Blog Post

Winter Annual Weeds and SCN: A Problematic Pair

Agronomic image of purple deadnettle

Alone, winter annual weeds can cause a headache for soybean growers the following season by potentially leading to delayed planting, lower yields and increased seedbed preparation costs. Combined by acting as the overwintering host to soybean cyst nematode (SCN), the most economically damaging soybean pest in the U.S., these weeds may further lower soybean production. The Purdue University Extension identified 6 winter weeds that can serve as hosts for SCN:

  • Purple deadnettle
  • Henbit
  • Field pennycress
  • Shepherd’s purse
  • Small-flowered bittercrest
  • Common chickweed

SCN juveniles feed on the roots of these weeds. On some weeds, such as purple deadnettle (pictured above) and henbit, SCN can complete several life cycles before planting begins the following spring. Greenhouse studies ranked purple deadnettle and henbit as strong hosts because SCN reproduction on those 2 weeds either equaled or exceeded reproduction on SCN-susceptible soybeans.

Controlling these 6 weeds should be an important goal within any farm’s SCN management program. Scout fields now for winter annual weeds and remove them prior to planting. As the next step in an effective SCN management program, growers should plant and enhance them with a seed-applied nematicide like Clariva® Complete Beans seed treatment, a combination of separately registered products. Like most comprehensive crop protection programs, SCN management requires early action for better future yields.

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