| In this paper, there are three main research items: first, the major changes of the number of pests and natural enemies on cover crops+ cabbage. The second is the arthropod community structure and dynamics research on cover crops+ cabbage. The third is trapping on the Spodoptera litura moth with synthetic sex pheromone lures and control efficacy in the field. All the researches can provide the basis for ecosystem of pest's control and management with scientism data .The results are as follow(1)The pests and natural enemies of the main quantitative analysis on cover crops+ cabbageTwo years of datas show the main insect pests of cover crops+ cabbage belongs to Bruchidae,Ciccadellidae,Aphidian,Eysacoris,Pieridae,Chrysomeloidae. Aphididae,Chrysomeloidae,Pieris rapae and Plutella xylostella rapae is the major pest on cover crops+ cabbage. We can see that Pieris rapae, Plutella xylostella rapae and aphids on cover crops+ cabbage are was significantly lower than the control group. The main natural enemies of insects types of cabbage belong to Anthocoridae,Coccinellidae,Syrphidae and spider-type.Coccinellidae including Propylaea japonica,Coccinella septempunctata and Harmonia axyridis . There are significant differences between Cover crops + cabbage and CK+ cabbage on the natural enemies. more and more Aphidiidae,,ladybug,orb weaver and the ball round spider appeared on cover crops+ cabbage, but the wolf spider and brown Clubiona like to appear on CK + cabbage.(2)The analysis of community structure and dynamicCompared to arthropod community of on the control group, we can see there are more species richness, relatively stable, and diverse types of pest sub-community on cover crops+ cabbage. The characteristics of arthropod community---- H′(Shannon-Winner),S(Species numbers),R(Species richness)and J (Pielou)are greater than the CK group, but D(dominance),C(Dominant concentration),N(number)are less than the control group. In general, if D is larger, then C is also larger, and H ',J are lower than CK + cabbage ,the stability of communities are more poorer. This also shows that there are more balanced distribution, more reasonable community structure and more competitive in the mutual inter-population balance on HMC+ cabbage, CD+ cabbage, MU +cabbage .The component analysis on the total arthropod community shows that the Aphididae,Pieris rapae and Plutella xylostella rapae,Various types of natural predators(especially spiders category and Coccinellidae)'s contribution are large than others on cover crops+ cabbage. But on CK group Pieris rapae and Plutella xylostella rapae,Aphididae,spider-type(especially the wolf spider and brown Clubiona ) and Aphidiidae's contribution are large than others.(3) Trapping on the Spodoptera litura moth with synthetic sex pheromone lures and control efficacy in the fieldIn 2004,2005,2006 and 2007, at Hexian, the dynamics of the Spodoptera litura moth was investigated by mass trapping with synthetic sex pheromone lure, and the control efficacy in the field was conducted based on occurring time of the 1-2 instar larvae in the field predicted from the moth peak day in 2004. The results showed that in 2004, there were four moth peak times, with moth catches per trap per day being 7.917±0.882,19.333±8.55,22.113±6.95 and 36.387±10.1 ,respectively. The peak day was July 2,July 30, August 25 and September 12, respectively, and the number of moth trapped at peak days was 12.33,31.67,39.00 and 56.67 (capita per trap ) ,respectively. In 2005, there were four moth peak times too, with moth catches per trap per day being 2.267±0.546,20.75±12.4,24.89±14.1and 19.80±0.757, respectively. The peak day was June 1, June 30, August 1 and September 27, respectively, and the number of moth trapped at peak days was 5.00, 37.33, 37.00 and 105.00, respectively. In 2006, only two moth peak times were occurring, with moth catches per trap per day being 7.60±2.02,3.33±0.88, respectively. The peak day was June 2 and July 21, respectively, and the number of moth trapped at peak days was 12.00and 3.67, respectively. In 2007, there were three moth peak times, with moth catches per trap per day being 2.813±0.0.66,11.08±1.46 and 20.17±9.63, respectively. The peak day was June 2, July 10 and August 17, respectively, and the number of moth trapped at peak days was 3.67, 26.00 and 38.00, respectively. Field experiment confirmed that after 4 days application, the control efficacy of KKY400×, KKY500×+Leili 2000 and Anda was 83.6%,75.8% and 88%, respectively. These measures can control the population number of Spodoptera litura larva, and the Leili 2000 has significant affection of increasing efficacy.
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