South central Wisconsin is about 6 inches ahead of our average yearly precipitation, according to the UW Extension Research Station in Arlington, WI. As we are ahead of normal precipitation, we are still about 50 units of GDU behind our 30-year normal in heat accumulation. Late July and early August started to put us back on track. As abnormal as 2019 was, we are surprisingly on track to obtain almost average heat units. What does all this mean to current crop?
Late plantings and a fairly cool spring have our corn crop out to a late start. We know that a delay in planting from May 1st to May 20th can lower yields 9%. Another concern I have at this time is getting our crop to physiological maturity or “black layer”. Black layer occurs about 60 days after silking. A lot of our crop started silking the last week of July, into the first week of August. Our average killing frost in Arlington is around October 10th. If we were to add 60 days to the first week of August, it puts us into the first week of October. Hope for a normal to warm September. We do not need an early frost this year, which would negatively affect our kernel weight and grain moistures.
We currently have a lot of corn in the milk stage. One can approximate silage harvest dates very closely with this information. About 35 days after silking, most hybrids will be about half milkline, with whole plant moistures in 65-70% range. This puts a lot of our silage harvest dates about September 1st.
As we move from R3 into R4 and forward, we are really finished with the management of our soybean crop. Overall, in Dane and Columbia County, insects were not a problem this year, with a fairly sparse population of Japanese beetles, spider mites that were non-existent, and soybean aphids that are just showing up now. As beans start to mature and change color in the next month, evaluate your R3 treatments. Ideally, the crop should change color uniformly. Did the fungicide treated acres stay green and hold leaves longer? Walk out into the headlands where the beans may be double planted. Is White Mold present? Evaluate standability now. Look for foliar diseases like Brown Spot and Cercospora. As we lose the leaves in the beans this fall, a lot of the story of 2019 will be lost.
Even though we had more than adequate moisture this year, most growers had struggles with alfalfa management. Right out of the gate, many established fields were affected by winter kill. Because alfalfa prices were high and feed inventories were low due to 2018, growers elected to keep sub-standard alfalfa into 2019. Seeding were planted late into saturated soils. These plantings really struggled with disease pressure. It can be hard to evaluate alfalfa varieties for diseases, because most growers only plant one or two on their farm. Work with a trusted agronomist to identify alfalfa disease and put a plan into place to protect your plants. A few new alfalfa varieties have recently been released with new levels of disease resistance to Fusarium, Verticillium, Anthracnose, Aphanomyces races 1,2,3, and now even 5. Along with planting a disease resistant plant, consider using a fungicide on your alfalfa stands. Along with additional yield, fungicides can help extend the life of your alfalfa stands, by limiting diseases like crown rot from getting into your plants.
In my 18 years of experience, 2019 had the highest level of leafhoppers in our area. Most growers are scouting and treating fields over thresholds. While making this pass, consider other products to enhance yields. Micronutrients, fungicides and other foliar fertilizers can enhance yields and increase RFV. While alfalfa prices are high, take advantage of higher ROI.