Morphology and biology of Trichogrammatoidea bactrae (Hymenoptera: Trichogrammatidae), imported from Australia as a parasitoid of pink bollworm (Lepidoptera: Gelechiidae) eggs

Morphological and selected biological studies are described for Trichogrammatoidea bactrae Nagaraja, recently imported into the United States from Australia as an egg parasitoid of the pink bollworm, Pectinophora gossypiella (Saunders). Females maintained at 24 degree C averaged 23.2 plus or minus 6.3 (SD) eggs per ovary. Unlike many Trichogramma species that apparently have four larval instars, T. bactrae develops through only two instars. T. bactrae development, mortality, and adult fecundity and longevity were examined at several constant temperatures in the laboratory. Host age suitability studies were done at 25 degree C. Across all temperatures tested (15-32.5 degree C), the majority (x super(-) = 83.7%) of T. bactrae emerged between 0700-1000 hours, and the sex ratio (progeny from mated females) was predominately female (x super(-) = 64.9%). Virgin females exclusively produced males. Immature mortality ranged from 10.6 to 34.6% between 15 and 30 degree C; however, at 32.5 degree C mortality was 73%.