With more weeds becoming glyphosate-resistant or surviving glyphosate-only applications, corn growers continue to rely on residual herbicides to manage tough weeds and protect their yield.

“We need to maximize the number of sites of action,” says Travis Legleiter, weed program science specialist at Purdue University. “We don’t have a lot of sites of action left to us, so we need to maximize what we do have available to us and rotate them as much as we can. Avoid applying any site of action more than two times in a growing season. By applying a site of action more than two times in a growing season, we’re putting pressure on those weeds to become resistant to it.”

Utilizing three non-glyphosate modes of action, SureStart controls more than 60 grasses and broadleaf weeds, including herbicide-resistant species such as marestail, common and giant ragweed, waterhemp and pigweed. This corn and soybean herbicide chart describes mode of action in greater detail, by herbicide class.

By eliminating weed pressure early, growers can protect corn during critical stages of development as well as optimizing yield potential. SureStart offers unmatched application flexibility for residual control of these weed threats and many others for up to six weeks.

Watch for these five high-anxiety weeds that could threaten your corn yields this season:

Lambsquarters 

  • Trend: According to Weedscience.org, the lambsquarters population remains steady or is increasing in 20 states.
  • Germination timing: Summer annual; emerges in the spring; sets seed in late summer/fall and dies.1
  • 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, WY2

Marestail

  • Trend: In 2012, 23.8 percent of growers reported the presence of glyphosate-resistant marestail on their farms, 8 percentage points more than in 2011.4
  • Germination timing: Marestail is generally considered a winter annual weed. However, it can germinate eight to nine months out of the year. It may be shifting to more spring and summer germination as a result of cropping systems and herbicide use patterns.5
  • 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, WY2

Palmer amaranth

  • Trend: In 2012, 13.3 percent of growers reported the presence of glyphosate-resistant Palmer amaranth on their farms, 4.6 percentage points more than in 2011.4
  • Germination timing: Palmer amaranth has an extended emergence pattern, typically May to mid-July in the Southern United States. It has a rapid growth rate (up to 2½ inches per day) and high seed production, averaging 40,000 seeds per plant.6
  • Found in: AR, AZ, CA, CO, FL, GA, IL, KS, KY, LA, MA, MD, MO, MS, NC, NE, NJ, NM, NV, NY, OH, OK, PA, SC, TN, TX, UT, VA, WI, WV2

Waterhemp

  • Trend: In 2012, 16.5 percent of growers reported the presence of glyphosate-resistant waterhemp on their farms, 6 percentage points more than in 2011.4
  • Germination timing: Summer annual; waterhemp germination and emergence extends late into the growing season.
  • Found in: AL, AR, CA, CO, CT, DE,GA, IA, ID, IL, IN, KS, KY, LA, MA, ME, MI, MN, MO, MS, NC, ND, NE, NH, NJ, NM, NY, OH, OK, PA, SC, SD, TN, TX, VT, WA, WI, WV2

Velvetleaf

  • Trend: Velvetleaf has been hard to control with glyphosate alone and continues to show prevalence among row crops.
  • Germination timing: Summer annual. Emerges in the spring, sets seed in late summer/fall and dies.1
  • 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, WY2