Isoxaflutole

Biochemistry Rapidly metabolised in plants, and in the soil, by opening of the isoxazole ring, to form a diketonitrile, which is the active species (K. E. Pallett et al., Pest Manag. Sci. 57, 133 (2001) and refs. therein); this is a p-hydroxyphenyl pyruvate dioxygenase inhibitor. This enzyme converts p-hydroxyphenyl pyruvate to homogentisate, a key step in plastoquinone biosynthesis. Inhibition leads to indirect inhibition of carotenoid biosynthesis, giving rise to chlorosis of new growth. Mode of action Systemic by either root or foliar uptake. Uses Broad-spectrum grass and broad-leaved weed control in maize and sugar cane. Applied at 75-140 g/ha pre-emergence or pre-plant; the spectrum can be enhanced by mixture with other active ingredients. Formulation types SC; WG; WP.