Influence of Sulfonylurea and Other Herbicides on Selected Woody and Herbaceous Species

Abstract

Chlorsulfuron and metsulfuron were effective on Texas whitebrush, killing 70 to 75% of the plants at 0.28 kg ai ha, marginally effective on Macartney rose, killing 15 to 43% of the plants at 1.12 kg ha, but ineffective on honey mesquite and huisache, killing no more than 10% of the plants at 1.12 kg ha. Sulfometuron was ineffective on all woody species at 1.12 kg ai ha. Clopyralid and picloram were effective, killing 70 to 92% of the huisache at 2.24 kg ae ha. Tebuthiuron killed 72% of the Texas whitebrush at 1.12 kg ai ha. Sulfometuron generally reduced herbaceous plant cover the year of application. Chlorsulfuron and metsulfuron often resulted in increased grass cover the year of application. Most herbicides reduced broadleaf weeds the year of application. Woolly croton often was the first prominent broadleaf species to return to areas treated with clopyralid and sulfometuron. Few differences occurred among herbicides in herbaceous weed cover the year following treatment.