Evaluating the Direct and Indirect Toxicity of Nine Insecticides on an Important Predatory Natural Enemy in Rice...

Area of Science:

• Agricultural Entomology
• Pest Management
• Chemical Ecology

Background:

• Natural enemies are vital for integrated pest management (IPM) in rice cultivation.
• Compatibility of chemical insecticides with biological control agents in rice IPM requires thorough investigation.

Purpose of the Study:

• To evaluate the direct and indirect toxicity of nine insecticides against six key rice predators.
• To assess the impact of insecticides on the predatory activity of natural enemies in rice ecosystems.

Main Methods:

• Laboratory assessment of direct toxicity (mortality rates) of nine insecticides.
• Evaluation of indirect toxicity by measuring the effect on predatory activity.
• Testing against six important rice pest predators: Cyrtorhinus lividipennis, Paederus fuscipes, Ummeliata insecticeps, Tetragnatha maxillosa, Mendoza cancestrinnii, and Pardosa pseudoannulata.

Main Results:

• Tetraniliprole, triflumezopyrim, and chlorantraniliprole showed negligible direct toxicity and no significant impact on predatory activity for all tested predators.
• Spinetoram, avermectin, emamectin benzoate, nitenpyram, and imidacloprid exhibited high direct toxicity (mortality > 99%) and significantly reduced predatory activity.
• Nitenpyram, avermectin, emamectin benzoate, and spinetoram posed high to extreme risks to specific predators, impacting their efficacy in pest control.

Conclusions:

• Pymetrozine, spinetoram, nitenpyram, imidacloprid, emamectin benzoate, and avermectin demonstrated significant lethal or sublethal effects on rice predators.
• Tetraniliprole, triflumezopyrim, and chlorantraniliprole are identified as safer insecticide options for preserving natural enemy populations in rice IPM.