The Relationship Between Arthropod Diversity And Pest Occurrences In Different Tea Plantations

A systematical investigation on the arthropod community was carried out in five tea plantations in the ChengJia town,PuJiang district from Aug.2007 to Jul.2008:the pure tea plantation,the cinnamon-tea intercrop,pear-tea intercrop,pine-tea intercrop and the pine surrounding tea plantation.By the analysis on principal component and clustering the structure of arthropod community,occurrence dynamics,the relationship between arthropod diversity and pest occurrence in the five tea plantations were concluded as follows:1.In five different tea plantations there were in total 3546 individuals of arthropods, belonging to 97 species of 66 families of 14 order of two classes.Among them,2913 individuals were pests,belonging to 46 species of 32 families of 8 order of two classes; 587 individuals were natural enemies,belonging to 37 species of 23 families of 9 order of two classes;46 individuals were natural insects,belonging to 15 species of 14 families of 7 order of two classes.2.The Principal Component Analysis showed that there are differences in the species of the main pests in the five tea plantations.The main pests in the pine surrounding tea plantation are Oligonychus coffeae(Nietner),Pinnaspis theae,Thosea sinensis,Empoasca flavescens(Fabricius);In the pine-tea intercrop are Empoasca flavescens(Fabricius), Polyphagotarsonemus latus;In the pure tea plantation are Polyphagotarsonemus latus,Ectropis oblique,Clania minuscule Butler;In the pear-tea intercrop are Ceisha distinctissima(Walker),Anomala corpulenta,Clania variegate,Hypomeces squamosus Fabricius,Phlossa fasciata;and in the cinnamon-tea intercrop are Ectropis oblique, Ceroplastes ceriferus(Anderson),Icerya purchasi Maskell,Aspidiotus destructor, Polyphagotarsonemus latus.3.The results of the order of arthropods'population parameters in different plantations showed that,[1]the species:the pear-tea intercrop＞the pine surrounding tea plantation＞the cinnamon-tea intercrop＞the pure tea plantation＞the pine-tea intercrop;[2]the diversity index:the pear-tea intercrop＞the cinnamon-tea intercrop＞the pine surrounding tea plantation＞the pine-tea intercrop＞the pure tea plantation;[3]the evenness index:the cinnamon-tea intercrop＞the pear-tea intercrop＞the pine-tea intercrop＞the pine surrounding tea plantation＞the pure tea plantation;[4]the dominance index:the pure tea plantation＞the pine surrounding tea plantation＞the pine-tea intercrop＞the cinnamon-tea intercrop＞the pear-tea intercrop;[5]the dominance index of the population:the pure tea plantation＞the pine-tea intercrop＞the pine surrounding tea plantation＞the cinnamon-tea intercrop＞the pear-tea intercrop;[6]the individuals:the pure tea plantation＞the pine surrounding tea plantation＞the pear-tea intercrop＞the cinnamon-tea intercrop＞the pinetea intercrop.4.The comprehensive index contributes to discuss the relationship between diversity and stability theoretically.the order of comprehensive index in the method of principal component indicated that,about the diversity of the arthropods in the plantations,the pear-tea intercrop＞the cinnamon-tea intercrop＞the pine-tea intercrop＞the pine surrounding tea plantation＞the pure tea plantation;for the relatively stability of the arthropod population:the pear-tea intercrop＞the cinnamon-tea intercrop＞the pine-tea intercrop＞the pine surrounding tea plantation＞the pure tea plantation;the order of the pests' harm to the plantations:the pure tea plantation＞the pine surrounding tea plantation＞the pine-tea intercrop＞the cinnamon-tea intercrop＞the pear-tea intercrop The diversity of the arthropod in the plantations is positively correlated with stability,negatively correlated with the pests'occurrence.comparing the pear-tea intercrop, the cinnamon tea intercrop to the pure tea plantation,arthropod population are of good diversity and stability,also the low comprehensive index of the pests' occurrence. So the cinnamon tea intercrop and the pear-tea intercrop are good intercrop pattern.5.The order of the comprehensive index of natural enemies is the same as the order of the comprehensive index of the diversity and the stability,but contrary to the order of the comprehensive index of the pests'occurrence.Further indicated that the higher the diversity of the arthropod,the stronger the restricting power of the natural enemies,the more stable the plantation system,the lower the pests' harm to the plantation.