Selectivity of herbicides sprayed in pre-emergency in crambe crop

Abstract

In Brazil, there are no herbicides registered for crambe (Crambe abyssinica Hochst), and little is known about the selectivity of herbicides over this crop. Therefore, two experiments were conducted, simultaneously, in plastic green house, with the objective of evaluating the selectivity of herbicides sprayed in pre emergency over crambe crop initial development. In the first study, it was evaluated the answer-dose of herbicides treatments trifluralin (225, 450, 675 and 900 g ha-1), alachlor (240, 480, 720 and 960 g ha-1) and pendimethalin (250, 500, 750 and 1000 g ha-1), in factorial scheme (3x4) +1, represented by herbicides (three) and doses (four) factors and a check. In the second experiment, four herbicides tank mixtures were analyzed: trifluralin + alachlor (450+480 g ha-1), trifluralin + pendimethalin (450+500 g ha-1) and alachlor + pendimethalin (480+500 g ha-1) and a check. In both studies, vases containing 4 dm3 of soil were used in randomized entirely design with eight replications. Crambe crop was extremely sensitive to pre emergency herbicides evaluated. Only trifluralin, in doses inferior to 450 g ha-1 , demonstrated selective to crambe crop. Thus, it was evident the need for more comprehensive studies aimed to assessing the selectivity of herbicides to crambe crop.