Seems insect and disease pressure were very minimal in soybeans in 2015.

Soybeans are ripening rapidly. And while you may see the occasional green field, most fields are racing towards the finish line. It all begins with the canopy changing from vibrant green to a dull green, then yellow, then brown and finally leaf drop. This process takes about 2 weeks and the warm, dry and windy weather the last few weeks, beginning the week of Farm Progress, really sped up the maturation process—beans are turning rapidly.

This was a year for weather opposites. The spring started out ideally and corn got planted. Then it turned wet delaying soybean planting or causing some farmers to replant or take preventive planting. Then it basically stayed wet for the months of June and July. But by mid August it turned warm and dry and rains became more sporadic and less dependable. Combine the limited rain with heat and sunny weather and, perhaps, shallow roots and the soybean plants started to turn early. But at the end of the day soybean yields in 2015 will be average to above. Even though some fields weren’t planted or were planted so late yields will be down.

With the rainy weather up front many agronomists would have predicted that diseases and insects would be a problem. Wet soils at emergence give the SDS pathogen an opportunity to enter the roots and with warm weather in August there should have been a big outbreak, but SDS just never showed up in field sightings. Same goes for white mold and leaf diseases. The rainy weather and heavy canopy would suggest white mold and leaf diseases would be problem, however the hot and drier weather changed the environment enough that disease pressure was minimal.

And insects like Japanese beetle, soybean aphid and bean leaf beetle were largely absent as well. I’m sure you could find them, but they never built up to threshold levels requiring treatment. So when it comes to insects and diseases, Illinois growers in general hit the jackpot in 2015.

Combines will be running soon in fields once soybeans reach that 14% moisture level. As you combine try to note areas that had problems and why yield might have been impacted. No better time to record this then when combining.

Agronomist Dr. Daniel Davidson posts blogs on agronomy-related topics. Feel free to contact him at or leave a comment below.

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About the Author: Dan Davidson

Soybean agronomist Daniel Davidson, Ph.D., posts blogs on topics related to soybean agronomy. Feel free to contact him at or ring him at 402-649-5919.