Functional response ofNeoseiulus californicus(Acari: Phytoseiidae) toTetranychus urticae(Acari: Tetranychidae) on strawberry leaves

Abstract

AbstractNeoseiulus californicus(McGregor) is a predatory mite employed for biological control of the agricultural pestTetranychus urticae(Koch). We explored whether environmental differences, in this case the trichome densities of abaxial leaf surfaces of strawberry cultivars (‘Maehyang’ and ‘Sulhyang’ varieties) affect the functional response of adult femaleN. californicuspreying on immature stages (egg, larva and nymph) ofT. urticae. We also evaluated the functional response ofN. californicusto eggs ofT. urticaeat different temperatures (15, 20, 25, 30 and 35°C). We conducted a logistic regression of the proportion of prey consumed as a function of initial prey density to identify functional response types, and used nonlinear least‐squares regression and the random predator equation to estimate attack rates and handling times. The functional response of adult femaleN. californicustoT. urticaewas not influenced by non‐glandular trichomes on abaxial leaves but was affected by temperature. Overall, adult femaleN. californicusexhibited a type 2 functional response toT. urticae.The handling time ofN. californicuswas highest (1.9970 h) againstT. urticaenymphs. The attack rate did not change much at 15–30°C, but was significantly higher at 35°C. The handling time decreased significantly with increasing temperature at 15–35°C. At 35°C, the attack rate was highest (0.2087) and the handling time was lowest (0.9511 h).