Lethal and sublethal effects of fenazaquin and acequinocyl on demographic and some biochemical parameters of Panonychus citri (McGregor) (Acari: Tetranychidae)

ABSTRACT

A major pest of citrus orchards in northern regions of Iran is Panonychus citri which is mainly controlled by using chemical acaricides. Knowledge of the lethal and sublethal effects of pesticides on pests is necessary for successful performance of each control programme. In this study, the toxicities of fenazaquin and acequinocyl as well as the effects of the sublethal concentration LC₂₀ and LC₃₀ on demographic and some biochemical traits of P. citri offspring were studied. The results showed that the toxicity of acequinocyl was 2.18 times higher than that of fenazaquin. The developmental time of females was influenced and prolonged by sublethal concentrations of both acaricides. Sublethal concentration effects of both acaricides considerably decreased the total fecundity. A significant reduction was observed in the net reproduction rate (R₀), and intrinsic rate of natural increase (r) of the mites exposed to LC₂₀ and LC₃₀ concentrations of both acaricides compared to control. Both acaricides showed a negative impact on the content of lipid, carbohydrate, and glycogen. The LC₂₀ concentration of fenazaquin resulted in an increase in general esterase activity, and both acaricides inhibited glutathione S-transferase (GST) activities. Our findings show that the sublethal doses of both acaricides had adverse effects on the biological and physiological characters of P. citri.

KEYWORDS:

• Citrus red mite
• acaricide
• toxicity
• intrinsic rate of increase
• glutathione s-transferase

Disclosure statement

No potential conflict of interest was reported by the author(s).