Occurrence Dynamics And Green Control Technologies Of Chilo Suppressalis In Rudong County

China is a large agricultural country,and rice crop is one of the most important agricultural products in China.A series of rice issues such as rice cultivation,growth and yield have been the focus of agricultural research.The rice stem borer,Chilo suppressalis(Walker),is one of the most serious rice pests in Asia,Middle East and southern Europe.Due to the large-scale cultivation of hybrid rice and the change of environment and climate,outbreaks of the rice stem borer have occurred more frequently in recent years,especially in Yangtze River basin as well as Jiangsu and Zhejiang coastal areas.As a member of the southern rice-growing region,Rudong County in Jiangsu province is a large rice-growing county with a rice area of 820,000 mu and a long history of rice farming.Rudong is famous for its rice brands such as"Rudong Rice".In this paper,the occurrence dynamics and green control techniques of the rice stem borer in Rudong County were studied.A field investigation on the overwintering rice stem borer during 2016-2020 in Rudong County showed that the number of overwintering rice stem borer was not evenly distributed in different fields and decreased year by year.From 2016 to 2020,the first-generation of the rice stem borer mainly occurred in late June and early and middle July with varied damage in different fields.The second generation of the rice stem borer reached its peak in the middle and late August.In general,the damage caused by the first generation of the rice stem borer is more serious than that of the second generation,and the damage rate of the first and second generation of the rice stem borer decreased year by year from 2016,reaching the lowest value in 2020.To provide basis for chemical control of the rice stem borer,ten kinds of insecticides were used and control experiments were carried out.The results showed that the seedling protection effect and insecticidal effect of three treatments including 10 mL 20%chlorantraniliprole suspension concentrate(SC),30 mL 10%flubendiamide·abamectin SC and 40 mL 10%tetrachlorantraniliprole SC were higher than 95%,treatments including 50 g 20%dinotefuran water soluble granule(SG),50 mL 10%abamectin·methoxyfenozide SC,80 mL 3 billion PIB/ml Maestro brassica L.NPV SC had the seedling protection effect and insecticidal effect of more than 90%,whereas the control effects of four treatments including 24%methoxyfenozide SC,20%abamectin·diazinon emulsifiable concentrate(EC),16000IU/mL Bacillus thuringiensis wettable powder(WP)and 10 billion spores/mL Empedobacter breves SC were less than 80%.In addition to chemical control,the control effects of Trichogramma japonicum Ashmead and vetiver grass were also studied.Compared with chemical control,the control effect of Trichogramma japonicum Ashmead was more than 80%,and that of vetiver grass was more than 70%.While the biological control effect is relatively lower,the sustainability of the biological control is better than that of the chemical control,which has a certain guiding significance for green control of the rice stem borer.In order to improve the efficiency of agriculture and increase the income of farmers,the green control of the rice stem borer in Rudong County needs to promote the integrated control measures which include agricultural control,biological control and chemical control,expand the coverage rate of key technologies,reduce the use of pesticides.These measures will ensure the high and stable yield of rice in Rudong County.