The latest problem for American grain farmers can’t be fixed with a mask or social distancing. Southern corn rust is spreading to different parts of the country, putting crops at risk.

According to the Purdue Cooperative Extension, the rust comes from a type of fungus that causes circular bumps on the leaves. If anything hits those bumps, orange spores pour out, making it look like rust. But that’s just part of the problem. That rust spreads quickly once a plant is infected, damaging corn stalk quality and reducing the kernel fill.

If it happens early enough, you also run the risk of reducing the overall crop yield. Damaged corn stalks can’t pull in as much sunlight and result in smaller plants. In a year that’s already far from normal, the last thing you need is a fungus spreading through your crop.

Just like the name says, this is something Southern farmers deal with. You can find it anywhere from Texas up to West Virginia. On occasion, things change. The fungus spores “travel northward with prevailing weather systems,” the Purdue report says. It also points out this happened multiple times in the past, with corn rust hitting as far west as Indiana.

This year, it’s spreading farther than that. Already, farms in Nebraska, Iowa, Missouri and Kansas have reported problems. Officials in Colorado, Wyoming and both Dakotas are also putting out a warning. The good news, however, is that if caught early enough, rust can be treated.

How Does Corn Rust Develop?

All it takes is six hours. Six hours of dew provides enough moisture for a fungus like corn rust to develop in your fields. A year like this, when most parts of the country had more rain than normal, created a perfect opportunity for rust to grow and spread.

The temperature also contributed to the problem. A typical fungus needs temperatures between 61 to 77 degrees in order to survive. That’s not the case here. Corn rust needs high humidity and temperatures above 77 degrees. We’ve all had plenty of that this year as well.

That’s why we need to pay attention when walking through the fields. It’s not enough to check once a week. The day after it stops raining, we need to be checking each plant to stop it in time. Within one week’s time, it can spread fast enough to damage multiple plants. If you wait longer than that to check, your field could be at risk.

Now sure, if you’re not in the South, this isn’t something you’re used to searching for. Since you don’t deal with it a lot, you might also want to just shrug this off and assume corn rust won’t hit your crops. Farmers in Kentucky experienced it last month. So did folks in Nebraska. You also can’t assume it’s gone after treating or destroying one infected plant. Remember those spores I mentioned? They can infect plants too, traveling as far as the wind will carry them.

Steps to Treat Corn Rust

Once you’ve spotted corn rust on your plants, there are two options. First, you could destroy the infected plants by ripping them out of the ground. Sure, that’s cost effective. All you have to do is walk into the field, tear out the infected corn and burn it.

That doesn’t guarantee the rest of the field is safe, however. Before you destroyed the fungus, those spores may have already spread across the field. The infection just hasn’t reached a point you can see it yet.

Some of you reading this are probably shaking your heads at the idea of burning it already. Again, while it’s cheap, you could also cause more harm than good. If you burn those spores, they go up in the air and suddenly if your crop wasn’t infected before, it most likely will be now. The cure is often worse than the sickness.

With that in mind, I’d like to offer a second option. In order to guarantee the fungus is killed, you need to use fungicide. Yes, I know it’s an extra cost at a time when most farms are struggling. But as Purdue’s Cooperative Extension says, it’s “most effective at preventing yield loss when applied in susceptible inbreds or hybrids.” The report also says as soon as you see those corn rust bumps, it’s time to buy fungicide and use it on the entire field. Purdue officials recommend applying it at seven to 14-day intervals as long as the humid and wet conditions remain.

Keep Your Grain Secure

Once your grain is harvested, you can’t do anything to improve it. You have to do all you can when it’s in the field to ensure it is high quality grain when it comes time to store it.

With corn rust rising, it’s also important to protect the crop you’ve already harvested. Tri-State can do that through a variety of different options.

Give us a call at 712-336-0199 or send a message. One of our grain storage experts will get back to you and answer any questions you may have.

Tri-States Grain Conditioning General Manager, Dan Winkowitsch, answers the often-asked question, “Why monitor grain temperature?”






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