The present work evaluated the selectivity, efficacy and soil persistence of imazamox applyied to edible bean. The experiments were carried out from 1995 to 1997. In the selectivity experiments we tested: imazamox (20, 30 e 40 g/ha), imazamox + bentazon (30+480 g/ha), imazamox + fomesafen (30+125 g/ha) and control with no herbicides with the varieties, Pérola, Jalo Precoce, Novo Jalo and Xamego. The selectivity experiments were maintained weed-free by hand, and the visual fitotoxicity and grain yield were evaluated. The efficacy experiments tested the effects of imazamox (20, 30 and 40 g/ha), bentazon (480 g/ha), fomesafen (125 and 250 g/ha) imazamox + bentazon (30+480 g/ha), imazamox + fomesafen (30+125 g/ha), bentazon/imazamox (480/30 g/ha, sequential application), fomesafen/imazamox (125/30 g/ha, sequential application), fomesafen/fomesafen (100/100 g/ha, sequential application), on the control of Euphorbia heterophylla and Bidens pilosa. To study the persistence of imazamox in soil we conducted experiments in Goiânia (clay) and Jussara (loamy sand). Imazamox (40 g/ha) caused injury on common bean which meant a 15% decrease in grain yield (average of experiments). The tank mix of imazamox and bentazon caused less injuries and improved grain yield by 8%. Imazamox (40 g/ha) was inefficient to control Bidens pilosa while it was able to control Euphorbia heterophyla. Sequential application of fomesafen/imazamox (125/30 g i.a./ha) was efficient to control Bidens pilosa and Euphorbia heterophyla. The persistence of imazamox in soil, at both locations, was longer in 1995 than 1996. This was due to higher soil moisture content in 1996 than 1995. The rotational crops most sensitive to imazamox residues were, in decreasing order: sorghum, corn and rice. The period between herbicide application and rotational crop planting (INP) varied according to the sensitivity of that crop to the presence and persistence of herbicide residues in the soil. The INP for Imazamox (40 g/ha) ranged from 68 to 111 days for corn, 78 to 139 days for sorghum, and 25 to 75 days for rice.
Phaseolus vulgaris; herbicide; bioassay; residual activity