Optimization of short and long term storage duration for Trichogramma chilonis (Ishii) (Hymenoptera: Trichogrammatidae) at low temperatures.

Abstract

Efficient storage of the biological control agent is critical for commercial production. The purpose of this study is to assess the suitable storage temperature and duration for an important egg parasitoid, Trichogramma chilonis (Ishii) (Hymenoptera: Trichogrammatidae). The fitness life parameters of T. chilonis such as percent emergence, percent parasitism and adult longevity were investigated under laboratory conditions after stored at six constant temperatures (6, 8, 10, 12, 14 and 16°C ) for various storage durations (5, 10, 15, 20, 25, 30, 40, 50, 60, 70, 80 and 90 days) in incubators. Highest (96.6%) T. chilonis emergence recorded at 10 o C after 5 days storage and was similar to control (97.4%). However, emergence was reduced up to 22.8% at 10 o C after 90 days storage. The parasitism was highest (97.4%) at 10 o C after being kept for 5 days storage and was decreased to 42.2% at 10 o C when stored for 90 days at same temperature. Adult longevity was decreased from 6.3 to 3.0 days when stored at 10 o C from 5 to 90 days respectively. At 6 o C, T. chilonis development was completed only after 25 days storage whereas, at 12, 14 and 16 o C conditions, development were completed during storage hence these temperatures proved for short term storage. It was evident that, storage at 10 o C was very conducive for life parameters of T. chilonis to get short and long