Isoxaflutole (5-cyclopropyl isoxazol-4-yl-2-mesyl-4-trifluoromethylphenyl ketone) is a novel herbicide for preemergence control of a wide range of important broadleaf and grass weeds in corn and sugarcane producing characteristic foliar bleaching activity in susceptible species prior to plant death. Following either foliar or root uptake, isoxaflutole is rapidly converted to a diketonitrile derivative (2-cyclopropyl-3-(2-mesyl-4-trifluoromethylphenyl)-3-oxopropanenitrile) by opening of the isoxazole ring. This diketonitrile undergoes degradation to a benzoic acid derivative (2-mesyl-4-trifluoromethyl benzoic acid) in treated plants and the extent of this degradation is correlated to the degree of susceptibility, being most rapid in tolerant corn and slowest in susceptibleAbutilon theophrasti.
- Anti-resistant: Isoxaflutole is effective against weeds resistant to other herbicide classes such as glyphosate and atrazine.
- Reactivation: The reactivation ability of Isoxaflutole has proven its value with herbicides for the corn market. Reactivation is the power to control weeds after they have emerged with an activating rainfall event. Many herbicides cannot control late-emerging weeds; therefore, the weeds survive to compete with the crop. Field studies show that through reactivation the active ingredient can be taken up by weed roots with just a half-inch or more of rain, bleaching and killing late-emerging weeds that are up to two inches tall.
Mode of action
Isoxaflutole inhibits the 4-hydroxyphenylpyruvate dioxygenase (HPPD) enzyme in plants. This enzyme is key to the production of pigments and the development of chloroplasts in plant tissues. By inhibiting pigment and chloroplast biosynthesis, emerging plant tissue is bleached (white to pale yellow).
Application & dosage
Can be applied burndown or pre-plant (as much as 21 days prior to planting) up to emergence.
Method of Application
- Isoxaflutole products are formulated as emulsifiable concentrates and water-dispersible granules (dry flowables) and applied through ground spraying equipment.
Dosage: Isoxaflutole was usually applied from 0.047 to 0.094 lb ai/A
The use rate of isoxoflutole ranges from 0.024 lb ai/acre for sandy soils to 0.188 lb for soils high in organic matter. The use rate for central Pennsylvania silt loam soils ranges from 0.071 to 0.094 lb ai/acre.