Cold storage of Spodoptera litura eggs and Telenomus remus adults for improving mass‐rearing efficiency

Abstract

AbstractTelenomus remus (Nixon) has shown promising potential as a biological control agent for the major invasive agricultural pest, Spodoptera frugiperda (J. E. Smith). Application of biological control programmes in the field requires an efficient mass‐rearing system to provide sufficient numbers of beneficial insects. The short longevity of parasitoid adults and limited period of availability of host eggs are two factors affecting the mass‐rearing efficiency of T. remus. Using Spodoptera litura (Fabricius) eggs as an alternative host, the effects of cold storage of S. litura eggs and T. remus adults at 5°C, 8°C and 11°C for different time durations on the fitness of the parasitoid were investigated to identify the most suitable storage conditions. Results showed that T. remus can successfully exploit stored S. litura eggs, but the number of parasitized eggs decreased with increased egg storage duration and/or reduced storage temperature. For refrigerated adults, the survival rate declined gradually with longer storage duration, and the females' survival rate was higher than the males' at any treatment. Similarly, parasitism capacity of stored adults declined significantly with prolonged storage. Female adult longevity was significantly shorter than the control for all treatments. However, the offspring emergence rate and percentage of females were barely affected by cold storage. In conclusion, S. litura eggs can be stored at 11°C for up to 9 days and adult T. remus can be stored at 8°C or 11°C for up to 7 days without significant losses. Data obtained from this study will help coordinate different aspects of T. remus production, decreasing costs and improving the biocontrol materials' availability.