Everything has its season. Maybe that’s a bit tougher to recognize in Nebraska, where June freezes, November thunderstorms, and February sunshine leave us saying, “I thought it was summer!” Or winter or fall or spring. Not a season seems to pass without at least a little blip, a little jab from Mother Nature to keep us on our toes.Yet as uncertain as Nebraska weather goes, there is much that we can count on: Apple trees blossom, Sandhill cranes fly north, trees grow leaves, bird eggs hatch and turkeys mate. Cicadas emerge from their exoskeletons and drone in the branches, leaves turn brown and fall, Sandhill cranes fly south.
Friends, right now, we are in the season of the cotton flying from the cottonwoods, which means that this is the season of rootworm, which larva appear dependably upon an accumulation of 680-740 GDUs.
This is also the all-important season of nodal root growth (after a very challenging spring this year, too), and given the many goings-on underground, the season to dig up a few plants and do some diagnostics. In addition to checking for rootworm and evaluating nodal root growth, this is an excellent time to test for corn nematodes and investigate the extent and impact of sidewall compaction on your plants.
Rootworm issues can be rather easily diagnosed by digging up and examining a root ball. If you do discover trouble, be sure to apply an insecticide, which will interrupt their life cycle. Acting quickly will serve you well, as the season of rootworm will otherwise turn into the season of more rootworm.
Diagnosing nematodes requires that soil samples be sent to University of Nebraska labs for reading and counting, but it is a test worth the time (especially if you suspect a problem) to save future crops. The impact of nematodes this year can’t be remedied, but detecting their presence now will help you make some decisions about your fields next year. Nematocides are an option, but since corn nematodes can only subsist where their food (your corn plants) are in supply, you can rid your fields of them by changing crops. And since nematodes can easily hitch rides on your equipment into other fields, their presence should prompt you to evaluate your tillage system and sanitize your equipment.
Examining nodal root growth will give you an idea about both the impact of sidewall compaction in your fields and the balance of moisture in your soil through this difficult spring. Roots that are underdeveloped or that fizzle out quickly as they shoot away from the plant indicate a lack of moisture and will be helped by irrigation. ½ to ¾ inches of water will fix this issue in a hurry. Roots that appear strong, but that are knotted and turned around are an indication of sidewall compaction. Recognizing this issue in your fields provides feedback about the timing of planting this year and suggests that the soil was overly moist at that moment. This is useful information to have as you time planting next year.
A thorough root checkup now will prevent rootless corn syndrome later and yield valuable information about the health of your fields, ensuring that the rest of your growing season is one of success and prosperity.