August 2020


Current Weather Events and Old Disease Threats Can Join Forces to Become Big Problems for Corn Farmers


“You invest in seed; you invest in the fertility; you invest in weed management and invest in irrigation; don’t let diseases be the factor that takes away. Plan for them and anticipate what you can do, and a fungicide with the modes of action may be the difference in your program.”

-Dr. Bob Kemerait, University of Georgia

It happens in the middle of every summer – the weather becomes the topic of conversation. In fact, 55% of farmers make the decision to use a fungicide based on the weather: either the weather is going to make a great crop this year, or it’s going to be conducive to disease. Predicting your customer’s exact response to summer heat and storms can be as unsure as the weather itself. The only thing you know for sure is that Mother Nature will whip up a variety of threats to America’s farmland. So now is the time to be on high alert for the corn diseases that, with the help of severe weather conditions, can change rapidly.

The good news is this: your customers are interested in fungicides even those who don’t use them every year. It is also likely that 1:2 of those farmers may raise an objection that you might not know how to respond to prior to closing the sale. Navigating the discussion and getting comfortable with asking farmers to protect their investments are the last points before you succeed in getting them to make fungicide applications a necessary investment in their operation. BASF is here to help.

Diseases to Watch

Just like the weather, corn diseases don’t respect state lines or land boundaries. Take southern rust, for example. We see this disease move in late July or early August. According to an article from the University of Illinois Department of Crop Sciences, “Southern rust spores from pustules can be dispersed miles on air currents, allowing the disease to spread rapidly. Under hot, humid conditions, spores of the fungus can infect susceptible corn, and symptoms can be observed within three-four days. Within seven-ten days, spores are produced and can be dispersed. The cycle of spore-infect-spore can continue as long as conditions are conducive, and corn plants are green. Conditions that favor disease development include hot temperatures (morning low of 75°F and daytime high of 93°F) and at least four hours of consecutive leaf wetness.” Clearly, strong rains, winds and late-summer temperatures contribute to the spread of this disease. Now is the time to prepare your farmers, so they can prepare their fields.

“There’s this big train coming up the Mississippi Valley, otherwise known as a storm system, coming through Louisiana and picking up southern rust spores to deposit all along the storm track.”

-Dr. Bob Kemerait, University of Georgia

Gray leaf spot development is favored by warm temperatures, 80°F, and high humidity for 12 hours or more. Late summer and early fall weather conditions encourage the rapid spread of disease because that’s also the time when corn plants are more susceptible to stress due to grain fill.

Wisconsin State Farmer, a farm newspaper with Journal Community Publishing Group, described the spread of tar spot as “residue borne, but also disperses on air currents, and observations indicate the disease likely travels at least several miles from a source.” Once again, advising your farmers of this disease’s rapid spread and helping them put a preventive fungicide plan in place will serve as an effective yield preservation practice.

It’s important to note that at the end of the growing season, southern rust pustules can be mistaken for tar spot. However, rust spores burst can be scraped away from the pustules with a fingernail while tar spots cannot be scraped off the leaf tissue.

Regardless of which disease is pressuring a farmer’s field, they’re always looking for a product that will give them the best chance of success. Take Veltyma™ fungicide, for example. This fungicide is the swift, simple and secure solution for corn growers looking for great fields and bottom lines. With its combination of faster curative activity, easier application and longer residual, this is the fungicide corn growers can turn to with confidence when they need to be sure their fungicide performs against a range of seasonal diseases.

Overall, being proactive and working with your farmers to not only identify disease, but also the weather conditions that promote their spread, is an important element to your role as an adviser. We’re always interested in your feedback and stories of your firsthand experience. Whether disease related or not, let us know what you’re hearing from your farmers. Your input helps us deliver the information you want to know.

“Always read and follow label directions. Veltyma is a trademark of BASF.