Efecto del uso de metsulfuron-metil y glifosato sobre malezas asociadas a cafetales en Venezuela

with the objective of evaluating weed control in coffee plantations (coffea arabica l.) with emphasis in the bracken fern (pteridium aquilinum l. kuhn) and the effect of the continued use of the herbicides glyphosate and metsulfuron-metil on the flora associated to the crop, two tests were conduced in a plantation located in bruzual county, yaracuy state, venezuela. a randomized block design was used with four repetitions and the following five treatments: control, hand weeding, glyphosate (1920 g·ha-1), metsulfuron-metil (9 g·ha-1), and glyphosate+metsulfuron-metil. in test i total cover of weeds (tcw) in four groups (broadleaf, grassweed, cyperaceae and ferns) and fresh biomass of weeds were evaluated. in test ii the number of plants of bracken fern by square meter was evaluated. there were significant differences in tcw for the herbicides, with reductions of 25, 35 and 66 % for glyphosate, metsulfuron-metil and the mixture, respectively. besides, a differential effect among the groups of present weeds, occurred, which indicates the property that have those herbicides in continuous form during a period of relatively short time (374 days) to modify the composition of the weed populations associated to the coffee plantation. with the mixture of herbicide the smallest values of weed biomass was obteined, followed by the treatments of glyphosate and metsulfuron-metil. the treatments with glyphosate, metsulfuron-metil, and the mixture reduced the populations of bracken fern in 56, 87, 73 % respectively with respect to the initial values.