Revista Brasileira De Herbicidas 2014; 13(1): 8-14
Effect of herbicides applied as direct spray in the initial development of jatropha plants
The objective was to evaluate the effect of glyphosate, paraquat and glufosinate-ammonium applied as directed spray in initial development of jatropha plants. A randomized block design was used, with five replicates. The treatments consisted of glyphosate (180, 360, 720 and 1,440 g ha-1), paraquat (100, 200, 400 and 800 g ha-1) and glufosinate-ammonium (125, 250, 500 and 1,000 g ha-1) and a control (no application). Herbicide application was performed at 145 days after sowing, with spraying directed to the lower third middle of the plants. The rates glyphosate provided average phytointoxication of 2.4% and no reduction in leaf area, however, there was an average reduction of 9.0% of dry weight at 35 days after application (DAA). Paraquat, for rates ≤ 200 g ha-1, phytointoxication was lower than 20% to 35 DAA, however, there was a reduction in leaf area and plant dry mass of 47.0 and 18.2%, respectively. The rate of 125 g ha-1 glufosinate-ammonium was the one that gave the lowest values of phytointoxication (<20.0%), reduction in leaf area (2.7%) and dry mass (10.5%) plants up to 35 DAA. It was concluded that the contact of paraquat and glufosinate-ammonium with stems and lower leaves may impair the initial development of jatropha. However, application of glyphosate direct spray did not impair the initial development of jatropha, regardless of the rate used.
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