minireview: importance of herbicide-tolerant sunflower hybrids in suppressing common ragweed (ambrosia artemisiifolia) pollen production

Common ragweed (Ambrosia artemisiifolia) is the number one weed in Hungary: it covers ca. 5% of the arable land, causing huge losses in row crops, especially in sunflowers. In addition, because of the high allergenicity of its pollen, common ragweed is a heavy burden on the health care system. This minireview discusses the importance of use of herbicide-tolerant sunflower hybrids in eliminating common ragweed from sunflower fields, with special emphasis on the efficacy of common ragweed control of two acetolactate-synthase inhibitor postemergence herbicides (imazamox and tribenuron methyl) in several sunflower hybrids that carry the resistance gene against such herbicides. Common ragweed control by these herbicides was excellent: they suppressed the growth of the weed plant until the canopy closure of the crop (8-leaf stage). Common ragweed plants germinating after this date were unable to compete with the crop: although they survived, they remained small (ca. 70% reduction in height), produced ca. 90% less male inflorescences (source of the allergenic pollen), and caused no significant reduction in the crop yield. In order to stop the seed production by the few late-germinating weed plants we recommend a mechanical common measure (row-cultivator) in late August.