STUDIES ON TETRANYCHUS URTICAE KOCH INFESTING CERTAIN FRUIT TREES

Abstract

The two-spotted spider mite, Tetranychus urticae Koch, is considered one of the most destructive mite of the deciduous fruit trees in Egypt. The feeding activities of this mite causes loss on apple trees yield. During the last quarter of this century the acaricides have been widely used on the deciduous fruit trees. Most of these acaricides caused resistance strain of phytophagous mites, T. urticae.

The results obtained can be summarized as follows :

1- The susceptibility of parent strains of adult females of two­ spotted spider mite T. urticae before application any pesticides which collected from apple trees of Qalubia, Sharkia, Giza and Behera governorates and exposed to local petroleum oil (KZ oil 95 % EC), flufenoxuron (Cascade 10 % DC), abamectin (Vertimec 1.8 % EC), Malathion 57 % EC, fenpyroximate (Ortus 5 % SC) and pyriproxyfen (Admiral10% EC). The susceptibility of different field strains as compared with susceptible strain indicated that, the susceptibility of parent strain to KZ oil95% EC, Cascade 10% DC, Vertimec 1.8 % EC, Ortus 5 % SC and Admiral 10 % EC showed that Giza strain had the highest tolerant (7.15, 6.25, 9.36, 5.20 and 6.89-folds), respectively. In contrast, Giza strain had the lowest tolerant (1.51-fold), but Qalubia strain had the highest tolerant (4.36-fold) to Malathion 57% EC.