Don’t let these high-anxiety pests threaten yield this season
Find the right crop protection solution to control pest pressure

Wednesday, February, 25, 2015 10:00 AM EST

• Learn which high-anxiety weeds and insects pose the greatest threat to corn and soybean fields this spring. 
• Pests such as marestail, waterhemp and soybean aphids can infiltrate fields if not properly controlled. 
• Dow AgroSciences offers a strong portfolio of crop protection solutions. 

INDIANAPOLIS — Midwest row crops are increasingly susceptible to pest pressure as aggressive weeds and insect outbreaks threaten yield.  

Dow AgroSciences offers a robust crop protection portfolio with advanced technology to help corn and soybean producers cultivate cleaner fields by preventing the spread of high-anxiety pests.

Before growers enter fields this spring, they should consider how to protect crops from these yield-robbing threats.

Weeds to Watch

With the increase of glyphosate resistance, it’s important growers rely on residual herbicides to manage tough weeds and protect yield potential.

“In 2014, growers saw certain weeds become more aggressive, bringing a greater level of competition to crops for essential nutrients and water,” says Luke Peters, corn herbicides product manager, Dow AgroSciences. “This spring, growers should plan ahead to protect their crops for a strong start.”

By knowing what weeds pose a threat to fields and finding the right herbicide program, growers can protect crops during critical stages of development and reduce early season competition.

Corn and soybean growers should consider SureStart® II herbicide and Sonic® herbicide to control weeds with multiple modes of action plus residual control that lasts into the growing season.

Understand the trends and patterns of three high-anxiety weeds that, when left to grow wild, can devastate yield.


  • marestailMovement: Marestail historically has been a troublesome annual broadleaf weed in reduced- or no-till situations. It grows quickly and can rapidly dominate a site, which puts it on the list of one of the most troublesome weeds to watch for this season, Peters says. An estimated 83 percent of soybean yield is lost from 105 marestail plants per 10 square feet.1
  • Germination timing: Marestail is generally considered a winter annual weed. However, it can germinate eight to nine months of the year. It may be shifting to more spring and summer germination due to cropping systems and herbicide use patterns.2
  • Percentage of control: Using 2.5 pints per acre of SureStart II preemergence followed by Durango® DMA® herbicide: 93 percent.*


Palmer amaranth

  • palmeramaranthMovement: Palmer amaranth has made its presence known in the Midwest over the last few years. Because of its rapid seed production — ranging from several hundred thousand to more than a million seeds per plant3 — early control is vital to stop its spread and protect yield potential.
  • Germination timing: Palmer amaranth has an extended emergence pattern, typically May to mid-July, and a rapid growth rate (up to 2 to 3 inches per day).3
  • Percentage of control in corn: Using 2.5 pints per acre of SureStart II preemergence followed by Durango DMA: 99 percent.*
  • Percentage of control in soybeans: Using 4 ounces per acre of Sonic preemergence: 94 percent.**


  • waterhempMovement: Waterhemp is an aggressive, small-seeded annual broadleaf weed. It has developed widespread resistance, grows quickly and is one of the greatest weed control challenges in corn and soybean fields because of its competitive nature, Peters says. Scouting throughout the growing season is required to recognize this weed early and ensure timely applications of herbicides and to identify problem areas in the field the following year.
  • Germination timing: A summer annual, waterhemp germination and emergence extends late into the growing season.
  • Percentage of control in corn: Using 2.5 pints per acre of SureStart II preemergence followed by Durango DMA: 97 percent.*
  • Percentage of control in soybeans: Using 4 ounces per acre of Sonic preemergence: 94 percent.**

Insects to inspect for this spring

In Midwest corn and soybean crops, insect pressure can vary widely depending on many factors. Production practices, crop rotation, geographic location and particularly spring weather will dictate which insect pests will make an appearance this season.

“Some of the usual suspects are corn rootworm, western bean cutworms and corn armyworms,” says David Martin, Dow AgroSciences insecticides product manager. “In soybeans, beetles, spider mites and soybean aphids are a few that growers should have on their scouting list.”

Cobalt® Advanced insecticide is a go-to insecticide for control of many of the major pests that growers encounter each year in soybeans, corn, alfalfa, sorghum and wheat. They include Japanese beetles, bean leaf beetles, corn rootworm beetles, spider mites and other insect pests.

Transform® WG insecticide brings a unique mode of action for leading control of soybean aphids. Transform features contact and ingestion activity and can be applied in a tank mix with herbicides and fungicides. 

Martin says soybean aphids can pose a significant risk to soybean production because of their tremendous reproduction potential. In season, the population size can double every two or three days if weather conditions are ideal.

Soybean aphids

  • soybeanaphidsCharacteristics: Soybean aphids are small, soft-bodied insects and can be winged or wingless. They proliferate quickly under ideal weather conditions. Aphids are sap feeders and leave a honeydew residue on the leaves of the crop. A heavy infestation can result in a 40 percent yield loss.
  • Timing: Soybean aphids normally are found in soybean fields from late May through August.
  • Control: Transform works through contact and ingestion and moves through the plant via systemic and translaminar activity, which provides excellent residual control of aphids after the soybean plant has been sprayed.

“The soybean aphid is definitely an insect pest to watch this year,” Martin adds. “During an outbreak year, heavy infestations can reduce yields by 40 percent or more.”

To learn more about SureStart II and Sonic, visit and or contact your local ag retailer. For more information about Transform and Cobalt Advanced, visit and

*Data collected from university field trials spanning 19 states from 2010-11.
**Data is from a combination of Dow AgroSciences and university trials.

1Michigan State University. 2015. Horseweed (Marestail) (Conyza Canadensis (L.) Cronq.).
2Shoup, D., and D. Peterson. 2011. Understanding and Managing Marestail.
3Hager, A. 2014. Management of Palmer amaranth in Illinois.

About Dow AgroSciences
Dow AgroSciences discovers, develops, and brings to market crop protection and plant biotechnology solutions for the growing world. Based in Indianapolis, Indiana, USA, Dow AgroSciences is a wholly owned subsidiary of The Dow Chemical Company and had annual global sales of $7.3 billion in 2014. Learn more at Learn more at Follow Dow AgroSciences on FacebookTwitterLinkedIn, and Google+, or subscribe to our News Release RSS Feed.

Sarah Woodhurst
Bader Rutter

Luke Peters
Dow AgroSciences

David Martin
Dow AgroSciences


Cobalt Advanced is a federally Restricted Use Pesticide. ®DOW Diamond, Cobalt, DMA, Durango, Sonic, SureStart and Transform are trademarks of The Dow Chemical Company (“Dow”) or an affiliated company of Dow. Cobalt Advanced, Durango DMA, Sonic, SureStart II and Transform WG are not registered for sale or use in all states. SureStart II is not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.