Necessity of encountering Trichogramma brassicae Bezdenko wasps reared on alternative hosts, cereal moth Sitotroga cerealella Hubner and flour moth Anagasta kuehniella Zeller to target pest bollworm Helicoverpa armigera Hubner prior to release

Trichogramma brassicae Bezdenko is one of the most important species of Trichogramma in Iran that can be easily reared on laboratory hosts such as flour moth Anagasta kuehniella Zeller and cereal moth Sititroga cerealella Hubner. Bollworm Helicoverpa armigera Hubner, one of the most important hosts of this parasitic wasp is a serious pest of crops such as cotton, maize, and tomato. A problem often encounters in parasitoids reared on alternative hosts is declining parasitism rate on target pest following to release. It refers to weakened response of the wasp due to not being familiar to host kairomones. So, in order to overcome the problem, it is recommended that the parasitoidwas reared an additional generation on target pest prior to release. Necessity of such a quality control measure in the wasps reared on any of traditional laboratory hosts i.e. flour moth and cereal moth was investigated in this study. To achieve it, T. brassicae was reared on each of the above mentioned hosts for two sequential generations, followed by two additional generations on bollworm. Quality parameters such as developmental time, longevity, fecundity, sex ratio, and rate of adult emergence were compared among the four generations. It was revealed that wasp response to host change was different in each laboratory host. Adult longevity was the only variable that increased by host shifting from flour moth to bollworm, while fecundity and adult emergence were declined as well following host change from cereal moth to bollworm.