Comparison of Prestorage Heat Treatments on Fifth-Instar Codling Moth (Lepidoptera: Tortricidae) Mortality

The use of combined treatments of heat application followed by cold storage was shown to have potential as a quarantine treatment for 5th instars of codling moth, Cydia pomonella (L.). Larvae were subjected to heat treatments of 38, 42, and 46°C for up to 4 d, 24 h, and 12 h, respectively, alone or followed by cold storage at 0°C for 28 d. Larvae appeared to acclimate to the 38°C treatment. The 42 and 46°C treatments resulted in an increased mortality with increasing temperature and duration of heat treatment. Mortality was greatly increased for all heat treatments when followed by cold storage. Complete mortality was achieved only after exposure to 46°C for 8 h followed by 28 d of cold storage. Combinations of hot and cold treatments could be effective in fruit that tolerate short periods of heat stress and prolonged cold storage, such as apples and pears.