AUXINIC HERBICIDES AND TEMBOTRIONE SPRAYED ON SEED-PROPAGATED ELEPHANT GRASS

Abstract

Elephant grass plants propagated by seeds are more likely to have injuries to herbicides, in their initial cultivation phase, when compared to those from cuttings. This work evaluated the tolerance of elephant grass implanted by seeds to auxinic herbicides and tembotrione. Two experiments were conducted in the municipalities of Valença, Rio de Janeiro State, Brazil, and Coronel Pacheco, Minas Gerais State, Brazil. The experimental design was in randomized complete blocks, with four replications. The experimental treatments were: Auxinic herbicides [fluroxypyr + picloram (0.16 + 0.16 kg ae ha^-1); fluroxypyr + aminopyralide (0.16 + 0.08 kg ae ha^-1); fluroxypyr + triclopyr (0.16 + 0.48 kg ae ha^-1); 2,4-D (1.34 kg ae ha^-1); 2,4-D + picloram (0.72 + 0.045 kg ae ha^-1)] and tembotrione (0.084 kg ai ha^-1), in addition to the control without herbicides. Tembotrione was the most phytotoxic treatment to elephant grass propagated by seed, causing leaf bleaching and, consequently, reduced forage dry matter yield. The treatments with fluroxypyr + picloram, fluroxypyr + aminopyralide, fluroxypyr + triclopyr, 2,4-D and 2,4-D + picloram did not cause symptoms of phototoxicity capable of providing reduction in forage productivity, being potential herbicides for spraying in seed-propagated elephant grass fields.