Acetamiprid-Induced Toxicity Thresholds and Population Sensitivity in Trichogramma dendrolimi: Implications for...

Area of Science:

• Entomology
• Ecotoxicology
• Pest Management

Background:

• Trichogramma dendrolimi is a crucial parasitoid for controlling lepidopteran pests.
• Neonicotinoid insecticides, such as acetamiprid, are widely used in integrated pest management (IPM).
• Acetamiprid use may pose risks to beneficial insect populations like T. dendrolimi.

Purpose of the Study:

• To evaluate the acute and sublethal toxicity of acetamiprid to Trichogramma dendrolimi.
• To assess population-level risks using species sensitivity distribution (SSD).
• To inform pesticide regulations for conserving parasitoid-mediated ecosystem services.

Main Methods:

• Acute toxicity assays using glass-vial residues to determine LC50.
• Sublethal exposure experiments to assess effects on parasitism, emergence, and development.
• Species sensitivity distribution (SSD) analysis to estimate population-level risk.

Main Results:

• The 24-hour LC50 for adult T. dendrolimi was 0.12 mg a.i. L-1, significantly lower than field application rates.
• Sublethal exposure reduced parasitism and emergence rates (NOEC = 2.3 μg a.i. L-1) and shortened offspring development.
• SSD analysis identified T. dendrolimi as highly sensitive, with field rates potentially affecting 76.8-97.9% of the population.

Conclusions:

• Acetamiprid exhibits significant acute and sublethal toxicity to Trichogramma dendrolimi.
• Current field application rates pose a substantial risk to T. dendrolimi populations.
• Integrating sublethal effects into pesticide risk assessments and regulations is crucial for preserving biological control agents.