Influnce od plant texture on the feeding capacity and fecundity ofthe predatory mite, Phytoseiulus persimilis, A.-H.

Feeding capacity and fecundity of the predatory mite Phytoseiulus persimilis fed on nymphal stages of the two - spotted spider mites were highly affected by the plant texture and rearing substrates. The predatory mite individually attacked more preys on bean leaves. The feeding capacity during 10 days in the oviposition period was declined gradually on apple, fig, cotton and mango with an average of 16.37, 15.92, 10.28, 9.95 and 8.97 prey individuals/day, respectively. The statistical analysis proved that there were no significant differences between the values of prey consumption of P. persimilis on either bean and apple leaves or fig and cotton leaves, in spite of the differences in morphological characters between the aforementioned plants and the others are significant. Therefore, it can be concluded that both bean and apple leaves are more suitable substrates to rear and maintain P. persimilis. Also, egg deposition was significantly decreased when maintained on cucumber and squash leaves. The lowest rates of fecundity were obtained on mango and cotton leaves. Adult female of the predatory mite laid an average of 39.5, 37.3 and 36.1 eggs/10 days with daily rate of 3.95, 3.73 and 3.61 eggs __ day on bean, apple and fig leaves, respectively, compared to 31.5, 30.5, 25.6 and 25.1 egg __ on squash, cucumber, mango and cotton leaves, respectively. Among structures differences on the surfaces of leaves not only the venation type and hair density but also the raised veins that play an important role on the number of deposited eggs of predator and its feeding capacity on prey. P, persimilis attacked more prey and laid more eggs on smooth hairy leaves like those of bean and apple while cucumber, squash and cotton leaves are not suitable. Therefore, bean leaves are recommended to maintain P. persimilis cultures for biological control purposes.