Effects of Floating Carrier on Diffusion and Herbicidal Efficacy in Throw-in Type Formulation of Naproanilide

Abstract

Naproanilide behavior in water and herbicidal efficacy of a wettable powder containing floating carrier, hollow glass particles, packed in water soluble film was investigated. Naproanilide release from the formulation into water was dependent on the concentration of the floating carrier in the formulation. When the concentration of the carrier was high, the formulation floated on the water surface until the wettable powder completely diffused into water and naproanilide amount released from the formulation into water was large. If the concentration of the carrier was low, the entire body of the formulation sank soon after the film dissolved in water resulting in low release of naproanilide. In a greenhouse experiment, naproanilide diffusion in the water was sufficient to control Monochoria vaginalis growing throughout a test plot when the content of the floating carrier in the formulation was 20%. However, when carrier content was less than 14%, little amount of naproanilide diffused in the water and the herbicidal efficacy was extremely low.
These results indicate that this wettable powder packed in water soluble film containing 20% floating carrier has potential as a formulation which could reduce the labor of herbicide application in paddy fields.