Lawn Disease Control in Spring

Spring is in the air, the birds are chirping, the days are getting longer and daydreams about BBQs on lush green yards consume our every thought. What’s not on your mind is the fact that lawn fungus or disease could be taking over your warm season yard at this time. Disease control in the spring can seem tricky at first, but there are things you can do to prevent and control outbreaks.

Fungus can establish and persist in dormant, warm season lawns and go largely unnoticed in dormancy, that is until the “spring green up” hits. Before you know it, you are waging war with an outbreak instead of enjoying your lawn and the great weather. 

This article discusses disease control and a few recommended products to treat fungus so that you can spend more time enjoying your lawn instead of working on it.

What is disease in your lawn?

As mentioned in our Lawn Disease Control article, most diseases are caused by a form of fungus. Fungi need to obtain energy as a means of feeding off of either dead organic matter or finding and taking over a host plant. This is where your lawn comes in. Some common locations you will find fungi in your lawn will be on dead leaves or in excessive thatch.

For fungus to spread and be present, there needs to be three main factors:

a) a host, living or dead organic matter (thatch and leaves),

b) the right environmental conditions, such as shaded, moist areas to grow in,

c) and the pathogen.

These three factors are also known as the disease triangle. All three must be present for the fungus to grow and spread.

Symptoms of disease in your lawn

Turfgrass diseases can present themselves in various shapes and sizes. For example, gray leaf spot looks like small round or oval spots that appear on the surface of a grass blade. The spot is typically tan in color with a dark brown border.

Brown patch, a cool season grass disease that typically shows up in the summer, creates thin, circular patches of brown grass in lawns. The patches may vary in color from brown, tan or yellow. Large patch looks the same in warm season grasses.

Dollar spot has small, bleached round spots on the turfgrass ranging between 5–6 inches in home lawns. The disease also converts the color of the grass to a tan-ish color that looks similar to straw.

Sometimes it can be difficult to even diagnose the damaged area of grass as a turfgrass disease. We always recommend submitting a sample to your local extension service so that professionals can tell you exactly what you’re dealing with for an inexpensive price. 

If a fungus is in your lawn, it will generally present itself in circular or irregular patterns of damage as seen in the below images. It will generally have a clear dead zone where the fungus has fed, and a lighter yellow/brown ring around the outskirts where the fungus is spreading (with the exception of gray leaf spot). 

If you are one of those homeowners who struggles with severe disease issues, you can try combining fungicides with different chemistries to tackle even the most difficult of diseases. Read more in our Disease Control Strategies article.

Click the images below for a closer look at common turfgrass diseases.

Pictured above from left to right: Gray leaf spot, brown patch and dollar spot.

Common warm season grass diseases in the spring

There are a number of turfgrass diseases that occur in the spring. Diseases usually take over warm season lawns like zoysia, bermuda grass, St. Augustine, centipede or bahiagrass when temperatures are between 70 and 95 degrees Fahrenheit—the spring and fall seasons for warm season grasses. 

The spring and fall seasons are both transitional seasons as they move from hot summer temperatures to cold winter temperatures and vice versa. This is why spring and fall are more favorable for infection. Some of the most common spring diseases in warm season grass are:

• Large Patch
• Gray leaf spot in some southern areas
• Dollar spot in bermuda grass primarily
• Rust
• Fairy ring

Be sure to check out our Identifying Common Diseases article to help you identify which turfgrass disease you might be dealing with and how to treat it.

Common cool season grass diseases in the spring

Disease in cool season lawns are not likely at this time. If you have a cool season lawn such as ryegrass, fescue, bentgrass or bluegrass, you should not have to worry about disease during the spring. Cool season grasses are susceptible to disease outbreaks in the summer, though.

How do I prevent diseases from taking over my lawn?

Spring turfgrass disease in warm season lawns commonly take over or damage landscapes during the fall and winter as temperatures transition from hot to cold. 

The problem is, once your warm season lawn has entered dormancy, you can no longer see the areas of damage. Signs of disease often don’t show up until the spring once the grass starts to green up again. 

This is why we suggest applying a preventive fungicide in the fall—it serves as a safety net to help prevent disease from taking over and showing up in the spring. Learn more about preventive applications here.

How do I treat diseases in my lawn?

Cultural Control

Fungi also spread through spores, which are easily transferred through wind, rain, mowing and simply walking through a fungi outbreak. Once transferred, the spore penetrates into the host plant (your lawn), feeding and growing until it has taken over the host.

To keep turfgrass disease at bay, start by watching where you walk. If certain areas of your lawn look like they could be infected with a disease, walking through it and then through the rest of your lawn only spreads the disease.

Another suggestion is to refrain from mowing over any disease areas as this will also spread the disease. Clean your mower blades well between mowing sessions.

Watch out for shady locations in your landscape. Turfgrass disease loves to grow in these environmental conditions. Learn to manage shaded, moist areas here. If certain areas of the lawn are also really wet or moist, this is an optimal environment for disease outbreaks. 

Reduce watering your lawn as much or only provide those areas with less water. Most turfgrasses only need about 1 inch of water per week including rainfall. 

Conduct an irrigation audit to see which areas of your lawn are receiving the most water and save money by adjusting your irrigation bill at the same time.

If certain spots in your lawn are lower than others, this may cause puddles to pool up throughout the landscape. Consider leveling your lawn to keep this from happening.

Lastly, partake in a regular fertilizer schedule. The Lawnifi® Spring Fertilizer Box comes with everything you need to feed your lawn during the spring. 

Lawnifi Recover in particular is great for applying on the spots disease may have caused damage to AFTER the disease has been treated. Recover is designed to help lawns during stressful periods such as summer heat. It can also be used to help with the stress caused by disease.

Learn more about the Lawnifi product line here.

Chemical Control

Sometimes cultural control isn’t enough—especially for severe disease outbreaks. Stop what you’re doing and go purchase a systemic fungicide and treat the area immediately. Remember not to mow over that area or walk on it. 

Each area may take several treatments. We generally recommend applying a second application in approximately 21 days, but above all, refer to and follow the product label’s instructions. You may need a third application as well in three weeks just to be safe.

The method of application depends on which sort of fungicide you purchase. Granular fungicides will need to be applied with a broadcast or drop spreader while liquid fungicide will either need to be mixed in a spray tank or attached to your garden hose. 

A word of caution: be sure to check your lawn and treat for fungus prior to any fertilizing/feeding this spring. Most fertilizers contain nitrogen, which fungi love. 

If you feed your lawn prior to putting a fungicide down and you have a turfgrass disease, that disease may expand exponentially. This can be disastrous for your lawn.