Common ragweed is a highly competitive broadleaf weed that emerges early in the season and can threaten yield if left uncontrolled. Read the latest news on common ragweed and find helpful weed management information from Ryan Keller, Dow AgroSciences Enlist™ field specialist.
- Various types: Annual ragweed1
- Scientific name: Ambrosia artemisiifolia1
- Grass or broadleaf: Broadleaf
- Found in: AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY1
- Germination timing: Common ragweed germinates in early to mid-spring. When soil temperatures rise in late spring and early summer, common ragweed germination begins to taper off, according to Ryan Keller, Enlist field specialist, Dow AgroSciences.
- Common ragweed is extremely competitive and impactful to yield when it emerges or germinates at the same time as the crop emerges. If it isn’t controlled before planting, common ragweed’s early germination allows it to interfere with crop growth at critical times in its development.
- It tends to be more competitive in soybeans than in corn. Corn is a taller plant and shades weed competition. In addition, there are more effective herbicide options to control common ragweed in corn than soybeans.
- When left to grow with the crop, common ragweed can significantly reduce yield.2 A 30 percent yield reduction in soybeans can occur from a common ragweed density of two plants per 10 feet.3
- Resistance to glyphosate and acetolactate synthase (ALS) herbicides is not the only herbicide efficacy problem of common ragweed. Stem boring insects hollow out the inner stem of this weed species. When that occurs, herbicides do not translocate properly to provide adequate control of the weed.2
- The seed of common ragweed has very little to moderate dormancy in the soil. It takes less than one year for the seed bank to be reduced by 50 percent and about 10 years for 99 percent depletion.3
- Common ragweed can grow as tall as 3 to 6 feet. Its hairy stems are green to light pinkish-red. The leaves are up to 6 inches long and 4 inches across. The leaves are compound, deeply cut into lobes and usually much wider at the base than the tip.2
According to WeedScience.org:
- Herbicide classes
- Multiple resistance: two sites of action
*Resistance confirmation does not necessarily include all weeds and may vary among different areas of each state.
Weed management tips:
According to Keller:
- Common ragweed typically emerges in undisturbed seedbeds like those found in no-till fields. Pay extra attention to fields that are managed with no-till or minimal tillage.
- Scout areas of the field that tend to have standing water or are prone to leaching because common ragweed thrives in low-fertility environments.
- Control common ragweed with residual preemergence herbicides that have multiple modes of action, such as SureStart® II herbicide in corn and Sonic® herbicide in soybeans. It’s important to use preemergence herbicides to control common ragweed before early season weed competition occurs.
- Monitor fields seven to 10 days after herbicide applications to confirm common ragweed is controlled. If acceptable control hasn’t been obtained, rotate modes of action to a non-ALS or non-glyphosate application.
Dow AgroSciences weed control solutions:
More information can be found through these weed science resources: