高孢子含量Bt制剂对桃小食心虫毒效的初步试验

LABORATORY AND FIELD TESTS ON THE EFFICACY OF A.CHINESE PRODUCED BACILLUS THURINGIENSIS WETTABLE POWDER AGAINST PEACH FRUIT BORER, CARPOSINA NIPONENSIS[LEP.: CARPOSINIDAE]

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.