Studies On Biological Characteristics Of Chrysanthemum Gall Midge And Resistant Mechanism Of Chrysanthemum To Chrysanthemum Gall Midge

This paper includes three parts, the first part is the biology habit of chrysanthemum gall midge (Epiymiu sp.), the second part is the resistance of chrysanthemum to the chrysanthemum gall midge, the third part is the method to control the pest.The chrysanthemum gall midge is field insect pest feed directly on the chrysanthemum. It completes 5 generations per year. In the November, the matured larvae form the gray cocoon and stay in it over the winder in the soil. The next year, the first generation gall appears in May and the number of the gall arrives to its maximum in August and September. The eggs were laid on the tender part of chrysanthemum, which the larvae penetrate into.Fourteen varieties were used to appraise the chrysanthemum' s resistance to chrysanthemum gall midge. Four varieties with high resistance, and four varieties with middle resistance were selected. Analysis of resistance characteristic showed that there was positive correlation between the thickness of leaves, the density of leafpubescence, the number of leaves within the 10cm long of branch and the amount of the gall, while there was negative correlation between it and the phonel content. The volatile oil of the 4 varieties, including one susceptible variety and three resistance varieties, were distilled and sprayed on the one susceptible variety. The result indicates that the laying behavior of the chrysanthemum gall midge is related to the volatile oil on the top of the chrysanthemum. The volatile oil has been analyzed by GC--MS technique and 60 kinds of compounds have been determined.Field trial showed that 10% imidacloprid WP diluted 1000 times, 90% Shachongdan SP 500 times and 48%Chlorpyrifos EC 1000 times have effective control to Epiymiu sp., especially at the early stage of gall.