Isoxazolopyridines—a novel chemical cluster and a new (?) mode of action for dicot weed control

Isoxazolopyridines were identified as an herbicide class via random greenhouse screening, and structure–activity relations revealed good postemergence control of a large set of dicotyledon weed species. The selectivity of isoxazolopyridines to monocot crops was investigated and can be explained by differential biokinetics in grasses versus dicots. Initial mode-of-action studies, indicating an effect on plant carbohydrate metabolism, was supplemented by more in-depth studies indicating a possibly new target site within the photosystem.