Soybean Aphid

Soybean aphids are a serious pest for soybean crops in the Midwest. It’s important to scout for soybean aphids during growth stages R1 through R5, the most favorable time for their reproduction. The best management practices to combat the pest are to ensure you’re scouting frequently enough and sampling to determine if you need to apply chemical control.

Identification and Scouting

What It Looks Like

Soybean aphids are small, measuring in at less than 1/16 of an inch. Their bodies are yellow with black cornicles and may be winged or wingless.

Scouting Solutions

Scouting once or twice a week is important from the time of crop emergence through the full growth stage (R1-R6), with a critical monitoring period starting with beginning bloom through seed development. If you’re noticing high levels of activity, you should sample. The information on soybean aphids gathered during sampling will dictate when to apply chemical control. Here’s a sampling method to count affected plants with more than 250 soybean aphids per plant:

  • Count 20-30 plants roughly distributed that are representative of an entire field
  • Count the number of soybean aphids per plant
  • Note the soybean growth stage
  • Determine soybean stress level as a product of drought or other stressors

For more scouting solutions, information and insights — #TraitAnswers can help you make the right decisions for your fields.

Impact on Crops

A large presence of soybean aphids can affect plant growth rates and reduce yields. While damage varies significantly depending on individual field factors, yield losses of 10%-15% are not uncommon. It’s important to keep in mind that other plant stressors, such as drought, create a more favorable environment for soybean aphid reproduction rates and further exacerbate the pest problem.

Life Cycle

Eggs
Soybean aphids overwinter as eggs on buckthorn
Wingless Females
Eggs hatch into wingless females in the spring
Quick Cycles
Reproduction cycles are very quick, with several generations born in quick succession
Winged Females
A generation of winged females will be produced in June
Migration
Females will migrate into newly emerging soybean fields
Up to 18 Generations
Up to 18 generations can be produced on a soybean per season
Reproduction
During the fall, winged males and females migrate to buckthorn where they will lay eggs

Tracking

Weather plays a critical role in determining local potential for soybean aphid populations. With their preferred weather conditions, pest regeneration can be a matter of days. Here are some weather factors to look out for between planting your soybeans and the reproductive stages that indicate a need for close crop observation:

  • Temperatures between 75° F and 85° F
  • Light to moderate winds
  • Non-beating rainfall

Management

Regular scouting once or twice a week beginning during bloom and continuing through pod fill is important to monitor soybean aphid populations. This will help to determine when to apply chemical control. The action threshold is >250 soybean aphids per plant, which can be determined by using our sampling method. Spraying at this threshold works well from growth stages R1 through R5. For additional options for chemical application, consider choosing a solution like XtendFlex® soybeans.

Prevention

 XtendFlex® Soybeans

XtendFlex® soybeans (expected soon) will offer farmers the latest in the elite genetics they’ve come to know with the addition of glufosinate tolerance, helping farmers manage the weeds where soybean aphids make their home.

No dicamba may be used in-crop with XtendFlex® soybeans unless and until approved, and no dicamba formulations are currently registered for such use in the 2021 season.

*XtendFlex® soybeans have received full approval for planting in the United States but are pending approval in certain export markets. For 2020, XtendFlex® soybeans will be available as part of a stewarded introduction only to growers who have signed a 2020 XtendFlex® Stewardship Agreement and agree to follow the stewardship requirements.

*XtendFlex® soybeans have received full approval for planting in the United States but are pending approval in certain export markets. For 2020, XtendFlex® soybeans will be available as part of a stewarded introduction only to growers who have signed a 2020 XtendFlex® Stewardship Agreement and agree to follow the stewardship requirements.

Expert Advice

Trait Answers

Still have questions about protecting your soybean yield? The experts at #TraitAnswers have the information you need to make your next insect management decision your best one yet.