Comparative toxicity and dose-mortality analysis of acaricides and a horticultural mineral oil against Panonychus ulmi (Koch) (Acarina: Tetranychidae) on apple

AbstractThe acaricides tested against European red mite, Panonychus ulmi (Koch) included cyenopyrafen, fenazaquin, etoxazole, spiromesifen, hexythiazox, propargite and a combination of propargite + hexythiazox and compared with horticultural mineral oil (HMO). Cyenopyrafen has been reported to be most toxic acaricide to adults with an LC50 value of 100.35 ppm and a relative toxicity of 74.68, making it the most effective acaricide followed by fenazaquin with LC50 value of 130.22 ppm and a relative toxicity of 57.0. Other acaricides including etoxazole (LC50 203.25 ppm), spiromesifen (LC50 205.11 ppm), and hexythiazox (LC50 529.75 ppm) were comparatively less toxic with relative toxicities of 36.57, 36.20 and 14.03, respectively. On the other hand, propargite and propargite + hexythiazox exhibited lowest toxicity among tested chemicals with LC50 values of 626.47 and 629.65 ppm, and relative toxicities of 11.86 and 11.80, respectively. HMO was least toxic with an LC50 value of 7434.42 ppm. The order of toxicity based on LC50 values was cyenopyrafen followed by fenazaquin, etoxazole, spiromesifen, hexythiazox, propargite, propargite + hexythiazox and HMO. The fiducial limits of the acaricides varied, indicating differences in their range of effectiveness. Cyenopyrafen and fenazaquin were found most potent acaricides.