Investigation On The Damage Of Cylas Formicarius In Sweet Potato Producing Areas Of Guangxi And Study On Control Strategy

Sweet potato(Ipomoea botatas(L.)Lam.)is an important grain and feed crop in Guangxi.Sweet potato weevil(Cylas formicarius)is one of the main pests of sweet potato tuber root,which has a serious impact on the quality and yield of sweet potato and restricts the development of sweet potato industry in Guangxi.It is unclear whether the occurrence rules of sweet potato production areas in guangxi and the pest occurrence,In view of this,this paper selected 13 sweet potato producing areas in Guangxi as the investigation sites,from five aspects of different varieties,field management,origin,month and planting season to clarify the occurrence and distribution of sweet potato weevil and its harm to potato pieces,and explore the epidemic law of the insect.At the same time,through a questionnaire survey of local growers,it was found that there were prominent problems in the sweet potato weevil control in guangxi sweet potato producing areas,and carried out field tests on the control effectiveness of plant derived agents,in order to explore effective prevention and control countermeasures,to improve the sweet potato production and promote the sustainable development of guangxi sweet potato industry is of great significance.This paper adopts literature research method,field investigation method,questionnaire survey method,comprehensive analysis method and field control effect test method to carry out research.The main results are as follows:1.The pest situation of sweet potato weevil was different in different sweet potato varieties and field management.The damage of sweet potato weevil to Gui-jing Potato No.8 was relatively light,and the average pest index of sweet potato was 22.16,while the damage to Gui-wei potato No.1 was the most serious,and the average pest index of sweet potato was 53.68.In the same variety,the damage degree of sweet potato weevil to single row potato in small row was higher than that to single row potato and double row potato in large row.Compared with oblique insertion,flat insertion was more harmful to sweet potato weevil.In general,the harm of sweet potato weevil to the potato block treated with drugs was relatively light.Except for thiamethoxam,the other drugs had control effects on sweet potato weevil,but the overall efficacy was not good,and still did not reach the ideal state.2.The occurrence and insect pests of sweet potato weevil in different producing areas,months and planting seasons in Guangxi sweet potato producing areas were different.Small sweet potato weevil occurs in all producing areas of Guangxi,and the damage of small sweet potato weevil is more serious in hillside planting areas and high temperature and drought weather.From March,sweet potato weevil occurred sporadically.From April to September,the occurrence and damage of sweet potato weevil became more and more serious as the temperature gradually increased,and the average pest index of potato block showed a rapid increase trend.The damage degree of sweet potato weevil to summer potato chips was higher than that to autumn and winter potato chips.3.The results of field test showed that 70% pyrethrin emulsion 5000 times solution and 1% azadirachtin emulsion 2000 times solution had obvious control effect on sweet potato weevil.The control effect on Pushu32 was 83.05% and69.53%,and on Sweet potato 1 was 75.97% and 64.89%,respectively.4.Through the analysis of field and questionnaire survey results,it was found that there were some problems in the control of sweet potato weevil in Guangxi.Such as: lack of quarantine awareness,quarantine technology is not perfect,insect-resistant varieties selection strength is small,unreasonable farming,extensive field management,cleaning the countryside is not timely,medication awareness is weak,medication is not timely,drug is not safe and efficacy is not good.In view of the problems existing in the investigation of sweet potato weevil infestation in sweet potato producing areas,combined with the research results,this paper proposed relevant prevention and control countermeasures from quarantine,agriculture and pharmaceutical aspects,to provide theoretical basis for the sustainable development of sweet potato industry in Guangxi.