4 Common Lawn Diseases to Watch Out For

August 13, 2020
Est. Reading: 3 minutes

Taking care of your lawn goes beyond watering it every day and making sure it’s manicured. You’ll have to make sure that it’s lush, green, and healthy, meaning it’s free of diseases. However, it may be difficult to prevent common diseases that may be plaguing your lawn, so it’s important to learn how to recognize any warning signs. 

Lawn diseases can be hard to control as it can spread to cover other patches of grass, making it even more difficult to treat. With proper maintenance and care, most lawn diseases can be prevented and cured. Here are four common lawn diseases to watch out for and how to spot them:

Red Thread Disease

The red thread disease commonly affects perennial ryegrass, Bermuda grass, and bentgrass. It flourishes in grass that is planted in nutrient-poor soil and is in cool, humid weather, such as the end of winter and the beginning of spring.

The disease can be spotted by protruding thin, red hairs or strands that cause grass blades to stick together. Another sign is the appearance of red or bleached-looking patches in your grass, with the tips of the grass blades withering. 

Under fertilizing, poor air circulation, insufficient sunlight, and high humidity are common causes of the disease. If left untreated, it can go on for several years.

Brown Patch Disease

This common lawn disease usually affects a variety of grasses similar to the red thread disease, like the perennial ryegrass, Kentucky bluegrass, and bentgrass. This disease is especially common in lawns that are constantly exposed to hot and humid weather, making it a regular occurrence during the summer months without proper preventative maintenance.

The disease is characterized by circular patches of sunken, dead grass that can grow up to three feet wide. The grass is often wilted, taking on a grey colour despite the disease’s name. The inside typically takes on a lighter appearance than the outside.

To avoid this disease, make sure that you do not over-fertilize your grass or water it too frequently during hot weather, as this will cause the disease to spread further. Humidity is a huge factor in the disease, so water it only as needed.

Rust Disease

The disease is commonly found on similar grasses as the other diseases, such as Kentucky bluegrass and perennial ryegrass. It manifests around late summer months to early fall, specifically in areas with plenty of shade but a lack of ventilation. It may appear in spring if the grass wasn’t adequately fertilized. 

Uneven patches of weak, thinning grass with yellow specks are a surefire way to spot the disease. It takes its name from the yellow specks that eventually redden, giving it a rusty colour.

Making sure your lawn is sufficiently watered, exposed to sunlight, and fertilized is a way to avoid this. However, uncontrollable conditions such as high humidity or drought may also contribute to the disease.

Summer Patch Disease

This disease mainly affects Kentucky bluegrass and fine fescues, and usually manifests itself between June and September. The disease thrives in high humidity and warm temperatures.

It can be identified through misshapen patches of brown grass that are either crescent-shaped or ring-shaped. There are also often fungal threads, usually dark brown, covering the crowns, stolons, and rhizomes of grass plants.

A few factors contribute to contracting the disease, such as poor draining, mowing your lawn too low, or excess soil moisture.


There are several common lawn diseases to learn about so that you can prepare your lawn adequately in varying temperatures, and these are a few of them. By balancing the care of your lawn, such as watering it infrequently during hot and humid conditions, you will keep your lawn healthy year-round. Now that you know how to spot these diseases, you’ll be able to treat your lawn before it’s too late.

Are you in need of the best lawn care services in Mississauga? Let us know at Lawn Care Alert! We are the GTA’s best lawn and property maintenance company that also serves the Burlington, Oakville, and Milton areas. Get in touch with us today to give your lawn the best and most dedicated care available!

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