Effect of varying temperatures on in vitro parasitization efficiency and adult emergence of Trichogramma japonicum (Ashmed)

Abstract

The present experiment was conducted in the Biocontrol laboratory, SKS CARS, Surgi, Rajnandgaon (C.G.) during the years 2023-24 and 2024-25 on effect of varying temperatures (0 °C, 4 °C, and room temperature) on the in-vitro parasitizing efficiency and adult emergence of Trichogramma japonicum. According to the findings, the highest parasitization and emergence rates were recorded in the 1st week across all temperatures, followed by a significant decline. At 0 °C, activity of parasitoids ceased after the 2nd week, indicating poor viability at this temperature. Room temperature supported only short-term viability, with complete loss of parasitization and emergence after the 1st week. In contrast, 4 °C maintained moderate levels of parasitization and emergence over the 10-week period, though both declined gradually with time. These results suggest that 4 °C is the most suitable temperature for extended storage of T. japonicum.