A greenhouse experiment was conducted to evaluate the efficacy of the herbicide diclosulam (doses 21.8 and 25.2 g .i.a.. ha- 1) associated with Sorghum bicolor L. Moench mulch in controlling Ipomoea grandifolia and Sida rhombifolia. The treatments consisted of different modes of herbicide application, over and under the mulch, under different moisture conditions. The vases were filled with soil and the weeds were sown superficially and later covered with S. bicolor (6 t ha-1) mulch. The experimental design was completely randomized with four repetitions. The control was evaluated visually, through percent note scale and counting of the plants, besides dry mass evaluation. High control levels of diclosulam were observed at the lowest dose used (21.8 g a.i. ha-1) when applied directly on the soil, with or without mulch, or over the mulch and followed by 0 mm rainfall. The highest dose (25.2 .i.a. ha-1) promoted high levels of weed control efficacy under the different modes of herbicide application, except over wet or dry mulch without rainfall.
weed; mulch; no-tillage
