Effect of microwave on different stages of dates moth, Ephestia cautella (Walker) (Lepidoptera: Pyralidae) in stored dates
Abstract: Dates moth (fig moth), Ephestia cautella (Walker) is a major pest in storage and dates on the market. Eggs, larvae, pupae and adults of date moth E. cautella were exposed to three levels of microwave power (600, 800 and 1000 watts) at different exposure time (0, 6, 8, 10, 12, 14, 16, 18 and 20 seconds). The results showed that microwave had high ability to kill different stages of date moth. The effect increased by increasing of microwave power and exposure time. The percentage of egg mortality was 100% at 600 and 800 W, and 14 sec exposure time. Similarly, eggs mortality was also high at 1000 W, but in less than 12 sec. The highest mortality of larvae was 90% at 600 W and 96.7% at 800 W, when the exposure time was 10 sec The mortality was 100% at 1000 W and exposure time was 10 sec Male and female pupal mortality rate was 100% at 800 W, and 20 or 18 sec respectively. The range of lethal time of 50% and 95% (LT50, LT95) at 600-1000 W were 5.01-9.9 and 15.7-34.2, 3.0-7.5 and 9.0-50.0 and 3.2-4.8 and 7.9-39.1 for egg, larvae and pupae respectively. The results showed that all treatments of adults significantly affected longevity and emergence of adult male and female. The longevity of emerged males and females did not exceeded 4.3 and 5.3 days, respectively at 600 W and 6 sec whereas emerging of adults stopped at 800 W and 14 and 16 sec, for male and female pupae, respectively. The results of this investigation indicated the feasibility of microwave technique and could be used as alternative to methyl bromide in stored dates.