施設バラにおいてスピノサドの散布がチリカブリダニへ及ぼす影響

抄録

The effects of applying spinosad to Phytoseiulus persimilis Athias-Henriot on roses were evaluated by laboratory and field tests. In the laboratory tests, spinosad wettable powder (diluted 5,000 times) was applied with two different methods for P. persimilis: dipping rose leaves in the spinosad solution (dipping treatment) or spray application to the mites on roses (spraying treatment). Mortalities of P. persimilis after 72 h in the spinosad-treated group were 22.9% and 67.6% by the dipping and the spraying treatments, respectively. Statistical analysis showed that the survival of P. persimilis was significantly affected by application of spinosad and treatment methods. However, the harmful effects of the dipping treatment on the mites were moderate when compared with spraying. In the field tests conducted in commercial greenhouse roses where P. persimilis were released and colonized, different amounts of spinosad solution, l00 L/1,000 m² or 500 L/1,000 m², diluted 5,000 times were sprayed after surveying the numbers of Tetranychus urticae Koch and P. persimilis. Although the number of T. urticae significantly affected the number of P. persimilis, spraying spinosad did not affect P. persimilis. Thus, the generally used application rates of spinosad wettable powder for greenhouse roses did not significantly reduce P. persimilis density.