The efficiency of different herbicide combinations for weed control and tolerance and yield of UFVM2 popcorn maize were evaluated. The herbicide treatments and respective doses were: atrazine (1.500 g ha-1); foramsulfuron + iodosulfuron methyl sodium + atrazine (15+1+1.500 and 30+2+1.500 g ha-1); foramsulfuron + iodosulfuron methyl sodium (15+1, 30+2, 45+3, and 60+4 g ha-1); nicosulfuron + atrazine (8+1.500 and 16+1.500 g ha-1) and nicosulfuron (16 g ha-1). The herbicides were applied 25 days after crop emergence. The predominant weeds in the area were Brachiaria plantaginea, Brachiaria decumbens, and Ipomoea spp. The herbicides foramsulfuron + iodosulfuron methyl sodium in all doses provided the highest rates of toxicity in popcorn maize 7, 14, and 28 days after application (DAA). All herbicide combinations controlled over 90% of B. plantaginea and B. decumbens up to the 28 DAA. Nicosulfuron controlled only 80% with no atrazine control being observed. The competition with the weeds resulted in lower contents of total chlorophyll, N, P, and K in the leaf tissue of the popcorn maize plants and smaller grain yield. For the UFVM2 cultivar, the sulfonylureias isolated or associated to atrazine had no effect on the nutritional state of the culture, yield and kernel expansion volume of the maize-popcorn.
competition; sulfonylureias; atrazine
