Effects Of Green Prevention And Control Technology On Two-migration Of Rice Pests And Their Natural Enemies

The leaffolders Cnaphalocrocis medinalis and rice planthoppers are migratory pests of rice in China.Heavy,perennial yield losses by insect pests have been documented in China,especially by leaffolders and rice planthoppers.The environmentally friendly pest control techniques combine ecological regulation,biological control,physical control and reasonable chemical control to promote safe production of crops and to reduce the usage of pesticides.The effects of enviroumentally friendly pest control techniques on the population of rice migratory pests and their natural enemies were evaluated in Xizhu town,Yixing county,Chenji town,Yizheng county,and Shihe town,Huaian county.Moreover,the toxicity of pymetrozine and dinotefuran mixtures to Nilaparvata lugens to develop a compound for rice planthopper control.The results are as follows.(1)The environmentally friendly pest control techniques(non-chemical control)were evaluated in Xizhu town,Yixing county,Chenji town,Yizheng county and Shihe Town Huai’an county.The LED light trap was used to attract rice planthopper.More,sex pheromone lure and biopesticide,viral insecticide were used to the leaffolder.Rice paddy used chemical pesticides were considered as the control.The results indicated the number of C.medinalis larvae,the mumber of rolled leaves,and the number of C.medinalis moths in non-chemical control rice paddy were significantly lower than the control.The number of rice planthoppers in non-chemical control rice paddy were significantly higher than that of the control.However,it was below the economic threshold.Compared to the control,the number of spiders is higher in in non-chemical control rice paddy.No significant differences in the number of Cyrtorhinus lividipennis were found between non-chemical control rice paddy and the control.The results of the measurement showed that the number of panicles per pan,the number of grains per panicle,and the number of grains per plant in the three experimental plots were higher than that of the control plots,and the actual test yield field per acre was 2.42%-3.63%higher than that of the control plots.It indicated that the environmentally friendly pest control techniques could control the migratory pests of rice and protect their natural enemies when the pest amount of occurrence was not high.(2)Pymetrozine and dinotefuran were dissolved in acetone or in N,N-dimethylformamide Pymetrozine and dinotefuran mixtures were prepared,and rations of pymetrozine to dinotefuran were 1:1,1:2,1:4,4:1 and 2:1.A concentration-mortality relationship was established for each mixture using rice stem dipping method.The co-toxicity coefficients were 1162.24、1543.07、997.74、1430.78 and 2813.04,respectively.The control efficiency of the mixture was better than the single component.The co-toxicity coefficient was 2813.04 in the combination of pymetrozine and dinotefuran in a ratio of 2:1,in which the synergistic effect was the most obvious.The synergy factor is 27.13.