Crop disease outlook in 2020

Experts say there a few crop diseases to keep an eye on in the coming year. We decided to take a closer look.

During a visit to the Fremont Corn Expo, we talked with UNL Plant Pathologist Extension Specialist Tamra Jackson-Ziems about this topic. One disease that is top of mind this year is "tar spot". "It hasn't been confirmed in Nebraska yet, but we believe it's likely that we will have that moving into the state from Iowa," Jackson-Ziems said. "We've been watching it since 2019, and it's just east of our border right now. So, we ask people to be watching for that disease, and in particular, for black dots on leaves. That is the fungal structure. It literally looks like spots of tar."

Another crop disease that producers should be aware of this year is "frogeye leaf spot". This disease has been confirmed in 10 Nebraska counties as fungicide resistant. "We want to make sure that people understand it's there," Jackson-Ziems. "And if they've had frogeye in the past, it is likely they will see it again. But there are ways to manage that, including hybrid selection, and we can also rotate to corn or other crops. When it comes to fungicide, it may be necessary to use ones that are a mixture of two or three different classes to get the best control."

Producers are also being asked to keep an eye out for Physoderma brown spot. This disease was common and sometimes worse during 2019 because of favorable weather conditions. "We had a lot of wet conditions during a very sensitive time period," Jackson-Ziems said. "We had rainfall when corn was in a vulnerable stage. Thus, we saw the disease development. We saw it on the leaves, but in a few of them, we saw brittle stalks because of infection in a node low to the ground." Experts say if you had Physoderma brown spot last year, it doesn't necessarily mean you'll have a lot of it again, it depends on weather conditions.