محمد علی میر حسینی

The two-spotted spider mite (TSSM), Tetranychus urticae Koch is a polyphagous widespread herbivore pest and one of the most economically important species which feeds more than 1,100 plant species. The functional response at five different constant temperatures (15, 20, 25, 30 and 35 °C), prey switching, and mutual interference behaviors of the predatory coccinellid, Stethorus gilvifrons Mulsant on TSSM nymphs were assessed in laboratory conditions (25 ± 1 °C, 60 ± 5% RH and L:D 16:8 h) to evaluate its potential for biological control of TSSM. The predator showed a type II functional response at all tested temperatures. The shortest handling time (Th) and highest searching efficiency (α) were obtained at 30 °C and 20 °C, respectively. The highest and lowest values of the maximum attack rate (T/Th) of the predator were obtained at temperatures of 30 °C and 15 °C, respectively. The switching behavior was not observed in S. gilvifrons between different density proportions of TSSM nymph and adult. The highest value of total predation and lowest value of per capita predation rate belonged to the predator density of 16. The results revealed a strong predation capacity of S. gilvifrons on TSSM, especially in higher temperatures which makes it an efficient biocontrol agent in integrated TSSM management programs.