Herbicides, Pyridine Carboxylate

Abstract

The pyridinecaboxylates, dithiopyr, and thiazopyr are a new class of mitotic inhibitor herbicides used for the control of grasses and small‐seeded broadleaf weeds in turf, rice, and oranges and grapefruits. Dithiopyr and thiazopyr are the commercial entries from a large patent estate and share the common characteristic of having bis‐pentafluoro alkyl substitutions at the 2′ and 6′ positions on a pyridine ring. The pyridineczrboxylates have high unit activity, low water solubility, and bind tightly to organic matter, properties that are similar to the dinitroaniline herbicides. The pyridinecarboxylates have low mammalian and avian toxicity, and they are rapidly metabolized and eliminated. Discovery and understanding of the enzyme systems responsible for pyridinecarboxylate metabolism has led to the isolation of the genes for these systems. Transformation of plants with these genes has resulted in plants tolerant to pyridinecarboxylates.