As we roll into late summer, it’s important to continue to scout soybean fields for signs of disease, insect pests and weed escapes. The notes you take today can have a significant impact not only on this years crop, but can help you make more informed decisions in future years.

Soybean aphid scouting should be well underway at this point.  Aphid pressure has been relatively low throughout most of Latham country to this point, but it’s important to remain diligent in checking your fields. The generally accepted economic threshold for this pest is an average of 250 aphids per plant with more than 80 percent of plants infested, with an aphid population that is increasing. You’ll need multiple scouting reps to determine what is happening with aphid populations in your field.

Soybean Aphids

More than 100 soybean aphids collect on the underside of a soybean leaf. Pest feeding can inhibit the plant’s ability to make grain, or kill it outright.

Twospotted spider mites are another insect pest in soybeans that have the ability to rapidly increase in population under the hot and dry conditions some of our geography has faced. If mites are positively identified and causing plant damage, and hot, dry conditions are expected to persist, control measures should be considered. Field border treatments may be an option as sometimes infestations of spider mites are confined to field edges.

I’ve found a few articles from respected sources that I wanted to share. The University of Minnesota Extension has a great article that dives in deeper into soybean pests. Late summer is also the time of year when several soybean diseases will show up including Sudden Death Syndrome, Frogeye Leaf Spot, White Mold and others. South Dakota State University has a detailed article on late-season soybean diseases that I find beneficial. Our very own Phil Long, precision agronomy advisor, has an in depth video to help with late-season soybean issues on his series #AsktheAgronomist. Watch it here.

Knowing which diseases are currently present in your fields can help determine which variety to plant next year. Planting varieties with disease resistance can be the most effective and the most economical method of disease control. Latham® soybeans have great resistance to the major diseases that occur in our trade territory including: Soybean Cyst Nematode (SCN), Sudden Death Syndrome (SDS), Brown Stem Rot (BSR), Iron Deficiency Chlorosis (IDC), White Mold and Phytophthora. Check out Latham Seeds 2023 Soybean Lineup.

Soybean pests and diseases can be very serious issues. If you have any questions, feel free to contact me at (641) 692-3258.