Contact and Residual Effect of Different Acaricides Formulations of Control of Tetranychus urticae Koch (Acari: Tetranychidae)

The two-spotted spider mite, Tetranychus urticae Koch was considered the major pest of agricultural systems. The diversity of toxicological effect of different acaricide formulations recently recommended for use were done. Behera and Dakahlia populations were tested. Results showed thatthe individual LC₅₀s were not significantly different but Dakahlia population was considered more tolerant than Behera in hexythiazox, propargit, spirodiclofen, sulfur, abamectin and chlorfenapyr. The ratio between the LC₉₀values of all bioassays and the high recommended field dose were relatively higher for only abamectin in Dakahlia. The lowest adult survival percentage was recorded with chlorfenapyr, 15.66%, in Beheraan detoxazole, in Dakahlia15.0%recorded by contact treatment after 72h. The percentage of the eggs that not hatched was higher for clofentezine andetoxazole in both regions about 84%, but abamectin and spirodiclofen was the lowest reduction reached 67%.The residual effect at their recommended field rate, acaricides were non-significant to each other but significantly different from control. The estimated mortality percentages in Behera ranged between 94.0 to 74.6 % for pyridaben and abamectin respectively at1 day after application, while, mortality at 12 days after application was ranged between 52.6 to 30.6 % for spirodiclofen and abamectin respectively. The total effect of the acaricide tested in the two populations was ranged between 81.69 to 64.3 % in Behera and 80.7 to 65.3% in Dakahlia.