DEVELOPING A COMMERCIALLY VIABLE SYSTEM FOR BIOLOGICAL-CONTROL OF LIGHT BROWN APPLE MOTH (LEPIDOPTERA, TORTRICIDAE) IN GRAPES USING ENDEMICTRICHOGRAMMA (HYMENOPTERA, TRICHOGRAMMATIDAE)

A native species of Trichogramma, Trichogramma (Trichogrammanza) carve rae (Oatman & Pinto), has potential as a commercially viable control o ption for an Australian tortricid leafroller Epiphyas postvittana (Wal ker) in wine grapes. Four candidate species of Trichogramma were colle cted from E. postvittana egg masses in vineyards and assessed in the l aboratory for their suitability for commercial use. This led to the is olation of a strain of T. carverae for putative commercial release. In undative release trials using small blocks within commercial vineyards showed that >75% of the egg masses in the vineyard could be parasitiz ed by T. carverae at release rates of 70,000 Trichogramma per hectare with as few as 30 release sites per hectare. Parasitism was higher aro und release sites within the first 2 d but was fairly evenly distribut ed over the 0.05-ha release blocks in the 4-5 d trials. The wasps move d upwind when there was little to no wind and downwind when wind speed s were higher (usually >5 km/h). Monitoring systems for E. postvittana were developed to help determine effective timing of releases. This s tudy illustrates a relatively quick and inexpensive approach to the de velopment of new strains of Trichogramma for commercial use that could be adapted for other agricultural systems.