Efficacy of Selected Insecticides Applied to Hybrid Rice Seed

Area of Science:

• Agricultural Entomology
• Pest Management
• Agronomy

Background:

• Hybrid rice cultivation and insecticide seed treatments are key innovations in rice production.
• The impact of reduced seeding rates on seed treatment efficacy against rice water weevil remains uninvestigated.

Purpose of the Study:

• To assess the relationship between reduced seeding rates in hybrid rice and the effectiveness of insecticidal seed treatments.
• To evaluate the efficacy of labeled versus higher rates of specific insecticides for rice water weevil control.

Main Methods:

• A multi-location experiment (2011-2012) compared labeled and higher rates of thiamethoxam, chlorantraniliprole, and clothianidin.
• Study sites were categorized by rice water weevil larval densities: low, moderate, and high.
• Efficacy was measured by rice water weevil densities and crop yield.

Main Results:

• All tested seed treatments and rates reduced rice water weevil densities across all pressure levels.
• No yield or economic benefit was observed in low-pressure areas.
• Yield increases were noted in moderate and high-pressure areas, with all treatments outperforming untreated plots, though not always economically.

Conclusions:

• Insecticidal seed treatments are effective in reducing rice water weevil densities in hybrid rice.
• Labeled rates of current seed treatments provide effective and economic control of rice water weevil, particularly in high-pressure environments.