Methiozolin

Methiozolin is an oxazoline herbicide designed for selectively controlling annual bluegrass in turfgrass. At low concentrations, it strongly inhibits the biosynthesis of cellulose and hemicellulose in maize root cells. Methiozolin also inhibits recombinant Arabidopsis tyrosine aminotransferase, with an IC50 of approximately 200 µM. In addition to effectively controlling vegetative growth, methiozolin significantly inhibits inflorescence formation, aiding in seed bank reduction.

Methiozolin applied via a CO2-pressurized track sprayer (300 L ha^-1, 280 kPa) at doses of 250-4000 g a.i. ha^-1 is safe for turfgrass up to 1000 g a.i. ha^-1. Higher doses (2000-4000 g a.i. ha^-1) may cause temporary, reversible phytotoxicity, which subsides within 6 weeks post-application. Methiozolin (500-2000 g ha^-1; foliar application) dose-dependently inhibits Poa annua seedhead formation, with stronger suppression of seedhead number than length, achieving over 80% inhibition at 2000 g ha^-1. Its herbicidal action on Poa annua through foliage and soil sprays is entirely reliant on soil absorption, as foliar application alone is ineffective, while soil treatment alone mirrors the efficacy of combined approaches. When applied in autumn with a handheld sprayer (500-1000 g a.i. ha^-1; 1000 L ha^-1 every 3 weeks for a total of 12 applications), methiozolin achieves optimal control of Poa annua (approximately 90%-100%) and causes temporary, reversible damage to creeping bentgrass, clearing by June. Spring applications exhibit lower efficacy (40%-60%) without lasting damage.