Effect Of Microwave On Ephestia Elutella(Hübner) And Economic Threshold

Tobacco is an important economic crop in the world,but it is vulnerable to pests during storage,Ephestia elutella(Hübner)is one of the most serious tobacco storage pests.The study of biological characteristics,microwave control,and economic threshold of E.elutella is beneficial to scientific storage of tobacco,green and efficient control of this pest.In this paper,the insecticidal effect of microwave on E.elutella hidden in primary flue-cured tobacco leaves was studied by treating the eggs,larvae,and pupae of E.elutella with microwave equipment at different times and power.An artificial climate incubator was used to simulate warehouse environment,in total darkness,20±1℃,75±5%relative humidity conditions,the morphological features,life habits,and the feeding characters of the larvae were studied.The feeding amount,feeding leaf area,and the pollution to tobacco leaf by excretion of E.elutella in each instar at different larval densities were studied.The main results are as follows:The egg stage was 7.90±0.99 d,larval stage was 81.67±3.55 d,pupal stage was 15.93±1.44 d,pre-oviposition stage was 2.97±0.76 d,and the generation duration was 108.47±4.67 d.The head shell widths of the 1st to 6th instar larvae increased with the stadium increasing.When the microwave power and treatment time were 4 k W,220 s;5 k W,190 s;6k W and 170 s,the eggs,1st to 6th instar larvae,and pupae were killed100%,and the quality of tobacco leaves was not affected.There were two kinds of economic losses caused by larvae of E.elutella,direct economic losses and indirect economic losses.The indirect economic losses were much higher than the direct economic losses under all different larval densities.The economic loss rate caused by one larva was 0.40%,and the economic threshold was 3.04 larvae per one kg tobacco by using microwave oven.The results showed that E.elutella had a longer generation duration and could harm tobacco leaves for a long time in the storage environment.Microwave can be used to control E.elutella,the best microwave power and treatment time is 6k W and 170 s.According to the economic threshold obtained in this paper,we suggested the economic threshold of microwave control was three larvae per one kilogram tobacco.