Khan_2021_Exp.Appl.Acarol__

The citrus red mite (Panonychus citri) is a challenge to manage in citrus orchards due to resistance against several pesticides. There is a necessity therefore to find new pesticides for effective control of P. citri. This study was designed to evaluate the lethal and sublethal effects of emamectin benzoate against P. citri. The results showed that the LC(50) of emamectin benzoate to adults of P. citri was 0.35 (0.26-0.43) mg a.i. L(-1) and the LC(90) was 1.44 (1.16-1.96) mg a.i. L(-1). The sublethal concentration exposures (LC(10) and LC(30)) had a significant negative impact on the larval, protonymph, and deutonymph developmental periods. Male longevity was much lower in LC(30) treatments than in the controls. Although female longevity was unaffected, the fecundity (eggs per female) was decreased in the sublethal concentration treatments. Results revealed that the adult pre-oviposition period (APOP) and total pre-oviposition period (TPOP) were increased. Other growth parameters r, lambda, and R(0) decreased, whereas mean generation time (T) increased due to pesticide exposure. The survival rate (S(xj)), age-specific fecundity and net maternity, life expectancy (E(xj)), and reproduction (V(xj)) was reduced by LC(10) and LC(30) exposure. An increase in malondialdehyde (MDA) contents with increasing emamectin benzoate concentration demonstrates that emamectin benzoate induces oxidative stress in P. citri. The activity of antioxidant enzymes (superoxide dismutase, SOD and catalase, CAT) was decreased due to LC(30) and LC(10) treatments compared to the control. Detoxification enzyme activity (cytochrome P450, glutathione-S-transferases, GST and acetylcholinesterase, AChE) was increased in treated mites compared to the control. This study demonstrates that emamectin benzoate has both a lethal effect on citrus red mite and sublethal effects on its biology and physiology. It is, therefore, potentially an effective pesticide for management of P. citri.