COMMON DISEASES

Common Diseases

Anytime the same plants grow together, problems with disease can start and begin to spread before you even notice it's occurring. Disease, in particular, can be a real challenge for lawns due to them being made of hundreds of thousands of the same type of grass plants. Even when your lawn is getting excellent care, the grass can still become infected with a variety of lawn diseases that can lead to dead or discolored areas. Disease spores may float by in the air or hide in the soil, and once the conditions are right, they multiply.


That’s why it’s a good idea to protect your lawn, or fight back if disease has already taken hold.

Dollar Spot

Dollar spot is an infectious disease that affects the leaf or blade of grass and not the root. Dollar spot will have small round spots usually around 1-10 inches in diameter and looks like a "bleached spot". It is usually more of an aesthetic issue as opposed to other disease that can damage your turf. It is caused by fungus within the lawn. In morning hours with the dew on the ground, the fungus begins to produce. The fungus attacks when grass is actively growing during warm, humid days, cool nights and heavy dew in the spring, early summer and autumn.  It is more active when the daily temperatures do not rise above 70 degrees. Dollar spot is more severe on dry soils deficient in nitrogen. Applying fungicides preventively may be justified where dollar spot has been prevalent and difficult to control once the symptoms appear. Repeat applications are needed at 7-21 day intervals during moist weather in spring, summer and autumn when temperatures are between 60 and 90 degrees F. 

Summer Patch

Summer patch usually appears between the months of June and September. During periods of high humidity when daytime temperatures are over 85 degrees, summer patch can appear. It will show up in the form of irregular brown patches, rings, and crescent shapes in your lawn. While the disease may still be present during times of cooler weather, the symptoms won't be as visible.

Brown Spot

Too much water can turn grass brown and make it appear dead. In hot, humid weather, a fungus is responsible for the most common lawn disease known as "brown patch," which can affect nearly all grass varieties. Brown patch creates irregular 3-10 foot circles of grass blades with brown tips and bleached spots. In severe cases, the turf will appear sunken. Brown patch circles will look like targets, as the center of the circle sometimes recovers. Water early in the morning instead of in the evening, as wet grass is more susceptible to the spread of fungus overnight. Rather than brief, frequent watering, focus on deeper watering and let the turf dry between waterings. Also, aerate to improve drainage and avoid excessive nitrogen, especially during hot weather. 

Snow Mold

There are two types of snow mold: pink snow mold and gray snow mold. While snow mold usually grows under snow cover, pink snow mold can also grow during cool, wet weather even when there is no snow on the grass. It appears as grayish-white or whitish-pink patches of crusty, matted grass, and is most noticeable in early spring when the snow begins to disappear. As the snow melts, straw-colored circular patches ranging anyway from a few inches to several feet appear across the lawn. The grass in these patches are usually matted down and crusty. Pink snow mold can be more severe than gray snow mold, as it will kill the crown and roots of grass plants. Gray snow mold usually only affects the grass blade itself.

Rust Disease

Rust appears as an orange or yellowish-orange powder on grass leaf blades, in late summer to early fall when the weather is dry. The turf may assume a yellow, red or brown appearance. Cool nights with heavy dew and light, frequent rainfall add to the ideal conditions for rust to develop. Warm, cloudy, humid weather followed by hot, sunny weather also favors rust on lawns. Rust spreads by air, water, shoes equipment and vegetative turf material (sod). Maintain lawns through watering, mowing and fertilizing. Water early in the day so the grass dries quickly. Manage thatch. Early fall nitrogen application will help prevent rust. Do a soil testing to check soil phosphorus and potassium levels early spring. Assure good airflow over the lawn and light penetration by pruning shade trees and shrubs in areas by lawn. 

Read Thread

Red thread thrives in cool, humid conditions and shows up most frequently in lawns grown in nutrient-poor soils. You’ll know you have it if you see thin, red hairs or strands extending from the grass blades. Red thread can survive for years if left untreated.


If you see any signs of what could be disease in your lawn, contact us to see what we can do to get your grass back to health!

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