Aims: This study aimed to evaluate the control of Eleusine indica Gaertn. and Digitaria insularis (L.) Fedde through the combination of soil cover with green manure straw and herbicides applied in pre-emergence. Study Design: Each weed species was evaluated in different experiments. The experiments were set up in a greenhouse in a completely randomized design and arranged in a factorial scheme (5×4)+2, with four replications. Place and Duration of Study: Center of Agricultural Sciences, São Paulo, Brazil, from May 2019 to May 2020. Methodology: Seeds of Digitaria insularis and Eulesine indica were sown at a depth of 1 cm from the soil surface. Then, the pots were watered, and the straw of Cajanus cajan, Sorghum bicolor, Crotalaria juncea, Crotalaria spectabilis, and Crotalaria breviflora was deposited on the surface. The pre-emergence herbicides trifluralin (900 g ai ha−1), pendimethalin (1200 g ai ha−1), clomazone (1000 g ai ha−1), and s-metolachlor (1920 g ai ha−1) were applied one day after the weed seeds were sown. The percentage of weed control was evaluated at 10, 20, and 30 days after emergence (DAE). The plant shoot was cut at 30 DAE and the weight of dry biomass was determined. The control without herbicide and with soil cover crop and no herbicide and no soil cover were also evaluated. Results: Sorghum bicolor, Cajanus cajan, and Crotalaria breviflora were the most effective in controlling Eleusine indica when no herbicide was applied. Only Sorghum bicolor showed a satisfactory control of Digitaria insularis without the use of chemical management (above 80%). The association of pre-emergence herbicides with soil cover showed high control of weeds. Conclusion: The results showed that the association between chemical and cultural methods is an effective alternative to control Eulesine indica and Digitaria insularis.

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.