Side effects of spiromesifen and spirodiclofen on life table parameters of the predatory mite, Neoseiulus californicus McGregor (Acari: Phytoseiidae)

ABSTRACT

Knowledge of variation in the susceptibility of natural enemies to pesticides could help to better design integrated pest management strategies. In this study, laboratory bioassays were conducted to evaluate the lethal effects of spiromesifen and spirodiclofen on life table parameters of Neoseiulus californicus (McGregor) (Acari: Phytoseiidae), a potential predator of Tetranychus urticae Koch. The LC₉₀ values of N. californicus populations were determined with the leaf disc method under laboratory conditions (25 ± 2°C, 70 ± 5% relative humidity and 16:8 h (L:D)). The acaricides tested significantly increased the total development time of both sexes. The adults’ longevity, oviposition period, and mean fecundity decreased after exposure to treatments. The results indicated that adverse effects of the two treatments on population growth parameters (r, λ, R₀, T) of N. californicus were significant. The intrinsic rate of increase (r) in the control, and those treated with spiromesifen and spirodiclofen were 0.22, 0.15 and 0.12 days⁻¹, respectively. Based on these results, considering the effects of the acaricides on the population growth of N. californicus, spiromesifen and spirodiclofen should be used cautiously in conjunction with N. californicus to achieve efficient control of T. urticae management.

KEYWORDS:

• Tetranychus urticae
• Neoseiulus californicus
• life table parameters
• spiromesifen
• spirodiclofen

Disclosure statement

No potential conflict of interest was reported by the authors.