Initial growth of tree species under herbicide drift

Abstract

The present study aimed to evaluate the effect of different doses of the herbicides picloram, glyphosate, glyphosate + 2.4-D, and 2.4-D on the survival and growth of the tree species Croton floribundus and Heliocarpus americanus and Myrsine coriacea.The experimental design was completely randomized with four replicates. The tree species were sprayed with 0; 2.5; 5; 10; 20; 40; 60; 75; 90 and 100% of the commercial dose of each herbicide. The percentage of phytotoxicity, chlorophyll content, height, stem diameter, leaf area and aerial dry biomass of the species were evaluated. For H. americanus, the herbicides glyphosate, 2.4-D and glyphosate + 2.4-D were phytotoxic. Among the evaluated herbicides, picloram was the most phytotoxic for all species. Glyphosate presented lower phytotoxicity at lower doses for M. coriacea compared with C. floribundus and H. americanus. A negative impact of 2.4-D was verified in all species, even at the lowest doses. The mixture glyphosate + 2.4-D also presented high phytotoxicity, with lower values for the species M. coriacea. The results showed that the application of these herbicides should be directed and protected, and even low dosages have deleterious effects on these species.

Keywords

• Phytotoxicity
• Restoration
• Herbicides