Laboratory susceptibility of different stages of the spotted spider mite Tetranychus urticae to acaricides.

This study was carried out to investigate the efficacy of tested coonhounds against mite-eggs to select the most potent compou1Kis of ovicidal action to be used in the field prior to build up of injury from larval and adult stages of mite. The ovicidal action of 12 pesticides namely: nomite, fenpyroximate, dicofol M, neoron, dicofol, vertimec, propargite, chlorfenapyr, meothrin, fenazaquin, pegasus and selecron were tested against days old eggs ofthe mite T. urticae. Toxicity of the tested compounds were also evaluated against larvae, deutonymph and adults of T. urticae. The results indicated that: Fenpyroximate was the most potent compound against all embryonic developmental stages of eggs, followed by nomite and vertimec, while pegasus was the lowest one. The susceptibility of eggs to all compounds increased as the age of eggs increased. The data also showed that fenpyroximate was the most effcient compound followed by dicofol and dicofoI-M while pegasus was the lowest one, against larval and deutonymphal stages. The data obtained on the adult female stage showed that vertimec was the most potent compound followed by dicofol-M, nomite, fenpyroximate, dicofol, selecron, chlorfenapyr, neoron, meothrin, fenazaquin, propargite and in diafenthiuron which was the lowest effective pesticide against all stages.