白僵菌孢子悬乳剂田间控蚜效果与常温货架寿命测定

将高纯度球孢白僵菌分生孢子粉兑入一种含悬浮稳定剂及紫外保护剂的矿物油中,配成含孢量为100亿/ml的孢子悬乳剂(纯菌剂),再添加3%的吡虫啉10%可湿剂而得菌药混配剂,于2003年5月在浙江余姚进行了防治蔬菜蚜虫的田间药效试验和农户示范。在两块夏熟白菜地中,纯菌剂和菌药混配剂均用1000倍稀释液(107个孢子/ml)常规喷雾2次,并设清水对照和低用量吡虫啉对照。结果表明,混配剂在两块菜地的相对防效分别达94.5%和86.2%,纯菌剂分别达86.4%和73.1%,而低用量吡虫啉处理的最高防效仅为50%左右。在入夏豇豆、甘蓝、白菜、萝卜及梨树上用菌药混配剂1000倍稀释液对多种蚜虫进行的农户示范试验中,一次性喷雾后5~10d内对菜蚜防效为48%~68%,尤对梨二叉蚜的防效高达99%。在对含有和不含添加剂的两配方孢子悬乳剂进行的常温避光18个月贮存中,活孢率在头7个月均稳定在95%左右且未受配方影响,第10个月活孢率仍有75%左右。而后,含添加剂配方的活孢率下降加速,至16个月时基本失活;而不含添加剂配方的活孢率在第16、17及18个月时还有57%、51%和42%。

FIELD TRIALS OF A BEAUVERIA BASSIANA FORMULATION AGAINST APHIDS AND ITS SHELF-LIFE AT AMBIENT TEMPERATURE

An emulsifiable formulation of Beauveria bassiana conidia (Bb), prepared with an oil-based liquid containing stabilizer and UV protectant and standardized as 1010 conidia/ml, was tested alone or together with 3% of imidacloprid 10%WP (Bb Im) for efficacy against Myzus persicae on Chinese cabbage in Yuyao, Zhejiang during May 2003. After spraying 1000-fold dilutions twice in two fields at 10-day interval, relative efficacies reached up to 94.5% and 86.2% for the Bb Im, 86.4% and 73.1% for the Bb, but only about 50% when imidacloprid was applied at the low rate added to the Bb Im. In extensive field trials for control of various aphids on cowpea, cabbage, Chinese cabbage, turnip and pear trees during the summer, relative efficacies against vegetable aphids ranged from 48% to 68% within 5-10 days after one spray of 1000-fold dilution of the mixed formulation Bb Im. Particularly, the mixed formulation resulted in a 99% control of Schizaphis piricola population on pear trees. During an 18-month period of storage at ambient temperature in dark, the oil-based B. bassiana formulations with or without the additives were very stable with conidial viabilities fluctuating around 95% during the first 7 months and remaining about 75% by the end of 10 months. Thereafter, however, the viability of the conidia in the formulation containing the additives decreased rapidly and was not detected by the end of 16 months. In contrast, the formulation not containing the additives had conidial viabilities of 57%, 51%, and 42% on months 16, 17, and 18, respectively.