Selectivity of Pre-Emergence Herbicides to Physic Nut (Jatropha curcas)

In recent years, the areas cultivated with physic nut (Jatropha curcas) have expanded in Brazil, aiming at its use in biofuel production. However, one of the problems faced by the producers is the lack of studies on its tolerance to the herbicides registered in Brazil. The objective of this work was to evaluate the tolerance of physic nut genotypes to herbicides applied at pre-emergence. The experiment was arranged in a randomized block design, with four replications, in a factorial design, 3 x 6. Factor A was composed by the genotypes (Filomena, Goncalo and Paraguacu), and factor B by the herbicides (isoxaflutole, oxyfluorfen, sulfentrazone, pendimethalin and tebuthiuron), plus one non-treated control. Intoxication by the herbicides was evaluated at 19, 32, 40, 48, 56 and 64 days after treatments (DAT). Height, leaf area, and plant dry matter were evaluated at 64 DAT. It was verified that the jatropha genotypes have different tolerance to the herbicides studied. Isoxaflutole and tebuthiuron caused severe injuries to all genotypes and negatively affected all the variables evaluated. On the other hand, oxyfluorfen and pendimethalin proved to be selective to the crop and should be evaluated in further studies to be recommended to the crop.