Evaluación de herbicidas sulfonilureas para el control de malezas en cafetales

Evaluation of sulfonylurea herbicides for weed control in coffee plantations To evaluate the efficiency for weed control of sulfonylureas herbicides in coffee tree plantations (Coffea arabica L.), a test was conducted in the locality of Villa Nueva, Lara State, Venezuela. The experimental design was a randomized complete blocks with six treatments and four repetitions. The treatments were: uncontrolled weed (control), hand weed control (with cane knife) and four chemical controls (glyphosate 1230 g a.i.·ha -1 , rimsulfuron 30 g a.i.·ha -1 , metsulfuron-metil 10.8 g a.i.·ha -1 and nicosulfuron 45 g a.i.·ha -1 ). The test was run in two steps, and cover of ground by weeds, weed control by species, damage to the crop, level of weed control, fresh biomass of weeds, and days of control were evaluated. In general, the use of herbicides resulted to be more effective than control by the manual method. Glyphosate was better for weed control in coffee plantations than all sulfonylureas under this trial conditions. Among the sulfonylureas, nicosulfuron and metsulfuron-metil distinguished in the control of weeds, although with limitations in the control of certain species. Nicosulfuron was the sulfonylurea that most limited weed biomass, but it needed more than a one application to reach good weed control whereas metsulfuron-metil and glyphosate produced acceptable levels of weed control with fewer applications. The sulfonylureas nicosulfuron and metsulfuron-metil can be used for the control of particular species as alternative to traditional herbicides used in coffee plantations, and can be considered effective tools for integrated weed management in this crop.