Laboratory and field tests on the efficacy of a Chinese produced Bacillus thuringiensis wettable powder against peach fruit borer, Carposina niponensis (Lep.: Carposinidae).
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 pest, Carposina niponensis [C. sasakii]. In a laboratory test, apple fruits were sprayed with the Bt wettable powder diluted 1000 and 2000 times, resp., and newly-hatched larvae of C. sasakii were introduced. The treatments provided complete protection of the fruits for 3 days, with no infestation found on the 3rd day after treatment. This was similar to that obtained with 2.5% deltamethrin. However, introduction of the larvae on the 3rd and 6th day after treatment with the Bt wettable powder resulted in 45.5 and 54.6% of larval mortality, resp., indicating a relatively short residual effect of the product. A mixture of the Bt wettable powder with low concn (2.5%) of deltamethrin showed a prolonged residual effect against the pest. Larval mortality on the 3rd and 6th day after treatment were 84.4 and 73.2%, resp. This was similar to control obtained with 50% parathion (diluted 1500 times ) commonly used by growers in China.