两种杀虫真菌制剂对茶小绿叶蝉的田间防效评价

Efficacy of emulsifiable formulations of two entomopathogenic fungi against small green leafhoppers on tea plant.

于 2 0 0 2年盛夏在浙江遂昌一高山茶园对茶小绿叶蝉 (Empoascaspp )进行了真菌杀虫剂的田间药效试验 .所用菌剂为球孢白僵菌 (Beauveriabassiana)和玫烟色拟青霉 (Paecilomycesfumosoroseus)的纯孢子悬乳剂及其与 3%吡虫啉 10 %可湿剂的混配剂 .各菌剂稀释 5 0 0倍喷雾 2次 ,间隔 12d .结果表明 ,两种真菌的混配剂明显优于纯菌剂 ,其中球孢白僵菌混配剂的最高防效达 83 4 % ,而玫烟色拟青霉的最高防效为 71 3% .根据 2 5d期间历次调查结果计算平均防效 ,球孢白僵菌混配剂达 6 6 8% ,玫烟色拟青霉混配剂为 6 2 1% ,含微量吡虫啉的矿物油为 5 0 3% ,球孢白僵菌和玫烟色拟青霉的纯菌剂分别为 4 9 5 %和19 0 % .结合试验期间气候及田间种群结构特征 。

A field trial was conducted to test the efficacy of emulsifiable formulations of Beauveria bassiana (Bb) and Paecilomyces fumosoroseus (Pf) conidia in controlling small green leafhoppers (Empoasca spp.) on tea plant in a hillside tea garden located in Shuichang,Zhejiang during mid-summer 2002.Both Bb and Pf formulations contained 10 10 conidia·ml -1.Adding 3% of imidacloprid 10% WP to each fungal formulation (W/V) resulted in two other formulations,i.e.,Bb-imidacloprid mixture (BbIM) and Pf-imidacloprid mixture (PfIM).Besides the four formulations,a mineral oil-based liquid used to formulate the fungal conidia and containing 3% of imidacloprid 10% WP (OBLI) was also tested,and water spray was used as control (CK).Each of the treatments included three 60-m 2 plots (replicates),which were sprayed twice with a 500-fold aqueous dilution of the corresponding formulation or preparation at a 12-d interval.Based on the leafhopper densities estimated by sampling in all plots at 3- or 4-d intervals after the first spray,the spray of BbIM or PfIM could better control the leafhoppers than the spray of Bb or Pf formulation.The maximal efficacy relative to CK reached 83.4% and 71.3% in the BbIM and PfIM treatments,respectively.Estimates of field efficacy obtained during the 25-d period after the first spray was 66.8% for BbIM,62.1% for PfIM,50.3% for OBLI,49.5% for Bb,and 19.0% for Pf,respectively.A discussion was also given on the effect of local weather pattern and leafhopper population age structure on the results of the field trial,and on the application techniques to enhance the efficacy of mycoinsecticides against Empoasca species on tea plant.