Selectivity and herbicides efficiency pre-emergence applied in papaya crop

Abstract

In papaya culture, there is little information on selective herbicides when pre-emergence applied. A field experiment was conducted to evaluate the selectivity and efficacy of herbicides pre-emergence applied to control weeds in papaya cultivation. The experiment was conducted in a randomized blocks design with four replications. The treatments were: ametryn (1500 g ha^-1 i.a.), diuron (1500 g ha^-1 i.a), ametryn + diuron (1500 + 1500 g ha^-1 i.a.), flumioxazin (50 g ha^-1 i.a.) and isoxaflutole (150 g ha^-1 i.a.), applied pre-emergence of weeds and before transplanting the papaya seedlings, as well as two controls, one kept in clean through hoeing and another without weed control. At 7, 14, 21 and 28 days after application (DAA) of the herbicides visual assessments of intoxication in papaya plants were made at 0, 28, 42, 56 and 72 DAA, plant height and stem diameter were evaluated, and at 21, 42 and 63 DAA the dry matter weight of the weed plants were evaluated. The herbicides ametryne, diuron, flumioxazin and the mixture ametryn + diuron caused the death of papaya seedlings, and isoxaflutole caused poisoning in seedlings with subsequent recovery. The weed interference resulted in papaya plants with smaller stem diameter, although the plant height was not influenced.