Investigation methods for population size of Eriosoma lanigerum in the orchard

Author of the article:SUN L-i Ning1** , TAN Xiu-Mei1 , ZHOU Hong-Xu1*** , GU Song-Dong1 , GUO Jian-Ying2, WAN Fang-Hao2

Author's Workplace：1. College of Plant Protection, Qingdao Agriculture University , Qingdao 266109, China; 2. State Key Laboratory for Biology of Plant Diseases and Insect Pests , I nstitute of Plant Pr otection, Chinese Academy of Agricultural Sciences, Beijing 100094, China

Key Words：Eriosoma lanigerum, population, investigation methods, Aphelinus mali

Abstract：Laiyang, Shandong from middle June to late October in 2007. Numbers and area of colonies in 5 fixed apple trees were investigated, and 20 randomly selected colonies from other apple trees were checked to count the average number of living E. lanigerum in per squared centimeter of the colony. The results showed that it was an accurate method to present the population size of E. lanigerum by the area of the colonies and the averaged density of alive and ex cluding the parasitized E . lanigerum in the colonies. Thus parasitization of E . lanigerum by Aphelinus mali were excluded.