May 23: Corn is looking good for the most part with few major concerns yet. Some have commented on the yellow-looking corn. This is most likely due to cool, wet soils rather than any nutrient issues. There may be field-specific issues such as saturated soils, compaction, and some herbicides that can cause this yellowing too. Also had a call on cutworms in seed corn but not widespread calls on this yet. Extension Educators have set up light traps for tracking cutworm moths and you can find that information here: http://go.unl.edu/rhhe. Cutworms will cause the most damage the first 7 days after corn emergence so scouting is important. The York County Corn Grower Plot was planted on April 24th with the corn currently at 2 leaf stage. Special thanks to Ron, Ray, and Brad Makovicka for hosting and the work put into this plot each year!
May 1: It never ceases to amaze me how quickly planting occurs each year! Corn planted the week of April 10th has emerged and for those fields that received hail from last week’s storms, I’m hoping we don’t see disease issues later on. Also of note, some have asked me about the CropWatch soil temperatures as they are higher than what some of you have been measuring in your fields before planting. The CropWatch soil temps at http://cropwatch.unl.edu/cropwatchsoiltemperature are averages of 24 hours under bare soil which may be different than the residue conditions in your fields and is an average of the entire day vs. one point in time. This may help explain some of the differences.
Many stands of alfalfa are lush green with over a foot of growth at this point. I looked at some alfalfa in Clay County that got dinged by cold temperatures in areas of the field and stopped growing. At this time I’m also finding quite a few aphids and a few alfalfa weevils. A disease common this time of year called spring black stem can be observed in nearly all alfalfa fields right now in the lower canopies. This disease consists of small black lesions on the leaves which eventually cause the leaves to turn yellow and drop. Normally this disappears with later cuttings as humidity and rainfall are typically high during the first cutting and can be managed with cutting the alfalfa. One option to consider according to Dr. Bruce Anderson, our Extension Forage Specialist, is to consider cutting alfalfa before bloom. He shares that weather can cause long delays and alfalfa doesn’t bloom very aggressively during spring. Bruce felt there were advantages to cutting alfalfa when it is 15-20” tall before bloom during first cutting including: weather compared to later spring, spread out alfalfa harvest if you consider cutting one field earlier, reduction in insect and disease problems by early harvest, and high feed value. It also potentially allows the second cutting to be ready before the summer heat which can lower forage quality. Disadvantages include lower yield from cutting early which could be made up in later harvest, regrowth may be slower if cut early, and the need to allow for longer recovery after first or second cutting to maintain long-term stands. So, harvesting before bloom may be something you wish to test in one of your fields this year and consider how this works for you, especially if you did have some frost damage or are having insect/disease issues in your alfalfa right now.
They’re everywhere! Finding ways to get inside homes, lining the sides of houses, and swarming around lights at night. The number one question last week from farmers, crop consultants, and home-owners was “what are the millers/moths flying around?” They are mostly army cutworm moths that are on their annual migration from the south. Usually they arrive in our area in May but everything this year seems to be about 2.5 weeks ahead of schedule. They can stay in the area for 2-3 weeks or as long as 6 weeks if cool, wet conditions occur. Hot, dry conditions will move them out of the area. While a nuisance, they are mostly a pest in wheat and alfalfa-so farmers with these crops need to be scouting. In alfalfa, we’re close enough to first cutting that I don’t anticipate needing an insecticide for it, but I do encourage you to watch regrowth for the second cutting as the larvae may be feeding by then. Since we’re not cutting wheat, be scouting it to ensure larvae aren’t causing significant damage. We may need to consider an insecticide treatment with fungicides this year in wheat when trying to protect the flag leaf. Some have been concerned that these are black cutworm moths and have been applying ½ rates of insecticides during corn planting. We don’t recommend this at UNL as these are army cutworm moths and don’t anticipate a problem to our corn crop from them. We recommend scouting once corn has emerged as it’s a better integrated pest management (IPM) strategy and saves you money not to needlessly apply insecticides on broad acres when black cutworm problems are typically patchy within certain fields every year.
For homeowners, if you have shrubs or bushy plants around your homes, you may notice more of these millers as they reside in these types of areas. There’s no chemical for controlling them. Some things you can do are change your outside lights from white to yellow and keep outside lighting to a minimum. Also caulking can help. Ultimately, they’re a short term nuisance and more information about their life cycle and management from Dr. Bob Wright, UNL Extension Entomologist, can be found at our UNL CropWatch Web site.