Soybean Aphids: Time To Scout

Aug 08, 2022

By David Kee

According to the latest USDA-NASS report, 66% of the Minnesota soybean crop is rated good to excellent and about 81% of the crop is in flowering (five days behind the five-year average). It looks like certain areas may be in position to produce a decent crop. However, reports from across the state indicate that soybean aphids are present in increasing numbers.

The foundation of a good Integrated Pest Management (IPM) program is a properly implemented scouting program. With the development of pyrethroid resistance, using the threshold of 250 aphid per-plant and a majority of the plants infested is critical for the stewardship of our chemical resources. Utilization of the threshold also allows the predators such as ladybugs, and a growing population of the Aphelinus certus parasitic wasp, to keep the aphid population below damaging levels. This saves time and expense of spraying an insecticide until needed. Some salespeople will still suggest throwing in some insecticide, usually a generic “Warrior” with your fungicide application, regardless of the scouting reports. However, this kind of thinking can lead to the development of pesticide resistance.

Minnesota Soybean checkoff resources support several exceptional entomology projects. Listed below is a recent article developed by Bob Koch and Bruce Potter. We lost chlorpyrifos, but we have three relatively new insecticides (Sivanto, Transform and Sefina) labeled for use in 2022.

Over the last six years, we have seen reports of pyrethroid resistant aphids over a broad geography. If your fields require an aphid insecticide application, contact your local agronomist about development of resistance near you. If you apply an insecticide and have failure to control the pest, eliminate the normal paths of insecticide failure (rate to low, improper application, etc.). If you need to treat the field again, choose an insecticide from a different insecticide group. In addition, contact Bob Koch or Bruce Potter, . The University, with support from Minnesota Soybean checkoff dollars, has developed a quick laboratory assay to determine if a soybean aphid population has developed resistance to pyrethroids. Applying pyrethroids to pyrethroid resistant aphids will not make a farmer much money and will make the aphids more resistant. As you examine the pesticide choices, remember to read the pesticide labels.

It is essential that we all better steward our chemical tools. While there are dozens of insecticide products labeled to control soybean aphids, there are limited groups (families) of chemicals. To steward your chemical families, one should rotate chemistry. Given the spread of pyrethroid resistant aphids, starting with a pyrethroid is probably not a safe bet.

Soybean aphid control can be a complex problem, use all your tools wisely.

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Video: Dicamba Returns for Georgia Farmers: What the New EPA Ruling Means for Cotton Growers

After being unavailable in 2024 due to registration issues, dicamba products are returning for Georgia farmers this growing season — but under strict new conditions.

In this report from Tifton, Extension Weed Specialist Stanley Culpepper explains the updated EPA ruling, including new application limits, mandatory training requirements, and the need for a restricted use pesticide license. Among the key changes: a cap of two ½-pound applications per year and the required use of an approved volatility reduction agent with every application.

For Georgia cotton producers, the ruling is significant. According to Taylor Sills with the Georgia Cotton Commission, the vast majority of cotton planted in the state carries the dicamba-tolerant trait — meaning farmers had been paying for technology they couldn’t use.

While environmental groups have expressed concerns over spray drift, Georgia growers have reduced off-target pesticide movement by more than 91% over the past decade. Still, this two-year registration period will come with increased scrutiny, making stewardship and compliance more important than ever.