Effect of Sugar and Alcohol Industry Byproducts on Pre-Emergence Herbicide Efficacy

The present study evaluate the effects of vinasse and filter cake on the efficacy of indaziflam, saflufenacil, and sulfentrazone for the control of morning glory (Ipomoea triloba L.) and crabgrass (Digitaria horizontalis Wiild), as well as the effects of these byproducts on the emergence of these weeds. The experiments were established in a greenhouse with a completely randomized design and four replications at the Agricultural Science Center, Sao Paulo, Brazil, between May 2017 and May 2018. In the first assay, four herbicide doses: indaziflam (0, 37.5, 75, and 150 g ai ha-1), saflufenacil (0, 42, 84, and 168 g a.i ha-1), and sulfentrazone (0, 300, 600, and 1200 g ai ha-1) were applied for pre-emergent weeds in three soil covers (without byproduct, with vinasse, and with filter cake).In the second assay, seven treatments were evaluated, comparing the effects of the different vinasse and filter cake doses, and absence of byproduct on the weeds emergence. When the doses required for 80% effective control were considered, the results showed that for indaziflam, the filter cake negatively affected crabgrass control. In contrast, vinasse had a positive effect on morning glory control by saflufenacil. For sulfentrazone, the filter cake had a negative effect, requiring twice the dose used on the treatment without byproduct for effective morning glory control. Relative to assay 2, the vinasse addition affected the emergence of morning glory but not of crabgrass; however, the filter cake increased the weed biomass accumulation. Vinasse and filter cake byproducts can negatively or positively affect the performance of pre-emergence herbicides, according to the active ingredient used. However, these effects occur at doses below those recommended for the herbicides. Byproducts can affect the emergence and the weed biomass accumulation.