It’s the goal every farmer strives for — attaining the highest yield possible while maximizing profits. Sounds easy, but it is much easier to do it with a pencil than it is to do in the field.

What keeps most farmers from achieving utopia? Too many to be mentioned in this article, and some (like the weather) are totally out of control of the farmer. Nature can be the mother of all monkey wrenches.

So, let’s focus on one area producers can control. Managing diseases is paramount to reaching that high yield threshold. The LSU AgCenter has an entire Department of Plant Pathology geared toward fighting diseases that reduce yields.

Two pathologists tasked with developing strategies for disease management in corn, grain sorghum and soybean are Boyd Padgett and Trey Price. These two scientists have more than 50 years of combined experience combatting diseases of these row crops.

Price is housed at the Macon Ridge Research Station near Winnsboro, where he studies corn diseases like rust, northern corn leaf blight and Curvularia leaf spot (CLS), which is becoming an annual issue in Louisiana.

Left: A close-up of frogeye leaf spot on a soybean plant. It is a common disease in soybeans, and severe infestations can result in yield reductions of approximately 20%.
Right: Trey Price, plant pathologist at the Macon Ridge Research Station, operates a spray rig used for fungicide experiments in an on-farm test on soybeans. These trials are used to help determine the efficacy of various fungicides on common diseases found in soybean fields. Photos provided by Boyd Padgett

The first step a producer should take in managing diseases such as CLS is to select resistant hybrids, not only sound advice for corn but any commodity.

“There are already hybrids with resistance,” Price said. “We have rated official hybrid trials for the past two years and identified susceptible and resistant hybrids that are commercially available.”

Another problem related to CLS is that neither yield loss potential nor effective fungicides have yet to be well-defined regarding the disease. For the 2023 growing season, Price and colleagues were able to obtain ratings for CLS, which should help lead to finding effective fungicides and determine potential yield loss.

Price is excited that the Macon Ridge Research Station has a new research plot sprayer that will allow for ground applications in corn. This equipment will facilitate research regarding water volume.

“Fungicide efficacy will likely increase with water volume,” Price said. “Farmers may be reluctant to do it because they are irrigating at the same time fungicides would need to be applied.”

Padgett works primarily out of the Dean Lee Research Station on the LSU-Alexandria campus. One area of research he is working on is fungicide efficacy, an area that needs to be constantly monitored.

Cercospora and aerial blight in soybean have documented resistance to some fungicides, but according to Padgett, some new fungicides have activity on the two diseases.

“To extend the usefulness of these new fungicides, producers should only apply these products when needed,” Padgett said. “We will continue to do work as to when the applications are justified.”

Because of the chemistry complexity of fungicides, Padgett is staying watchful for any pathogen resistance.

“If we suspect any resistance, we are going to take samples and evaluate for sensitivity,” he said. “It is imperative that farmers and chemical companies know as soon as possible if resistance occurs.”

Looking for another step producers can take that may lead to less disease pressure and increase yield?

Very simply, get your crop planted in the optimal window.

According to Padgett, preliminary research findings indicate disease severity is influenced by planting date. He cautions that more research is needed, and he plans to continue research in this area.

“Some diseases, such as Cercospora leaf blight, frogeye leaf spot and aerial blight, are not big problems every year,” Padgett said. “If we can fully document that planting dates reduce the risk, then this will increase profits at no additional cost.”

Both Padgett and Price believe that the 2023 growing season was one of the most difficult in memory. One of the very few benefits from the excessive heat and drought is that it minimized disease development. While that was good for producers, it did affect researchers studying diseases.

The two researchers plan to continue research studying issues such as fungicide efficacy and disease resistance on corn hybrids, soybean, grain sorghum and wheat.