RELATIVE TOXICITY OF SOME ACARICIDES AGAINST SPIDER MITE, TETRANYCHUS URTICAE KOCH

Abstract

The ovicidal activity of acaricides was assessed by determining their LC values for eggs. 50 Fenpyroximate was effective ovicidal treatment with the lowest LC value of 1.97 ppm followed by 50 fenpropathrin (4.59 ppm), fenazaquin (6.70 ppm) and hexythiazox (10.34 ppm). The descending order of ovicidal activity of different acaricides against T. urticae was fenpyroximate (1.97 ppm) > fenpropathrin
(4.59 ppm) > fenazaquin (6.70 ppm) > hexythiazox (10.34 ppm) > propargite (34.56 ppm) > chlorfenapyr (55.91 ppm) > diafenthiuron (71.79 ppm) > buprofezin (135.99 ppm) > spiromesifen (361.84 ppm). Based on the LC values determined from laboratory bioassays with adult females of T. urticae, fenpyroximate and 50 fenpropathrin were found more toxic (2.16 and 2.41 ppm, respectively), while spiromesifen was least toxic with the highest LC value of 414.03 ppm. The order of relative toxicity of different acaricides to adult 50
females was fenpyroximate (2.16 ppm) > fenpropathrin (2.41 ppm) > fenazaquin (7.75 ppm) > hexythiazox (12.46 ppm) > propargite (27.88 ppm) > diafenthiuron (52.33 ppm) > chlorfenapyr (61.18) > buprofezin (94.92 ppm) > spiromesifen (414.03 ppm).