土着天敵の種構成が異なるカンキツ園における殺虫剤散布後のミカンハダニ（ダニ目：ハダニ科）の密度変化

抄録

I investigated the impact of insecticide application on the population density of Panonychus citri（McGregor）in two citrus orchards in Shizuoka Prefecture with different species of mite predators. In one citrus orchard, Neoseiulus californicus（McGregor）was the main mite predator species. The application of tolfenpyrad reduced the density of N. californicus and resulted in an increase of P. citri, whereas the application of imidacloprid or chlorfenapyr did not affect the densities of N. californicus and P. citri. In the other citrus orchard, Stethorus spp. were the main mite predator. The application of imidacloprid reduced the density of the predators and increased the density of P. citri, whereas the application of chlorfenapyr did not affect the density of P. citri and the predators. The application of tolfenpyrad reduced the density of the predators, but P. citri did not increase. These results demonstrate that biological control of P. citri requires careful selection of insecticides that will not have a detrimental effect on the region-specific species of mite predators in citrus orchards.