Study On Occurrence Regularity And Establishment Of Green Control Techniques Of Main Summer Corn Pests In Linquan County

In recent years,the pest species,dominant species and occurrence quantity have changed,due to changes in agricultural management and cropping pattern,such as straw burning,decreasing spring corn planting area,increasing summer corn planting area and mixture pattern of spring and summer corn.In this study,we firstly analyzed the occurrence and infestation regularity of major pests on summer corn based on nearly five years of investigation in Linquan county.Secondly,we carried out screening tests for safe and efficacious insecticide against invasive pest Spodoptera frugiperda,aimed to provide guidance on making pest management plans.Finally,considering pest species and their occurrence regularity in Linquan,we put forward a green prevention and control system of corn insect pests.The main research results are as follows:1.It is preliminarily proved that there are 30 species of corn pests in Linquan County,belonging to 2 phyla,3 classes,7 orders and 17 families.Among them,Mythimna separate,Rhopalosiphum maidis,Ostrinia furnacalis,Spodoptera exigua and Spodoptera frugiperda are dominant pests of summer corn in Linquan county.M.separate mainly causes damage on the seedling stage of corn.R.maidis is mainly found during the heading and flowering stage and grain filling and fruiting stage.O.furnacalis mainly damages filling and fruiting stage corn.S.exigua mainly damages seedling stage and jointing stage corn,whereas S.frugiperda mainly damages from seedling stage to the big trumpet stage.2.The annual occurrence of pest populations shows that armyworms are generally stable and moderately occurring,with no obvious differences between years;the occurrence of corn aphid has been increasing year by year since 2018,and moderately occurred in 2020;the overall occurrence of corn borer has decreased The incidence of Spodoptera exigua is on the rise as a whole;the invasive pest Spodoptera frugiperda was first discovered in June2019,with mild damage and a small damage area.3.In the insecticides screening test,field efficacy trials indicated that 4 kinds of pesticides had certain effects for controlling S.frugiperda.Among them,15%Avidin·Indoxacarb had the best control effect,and after 3 days the control effect reached to97.44%,control effect reached to 100% after 7 days.The control effect of 10%tetrachlorantraniliprole and 20% chlorantraniliprole was in the second place,reaching to more than 90% after 7 days,and the biological source was low-toxic and insecticidal.The control effect of 32000IU/mg Bacillus thuringiensis was also more than 60% after 7 days,which can be used as a recommended pesticide for the prevention and control of S.frugiperda.4.A green prevention and control system of summer corn pests in Linquan is put forward.It adopts a variety of pest control methods,like straw crushing and returning to the field,seed treatment,trapping and killing adult insects,protection and utilization of natural enemies,mid-late stage pest management.This pest management system also integrated physical control and biological control,mainly including trapping and biochemical pesticides,supplemented by appropriate chemical control during critical outbreak stages based on accurate forecasting.