Impact of extreme temperatures on Ectomyelois ceratoniae (Zeller, 1839) (Lepidoptera: Pyralidae) and their potential for pest management in food storage

In food storage, pest disinfestation can be achieved by applying high or low temperatures that modify the environment beyond pest-critical thresholds. The carob moth, Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) is a thermophilic species that can develop on fruits of several host plants, making damage in both field and post-harvest conditions. Identifying thermal survival thresholds can aid in developing post-harvest control strategies for this pest. This study examined lethal and sublethal effects of extreme temperatures on E. ceratoniae larvae through laboratory dose–response experiments. Following an exposure of 2 h, complete mortality of mature larvae was achieved at 47.9 °C or higher, or at −12.9 °C or lower. The temperature causing 50 % larval mortality was about 45 °C under heat exposure, and between −7.3 °C and −8.7 °C under cold exposure, depending on the assessment time. Larvae with lower body mass and scaled mass index exhibited higher mortality rates compared to those with higher scores. Treated larvae that survived heat or cold exposure showed temperature-dependent body mass changes, increasing under moderate conditions and decreasing at extreme temperatures. Temperature had no significant delayed sublethal effects on pupal duration or adult lifespan in larvae surviving extreme exposures. A higher delayed pre-adult mortality occurred in insects exposed to −10.0 °C, −7.5 °C, and 45.0 °C compared to those subjected to milder temperature regimes. This study highlights the lethal and delayed sublethal effects of extreme temperatures on mature E. ceratoniae larvae, highlighting their relevance for improving pest management in food storage.