Management of <i>Tithonia diversifolia</i> (hemsl.) A. gray with herbicides as a strategy to reduce biological invasion of the species

This study evaluated the efficiency of herbicides used in pre and post-emergence to control <i>Tithonia diversifolia</i>. The first study tested atrazine, oxyfluorfen, fomesafen, and nicosulfuron in pre and initial post-emergence applications. Post-emergence applications of glyphosate, glufosinate ammonium, 2,4-D, and picloram targeted young plants of seminiferous and vegetative origin. In the field, glyphosate, 2,4-D, and picloram were tested for adult plants. A control treatment without herbicide application was included for comparison. Atrazine, oxyfluorfen, and fomesafen achieved 100% control in pre and initial post-emergence, whereas nicosulfuron was ineffective against the species. Picloram provided excellent post-emergence control (>99%) of adult plants in the field and young plants from seeds and cuttings, even at doses lower than those recommended for other species. Glyphosate effectively controlled young plants, but doses above 2400 g a.e. ha^-1 were necessary for adult plants. Ammonium glufosinate at a dose of 800 g a.e. ha^-1 promoted control of over 80% in seedlings from seeds and cuttings. Higher doses of 2,4-D effectively controlled both adult and young plants. Glyphosate, 2,4-D, and picloram effectively controlled both young and adult plants. The study provides an alternative to control <i>T. diversifolia</i>, this important invader of natural and agricultural systems in tropical and subtropical regions.