Transgenerational sublethal effects of abamectin and pyridaben on demographic traits of Phytonemus pallidus (Banks) (Acari: Tarsonemidae)

Abstract

In addition to determining the lethal effects, identifying sublethal effects of a pesticide is crucial to understanding the total impact a pesticide may have on a pest population. We determined the sublethal effects the two pesticides, abamectin and pyridaben, have on the cyclamen mite, Phytonemus pallidus (Banks) (Acari: Tarsonemidae)a major pest of strawberry. Demographic traits of the P. pallidus progeny (F1 generation) produced by parents (F0 generation) treated with a low lethal concentration (LC15) of abamectin and pyridaben were assessed using the age-stage, two-sex life table theory. The total longevity of the F1 generation (males=10.78 days; female=14.35 days) was the shortest in the progeny of the abamectin treated parents, differing significantly from the progeny of mites treated with pyridaben (males=11.50 days, females=15.63 days), and the control population (males=13.50 days, females=17.81 days). The intrinsic rates of increase (r) and the finite rates of increase () of the progeny of abamectin (r=0.0854 day(-1), =1.0891 day(-1)) and pyridaben (r=0.0951 day(-1), =1.0997 day(-1)) treated parents were significantly lower than in the control mites (r=0.1455 day(-1), =1.1567 day(-1)). The lowest fecundity (5.35 eggs/female), occurred in F1 female offspring of parents treated with LC15 concentrations of abamectin, which was significantly lower than in the pyridaben (6.11 eggs/female) and control treatments (11.45 eggs/female). Transgenerational sublethal effects of abamectin and pyridaben in P. pallidus can be effectively used to for optimizing IPM programs against this pest on strawberries.