Cold-Storage of Piezodorus guildinii (Hemiptera: Pentatomidae) Eggs for Rearing Telenomus podisi (Hymenoptera: Platygastridae)

Abstract

Piezodorus guildinii (Hemiptera: Pentatomidae) is an important soybean pest, and one of its main natural enemies is Telenomus podisi (Hymenoptera: Platygastridae). Rearing of the parasitoid is constrained by the hosts' egg quality, which deteriorates after few generations in laboratory, therefore, cold-stored h ost eggs utilization could be a useful tool for augmentative biological control. Thus, the objective was to evaluate the quality of P. guildinii cold-stored eggs, on the performance of parental a nd F 1 generation of T. podisi . Host eggs 24 hour old were stored at -18°C for one (N= 53 ), two (N= 28) or three months (N= 29), and approximately 40 host eggs were offered to a T. podisi female per treatment, for 48 hours. The control treatment cons isted of 24-hour-old non-frozen host eggs, obtained and kept at 24°C (N= 55). Parental ge neration parasitism and progeny ́s emergence on frozen eggs was significantly lower th an on non-frozen eggs, even for the shorter storage period. Male proportion and preimag inal development time of the progeny increased with freezing period. However, pa rasitism proportion caused by adults of F 1 , and emergence, male proportion, and preimaginal d evelopment time of F 2 were not affected. Although the performance of T. podisi on frozen P. guildinii eggs was significantly lower than on nonfrozen ones, host eg gs storage for up to two months allowed obtaining a parasitism rate of 40% with a high emergence rate. This could be helpful enough to maintain mass rearings, mainly du ring the host hibernation period, and to enhance field parasitism when host is scarce. Keywords : Host storage, Mass-rearing, Parasitoids.