Action of pyrethrum-based formulations against grain weevils

Area of Science:

• Agricultural Science
• Entomology
• Pest Management

Background:

• Pyrethrum extract is a natural pesticide effective against stored product pests.
• Low light stability limits pyrethrum's effectiveness in outdoor applications.
• Gamma-cyclodextrin complexation can improve pyrethrum's stability and efficacy.

Purpose of the Study:

• To evaluate the insecticidal activity of gamma-cyclodextrin complexed pyrethrum extract against the grain weevil.
• To assess the synergistic effects of piperonyl butoxide, sesamol, and tocopherol acetate on pyrethrum's efficacy.
• To determine optimal concentrations for pyrethrum and synergists in pest control formulations.

Main Methods:

• Complexation of pyrethrum extract with gamma-cyclodextrin.
• Testing insecticidal activity against grain weevils with various pyrethrum formulations and synergists.
• Comparing efficacy against a commercial pyrethrum product.

Main Results:

• Gamma-cyclodextrin complexation slightly enhanced pyrethrum's insecticidal action compared to free pyrethrum.
• Piperonyl butoxide demonstrated significant synergistic activity.
• Natural synergists sesamol and tocopherol acetate showed minor synergistic effects, even at higher concentrations.

Conclusions:

• Complexation with gamma-cyclodextrin offers a viable strategy to improve pyrethrum's stability and insecticidal performance.
• Piperonyl butoxide is a highly effective synergist for pyrethrum-based insecticides.
• Optimal formulation involves 0.3% pyrethrum extract and 3% piperonyl butoxide for grain weevil control.