Functional response and mutual interference of Neoseiulus californicus and Typhlodromus bagdasarjani (Acari: Phytoseiidae) on Tetranychus urticae ( Acari: Tetranychidae)

The two-spotted spider mite, Tetranychus urticae Koch, is one of the most economically important pestson a wide range of crops over the world. This study was carried out to evaluate the efficacy of two predatorymite species, Neoseiulus californicus (McGregor), an exogenous species in Iran, and Typhlodromusbagdasarjani Wainstein & Arutunjan, a native species, as biological control agents of T. urticae. Thefunctional response and mutual interference of these two phytoseiid mites were determined under laboratoryconditions (at 25˚C, RH 65% and a photoperiod of 16h light: 8h dark). The functional response of the twopredator species to different densities of eggs and nymphs of T. urticae using the logistic regression was typeII. The highest attack rate (0.0936) and the lowest handling time (1.6451 h) were recorded for N.californicuson eggs and the lowest attack rate (0.0473) and the highest handling time (2.399 h) were estimated for T.bagdasarjani on nymphs of T. urticae.The Nicholson‟s model and linear regression were used to determineper capita searching efficiency and interference coefficient, respectively. The per capita searching efficiencyof the two predators decreased significantly with increasing predator density from 1 to 16 on 250 hostnymphs. The interference coefficient for N. californicus was less than T. bagdasarjani. Also N. californicushad the highest predation potential, in particular on eggs of T.urticae. Therefore, based on the attack rate,handling time and interference coefficient, N. californicus compared to T. bagdasarjani may be a sufficientbiological control agent on cucumber leaf disc.

کلیدواژه ها:

Neoseiulus californicus ، Typhlodromus bagdasarjani ، Functional response ، Mutual interference Tetranychus urticae