摘要
试验证明复方青虫菌6号商品制剂在通常稀释1000倍的剂量下(含氯氰菊酯0.5ppm),能100％杀死伪钝绥螨和智利植绥螨。不含氯氰菊酯的青虫菌制剂对两种捕食螨的死亡率分别为1.7％和7.1％。复方制剂1000倍液和500倍液在温室中施药10天后,其残效仍能使智利螨的初孵幼螨死亡率分别达到52.5％和70.7％。用含氯氰菊酯农药0.1ppm的液剂处理感染叶螨的菜豆叶,饲养智利螨雌成螨,产卵量比对照减少80％左右。为避免含有化学农药的生物制剂杀伤天敌的副作用,作者认为生物制剂中以不加化学农药为宜。必要时可根据实际情况,在使用前再加入适量的化学农药。
Some Chinese preparations of Bacillus thuringiensis, or Bt, contain chemical insecticides to enhance their toxicity or broaden spectrum. Effects of these commercial Bt preparations on predacious mites were tested in the greenhouse in Beijing. Foliage application of a 1,000 fold dilution of 'Qing-Chong-Jun No.6', which contained B. thuringiensis var. galleriae and 0.5 ppm of cypermethrin, caused 100% mortality of Amblyseius fallaces and Phytoseiulus persimilis [Acari:Phytoseiidae]. Whereas another preparation with no chemical ingredient caused only 1.7% and 7.1% mortalities of the two predacious mites, .respectively. Mortalities of newly hatched P. persimilis on the leaves applied with 1,000 fold and 500 fold dilutions of Qing-Chong-Jun No. 6 were 52.5% and 70.7%, respectively, 10 days after the application. When P. persimilis was reared with spider mites feeding on leaves of common bean (Phaseolus vulgaris) treated with Bt preparations containing 0.1 ppm cypermethrin, the oviposition of the predator was reduced by 80%. It is suggested that chemical pesticides should not be added into Bt preparations to avoid its detrimental effect on natural enemies. If necessary, chemical insecticides may be mixed with Bt preparation in the field immediately before application.
关键词
苏云金杆菌
氯氰菊酯
捕食螨
Bacillus thuringiensis cypermethrin Phytoseiulus persimilis predator
