The cool, damp weather has put the brakes on many acres of soybean harvest this year. Although South Dakota has seen late harvest seasons in the past, this year is testing many farmers’ patience considering the wet weather of the past few weeks and current climate outlook.
Kochia is an issue with row crop production in the north central area of South Dakota. New Post-emergent options in corn and soybean have helped alleviate Kochia competition from many fields, but these herbicide options shouldn’t be completely relied upon for a long term plan for control.
No-till crop production in South Dakota is on the rise. Marestail (also known as horseweed) is a native plant to the United States, and is considered either a winter annual or biennial species that is often difficult to identify at the rosette stage.
A famous nematologist in the region once asked the question “Who should be concerned about the soybean cyst nematode” and the answer was “those who know they have SCN in their fields and those who don’t”. In other words, all of us should be concerned.
In South Dakota, a lot of soybean fields are naturally beginning to change colors as soybean senescence has started. This is going to greatly affect how we determine whether or not fields are infested with gall midge larvae.
We are still receiving confirmations of gall midge in South Dakota and the number of counties where this pest is present continues to increase. However, as soybean begins to senesce, using discoloration around field edges will no longer be viable for finding infestations.
Several soybean fields scouted in a number of counties have plants dying or dropping leaves prematurely and are being mistaken for early senescence. Close examination of these plants indicates that stem canker is causing the premature plant death.
While scouting fields for gall midge this week I have been noticing a lot of holes in soybean leaves. The majority of the defoliation is due to the second-generation bean leaf beetle adults.
Gall midge are still being found in more counties in South Dakota. However, as we previously mentioned not all of the fields that the gall midge larvae are found in are exhibiting clear signs of infestation.
We are continuing to confirm more counties where gall midge larvae are causing issues in soybean fields. While scouting this week, we have noticed a trend that soybean near groves or shelterbelts tend to have higher likelihood of being infested.