Invasive Ambrosia Beetle Conference The Situation in California August 12 14, 2012 Meeting sponsored by: The Hofshi Foundation University of California, Riverside UC Center for Invasive Pest Research The Huntington Botanical Gardens The Los Angeles Arboretum
Invasive Ambrosia Beetle Conference The Situation in California August 12 14, 2012 Session 3 Biology of the Beetles
Shot Hole Borer of Tea - The Situation in Sri Lanka Invasive Ambrosia Beetle Conference The Situation in California Sampath Walgama August 2012 Riverside, CA
World Distribution of TSHB Distribution TSHB in the world = Present, no further details = Widespread = Localized
History of TSHB First described in 1868 by Eichoff (host unknown, locality unknown) First observed in 1892 a tea plantation situated in the mid elevations (600-1200m asl) Spread in almost all tea growing areas and presntly gained a pest status in tea plantations from near sea level to about 1400m asl.
Biology of TSHB Life cycle - eggs, 3 larval instars, pupa and sexually dimorphic adults Takes about 45 days to complete (depend on the temperature) Multivoltine Mycetophagous larvae feed on symbiotic fungus cultivated in the galleries by the mother beetle (Monacrosporium ambrosium) Inbreeding (brother-sister mating) occurs
Number of SHB generations in different agro ecological regions Region Location Number of DD accumulated Approximate number per year (above 15 0 C) of generations High country Sita Eliya 687 ± 87.5 1.8 ± 0.36 Mid country Hantana 3371 ± 92.2 9.0 ± 0.40 (wet) Mid country Bandarawela 2092 ± 102.4 6.0 ± 0.43 (dry) Low country Ratnapura 4788 ± 121.5 12.0 ± 0.51 Temperature ( 0 C) 35 30 25 20 15 10 5 0 Average temperature Development threshold (15.7C) 1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201 211 221 231 241 251 261 271 281 291 301 311 321 331 341 351 361 Temperature ( 0 C) 35 30 25 20 15 10 5 0 Average temperature Development threshold (15.7C) 1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201 211 221 231 241 251 261 271 281 291 301 311 321 331 341 351 361 Day of year Day of year
1.2 Eggs Larvae Pupae Adults 1.0 0.8 0.6 0.4 0.2 0.0 15.02.99 22.03.99 26.04.99 24.05.99 08.06.99 19.07.99 16.08.99 27.09.99 26.10.99 15.11.99 28.12.99 24.01.20 14.02.20 27.03.20 24.04.20 Proportion of stages 1.2 Sampling date Eggs Larvae Pupae Adults 1.0 0.8 0.6 0.4 0.2 0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Prportion of stages Sampling Appearance of life stages of shot-hole borer expressed as proportions over the sampling period in the pruning cycle in Nayapana estate representing mid country (wet zone).
Biology of TSHB Life cycle - eggs, 3 larval instars, pupa and sexually dimorphic adults Takes about 45 days to complete (depend on the temperature) Multivoltine Mycetophagous larvae feed on symbiotic fungus cultivated in the galleries by the mother beetle (Monacrosporium ambrosium) (Gadd & Loos 1947) Inbreeding (brother-sister mating) occurs
35.0 30.0 25.0 20.0 15.0 10.0 5.0 0.0 Occupied galleries Open galleries Healed galleries Total population 60.0 50.0 40.0 30.0 20.0 10.0 0.0 15.02.99 22.03.99 26.04.99 24.05.99 08.06.99 19.07.99 16.08.99 27.09.99 26.10.99 15.11.99 28.12.99 24.01.20 14.02.20 27.03.20 24.04.20 Average number of galleries (4 replicates) Average population ( 4 replicates) Date Fluctuation of shot-hole borer population and the infestation (galleries), over a course of a pruning cycle in Nayapana estate, representing mid country (wet zone) and the sampling was initiated in the 10 th month after prune (arrow).
Highly polyphagous
Damage of TSHB Primary damage branch breakage as a result of construction of galleries
Secondary damage Rotting of wood as a result of wood rotting fungi entering through gallery holes or from exposed unprotected prune cuts Leads to long term debilitation of the bush and thereby, capital loss
>1200m asl 600-1200m asl 0% 2% 3% 0% 2% 0% 0% 5% 11% 77% <600m asl 0-10 11-21-30 31-40 41-50 51-60 61-70 71-80 81-90 91-100
Management/control of TSHB Plant resistance Resistant/tolerant cultivars produced by the institute Recommended different cultivars for different agro ecological regions based on specific charateristics (yield potential, quality, resistant to pest and diseases and drought etc etc.
Cultivar TRI 2023 (resistant to SHB) Cultivar TRI 2025 (Susceptible to SHB)
100 80 60 40 20 0 MAYFIELD DRAYTON BOGAHAWATTE MOUNT VERNON STONYCLIFF CRAIGILEA YUILIFIELD KELIEWATTE CHRYSTLERSFAR M % Infested stems (per sample) 100 80 60 40 20 0 TRI 2025 DT 1 Estates Percentage Mayfield Drayton Bogahawatte Mount Vernon Stonycliff Craigilea Yuillefield Kelliewatte Chrystler Farm Estates TRI 2025 (grown for yield) DT 1 (grown for quality) Both cultivars are highly susceptible to SHB 0THERS TRI 2025 DT 1
Chemical control IPM CONCEPT Fenthion recommended Many types tested but came very few into recommendations from time to time OP s used (since 1985 it was Fenthion only in recommendation)
Cultural control Cleaning dead areas at prune (sanitary cleaning) to remove decayed parts Application of wound dressings on surfaces more than 5 cm s in diameter
SHOT - HOLE BORER IN SRI LANKA GREENHOUSE EFFECT 1500 6.0 Annual DD accumulation 1250 1000 750 500 250 0 5.0 4.0 3.0 2.0 No. of generaions Current 0.5 Increase 1.0 Increase 1.5 Increase 2.0 Increase Temperature ( 0 C) Annual DD accumulation No. of generations Range extension into cooler areas above 1400m asl is a concern
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