Revista Brasileira De Herbicidas 2001; 2(1-2): 13-18
Selectivity of herbicides applied in pre and postemergence of perennial peanut (Arachis pintoi)
Two experiments were installed under greenhouse conditions at Escola Superior de Agricultura “Luiz de Queiroz”, Piracicaba – SP, Brazil, in order to evaluate the dry biomass production and toxicity due to pre and postemergence herbicides on the perennial cover crop Arachis pintoi. The experiment was conducted in randomized complete blocks with four replicates. The herbicides sprayed in preemergence conditions (one experiment) were trifluralin at 0.25 kg/ha, diuron at 1.5 kgi ha, oxyfluorfen at 0.6 kg/ha, atrazine at 2.0 kg/ha, metolachlor at 2.88 kg/ha, and a control plot without herbicide application. In the experiment with postemergence herbicides, the treatments were fluazifop-p-butyl at 0.25 kg/ha, MSMA at 1.92 kg/ha, glyphosate at 0.72 kglha, ammonium glufosinate at 0.40 kg/ha, sulfosate at 0.96 kg/ha and a control plot without herbicide application. The evaluations were carried out at 30, 45, 60 and 75 days after pre-emergence herbicide treatments, and 7, 14, 21 and 28 days after post-ernergence herbicide treatments. The results showed that atrazine, glyphosate, arnmonium- glufosinate and sulfosate, at the sprayed rates, should not be applied on the cover crop; however, the herbicides trifluralin, oxyfluorfen and metolachlor can be sprayed at recommended crop rates, with some effects on the development of A. pintoi. Diuron, fluazifop-p-butyl and MSMA are fully selective to the green manure. It can also be concluded from the experiment, that, in general, pre-ernergence treatments are more selective to A. pintoi than post-emergence herbicides, causing lower toxicity and dry biomass reduction, when compared to post-ernergence herbicides.
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