Revista Brasileira De Herbicidas 2017; 16(2): 91-102
Alternatives for the chemical control of voluntary plants of showy crotalaria in different application modalities
With the insertion of showy crotalaria as an antagonistic plant in areas with nematodes infestation history, the occurrence of volunteer plants from this species became common, making it necessary to adopt measures for their management. Thus, this work had the goal to evaluate the effectiveness of herbicides used on different species that where grown in rotation with showy crotalaria (C. spectabilis), aiming at its use in controlling volunteer plants from this species. Two experiments (herbicides applied in pre and post-emergence) were conducted on the field using the randomized block design, in (8×2)+1 factor scheme, with four replications. The variable evaluated in the experiments was the control percentage in different periods after treatment application; a plant stand was performed in the experiment with herbicides applied in pre-emergence. Atrazine and diuron, applied in pre-emergence, were the best treatments to control showy crotalaria volunteer plants; they did not suffer any influence from the applied dose. In addition to these, flumioxazin and fomesafen (60 and 375 g ha-1, respectively) were also good alternatives to control showy crotalaria in this application modality. For pre-emergent herbicides, with the exception of diuron (1500 g ha-1), all the other treatments were effective in controlling showy crotalaria in applications performed on plants with 2 to 4 leaves. As for the second application stage, 6 to 8 leaves, in addition to diuron (both doses), fomesafen applied in a lower dose (187.5 g ha-1), was not effective in controlling showy crotalaria, either.
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