The effects of a novel botanical pesticide on demographic and some biochemical parameters of Panonychus citri (McGregor)

ABSTRACT

Panonychus citri (McGregor) is one of the most destructive pests of citrus trees. Its control is difficult because it has developed resistance to some synthetic pesticides. GC-mite is a novel botanical pesticide based on cottonseed, clove, and garlic oils that has shown the potential to control tetranychid mites. This study aimed to evaluate the effects of sublethal concentrations of GC-mite on the life history and biochemical parameters of P. citri. Age-stage life table procedure was used to evaluate the effects of two sublethal concentrations (LC₂₀ = 59.40 μg ml⁻¹ and LC₃₀ = 78.66 μg ml⁻¹) of GC-mite on the development, longevity, and reproduction of P. citri. The biochemical analysis included the content of lipids, carbohydrates and glycogen, esterase, and glutathione S-transferase (GST) activities. The developmental time of treated mites with LC₃₀ was significantly longer than the control but the adult longevity and oviposition days of P. citri treated with both sublethal concentrations decreased. The total fecundity of treated mites decreased with increasing GC-mite concentration applied. The life table analysis showed that sublethal concentrations of GC-mite significantly affected gross reproductive rate (GRR), net reproductive rate (R₀), intrinsic rate of increase (r), and mean generation time (T). The estimated values of r were significantly lower than the control in LC₂₀ (0.130 day⁻¹) and LC₃₀ (0.117 day⁻¹). The lipids, carbohydrates and glycogen contents as well as esterase and GST activities were significantly lower in mites treated with LC₃₀ concentration, but no significant effect was found in mites treated with LC₂₀ and control. These results suggest that sublethal concentrations of GC-mite had significant effects on both demographic and biochemical parameters of P. citri.

KEYWORDS:

• Citrus red mite
• acaricide
• sublethal effects
• life table
• lipids
• enzymes

Acknowledgments

This project was supported by Lorestan University, which is greatly appreciated.

Disclosure statement

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