Effects of cold storage on the growth and development of Trichopria drosophilae (Hymenoptera: Diapriidae)

Drosophila suzukii (Diptera: Drosophilidae) is a polyphagous pest native to Asia that can cause serious economic damage. In this study, the effects of low-temperature storage on growth and development of Trichopria drosophilae were studied by using the methods of cold storage pupae to evaluate the cold storage tolerance and quality assessment of T. drosophilae, providing a theoretical basis for solving the mass production, storage and concentrated release of T. drosophilae. The results showed that the emergence rate of the 4th instar larvae decreased with extension of storage time from 10 to 20 d at 8 °C, 10 °C and 12 °C. The emergence rate remained as high as 79.24% after storage for 15 d at 16 °C. At 14 °C and 16 °C, the emergence rate of the 1-day-old pupae was not significantly different from that of control (77.27%). The above results indicated that the 4th instar and 1-day-old pupae of T. drosophilae were more suitable for long-term storage at 14 °C and 16 °C. Under the above experimental conditions, T. drosophila quality after cold storage for 10, 15 and 20 d was continuously investigated. The results showed that parasitism rates of different stages after treatment were significantly affected by storage temperature and time. Long-term cold storage could reduce the emergence rate and sex ratio of F1 generation. The emergence time of the 1-day-old pupae was gradually shortened with extension of storage time at 16 °C. The starvation-resistant lifespan of T. drosophilae after cold storage was significantly longer than that of control. This study results will further clarify the effects of cold temperature storage on growth and development of T. drosophilae.