Integrated effect of gamma radiation and temperature on Plodia interpunctella (Lepidoptera: Pyralidae)

The Indian meal moth, Plodia interpunctella (Hubner), is one of the main economic pests of stored products, including dried figs, in Iran and the world. In this research, the effect of different doses of gamma radiation (50-1000 Gy) and temperature (20-35 ± 1 °C) was investigated on the life stages of P. interpunctella. The results showed that P. interpunctella eggs and adults exposed to gamma radiation (50 Gy) died after a short time. Therefore these stages are so sensitive to gamma radiation and were not used for further investigation on a combination of gamma radiation and temperature. In all temperatures, the survival period of larvae significantly decreased with increased radiation doses, especially at 600, 800, and 1000 Gy. Similarly, at 33 and 35 °C, low gamma radiation doses (50, 100, and 200 Gy) caused early larval mortality. In all temperatures, doses of 800 and 1000 Gy of gamma radiation resulted in 100% mortality of pupae; thereby, adult emergence declined to zero. However, in lower radiation doses of 50, 100, and 200 Gy and at 35 °C, the pupal mortality increased to 70, 70, and 83.33%, respectively. Results are promising for the integrated management of P. interpunctella on dried figs in storage.