Effects Of Different Temperatures And Host Plants On Growth Development And Metabolization Enzyme Activity Of Beet Armyworm, Spodoptera Exigua (Hübner)

Beet armyworm, Spodoptera exigua (Hübner) is one of world-wild polyphagous pest insects and broke out intermittently in China. It has characteristics of wide distribute range, many host plants, strong ability of migration and dispersal, liking warm and ability of abiding high temperature. In this study, first of all artificial raise of S. exigua was groped. On the basis of the characteristics of biology and ecology of S. exigua, effects of different temperatures and host plants on growth development and reproduction of S. exigua were studied. Main results were as follows:1. Developmental periods of eggs, larvae and pupae were decreased significantly with increasing temperatures within the range of 20-35℃,. Temperature range in which the beet armyworm can be best growth and development is from 23 to 32℃.2. Temperature effected not only the developmental periods of S. exigua, but also egg hatching, larval survival, pupation rate, adult emerging rate and laying egg number. 26-29℃was the most suitable for development and production to S. exigua. Egg hatching, survival of larva, pupation rate, rate of adults emerged, eggs laid in higher temperature or lower temperatures were lower.3. The effect 10 kinds of host plants on development and production to S. exigua were different. The nutrition effect of artificial diet is the best to S. exigua, the development periods were the shortest; survival of larva, rate of adults emerged and eggs laid were the highest. Followed by Lactuca Sativa > Cucumis sativus > Chrysanthemum coronarium > Medicago sativa > Amaranthus viridis > Raphanus sativus > Brassica campestris > Triticum aestivum > Zea mays.4. The effect of temperatures on protection enzymes of S. exigua showed that Activity of protection enzymes at 32-35℃declined with temperature rising; activity of protection enzymes at 20-23℃declined rapidly with temperature falling. Close correlation was found between protection enzymes and values of higher and lower temperatures. The scale of better temperature was 23-32℃, the range of best temperature was 26-29℃.5. The activity of ACP, AKP, AChE and GSTs of S. exigua fed on different host plants were measured, and the result showed that host plants affected the activity of enzymes significantly. The ACP activity sequence was Raphanus sativus > Medicago sativa > Amaranthus viridis > Cucumis sativus > Brassica campestris > artificial diet > Lactuca sativa > Zea mays > Chrysanthemum coronarium > Triticum aestivum; the AKP activity sequence was Medicago sativa > Amaranthus viridis > Cucumis sativus > Raphanus sativus > Brassica campestris > Lactuca sativa > Triticum aestivum > Artificial diet > Zea mays > Chrysanthemum coronarium; the AChE activity sequence was Artificial diet > Cucumis sativus > Brassica campestris > Raphanus sativus > Chrysanthemum coronarium > Lactuca Sativa > Medicago sativa > Amaranthus viridis > Triticum aestivum > Zea mays; the GSTs activity sequence was Lactuca sativa > artificial diet > Cucumis sativus > Medicago sativa > Raphanus sativus > Brassica campestris > Amaranthus viridis > Chrysanthemum coronarium > Triticum aestivum > Zea mays.