Cropping Issues in Northwest Minnesota

By Angie Peltier and Liz Stahl, Extension educators - crops Photo: Dave Nicolai Saprophyte – this is a fancy term for fungi that make their living by colonizing and extracting nutrients from dead tissue. Saprophytes are the reason continuous corn fields aren’t packed with piles of corn residue taller than us – saprophytic fungi help to degrade dead tissue as they complete their own life cycles. In years where we have rain after the corn crop has matured, but before the crop is harvested, saprophytic fungi are able to colonize and begin degrading corn tissue. The dark-colored dust that has been trailing combines in southern MN this year is most likely spores of saprophytic fungi that are helping to decay corn residue. When you are out 'push-testing' your crop, the mold can even work its way through your clothing and cover your face ( Figure ). Figure. The author covered in a 'mold beard'. Note: the shirt has gone through a heavy-duty wash cycle twice and still is not cl

One of my favorite times of the year is when I get to spend some 'quality time' in northwest Minnesota corn fields looking for European corn borer injury and checking stalk strength. Corn harvest will be delayed with the rainy weather. As you are waiting for soil to dry a bit before resuming harvest, time spent checking stalk strength will be time well spent. Kernels demand sugars. Developing corn kernels place a very high demand on the plant for sugars. Stress reduces the rate of photosynthesis, thereby reducing the amount of sugars that the plant is able to produce. Many different stresses can reduce the rate of photosynthesis: too much or too little moisture, nutrient imbalances, plant injury (ex.: hail, insects, diseases), excessive plant populations, and even long-periods of cloudy weather. In northwest Minnesota in 2023 these stresses from May 1 through September 15 included average daily high temperatures 2 to 4 degrees warmer than normal ( Figure 1 ), average