Preliminary Study On Forest Insect Diversity And Risk Analysis Of Main Pets In Jintang County,Sichuan Province

With the implementation of natural forest resources protection project,returning farmland to forest project and Longquan Mountain ecological vegetation restoration project,the forest insect species in Jintang county has changed greatly.The forest insect species database of Jintang county was established and improved by the route survey and sample-plot survey.The harmful insects of Coleoptera with the largest proportion of the number of families and species were taken as the sample to carry out the biodiversity research and to understand the occurrence rules of forest insects.The risk of some forest pests with wide distribution and large occurrence area was analyzed,which provided basic data for prevention and control in the future.The main conclusions are as follows:(1)The survey of forest insects showed: there were 91 species of forest insects including 46 families and 6 orders,of which 14 were natural enemies and 77 were harmful insects covering 39 families and 5 orders in Jintang county.Coleoptera insets accounted for 48% of the total number of species and 39% of the total number of families.Batocera horsfieldi,Monochamus alternatus,Dyscerus cribripennis,Sympiezomias velatus,Anoplophora chinensis,Cyrtotrachelus thompsoni,Cyrtotrachelus buqueti and Mesoneura rufonota are the more serious harmful insects with frequent or sudden occurrence in the local area,while Corythucha ciliata and Leptocybe invasa are the foreign harmful insects.(2)The study on biodiversity of harmful coleoptera insects with the largest proportion of families and species shows 4 conclusion.First,the species and individual numbers are relatively abundant in the family Cerambycidae and Curculionidae in terms of community structure.Second,the overall change in the time sequence of the number of individuals presented a parabolic trend: July > June > August > May > April > October.Third,Shannon-wiener index reached its peak in July but Berger-Parker dominance index is completely opposite.Pielou evenness index is highest in May and the pecies richness indexes is highest in July.Fourth,the number and species of individuals at different altitudes all increased first and then decreased.The number and species of individuals at altitudes of 600～800m were the largest.(3)The risk analysis of Leptocybe invasa,Monochamus alternatus,Dyscerus cribripennis and Corythucha ciliata forest pests with wide distribution and large occurrence area was carried out.The risk R value of Leptocybe invasa was 1.48,indicating low risk.The risk R value of Monochamus alternatus was 1.57,indicating the moderate risk type.The risk R value of Dyscerus cribripennis was 1.75,indicating the moderate risk type.The risk R of Corythucha ciliata was 1.87,indicating the moderate risk category.In short,the abundant forest resources and suitable climatic conditions in Jintang county provide favorable conditions for the growth and reproduction of forest insects.There are a large amount of harmful insect species and Coleoptera are the maximum number but there are few dangerous ones.It is found that the number of insect community is related to the occurrence time,temperature,altitude and habitat.The risk analysis of four kinds of forest pests reminds us to strengthen forest pest monitoring and control measures.