The 2016 growing season will go in the books as another full of unique challenges and weather variability. In many areas of the state, especially western Iowa, the planting season was delayed with challenges caused by saturated conditions and cool soil temperatures. Due to these soil and weather challenges, some areas saw above average replants of both corn and soybeans this spring. Conversely, some parts of the state saw optimal, drier planting conditions. It seemed after we were able to get the corn plants out of the ground and actively growing, crop conditions and early outlooks improved dramatically. During late vegetative growth, many areas saw a dry spell. However, good soil moisture from early season rains carried us through in most situations. The weather during pollination was favorable and most counties saw a very high kernel pollination percentage.
The growing conditions that have followed pollination have been favorable for development of some leaf and stalk diseases as well as ear mold. The heavy dew, coupled with extended cloudy conditions and frequent rain events, has led to an environment ripe for late season disease development. As I travel across many counties of the state, there are some fields showing symptoms of Anthracnose infections. Symptoms are often visualized four to six weeks after pollination when the upper canopy begins to "die back" early, leaving the lower parts of the plant green. Development of this disease is favored by the warm, humid conditions that we have experienced. The leaf blight phase of this disease is of less concern than the stalk-rot phase, which poses a far greater risk for harvest issues. When Anthracnose stalk rot progresses rapidly, it can prematurely kill several nodes of the plant and often lead to lodging or breakage concerns. Many times stalk rots aren't limited to just a single fungi infection, but a causal relationship of several disease causing fungi. While Anthracnose isn't the only impactful stalk rot concern this season, since foliar symptoms have already presented themselves in many fields, your field scouting will enable you to make timely decisions to mitigate risk this harvest season.
While scouting your fields to make harvest decisions, also make note of grain quality by checking for mold issues of the ears, kernels or cobs. The development of many ear and kernel rots can be attributed to extended periods of damp plant conditions which we've had during grain fill in much of the state. If the presence of ear rot is found to be widespread within a field, it would be wise to harvest these fields early as the potential for decreased grain quality and mycotoxin development increases with delayed harvest.
While everyone is preparing to hang their hat on managing the 2016 growing season, don't forget pre-harvest scouting as it can provide you with the information you need to make this year's harvest a successful one. If you have any questions about what you are seeing in your fields or need help with diagnoses, please contact your local FS crop specialist to help with your harvest management decisions.
Brett Schippers serves the FS System as GROWMARK field sales agronomist. He can be reached at bschippers@growmark.com.