Soybean Response and Weed Control With Flumioxazin, and Sorption, Degradation, and Weed Control With Isoxaflutole

Isoxaflutole is a new herbicide for selective use in field corn to control a wide range of grass and broadleaf species. It exhibits a new mode of action, inhibition of 4-hydroxyphenylpyruvate dioxygenase, an enzyme found in the pathway for carotenoid biosynthesis. In field studies conducted in 1998 and 1999 at Urbana and Dekalb, a wide range of isoxaflutole rates were tank-mixed with S-metolachlor/atrazine to compare velvetleaf density, weed control, corn injury, and corn yield. Herbicide applications were made at three different timings: early preplant, preplant incorporated, and preemergence. The environmental fate of isoxaflutole was characterized in sorption and degradation studies. In a qualitative kinetic evaluation, the hydrolysis of isoxaflutole was found to be more rapid in a soil solution than in a soil-free system. The sorption of isoxaflutole was 6 to 12-fold greater for isoxaflutole than diketonitrile based on Freundlich Kd values calculated from batch isotherms. The effect of moisture, temperature, and biological activity on isoxaflutole degradation was investigated in 56-day laboratory incubations. In the soil, isoxaflutole rapidly hydrolyzed to diketonitrile, which was subsequently metabolized to the inactive benzoic acid derivative. Degradation was moisture and temperature dependent. In sterile soil, the conversion of isoxaflutole to diketonitrile was similar to non-sterile soil, but the transformation of diketonitrile to benzoic acid and the production of unknown products were greatly reduced.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Agronomy

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Lovell, Sarah Taylor

Contributors dc:contributor

• Wax, Loyd M.

• Agriculture, Soil Science

Language dc:language

eng

Identifier

(MiAaPQ)AAI9990066

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/87690