Behavior of Trichogramma pretiosum Exposed to Extreme Temperatures for Different Periods on Ephestia Kuehniella (Zeller)

Abstract

Biological control is essential in modern agriculture, as it suppresses pest populations, minimizing dependence on chemical pesticides, and safeguarding ecosystem services. Multiple biological control strategies can be combined with agronomic pest management measures. Among them, parasitoids are a viable alternative, as they prevent insect pest eggs from hatching, preventing damage from a new population. To evaluate the control potential of parasitic wasps under adverse environmental conditions in the field, this study examined the biological characteristics of trichogrammatids under different temperatures. Therefore, the objective of this study was to evaluate the biological characteristics of a species/strain of Trichogramma pretiosum (Hymenoptera, Trichogrammatidae) under different temperature regimes for different periods. At extreme temperatures of 18°C and 30°C, female Trichogrammatidae showed inactivity for at least 4 hours, and continued to be inactive for a period of time after returning to the ideal temperature (25°C), indicating that their adaptability to temperature changes is weak. The T. pretiosum needs time to adapt to changing environmental conditions. Taken together, the results indicate that abrupt climate-related temperature variations can temporarily impair parasitoid performance, highlighting the need to adjust release strategies to maintain effective biological control in the face of ongoing global warming.