SELETIVIDADE DE HERBICIDAS APLICADOS EM PRé E PóS-TRANSPLANTIO DE ABóBORA JAPONESA

摘要

The slow initial growth and the small size of the pumpkin favor the establishment of weeds in the cultivated areas, requiring adequate management so that there is no reduction in productivity. However, there are currently no herbicides registered for pumpkin cultivation. Thus, the objective was to verify the selectivity of herbicides in pre and post-planting Japanese pumpkin seedlings. The experiments were conducted in a randomized block design with four replications. For pre-planting and post-planting applications, treatments were composed of herbicides; flumioxazin (30 g a.i. ha-1), oxyfluorfen (240 g a.i. ha-1), clomazone (600 g a.i. ha-1), fomesafen (250 g a.i. ha-1), fluzifop-p-butyl (125 g a.i. ha-1) and the control. In addition, a pre-planting treatment with paraquat (400 g a.i. ha-1) was tested. Visual intoxication was evaluated 7, 14 and 21 days after herbicide application (DAA). At 21 DAA, plant height, stem diameter, number of leaves and dry matter of aerial part, root and total were evaluated. The herbicides oxyfluorfen (240 g a.i. ha-1), fomesafen (250 g a.i. ha-1), fluzifop-p-butyl (125 g a.i. ha-1) and paraquat (400 g a.i. ha-1) showed high selectivity in pre -planting japanese pumpkin seedlings, with low intoxication (between 0 and 4%), less dry matter loss and less variation in plant growth parameters. In post-planting, flumioxazin (30 g a.i. ha-1) did not show a significant reduction in dry matter and growth variables, but it caused poisoning greater than (24%). Fluzifop-p-butyl (125 g ia ha-1) and fomesafen (250 g ia ha-1) showed greater selectivity (intoxication between 0 and 4%) in post-planting when compared to the control and other herbicide treatments evaluated.