Optimization of the field performance of released Trichogramma spp. in olive groves in Egypt

The egg parasitoid species Trichogramma bourarachae Pinturaeu and Babault, T. codubensis Vargas and Cabello, T. euproctidis Girault, all collected from olive groves in Egypt as well as the commercially available T. evanscens Westwood. originating from sugarcane fields in Egypt, were released and Monitored under laboratory and olive Field conditions in 2004 season to Study their emergence rate and duration of Wasp availability. The releasing doses were ca 3000 wasps/card/species. Peaks of adult emergence varied according to the species and date of testing. In contrast to the commercial species, the achieved doses of the three local Species did not differ between the laboratory bind field conditions also during the third trial "release" and accounted in all cases to satisfying Values. However, reduction ill emerged T. evanescens wasp was significantly greater under field conditions (41%) than Under laboratory conditions (23%). The results suggested that T bourarachae and T. cordubensis were better adapted to warm and dry weather conditions than the other test species. The pattern of emergence and the resulting duration of availability of wasps in the field were more promising for the species T bourarachae and T cordubensis to be used for inundative releases in olive farms ill arid areas. The results: a) suggest the importance of Such Studies to select and manage available local wasp species as a prerequisite for Successful control of target pests and 2) provide useful information for timing of inundative releases during the olive season.