Managing disease pressure.

Let’s face it: it’s not exactly fun.

Yet as a grower, you understand that staying on top of whatever threatens your corn crop can be the difference between a bumper yield and an insurance claim.

This job becomes more challenging as new threats spread across growing areas.

One of those newer threats is bacterial leaf streak.

First showing up in Nebraska in 2016, bacterial leaf streak (BLS) has slowly spread outward from the Cornhusker State, infecting fields throughout the Corn Belt.

BLS is not as well understood as diseases that have been around for decades. But experts have learned a thing or two that can help you scout for this disease on your farm.

Grab your shovel, and let’s dig in.

Cause

Bacterial leaf streak is caused by a bacterium: Xanthomonas vasicola. Before 2016, this bacterium only affected corn in South Africa. Here in the U.S., the disease has been found in field (dent) corn, seed corn, popcorn and sweet corn.

Bacterial diseases are tricky—they can quickly spread and are hard to control. Unlike common fungal infections, you can’t just spray fungicides to kill the pathogen. There just aren’t a lot of options.

Xanthomonas vasicola overwinters in corn residue, ready to attack when the weather gets warm.

Like several other causal agents, this bacterium enters through damaged areas of the plant. Hail damage, wind damage and even tiny cuts from blowing sand can cut openings in the leaves that expose plants to infection.

But that’s not all. What makes BLS especially nasty is the bacteria’s ability to simply enter through leaf stomata—the tiny openings in leaves that allow for gas exchange. That’s pretty rough, because you can’t just close stomata (and you wouldn’t want to).

Symptoms

We know what causes bacterial leaf streak, but how can you identify it?

Here’s a good rule of thumb: contact your LG Seeds agronomist.

You’re a farmer, and you have plenty of experience identifying issues in the field. But this is a tough one because at first glance, the symptoms mimic the fungal gray leaf spot. That’s why it’s best to bring in your reliable partner to help you make an expert identification.

Bacterial leaf streak creates some pretty nasty lesions on corn leaves similar to gray leaf spot. But if you look closely, symptoms from the two diseases differ:

• The margins of BLS lesions have wavy edges. GLS lesions tend to have regular, rectangular margins.

• BLS lesions are typically longer than GLS lesions. Bacterial leaf streak lesions can range from less than an inch to several inches long.

• Bacterial leaf streak lesions are usually brown, orange or even reddish in color. The lesions often appear yellow or transparent when backlit (i.e., held up to the sun).

Management

As mentioned, there aren’t really any disease control methods to employ once you have identified BLS in your corn. However, knowing more about the disease may help you mitigate future BLS risk on your farm.

Managing corn residue is important. The disease has been linked to heavy corn stover and corn-on-corn practices. Crop rotation and proper residue management could reduce disease risk.

Irrigation, hard rains and warm temperatures also exacerbate the problem. You can’t control Mother Nature (and your dry acres definitely need water), but knowing these risk factors can help you pick disease-resistant LG Seeds corn hybrids.

The list of challenges facing farmers is lengthy, and corn diseases are high up on that list. From planting to harvest, LG Seeds is by your side—no nonsense, no excuses. For seed advice and disease management tips, reach out to your LG Seeds agronomist today.