The Role of Host Storage in the Quality of Trichogramma brassicae Bezdenko

     Most natural enemies have low maintenance capabilities so they are often cultivated shortly before release. In the case of parasitoids, their hosts can be stored instead of parasitoids. Since storage of host eggs can increase the efficiency of the mass production units of Trichogramma wasps, this approach has been suggested by various researchers as a suitable method for mass production of Trichogramma species. As regards that there are few studies on the effect of low temperatures on the growth population parameters of parasitoid, so in this study the effect of cold storage of Phthorimaea operculella (Zeller) eggs at 4°C for 0, 1, 4, 7, 15 and 30 days on biological and population parameters of Trichogramma brassicae Bezdenko were investigated. This experiment was conducted in a completely randomized design with 25 replications. Mean comparisons were performed using Duncan's test. The results showed that developmental time, longevity, parasitism rate, percentage of emergence, fecundity and oviposition period of T. brassicae were significantly different between treatments and the all parameters decreased when the storage period increased. It was also determined that all population growth parameters had a significant difference between the control and cold treatments. Due to the parasitism and adult emergency rate, longevity and fecundity of T. brassicae on stored host, eggs of P. operculella can be stored at 4°C for up to two weeks without significant negative effect on the efficiency of the T. brassicae. However, based on population growth parameters, maintenance of host eggs for up to one week are most recommended.