Cold storage of Trichogramma ostriniae reared on Sitotroga cerealella eggs

摘要

Efficient storage of the biological control agent Trichogramma ostriniae could improve current parasitoid production methods by making the system more flexible and efficient. Initial studies compared emergence rates of T. ostriniae reared on Sitotroga cerealella eggs held at 6 ℃, 9 ℃, 12 ℃, 15 ℃, and 24 ℃ for up to 8 weeks after parasitism. At 15 ℃, emergence occurred in 80 for parasitized eggs stored at 9 ℃ and 12 ℃ for 4 and 6 weeks respectively. Storage at 6 ℃ caused a significant decline in emergence after 2 weeks. Subsequent trials focused on fitness of stored T. ostriniae. Percentage of emerged females parasitizing eggs, female longevity, and fecundity were quantified after storage. The percentage of females successfully parasitizing O. nubilalis eggs was greatest for the 9 ℃ four-week treatment 9100). Compared to 24 ℃ controls, storage at 12 ℃ for 6 weeks or at 9 ℃ for 8 weeks reduced the percentage of females parasitizing. Longevity of females held in cold storage was generally less than that of controls. Rates of parasitism by stored Trichogramma was generally similar to control after 2 to 4 weeks' storage at 9 ℃ and 12 ℃ but declined with storage longer than 4 weeks. Emergence of progeny of cold-stored females was lower than controls for all treatments. The percentage of female progeny from cold stored females was comparable to controls up to 4 weeks of storage.