Selective Postemergence Herbicides for Grass Control in Sunflower (Helianthus annuus L.)

Selective postemergence herbicides to control grass weeds in broadleaf crops have become available in recent years. However, the efficacy of these new herbicides in controlling grasses in sunflower has not been extensively evaluated. Field experiments were conducted to evaluate five selective herbicides for their efficacy on crabgrass ( Digitaria sanguinalis L. Scop) and barnyard grass ( Echinochloa crusgalli L. Beav.) control in sunflower ( Helianthus annuus L.) in 1983 and 1984. Commercial sunflower varieties, Interstate 7775 and Stauffer 3101 were planted on Calloway silt loam and Portland clay in 1983 and 1984, respectively. Herbicides were applied when sunflower was 10 cm tall, at 4- to 5-leaf stage, and target grass weeds at the 3- to 4-leaf stage. All herbicides, sethoxydim, xylofop-ethyl, haloxyfop, fluazifop butyl, and CGA 82725, gave good to excellent control of the target weeds. Herbicide injury to sunflower ranged from very minor to none. None of the herbicides greatly affected yield, test weight, seed weight, head diameter or plant height of sunflower. Difference in soil types tended to influence the effectiveness of herbicides.