Crop injury can occur from pre- or post-emergence corn herbicide application. It usually occurs due to poor application timing, improper application rate, carryover from the previous year’s application or leftover residual in the spray tanks, lines and filters. Fortunately, yield loss, in most cases, is minimal. Be aware of herbicide injury symptoms and ways to prevent them.

Zipper ears, or ears with missing kernel rows, are a result of stress during pollination or grain fill. Ears affected by zippering have kernels that developed poorly or more slowly than other kernels or have ovules that aborted shortly after pollination. It’s important to understand how and why zipper ears occur and how to minimize their occurrence in the future.

Between the V3 and V5 growth stages, corn transitions from deriving energy directly from the seed to acquiring energy from sunlight through photosynthesis. Visual appearances during these stages offer clues to overall plant health.

Stand establishment depends not only on the success or failure of germination but also on early season stresses. If you notice early stand problems, carefully examine damaged seedlings to discover clues to the likely causes.

Northern corn rootworm (NCRW) is one of the most damaging corn pests in North America. Because the NCRW typically has a one-year life cycle, rotating corn with another crop has been a successful management strategy. Unfortunately, some populations of NCRW have successfully adapted to a corn soybean rotation and now have a two-year life cycle. This is called extended diapause because the eggs remain dormant in the soil for almost two years before hatching.

Wet and/or humid conditions can lead to black, sooty molds in cornfields at harvest. Sooty molds are species of secondary saprophytic fungi — microorganisms that feed on dead plant material. The presence of these molds can create excessive amounts of black dust when harvesting affected cornfields.

In areas of the Corn Belt, frost and variable soil temperatures can place corn under significant stress after planting.

Increased use of reduced tillage and no-till production practices has increased gray leaf spot occurrence. Caused by a fungus, the disease leads to leaf tissue loss, resulting in a decrease in plant sugars and decreased grain production. Potential yield losses range from 5 percent to 40 percent.

Crop harvest removes valuable nutrients from the soil. Understanding the amount of nutrients removed is crucial to understanding how to fertilize for the highest yield potential next season. With high input costs, it can be tempting to skimp on nutrients to save cost. Over time, however, this approach can reduce yield potential and profitability.

Hailstorms regularly strike growing corn fields. But not all damage is created equal. Know how to accurately assess yield loss.

When low temperatures or frost injure young corn plants, you may wonder if these plants will recover. Carefully weigh your options and don’t make any quick replanting decisions. The key to assessing corn seedling viability is to find and observe the growing point.