| With the increase of rice varieties and the increase of cultivation system in Jiangdu district of Yangzhou City,and the impact of global warming,the number of outbreaks of Cnaphalocrocis medinalis,one of the "two-shifted" pests in Jiangdu district,has increased in recent years,and the damage period has been extended.This will seriously affect the normal growth and development of rice in this region,which in turn will have an impact on rice yield.In order to improve the damage status of C.medinalis in this district and provide scientific basis for prevention and control of its occurrence,in this study the author systematically investigated the occurrence dynamics of C.medinalis in Jiangdu district from 2015 to 2017,and it was also analyzed by combining it with 2008?2014 data from under light;at the same time,the resistance of C.medinalis in the Jiangdu district was monitored,and the commonly used pesticides were screened.Finally,green control was proposed for the control of C.medinalis in the Jiangdu district.The results are summarized as follows:1.The number of light-trapping moths in Jiangdu district from 2008 to 2017 was analyzed.The result demonstrated although moths of C.medinalis were found under light at different times every year,the moths of C.medinalis occurred mostly around August 30,which was the sixth(four)generation.Therefore,the C.medinalis from the sixth(four)generation was mainly damaged generation,and the number of C.medinalis moths has been increasing year by year.2.The results of pesticide resistance monitoring of C.medinalis in the Jiangdu district showed that the LC50 of coragen in Jiangdu district was 1.1323 g/L in 2018,and the resistance was about 125 times,which was a high resistance level.The LC50 of chlorpyrifos was 7.7954 g/L,the resistance was about 25 times,and it was medium resistance.The LC50 of avermectin was 0.2135 g/L and about a resistance of 25 times,which was a medium resistance level.The LC50 of emamectin benzoate was 4.7211 g/L,and the resistance was about 10 times,which was a low resistance level.Therefore,it was recommended that the future medication should consider the mixing of the medicaments and the rotation of the medicaments.3.According to the screening results of the C.medinalis,it was concluded that in terms of control effect,methoxyfenozide had the best effect of controlling C.medinalis,and the control effect of emamectin on benzoate was the worst.The effect of leaf retention from high to low was:methoxyfenozide>coragen>indoxacarb>spinetoram>emamectin benzoate.In addition to emamectin benzoate,the other effects were the similar,and the number of rolled leaves in the plot treated with methoxamide was only 2.10,and no residual larvae of rice leaf roller were found.However,the C.medinalis is an explosive migration insect,and the population comes from many regions.Therefore,we should always pay attention to the number of C.medinalis transplanted into the Jiangdu district.And we should timely grasp the used situation of pesticides in the emigration area,between the immigration area and the emigration area,between the immigration generation and the local reproduction generation,using different interaction mechanisms and without cross-resistant pesticides to achieve optimal control of C.medinalis.4.For the moment,in addition to chemical control,other prevention and control measures should be activated to control the density of insect populations in the Jiangdu district.For example,weeds are removed from the field to reduce the number of C.medinalis.The phototaxis of C.medinalis aduls can be used to control pests.In addition,we should also promote the promotion of green prevention and control,such as establishing organizations,conscientiously summarization,formulating prevention strategies,strengthening publicity,and popularizing technologies to achieve promotion purposes. |
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