dgenous larval paraste, Datraeophaga stratalstowns was absent from the study area. D stratals orgnally occurred only n East Java where ts dstrbuton was apparently restrcted to damp and cool habtats around Jatroto (Ghan and Wllams3). Ths paraste was ntroduced nto many countres to combat the sugar cane moth borer, C saccharphagus, but the results were not promsng (Bennet', Etene2 and Ghan and Wllams3,). Wroatmodo9, however, reported that bologcal control of sugar cane moth borers, Chlo spp, n West Java by D stratals had acheved good results. Ths s n dsagreement wth Ghan and Wllams3 who collected paraste pupara from Jatroto and reported that no D stratals were obtaned from larvae of C aurclus. Several thousands of D stratals were therefore ntroduced to the Srag Sugar Plantatons. Ths programme amed at supplementng the effects of exstng parastes aganst the cane moth borer, C aurclus. MATERALS AND METHODS Approxmately pupara of D stratals were sent to Srag Sugar Plantatons durng the perod September to December The paraste pupara were obtaned from a 81 8

2 laboratory culture at the ndonesan Sugar Research nsttute, bred on larvae of C aurclus. After emergence, the tachnd parastes were allowed to mate n the musln cage before beng released to the felds. Several hundred larvae of the borer were then collected from the released areas n January 1976 to assess whether or not the paraste had become establshed. Only older larvae were collected. The larval parastsm was determned by rearng the feld collected larvae n the laboratory. The pupara of D stratals n the felds were also collected to nvestgate the presence of secondary parastes. n addton a sample of 10 X 10 stalks of cane was taken at random from each of the sampled felds at the tme of harvest n 1976 to determne the percentage of ntensty of nfestaton (~etcalfe~). The sampled stalks were splt and the total numbers of jonts as well as the numbers bored were recorded. the ntensty of nfestaton was calculated on the bass of percentage of jonts bored. The numbers of borer larvae and paraste pupara found n the sampled stalks were also recorded. To calculate the average of ~ntensty of nfestaton of the moth borer and paraste populatons, the data were then pooled. The feld surveys were repeated n 1986 and 1987, about ten years after the paraste establshment. Ths long perod of tme was ntended to allow the establshed Dstratals to reduce the numbers of the moth borer and to demonstrate ts capacty to keep the borer populaton at an economcally low fgure. RESULTS AND DSCUSSON Table 1 shows the means of ntensty of moth borer nfestatons at the tme of harvest before and after the release of D stratals. The percentage of onts bored decreased sharply followng lberaton, e from 31.99% n 1974 to 9.47% n Further decreases of the percentage of jonts bored were observed at harvest tmes n 1986 and 1987, 12 years after the paraste release. The means of percentage of onts bored at the tmes of harvest n 1986 and 1987 were only 1.25% and 0.28% respectvely. These data, however, provded only an ndcaton of the mpact of the ntroduced paraste snce, n feld condtons, there are many other factors whch may cause a decrease n the ntensty of moth borer nfestaton. Table 1 - The means of ntensty of moth borer nfestaton at tme of harvest before and after D stratals release. * Before paraste release More convncng evdence of the mpact of the ntroduced paraste s the reducton n host equlbrum release (Legner4) as presented n Table 2. t shows clearly the decrease n numbers of larvae of the moth borer n the felds followng the paraste release, and ths was accompaned by an ncrease n the numbers of paraste pupara, as well as percentage of larval parastsm. Thus, the feld survey data of 1986 and 1987 (Table 2) confrmed the establshment of D stratals on Caurclus and suggested that the tachnd paraste was able to keep the numbers of the cane moth borer at low levels.

3 Table 2 - The average numbers of larvae and pupara of moth borer D stratals, and the levels of larval parastsm by D stratals and other parastes before and after release of the tachnd paraste. Years Numbers of larvae * of moth borer per 100 stalks Numbers of pupae of D stratals per 100 stalks Percentage of parastzed larvae by D stratals Others ** * Only older larvae were collected ** Parastsm by Apanteles flavpes and Campyloneurus spp *** Before D stratals release t can be seen n Table 2 that the actvty of the other larval parastes, A flavpes and Campyloneurusspp, was low. A soltary and a gregarous speces of secondary paraste emerged from laboratory rearng of tachnd pupara. The gregarous secondary paraste s probably the same speces as that reported by Ghan and Wllams3, e Trchopora tachndarum Ferr (Daprdae). The ncdence of secondary parastsm on D stratals pupara, however, was not sgnfcant. CONCLUSONS The results obtaned n ths feld study confrmed the establshment of the tachnd paraste, D stratals, n the area of Srag Sugar Plantatons and suggested that the paraste has demonstrated ts capacty to keep the numbers of the cane moth borer at a low fgure. ACKNOWLEDGEMENTS The author wshes to thank the manager of Srag Sugar Plantatons for the excellent facltes provded. Thanks are due also to Dr B Wroatmodo, Vce Drector of lsrl and formerly head of the Entomology Unt, for hs help and encouragement durng early stages of ths study. " REFERENCES / 1. Bennet, FD (1969). Tachnd fles as bologcal control agentsfor sugar cane moth borers. n pests of sugar cane. JR Wllams, JR Metcalfe, RW Mungomery and R Mathes (Eds). Elsever, Amsterdam. 2. Etene, J (1969). Two years rearng of the Javanese tachnd Datraeophaga stratals Towns, a paraste of the cane moth borer Proceras saccharphagus Bo, n Reunon sland. Proc nt Soc Sug Cane Technol 12: Ghan, MA and Wllams JR (1963). An attempt to establsh the Javanese fly, Datraeophaga stratals Towns, n Maurtus for control of the cane moth borer, Proceras saccharphagus Boj, wth notes upon parastes of cane moth borers n Java. Proc nt Soc Sug Cane Technol 10: Legner, EF (1969). Dstrbuton pattern of host and parastzaton by Spalanga drosophlae (Hymenoptera, Pteromaldae). Can Entomol 101:

4 5. Mathes, R, ngram, JW and Charpenter, LJ (1954). A method for determnng losses caused by the sugar cane borer. Proc nt Soc Sug Cane Technol 8: Metcalfe, JR (1963). A revew of the methods of estmaton of damage due to moth borer (Datraea saccharals (F)) n Barbados wth specal reference to the Trchogramma campagn. Proc nt Soc Sug Cane Technol 11: Samoed, D and Wroatmodjo, B (1974). Pests of sugar cane. n annual report of the ndonesan sugar Res nt (1974) (Englsh Summary): Wroatmodo, B (1973). A bref report of the sugar cane pests at present and ts control. Berta no 1 SR, Pasuruan, ndonesa: 18 pp. 9. Wroatmodo, B (1974). An attempt to control sugar cane stemborers wth the dpterous paraste Datraeophaga stratals Towns. Proc nt 5oc Sug Cane Technol 15: H t LES EFFECTS DE LA LBERATON EN MASSE DU DATRAEBPHAGA STRlATALlS TOWNS SUR LA POPULATON ET L'NTENSTE D'NFESTATON DU CHlLO AURlClLlUS DU DG., BORER DE LA CANNE A SUCRE EN JAVA CENTRAL D. Samoed lnsttut de Recherches Sucrbres d'lndonese, Pasuruan, lndonese Mots-cles: Datracophaga stratals Towns, borer de la canne b sucre, Chlo aurclus Dudg., les effets de la lberaton du paraste. Les effets de la lberaton en masse du Datraeophaga stratals Towns (Dptbre, Tachlnldes), paraste du state larvare de Chlo aurclus (lepdoptbre, Pyraldes) - borer de la canne b sucre - ont kt6 etudees sur les recoltes 1985/86 et au Sragl Sugar 32 Plantatons, Java Central, La premlere llberatlon en masse du paraslte tachnalre fut effectuee entre septembre et dhcembre fut confrm6 que le paraste s'mplantat avec succbs et contrdlat effcacement le bo- P rer de la canne b sucre. En comparant les resultats des observatons fates aux champs avant et aprbs la lberaton du paraste, on constate un decrosssement b la fos de la populaton du borer et du pourcentage d1ntenst6 de 'lnfestaton en meme temps qu'un accrossement du nombre de pupes parastares et du taux de parasltsme larvare. Ces resultats dbmontrent que le 0. stratals contrdle effcacement le C. aurc~lus.

5 ENTOMOLOGY LOS MPACTOS DE LA LlBERAClON MASlVA DE DATRAEOPHAGA STRlATALlS TOWNS SOBRE LA POBLACON E NTENSDAD DE. NFESTACON DEL GUSANO BARRENADOR DE LA CANA DE AZUCAR, Chlo Aurclus Dudg., EN JAVA CENTRAL D. Samoed Samoed ndonesan Sugar Research nsttute, Pasuruan, ndonesa Palabras claves: Datrueophaga stratals Towns., gusano barrenador de la cafa de azocar, Shlo aurclus Dudge., mpact0 de la lberac6n del parasto. RESUMEN En plantacones de cata de azljcar de Srag, Java Central, se estud6 durante las campaas 1985/86 y 1986/87, 10s mpactos de la lberac6n masva y el establecmento del parasto larval, Datraeophaga stratals Towns. (Dptero-Tach~ndae) sobre el gusano barrenador de la cata de azrcar, Chlo aurclus (Lep~doptera, Pyraldae). Las ~beracones masvas ncales del parasto tachndo fueron realzadas entre 10s meses de Septembre a Dcembre de Se confrm6 que el parasto se establec6 y efectvamente control6 al gusano barrenador de la caa de azljcar. El analss de 10s datos de campo, antes y despues de la lberacbn del parasto, mostr6 la dsmnuc6n tanto de la poblac6n del gusano barrenador como del porcentae de ntensdad de nfestacbn, esto fue acompatado por el ncrernento en el nrmero de pupas y del % de larvas parastadas. Los resultados sugeren. que el control de C. aurclus por D. stratals ha sdo extoso.