两种杀虫真菌制剂与低用量吡虫啉对温室粉虱的协同防效评价

在昆明市郊蔬菜基地4间大棚(5m×100m·间^-1)栽培的生菜上，用球孢白僵菌(Beauveriabassiana)和玫烟色拟青霉(Paecilomyces fumasonoseus)的纯孢子乳悬剂(有效含孢量10^10·ml^-1)及其与1％和3％(w／v)的吡虫啉10％WP的混配剂对温室粉虱(Trialeurodes vaporariorum)进行了协同药效试验，吡虫啉添加量仅相当于推荐用量的6．4％～9．5％和19．1％～28．6％，试验含6个菌剂处理、2个低用量吡虫啉处理和1个清水对照，各有3个小区(7m×5m·小区^-1)重复，随机区组排列，稀释1000倍的菌液(含孢量10^7·ml^-1)和吡虫啉液于生菜移栽后第11d首次喷雾，15d后喷第二次，首次用菌前调查初始粉虱密度，用菌后每隔5d调查活虫数和死虫数，从8月20日起历时30d，结果表明，连续2次用菌有效地控制了粉虱对当季大棚生菜的危害，各菌剂处理的最终相对防效和虫口减退率均达到95％以上，极显著地高于低用量吡虫啉处理，其中，玫烟色拟青霉制剂对粉虱的控制效果一般优于球孢白僵菌制剂，且与吡虫啉的添加量呈正相关，但是，各菌剂处理间控虫效果的差异主要发生在首次用菌后第5d和10d，此后差异逐渐缩小，至第二次用菌后第10d各菌剂处理间无显著差异，本试验结果表明，两种真菌的孢子乳悬剂均可用于温室粉虱的防治，添加微量吡虫啉可增强菌剂的防效。

Evaluation of interactive efficacy of two mycoinsecticides and low application rate imidacloprid in controlling greenhouse whitefly Trialeurodes vaporariorum (Homoptera: Aleyrodidae)

The interactive effects of pure emulsifiable formulations (10(10) conidia.ml-1) of Beauveria bassiana and Paecilomyces fumosoroseus conidia and 1% and 3% of imidacloprid 10% WP were tested for controlling greenhouse whitefly, Trialeurodes vaporariorum, on lettuce grown in four polyethylene film-covered greenhouses (5 m x 100 m) in Kunming, Yunnan. Six fungal treatments, two imidacloprid ones, and one water-spray control were included in the experiment, with each being replicated in three plots (7 m x 5 m.plot-1). For each of the treatments, 1000-fold aqueous dilution (10(7) conidia.ml-1) was sprayed twice at a 15-d interval, with the first spray given on day 11 after lettuce transplantation. Counts of live and dead whiteflies from each treatment were made on the initial day, and then, once every five days. During a 30-d period of observation from August 20, the two applications of the fungal formulations alone or those containing low rates of imidacloprid 10% WP effectively protected the lettuce from damage by T. vaporariorum, and generated relative efficacies. Whitefly density decreased > 95%, which was significantly higher than that attributed to the low application rates of imidacloprid 10% WP. Based on the estimations of relative efficacy and percent density decrease, P. fumosoroseus treatments controlled the whiteflies better than B. bassiana ones, and the effects of both fungi on the pest population were apparently enhanced with the quantity of imidacloprid added. The differences among the fungal treatments in the two estimations were larger during the first 10 days, but decreased thereafter, becoming insignificant on day 10 after the second spray. The results indicated that the fungal formulations tested in this study are of great potential for practical use in whitefly control, and their efficacy could be enhanced with low rates of imidacloprid.