Effect of Pyrifluquinazon and Pymetrozine on the Omnivorous Predator, Nesidiocoris tenuis (Reuter)

Abstract

We evaluated the effect of the insecticides, pyrifluquinazon and pymetrozine, on the predatory mirid bug, Nesidiocoris tenuis (Reuter). The mortality of N. tenuis was not significantly different between both of the insecticides and control by two methods, insect-dip and tomato leaf-dip. In an experiment of insecticide application on tomatoes in a greenhouse, the density of N. tenuis in the pyrifluquinazon plot was significantly lower than in the control plot. No significant difference was shown in the pymetrozine plot compared to the control plot. In an experiment of insecticide application to N. tenuis on a tomato seedling in a cage under laboratory conditions, numbers of N. tenuis remaining on tomato in the pyrifluquinazon plot was significantly smaller than in the control plot although the number recovered over time. No significant difference was shown in the pymetrozine plot from the control plot. Mortality of N. tenuis was not significantly different between the treatment and the control plot. A similar result was shown in an experiment of released insects to the insecticide applied tomato seedling in a cage. These results indicate that pyrifluquinazon suppresses the density of N. tenuis by inhibiting its orientation behavior although both of the insecticides, pyrifluquinazon and pymetrozine, show little direct activation on the killing activity of N. tenuis.