Effects of Temperature on the Development of Ephestia cautella (Walker) (Pyralidae: Lepidoptera): A Case Study for its Possible Control Under Storage Conditions

Abstract

Ephestia cautella (Walker) is a serious pest of dates both in the field and under storage conditions. The control of stored product pests and especially those of food products by manipulating temperature would be the best and safe choice. In this study, we examined the effects of temperature on developmental traits of E. cautella under laboratory conditions. For this study, newly hatched E. cautella larvae were reared at 25°C and 35°C, with 65 ± 5% relative humidity and a photoperiod of 15:9 (L:D). Biological parameters studied were: number and duration of larval instars; survival rate of larvae, pupae, and adults; total life span; and fecundity and fertility. Temperature had a significant impact on E. cautella development. At 5°C, there was 100% mortality; eggs failed to hatch, and no larval or pupal survival was observed. On the other hand, E. cautella pupated after five larval instars at 25°C while six instars were observed at 35°C. The larval period significantly increased at 35°C. However, total lifespan of both sexes was considerably longer at 25°C. Of the three temperatures studied, 25°C was highly favorable for fecundity, egg hatchability, and overall survival of all life stages. Complete mortality at 5°C indicated that storage at lower temperatures can prevent the storage losses inflicted by E. cautella.