Residual Toxicity of Abamectin, Milbemectin and Chlorfenapyr to Different Populations of Two Spotted Spider Mite, Tetranychus Urticae Koch, (Acari: Tetranychidae) on Cucumber in Jordan

3 Abstract: Laboratory studies were conducted during the year 2010 to evaluate the duration of residual toxicity of the acaricides; abamectin, milbemectin and chlorfenapyr to six populations of the two spotted spider mite (Tetranychus urticae Koch, (Acari: Tetranychidae) collected from cucumber grown under plastic houses in the six main cultivated areas in Jordan ( Ramta, Baqa', Zyzya, Krimeh, Dier Alla and Karamah), compared to a Syrian susceptible strain. Loss of susceptibility in the six populations to the closely related acaricides abamectin and milbemectin were clearly indicated even after one day of application, where the mortality did not exceed 24 and 33%, compared to 96 and 97% for Syrian susceptible strain for the two acaricides, respectively. In contrast, mortality from residual toxicity of chlorfenapyr were considered efficacious after one day of application and reached acceptable level even after 15 days of application. The mortality was ranged between 92 - 98% after one day of application and 48 - 68% after 15 days of application, in four out of six populations. The mite populations collected from Karamah and Krimeh were the least susceptible. Mortality from residual toxicity after one day of application were 75 and 88%, respectively, compared to 98% mortality in the Syrian susceptible strain.