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

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 (λ) of the progeny of abamectin (r = 0.0854 day⁻¹, λ = 1.0891 day⁻¹) and pyridaben (r = 0.0951 day⁻¹, λ = 1.0997 day⁻¹) treated parents were significantly lower than in the control mites (r = 0.1455 day⁻¹, λ = 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.