Revista Brasileira De Herbicidas 2000; 1(1): 11-16
Effect of preemengence herbicides diclosulam and metolochlor for Sida rhombifolia control in soybean
DOI: 10.7824/rbh.v1i1.308
An experiment was conducted on a Cerrado oxisol during 1996/97. The objective of experiment was to evaluate the effects of diclosulam and metolochlor alone or in combination, in preemergence control of Sida rhombifolia in soybean. The experimental design was a complete randomized block with four replications. Treatrnents were as follows: diclosulam at 25 and 35 g/ha, diclosulam + metolachlor at 25+1200,25+1800,35+1200 and 35+1800 g/ha, metolachlor at 1200,1800 and 2400 g/ha, and a tank mix of chlorimuron + lactofem at 1.5+96 g/ha used for comparison. A weedy and a weeded control were also included. Soybean seeds (BR-16 cultivar) were sowed December 5. 1996 and herbicides applied in the same day using a back sprayer, with four 110-02XP nozzles, operated at 2,45 kg/cm- to deliver 200 Ilha. Diclosulam and diclosulam + metolachlor at the smaller rates gave good control of S. rhombifolia, with no significant differences to the highest dosages. Metolachlor at 1800 and 2400 g/ha contralled about 80% of the weed. These results were significantly different frorn the results with diclosulam and diclosulam + metolochlor. Due to adverse climate condition in the area, chlorimuron + lactofen was applied when S. rhombifolia had 4-12 leaves and 5-25 em high. After 49 days chlorimuron + lactofen had controlled 80% of S. rhombifolia, wich was equal to metolachlor (2400 g/ha) results. Diclosulam and diclosulam + metolachlor gave less than 5% toxicity to soybean. lt was concluded that diclosulam at 25 g/ha and diclosulam + metolachlor at 25+ 1200 g/ha gave good control of S. rhombifolia.
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