Dollar Spot Identification and Control

Pride in Turf, as a lawn fungus treatment company, understands how challenging it is to maintain a lush and healthy lawn, as it requires a lot of vigilance and care. As summer ends and cooler temperatures arrive in Georgia, it is time to assess your lawn and see what kind of damage summer left behind. Lack of rain, too much rain, high heat, humidity, heavy traffic, and mowing can take their toll on your turf.

These types of stressors can weaken the immune system of your grass and leave it vulnerable to a number of fungal infections that can destroy that beautiful lawn. Dollar spot is a prevalent fungal disease that affects not only in Georgia, but worldwide. In this article, we will provide information about dollar spot - identification, symptoms, causes, and effective treatment.

Dollar spot lawn fungus is a common and frustrating problem for homeowners striving for an attractive and healthy lawn. Pride in Turf wants to help you restore your lawn to its former glory and keep it that way.

Identification of Dollar Spot

Dollar spot, scientifically known as Sclerotinia homoeocarpa, is a prevalent fungal disease. It gets its name, dollar spot, from the small round spots that are approximately the size of a silver dollar it forms on the grass blades. The spots are generally straw-colored or light tan lesions with distinct reddish-brown margins. As the disease progresses, the spots can merge to form larger, irregular patches. These can range from a few inches to several feet in diameter. Dollar spot is the most common turfgrass disease in North America.

Dollar spot primarily affects bermudagrass, but can impact warm season grasses as well as cool season grasses. Some other types of grass that can be affected include Kentucky bluegrass, creeping bent grass, perennial rye grass, annual bluegrass and fescue. Once primarily known for wreaking havoc on golf courses and recreational turf, dollar spot has become a common lawn problem for homeowners as well.

Symptoms of Dollar Spot

One of the primary symptoms of dollar spot is the presence of small spots on the grass blades. These spots are typically between 1 - 6 inches in diameter and appear bleached or light tan colored. They are often surrounded by a reddish-brown border, giving them a distinctive appearance different from a fungal disease like Pythium blight.

Over time, the affected areas may start to thin out and turn brown. The grass in these areas may become weak and lose its vigor. If left untreated, the patches can expand and merge, leading to larger areas of damage. In the early morning, or during periods of high humidity, you may notice a web-like mycelium or the grass blades. This white, cottony-growth is a clear indicator of dollar spot infection.

Under favorable conditions, such as extended periods of high humidity or excessive moisture, small tan-colored fungal structures called sclerotia may develop on the infected grass. These structures resemble tiny grains of sand and can be observed on the leaf blade, stems, or thatch layer.

Causes of Dollar Spot

Several factors contribute to disease development and the spread of dollar spot fungus. Some of the primary causes are discussed below:

Environmental Conditions: Dollar spot thrives in moderate temperatures ranging from 60 to 88 degrees. Additionally, extended periods of high humidity, dew, or foliar wetness provide ideal conditions for the fungus to grow and spread. Disease development is favored by warm, humid weather followed by cool nights that produce heavy dew in the spring and early summer. Dollar spot occurs primarily on home lawns and golf courses. The pathogen can survive unfavorable periods as dormant mycelium on infected plants and plant debris.

Low Nitrogen Levels: Nitrogen deficiency in the soil weakens the grass and makes it more susceptible to diseases, like dollar spot. Insufficient levels of nitrogen impair the grass's ability to grow and recover, allowing the fungus to gain a foothold.

Moisture Imbalance: Overwatering or watering at inappropriate times, such as late in the day, can create a moisture imbalance in the lawn. Excess moisture on the grass blades promotes the growth and spread of dollar spot. Excessive leaf wetness and fog contribute to lawn disease, as do water stress and excess thatch development.

Low Mowing Height: Mowing the grass too short weakens the turf and exposes it to stresses that encourage dollar spot development. Shorter grass blades have reduced energy reserves, making them more susceptible to fungal infections. Also, short lawns (under 3 inches) hold moisture on grass leaves and are more susceptible to this turfgrass disease.

Treatment and Prevention of Dollar Spot

Dollar spot disease is definitely frustrating; however, by creating optimal conditions for the grass to grow and thrive, you can reduce its susceptibility to diseases. As we know, healthy grass is much less prone to lawn diseases like dollar spot. Here are some key practices to consider controlling dollar spot:

Proper Mowing:

Maintain the proper mowing height for your grass type. Generally, keeping the grass a bit longer helps develop stronger roots and provides shade to the soil, reducing moisture evaporation. Adjust your mower height to allow the grass blades to reach a height of 2.5 to 3 inches.

Avoid removing more than one-third of the grass blade length during each mowing session. Frequent mowing helps prevent the grass from becoming stressed and weak, making it less prone to fungal infections.

Proper Watering:

Water deeply and infrequently to encourage deep root growth. Aim for about 1 inch of water per week, including rainfall. Watering deeply allows the roots to access moisture from the lower soil levels and reduces surface moisture that promotes fungal growth. Watering in the early morning helps the grass blades dry throughout the day, preventing prolonged leaf wetness.

Improve Soil Drainage:

Adequate soil drainage is essential for preventing excessive moisture accumulation, which can contribute to dollar spot development. If your lawn has poor drainage, consider aerating the soil to improve its structure and allow water to penetrate more effectively.

Fertilization:

Maintain a proper fertilization schedule to ensure the grass has sufficient nutrients for healthy growth. Regular applications of nitrogen-rich fertilizers promote vigorous grass growth, increasing its resistance to diseases. However, be cautious not to over-fertilize, as excessive nitrogen can lead to other issues. Light, frequent applications will reduce disease severity and promote recovery.

Thatch Management:

Thatch buildup can create an environment conducive to dollar spot development. Thatch is a layer of dead organic matter that accumulates between the grass blades and the soil surface. Excessive thatch prevents adequate air circulation, retains moisture, and provides a favorable habitat for fungal pathogens. Regular dethatching or core aeration can help manage thatch buildup and improve the overall health of the lawn.

Dethatching: Use a dethatching rake or a power dethatcher to remove excess thatch from the lawn. Dethatching should be done when the grass is actively growing, typically during the spring or early fall. Take care not to remove more than one-third of the grass blades in a single dethatching session.

Core Aeration: Core aeration involves removing small plugs of soil from the lawn, creating channels for air, water, and nutrients to penetrate the soil. Aeration helps alleviate soil compaction and promotes better drainage, reducing the chances of dollar spot development.

Overseeding and Reseeding:

Overseeding and reseeding are beneficial practices that can help fill in bare spots and maintain a dense and healthy lawn. By introducing new grass varieties, you can enhance the overall resilience of your lawn against dollar spot and other lawn diseases.

Select Disease-Resistant Varieties: When overseeding or reseeding, choose grass varieties that are known for their resistance to dollar spot. Consult Pride in Turf to identify the most suitable options for your region and climate.

Proper Seeding Techniques: Follow proper seeding techniques, ensuring good seed-to-soil contact for optimal germination. Water the newly seeded areas regularly to keep the soil consistently moist until the grass is well-established.

Good Hygiene and Sanitation:

Yes, good hygiene practices are also helpful in your lawn care routine. Maintaining good hygiene practices can help prevent the spread of dollar spot and other diseases. Implement the following measures:

Clean Mowing Equipment: Regularly clean and disinfect your mowing equipment, including the blades, to prevent cross-contamination between healthy and infected areas of your lawn.

Remove Diseased Debris: Remove and dispose of any diseased grass clippings or infected plant debris properly. This reduces the chances of the fungus spreading to other areas and dollar spot severity.

Avoid Traffic on Wet Grass: Limit foot traffic and equipment use on wet grass. Wet conditions can facilitate the spread of fungal spores, including those responsible for dollar spot.

Fungicide Applications

In severe cases or when cultural practices alone are insufficient, the use of fungicides can help control and manage dollar spot. Fungicides are available in different forms, including liquids, granules, and powders. It is crucial to choose a fungicide specifically formulated for dollar spot and follow the instructions provided. Consider the following points when using fungicides:

Timing: Apply fungicides at the first signs of dollar spot symptoms or when conditions are favorable for disease development. Early intervention helps prevent the spread and further damage. Consult wit Pride in Turf to determine the appropriate timing for your area.

Application Frequency: Depending on the product used, you may need to reapply the fungicide at specified intervals. Follow the label instructions carefully and adhere to the recommended application frequency.

Rotation of Products: To prevent the development of fungicide resistance in dollar spot pathogen, it is advisable to rotate between different fungicide products with varying active ingredients. Alternating between different chemical classes can help maximize effectiveness. Resistance to certain fungicides has occurred with Sclerotinia homoeocarpa, so using a control program is suggested.

Systemic vs. Contact Fungicides: Systemic fungicides are absorbed by the grass and provide long-lasting protection from within. Contact fungicides, on the other hand, remain on the surface of the grass blades and offer temporary protection. Both types have their advantages, and the choice depends on the severity of the dollar spot infection and personal preference.

We recommend that you contact us at Pride in Turf for recommendations and assistance with fungicide products and applications. We have access to fungicides that work for specific lawn diseases that you may not have access to. It is also important to make sure this is done correctly, and the experts at Pride in Turf will ensure the job is being done right.

Summary

Preventing and controlling dollar spot lawn fungus requires a combination of proper cultural practices, diligent lawn care, and the strategic use of fungicides when necessary. By implementing these measures, you can maintain a healthy and vibrant lawn that is resistant to the development and spread of dollar spot. Remember, consistency and regular maintenance are key to long-term success in managing this fungal disease.

Dealing with lawn diseases can be very challenging for the homeowner. Please contact Pride in Turf with questions or assistance. Our experts can analyze your lawn and know exactly what is needed to help you get your beautiful lawn back and prevent future outbreaks of lawn disease.

Pride in Turf wants your lawn to be the envy of the neighborhood!