摘要
本文报道国产高孢子含量Bt(1.6×10^4IU)可湿性粉剂对桃小食心虫初孵幼虫的室内和田间药效,及其与低浓度化学农药混用的试验结果。室内实验表明,在苹果上分别喷酒高含量Bt可湿粉1000和2000倍液后接虫,第3天幼虫蛀果率均为零;喷酒2.5%溴氰菊酯(3个供试浓度)的结果与之相同,亦无1头幼虫蛀入果内。但是,高含量Bt可湿粉2000倍液在田间的残效期较短,施药后第3天和第6天在苹果上接虫。
This, paper is the first report on the efficacy of a Chinese produced Bacillus thuringiensis (Bt) wettable powder (16,000 IU) for the control of the peach fruit borer, Carposina niponensis. In the laboratory test, apple fruits were sprayed with the Bt wettable powder diluted 1,000 and 2,000 times, respectively and followed by introduction of newly hatched larvae of C. niponensis. The treatments provided a complete protection of the fruits for three days, with no infestation found on the third day after the treatment. This was similar to that obtained with 2.5% deltamethrin diluted at three different rates. However, introduction of the larvae on the third and sixth day after treatment with the Bt wettable powder resulted in 45.5% and 54.6% of larval mortality, respectively, indicating a relatively short residual effect of the product. A mixture of the Bt wettable powder with low concentration (2.5%) of deltamethrin showed a prolonged residual effect against the pest. The larval mortality on the third and sixth day after the treatment were 84.4% and 73.2%, respectively. This was similar to that obtained with 1,500 times of 50% parathion commonly used by growers in China.
关键词
BT制剂
桃小食心虫
毒效试验
苹果
Bacillus thuringiensis deltamethrin parathion wettable powder bio-insecticide