Evaluation of the different control methods for the two-spotted spider mites by computer software and percentage efficacy.

摘要

Trials were carried out under greenhouse conditions in Ankara, Turkey, to control the two spotted spider mite (TSSM) Tetranychus urticae as part of a mite management programme in 2007 season, on cucumber (Cucumis sativus). Three different control methods namely, chemical (by using hexythiazox, bifenthrin and dimethoate), biological (by releasing Phytoseiulus persimilis and Amblyseius californicus [Neoseiulus californicus]) and a combination of chemical and biological control were applied and evaluated by two different methods. One of them depended on measuring the feeding damage rate of TSSM by computer software (Compu Eye, leaf and Symptom Area). The other one was commonly used and relied on calculating the percentage efficacy by mathematical formula (Henderson and Tilton formula). The ANOVA analysis of results of the tested evaluation methods could separate the mean of values of percentage efficacy and feeding damage rate and relatively assemble into counterpart groups and give the same decision in evaluating the effectiveness of the control methods. The results indicated that hexythiazox and dimethoate could not repress the TSSM population, which gave significant damage rate in its treatments and the efficacy of the aforementioned pesticides did not provide good control, which was low to TSSM compared with bifenthrin, predators and combination of chemical and predators. Bifenthrin and hexythiazox combined with predators or bifenthrin alone could repress well the TSSM population so that the damage rate was low, but its percentage efficacy was high. Feeding damage rate, which was assessed by computer software may be satisfactorily recommended to evaluate the effectiveness of control methods against spider mites under IPM programmes.