Abstract:By laboratory feeding experiments and biochemistry detection methods, the nutrition substances of three kinds of host plant (sugar beet, maize and cucumber) were detected, and the effects of these host plants on development and oviposition of beet armyworm Spodoptera exigua (Hübner), total amino acid contents and the digestive enzyme activities in the 5th instar larvae were compared. It showed that comparing with those fed on maize and cucumber, S.exigua individuals fed on sugar beet had shorter larval and pupal periods, higher pupal survival rate, longer adult lifespan and laid significantly more eggs per female, which was 11.4d, 5.6d, 100%, 26.3d, 301.8 eggs respectively. Among the three feeding treatments, the protein contents in the 5th instar S.exigua larvae showed no significant difference, whereas total amino acid contents, amylase and lipase activities differed significantly. According to the host plants, the amylase and lipase activities in S.exigua ranked as maize>sugar beet>cucumber. It also showed positive correlation between larval development and amylase and lipase activities in S.exigua feeding on different host plants.