Spotlight: Common Summer Lawn Diseases
Summer is a beautiful time for your lawn to shine its brightest. However, the warmer months also bring about a host of lawn diseases that can tarnish that vibrant green. Lawn diseases are common during this time, when heat and humidity create the perfect breeding ground for a variety of pathogens. Some of these diseases can cause unsightly patches, hinder growth, and potentially damage the overall health of your lawn.
It’s crucial to recognize the symptoms of these common summer lawn diseases early. Early detection and proper treatment can prevent minor issues from becoming major headaches. With a proactive approach and expert guidance, you can maintain a lush and healthy lawn throughout the summer.
With that in mind, we’ll spotlight several common summer lawn diseases, detailing their symptoms, causes, and recommended treatment methods. By understanding these diseases, you can better protect your lawn and keep it in optimal condition.
At Pure Green, we offer a wide range of lawn care services in Middle TN to help you manage and prevent these problems. Our team combines knowledge, experience, and science-backed methods to ensure your lawn remains in peak health, even during the challenging summer months.
Let’s dive into the most common summer lawn diseases you need to be aware of and how to effectively combat them!
Diagnosing and Curing Lawn Diseases
1. Brown Patch Disease
Brown Patch is one of the most common summer lawn diseases. It primarily affects cool-season grasses like fescue, ryegrass, and bluegrass. The disease is caused by the fungus Rhizoctonia solani and thrives in hot, humid conditions.
Symptoms:
Brown Patch typically appears as circular patches of dead or dying grass. These patches can range from a few inches to several feet in diameter. In the early stages, the grass may look water-soaked or dark. As the disease progresses, the center of the patch may turn brown while the edges remain green, forming a “smoke ring” effect.
Causes:
The main cause of Brown Patch is excessive moisture combined with high temperatures. Overwatering, poor drainage, and heavy fertilization can create conditions that promote fungal growth. Grass that is mowed too short or has thick thatch layers is also more susceptible.
Treatment:
To treat Brown Patch, begin by reducing the amount of water your lawn receives. Water early in the morning to allow the grass to dry out during the day. Adjust your mowing practices to keep the grass at a taller height, which can help reduce stress. Fungicides can be used as a last resort, but it’s essential to follow the label instructions carefully.
2. Dollar Spot Disease
Dollar Spot is another prevalent summer lawn disease, named for the small, silver-dollar-sized spots it creates. This fungal disease affects a variety of grasses, including bentgrass, Kentucky bluegrass, and Bermuda grass.
Symptoms:
Dollar Spot disease manifests as small, round patches of light tan or straw-colored grass. These spots are usually less than two inches in diameter but can merge to create larger areas of damage. The affected grass blades may have lesions that are bleached with reddish-brown borders.
Causes:
The fungus that causes Dollar Spot, Sclerotinia homoeocarpa, thrives in warm, humid conditions and is spread by wind, water, and mowing equipment. Factors such as low nitrogen levels, excessive thatch, and poor air circulation can also contribute to the development of Dollar Spot.
Treatment:
Maintaining proper lawn care practices is key to preventing and treating Dollar Spot. Ensure your lawn has adequate nitrogen by following a balanced fertilization schedule. Reduce thatch buildup through regular aeration and dethatching. Water deeply but infrequently to promote healthy root growth. Fungicides may be necessary for severe cases but should be applied as directed.
3. Pythium Blight
Pythium Blight, also known as Grease Spot, is a severe fungal disease that can rapidly devastate a lawn. It primarily affects cool-season grasses but can also harm warm-season varieties.
Symptoms:
Pythium Blight appears as water-soaked, slimy patches of grass that can quickly turn brown and die. These patches often have a grayish-white, cottony growth, especially in the early morning when there is dew. The disease spreads rapidly, with patches expanding in size within a few days.
Causes:
The disease is caused by Pythium fungi, which thrive in wet, hot conditions, particularly when nighttime temperatures remain warm. Overwatering, poor drainage, and excessive nitrogen fertilization can increase the risk of Pythium Blight.
Treatment:
Immediate action is crucial when dealing with Pythium Blight. Reduce watering and improve drainage to keep the lawn as dry as possible. Avoid fertilizing the lawn until the disease is under control. Fungicides specifically labeled for Pythium can be effective but should be used promptly and according to instructions.
4. Rust Disease
Rust Disease is a common summer ailment that affects many types of grasses, including Kentucky bluegrass, ryegrass, and zoysia grass. It is caused by various fungi in the Puccinia genus.
Symptoms:
Rust Disease is easy to identify by the orange-red powdery spores that cover the grass blades. Affected grass may also have yellowing and thinning, resulting in an uneven, patchy appearance. The spores can easily rub off on shoes, pets, and lawn equipment, contributing to the disease’s spread.
Causes:
Rust Disease develops in mild, humid conditions, particularly when grass growth is slow due to drought or insufficient fertilization. It can spread rapidly through wind, water, and physical contact.
Treatment:
To combat Rust Disease, ensure your lawn is properly fertilized to promote vigorous growth. Water deeply and infrequently to help strengthen the grass. Improve air circulation by trimming nearby trees or shrubs. In severe cases, fungicides can help control the disease, but maintaining good lawn health is the best long-term strategy.
5. Red Thread Disease
Red Thread Disease is a common summer lawn disease that affects many cool-season grasses, such as fescue, perennial ryegrass, and Kentucky bluegrass. This fungal disease is caused by Laetisaria fuciformis and is typically seen during cooler, moist periods of the summer.
Symptoms:
Red Thread disease is characterized by pink or red threadlike structures that appear on the grass blades. These structures, called sclerotia, give the disease its name. Infected areas can look reddish to tan and can range from small patches to larger, irregular areas. Grass in these patches may appear thin and weak.
Causes:
The disease thrives in areas with low fertility, poor air circulation, and excessive thatch. Grass that is undernourished or stressed from drought is more susceptible to Red Thread. The fungus spreads through spores that can be carried by wind, rain, and lawn equipment.
Treatment:
Proper lawn care can prevent and manage Red Thread Disease. Fertilize your lawn to maintain adequate nutrient levels and promote healthy growth. Reduce thatch by aerating your lawn and improving drainage. Water deeply but less frequently to discourage fungal growth. Fungicides can be used in severe cases, but maintaining a healthy lawn is the best way to combat Red Thread.
6. Leaf Spot Disease
Leaf Spot Disease, caused by several fungi, including Drechslera and Bipolaris species, is another prevalent summer lawn disease. This disease affects both cool and warm-season grasses and can cause significant damage if left untreated.
Symptoms:
Leaf Spot Disease results in small, dark spots on the grass blades. These spots can range from dark brown to black and may have a light tan center with a dark border. As the disease progresses, the spots can merge, causing larger areas of dying grass. The infected grass can become thin, weak, and prone to further stress.
Causes:
Leaf Spot thrives in warm, humid conditions, especially when the lawn is overwatered or has poor drainage. Excessive nitrogen fertilization, compacted soil, and thatch buildup can also contribute to the development of this disease. The fungi spread through spores that are carried by wind, water, and lawn equipment.
Treatment:
To manage Leaf Spot Disease, reduce watering frequency and enable the grass to dry out between waterings. Aerate the soil to improve drainage and reduce compaction. Maintain a balanced fertilization schedule to avoid excessive nitrogen, which can promote fungal growth. Mow your lawn at the recommended height to reduce stress on the grass. In severe cases, fungicides may be necessary, but proper lawn care practices are most effective for prevention.
7. Powdery Mildew
Powdery Mildew, caused by the fungus Erysiphe graminis, is a common summer disease that affects many types of grasses, including Kentucky bluegrass and fescue. This disease thrives in shady, humid conditions.
Symptoms:
Powdery Mildew is easily identified by the white or gray powdery growth that appears on the grass blades, resembling flour. As the disease progresses, the infected grass can turn yellow, become thin, and eventually die. Affected areas can look unsightly and weaken the overall health of the lawn.
Causes:
The fungus responsible for Powdery Mildew thrives in low light and high humidity conditions. Lawns with poor air circulation and areas with excessive shade are more susceptible. The disease spreads through airborne spores that can be carried by wind and water.
Treatment:
To treat and prevent Powdery Mildew, improve air circulation by trimming nearby trees and shrubs. Increase sunlight exposure to affected areas by pruning branches. Water your lawn early in the morning to allow it to dry out during the day. Use resistant grass varieties in shaded areas if possible. Fungicides can help manage severe infections but are most effective when combined with proper cultural practices.
8. Summer Patch Disease
Summer Patch, also known as Magnaporthe poae, is a severe fungal disease that mainly affects Kentucky bluegrass, fine fescue, and annual bluegrass. This disease typically occurs during the hot, dry periods of summer.
Symptoms:
Summer Patch appears as small, circular patches of yellow or brown grass that can expand and merge into larger, irregular areas. The affected grass may wilt and die, and the roots can rot, leading to an overall thinning of the lawn. The diseased grass often has a frogeye pattern, with dead grass in the center and healthier grass surrounding it.
Causes:
The disease is caused by a soilborne fungus that infects the grass roots. It thrives in high temperatures combined with poor soil drainage, compacted soil, and excessive thatch. Lawns that are stressed from drought or improper mowing are more susceptible.
Treatment:
Managing Summer Patch involves improving soil health and reducing stress on the lawn. Aerate the soil to enhance drainage and reduce compaction. Maintain a balanced fertilization schedule to promote strong root growth. Water deeply and infrequently to encourage deep root development. Avoid mowing the grass too short. Fungicides can be effective when applied preventatively, but cultural practices are essential for long-term control.
9. Anthracnose Disease
Anthracnose is a common summer lawn disease caused by the fungi Colletotrichum graminicola and Microdochium bolleyi. It typically affects cool-season grasses like bentgrass and annual bluegrass, particularly on golf courses and high-maintenance lawns.
Symptoms:
Anthracnose manifests in two forms: foliar blight and basal rot. Foliar blight causes yellowing and browning of the grass leaves, making the lawn look patchy and discolored. Basal rot targets the base of the grass plant, causing the roots and crowns to rot. Affected grass tufts may pull away easily from the soil.
Causes:
The fungi that cause Anthracnose thrive in high temperatures and humid conditions, especially when the lawn is stressed. Poor mowing practices, inadequate fertilization, drought stress, and soil compaction increase the risk. The disease spreads through spores that can be carried by wind, water, and lawn equipment.
Treatment:
Proper lawn care is essential for managing Anthracnose. Maintain a balanced fertilization schedule to ensure your lawn has enough nutrients. Water deeply but infrequently, and keep your mower blades sharp to avoid stressing the grass. Improve drainage and aerate the soil to reduce compaction. Fungicides can be used for severe infections, but following good cultural practices is the best defense.
10. Gray Leaf Spot
Gray Leaf Spot, caused by the fungus Pyricularia grisea, is a destructive disease that primarily affects St. Augustinegrass but can also harm other turfgrasses like ryegrass and fescue.
Symptoms:
Gray Leaf Spot appears as small, water-soaked spots on the grass blades that gradually turn into grayish lesions with dark brown margins. As the disease progresses, the spots can coalesce, leading to large areas of blighted grass. Infected grass may turn yellow and die, leading to significant thinning of the turf.
Causes:
The fungus responsible for Gray Leaf Spot thrives in hot, humid weather and can spread rapidly in wet conditions. Overwatering, excessive nitrogen fertilization, and dense thatch layers can create an environment favorable for the disease. The spores are easily spread by wind, rain, and foot traffic.
Treatment:
Preventing and managing Gray Leaf Spot involves maintaining proper lawn care practices. Water your lawn early in the morning to allow the grass to dry out during the day. Follow a balanced fertilization schedule to avoid excessive nitrogen.
Reduce thatch buildup through regular aeration. In severe cases, fungicides labeled for Gray Leaf Spot can help control the disease. Keep an eye on weather conditions and take preventive measures if the forecast predicts prolonged heat and humidity.
11. Fusarium Blight
Fusarium Blight, also known as Fusarium Patch, is a fungal disease caused by Fusarium species that primarily affects Kentucky bluegrass, fine fescue, and perennial ryegrass. This disease is more prevalent during hot, dry periods of the summer.
Symptoms:
Fusarium Blight typically starts as small, circular patches of dead grass that can range from light green to reddish-brown in color. These patches can enlarge and develop into “frogeye” patterns, with healthy grass in the center and dead grass around the edges. The roots and crowns of the affected plants may show signs of rot and discoloration.
Causes:
The fungi that cause Fusarium Blight thrive in high temperatures and dry conditions. Lawns that experience drought stress, poor soil drainage, and low fertility are more susceptible. The disease can spread through spores in the soil, wind, water, and lawn equipment.
Treatment:
Managing Fusarium Blight requires a combination of cultural practices. Water your lawn deeply and infrequently to promote deep root growth and avoid drought stress. Maintain a balanced fertilization schedule to ensure your lawn has adequate nutrients. Aerate the soil to improve drainage and reduce compaction. Fungicides labeled for Fusarium Blight can be used for severe outbreaks, but proper lawn care is the best preventive measure.
12. Fairy Ring
Fairy Ring is a distinctive summer lawn disease caused by various soilborne fungi. This disease can affect all types of grasses and is characterized by its unique ring or arc patterns.
Symptoms:
Fairy Ring appears as rings or arcs of dark green, lush grass surrounded by a band of dead or dying grass. Within the rings, you may also see mushrooms or toadstools. The affected areas can range from a few inches to several feet in diameter. The fungi decompose organic matter in the soil, releasing nutrients that promote lush growth within the rings.
Causes:
Fairy Ring fungi thrive in well-drained soils and areas with large amounts of organic matter. The disease is more likely to appear in lawns with thick thatch or poorly decomposed organic debris. Drought stress and a lack of nutrients can make the symptoms more pronounced.
Treatment:
Controlling Fairy Ring involves improving soil health and lawn care practices. Aerate your lawn to reduce compaction and improve drainage. Remove thatch and organic debris to reduce the amount of decomposing material in the soil. Water deeply and infrequently to help the grass stay healthy. Fertilize the lawn to promote even growth. For severe Fairy Ring outbreaks, fungicides may be necessary, but cultural practices are crucial for long-term control.
Understanding these common summer lawn diseases and their treatments will help you take proactive steps to keep your lawn healthy. Regular monitoring and consistent lawn care are key to preventing these diseases and ensuring your lawn remains vibrant and resilient throughout the summer. Stay tuned for more information on managing other potential threats to your lawn’s well-being.
Protect Your Lawn from Summer Diseases
Maintaining a healthy, lush lawn during the summer can be challenging due to various lawn diseases. Implementing proper lawn care practices such as balanced fertilization, appropriate watering, regular aeration, and effective mowing can help prevent these diseases from taking hold. Early detection and timely intervention are crucial for managing outbreaks and protecting your lawn from extensive damage.
At Pure Green, we understand the importance of keeping your lawn healthy and disease-free. Our experts are here to provide tailored lawn care services in Nashville that address your specific needs and help you maintain a vibrant and resilient lawn throughout the summer.
If you’re struggling with lawn diseases or need professional assistance to keep your lawn in top shape, let us help. Our team offers comprehensive disease control services to ensure your lawn remains green and pristine.
Contact us today to schedule an appointment and take the first step toward a healthier lawn. Protect your investment and enjoy a beautiful yard all summer long!