Population Dynamics of Empoasca onukii and Host Resistance in Tea Production Region in Shaanxi Province
Population dynamics of the small green leafhopper Empoasca onukii Matsuda and spider (the natural enemy of the leafhopper) in Shaanxi tea region and also the resistance to pest of three main tea varieties were evaluated to provide a theoretical reference for the integrated management of E.onukii.The population dynamics of E.onukii and spiders at different layer in three tea varieties were investigated from August 15 to October 20 in 2011 and from March 12 to October 13 in 2012,respectively.The field investigation results showed that the occurrence regularity of adults and nymphs of E.onukii on the tea varieties were single-peak type,the population quantity increased rapidly from mid-July,the annual population of E.onukii reached the peak at the end of July.Further distribution analysis of the population of E.onukii on three kinds of tea varieties showed that the small green leafhopper distributed more at upper layer but less at middle layer and bottom layer.The Fuding and Ziyang varieties possess higher resistance to the small green leafhopper than Nanjiang variety.The population quantity of E.onukii and spiders were positively correlated in Ziyang (R=0.716,P<0.001),Fuding (R=0.476,P=0.007) and Nanjiang (R=0.652,P<0.001).The occurrence regularity of Empoasca onukii was single-peak type in Shaanxi tea region,Ziyang and Fuding varieties had excellent resistance to pests,spiders had obvious following effect to the small green leafhopper.