Comparison toxicity of plant pesticides, Tondexir® and chemichal acaricides, Ortus® on two spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) and its natural enemies Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae)
In this research, the effect of plant pesticides tondexir (Tondexir®) and chemical acaricides fenpyroximate (Ortus®) were investigated on the egg an adult of two spotted spider mite Tetranychus urticae and its natural enemies Phytoseiulus persimilis in lab condition. Also to evaluate the effect of field recommended concentrations (2000 ppm tondexir and 700 ppm fenpyroximate) an experiment was conducted with three treatments and four replications in a randomized complete block design under field conditions. The numbers of T. urticae and P.persimilis (egg and adult) on leaf samples were count on before treatment and 3, 7, 14 and 21 days after treatment. The LC50 value of tondexir and fenpyroximate on egg and adult of T. urticae were 661.01, 396.1 and 379.3, 291.6 ppm 72 h after treatment respectively. The egg and adult of P. persimilis were less susceptible to T. urticae and fenpyroximate toxicity was higher than the tondexir for this predatory mite. The field bioassay results showed tondexir have longer persistency effect than fenpyroximate. According to IOBC standards, 21 days after treatment, tondexir and fenpyroximate were categorized at moderately toxic and very toxic for both egg and adult of predatory mite respectively. Overall results showed that tondexir caused high mortality on egg and adult of spider mite and its toxicity is less than fenpyroximate to predatory mite.