Antioxidant activity modulations in Helicoverpa armigera under pesticide stress

The effective control of Helicoverpa armigera, a major agricultural pest, is increasingly challenging due to its adaptive responses to pesticide toxicity. This study explored the role of midgut antioxidant enzymes-superoxide dismutase (SOD) and catalase (CAT), in countering the toxic effects of chemical (chlorpyrifos) and biological (spinosad) pesticides. Pesticide-treated diets significantly reduced larval growth rates compared to controls. SOD activity increased at lower chlorpyrifos concentrations but decreased at higher concentrations of both pesticides. Lower spinosad concentrations enhanced CAT activity, while it remained unchanged under other conditions. In-gel visualization confirmed these enzyme activity changes. Additionally, superoxide (O₂-) and hydrogen peroxide (H₂O₂) levels increased with pesticide concentration, indicating oxidative stress. The results suggest that H. armigera employs differential SOD and CAT responses to mitigate pesticide toxicity but at the cost of reduced fitness. These insights are crucial for developing effective pest management strategies, promoting sustainable agricultural practices and reducing economic losses.