Fall in Louisiana brings relief from the scorching summer heat, but it also creates the perfect conditions for lawn fungus to thrive. As temperatures cool and moisture levels rise, the combination of high humidity, occasional rain, and mild temperatures can turn your otherwise healthy lawn into a breeding ground for fungal diseases. If you’re a homeowner or a commercial property manager, it’s important to understand how lawn fungus develops and what steps you can take to prevent and treat it during the fall season.

The Unique Climate Challenges of Louisiana
Louisiana’s climate is categorized as humid subtropical, which means that while winters are generally mild, the combination of warm, humid conditions in the fall creates an ideal environment for fungal growth. Lawns, especially those made of warm-season grasses like St. Augustine, Zoysia, and Bermuda, are prone to fungal infections when moisture levels are high and temperatures hover between 60°F and 80°F. The consistent moisture from morning dew, along with rain showers common during this season, keeps grass wet for prolonged periods, providing an ideal setting for lawn fungi to flourish.

Several types of lawn fungus are commonly found in Louisiana, particularly during the fall. Here’s a look at the most prevalent ones:

1. Brown Patch (Rhizoctonia solani): One of the most common fungal diseases in Louisiana, Brown Patch usually appears in the fall when nighttime temperatures drop and moisture levels increase. It causes large, circular patches of brown or yellow grass, often with a distinct ring of yellowing turf around the outer edge. Brown Patch is particularly harmful to St. Augustine and Zoysia grasses, two popular choices for lawns in Louisiana.
2. Dollar Spot (Sclerotinia homoeocarpa): This fungus typically creates small, silver-dollar-sized spots of discolored grass. While it primarily affects Bermuda and Zoysia grasses, it can also infect other types of warm-season grasses. Dollar Spot thrives in cool, moist conditions, making fall a peak time for its spread.
3. Gray Leaf Spot (Pyricularia grisea): This disease affects the leaves of grass, causing grayish, water-soaked lesions that eventually turn brown or tan. Gray Leaf Spot is particularly aggressive in humid conditions and can cause significant damage to St. Augustine grass.
4. Rust (Puccinia spp.): Rust appears as orange or rust-colored spores on grass blades and can cause grass to thin and weaken over time. This fungal disease thrives in humid, wet environments, which makes it a common issue in Louisiana during the fall.

Detecting lawn fungus early is key to preventing extensive damage. Here are some telltale signs that your lawn may be suffering from a fungal infection:

• Discolored Patches: Look for areas of brown, yellow, or gray patches in the grass. In the case of Brown Patch, these patches can be circular and several feet wide.
• Thinning Grass: If certain areas of your lawn seem to be thinning out or look less dense, this could be a sign of fungal damage.
• Spots on Grass Blades: Check the individual blades of grass for lesions, spots, or discoloration. Fungal infections like Gray Leaf Spot leave distinct spots on the leaves.
• Powdery Substances: Rust and other fungi may leave a powdery residue on the grass. If you brush your hand across the grass and it comes away with a red, orange, or brown powder, a fungus is likely present.
• Wilting Grass Despite Watering: If your lawn appears to be wilting or stressed despite regular watering, it could be due to a fungal infection that is disrupting the grass’s ability to absorb nutrients and moisture.

Several factors contribute to the development of lawn fungus during the fall. Understanding these causes can help you take preventive action before a full-blown fungal outbreak occurs.

1. Overwatering or Poor Drainage: Too much moisture on the lawn, whether from excessive watering or poor drainage, creates the perfect conditions for fungal growth. Grass that stays wet for too long becomes susceptible to fungal infections.
2. Improper Mowing: Cutting your grass too short weakens the blades and makes them more vulnerable to diseases like fungus. On the flip side, letting the grass grow too tall can trap moisture, encouraging fungal development.
3. Fertilization Issues: Too much nitrogen fertilizer can lead to rapid grass growth, which in turn makes the lawn more prone to fungus. On the other hand, insufficient fertilization can weaken the lawn, making it easier for fungus to take hold.
4. Compacted Soil: If your lawn’s soil is compacted, it can prevent proper drainage and air circulation, both of which are critical for maintaining a healthy lawn. Compacted soil creates a breeding ground for fungi.
5. Shady Areas: Lawns that don’t receive enough sunlight can stay damp for longer periods, especially in the fall. Shady areas are more likely to develop fungal infections because moisture evaporates more slowly.

The good news is that many fungal infections can be prevented with proper lawn care practices. Here are some steps you can take to protect your lawn during the fall:

1. Mow Properly: Maintain an appropriate mowing height for your type of grass. St. Augustine, for instance, should be kept at 2.5 to 4 inches tall. Avoid cutting more than one-third of the grass blade at a time, and make sure your mower blades are sharp to ensure a clean cut that doesn’t stress the grass.
2. Water Wisely: Water your lawn early in the day to allow time for the grass to dry out before evening. Aim for deeper, less frequent watering sessions rather than daily watering. This will encourage the grass to develop deeper roots and reduce the risk of fungal growth.
3. Improve Drainage: If your lawn has areas where water tends to pool, consider improving the drainage by aerating the soil or adding organic matter to help the soil absorb water more efficiently.
4. Fertilize Correctly: Use a balanced, slow-release fertilizer that provides your lawn with the nutrients it needs without encouraging excessive growth. Avoid applying too much nitrogen in the fall, as this can promote fungus development.
5. Control Shade: Trim back trees and shrubs to allow more sunlight to reach your lawn. This will help reduce moisture buildup in shaded areas and create a less hospitable environment for fungi.

If you’ve already noticed signs of fungal infection in your lawn, don’t panic—there are treatments available that can help stop the spread of the disease and restore your lawn’s health.

1. Fungicides: Apply a fungicide that is specifically designed for the type of fungus affecting your lawn. It’s important to follow the product’s instructions carefully, including the recommended application frequency and coverage area.
2. Cultural Practices: In conjunction with fungicides, improving your lawn care practices (such as proper mowing and watering) can help prevent the fungus from returning.
3. Aeration: Aerating your lawn can help break up compacted soil and improve airflow, which reduces the moisture levels that fungi thrive on.

Fall in Louisiana is a critical time for lawn care, particularly when it comes to managing the risk of fungal infections. By understanding the causes of lawn fungus and implementing proper preventive measures, you can keep your lawn healthy and vibrant throughout the season. Whether you’re dealing with Brown Patch, Dollar Spot, or another common fungus, early detection and treatment are key to maintaining a beautiful lawn in Louisiana’s unique climate.

Lawn care requires diligence, but by staying proactive, you can prevent fungal outbreaks and ensure that your grass stays strong as the seasons change.

​Different types of fungus can be found in too many places to name. However, some examples of where they can be located include your landscape, forests, and even you. Scientists were able to estimate that there were approximately 2.2 to 3.8 million species of fungi! Even though that is the case, the majority of those species have not yet been found. 

Fungi are phenomenal organisms. Inhabiting every environment on this earth, Fungi can be microscopic or can be seen with the naked human eye. The structure of fungi usually consists of hyphae which are usually thread-like filaments or roots. A group of hyphae is called a mycelium. They can reproduce sexually or asexually. They can reproduce asexually via spores. Like all organisms, fungi want to survive and reproduce. Fungi astoundingly have existed approximately 35 million years prior to land plants. 

​Fungi have a phenomenal ability to eat a wide viraety of things. They are heterotrophic and saprotrophs. Heterotrophic means that in order for their nutritional and metabolic needs to be fulfilled, all they need is carbon. Saprotrophs are organisms are able to attain all the needed nutrients from non-living organic material. Fungi are able to break down a viraety of different subject matter like dead animals, plants, and even plastic.
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However, there are some fungi that have the ability to be parasitic. When fungi are parasitic they infiltrate and attain nutrients from living organisms. When the fungi is parasitic it has the possibility of causing disease. 

You may be wondering how does or how can it can effect your everyday life? When looking into it, fungi has a lot of economic importance. Yeast is a type of fungi that is used to help raise bread. Mushrooms are also a type of fungi, and some of the mushrooms that exist are used frequently in food dishes. It is also used in drinks such as wine and beer.
Fungi also helps make medicine such as penicillin, mycophenolate, and micafungin. Pest control. It has even helped a greater of understanding of genetics in biochemistry, specifically the restriction enzyme.

What does brown patch look like?
Brown patch can look different depending on the type of grass in your lawn.
Dark brown border with a rounded shape. It can appear circular or irregular.
Thin grass inside middle of the border.
Brown patch damage can vary greatly in size, ranging from a couple of inches to a few feet.

Continuous wet weather leads to the right conditions for Entomosporium leaf spot to develop on your Indian Hawthorne bushes. Look for small, reddish-purple dots on new leaves that seem to die in the center of the spots. Yellow outlines will form on the outline of the spots. Later you will see the leaves turning red and falling off. This leaves your Indian Hawthorne with a lot less leaves and looking really unhealthy.

This fungus lives on the leaves that are infected and also on the surface of the ground. If you catch it early, remove the infected leaves. Like most fungi, removing select branches and allowing more airflow will let the plant dry quicker. This creates a less pleasant place for the fungus. Also remove the old leaves that have fallen to the ground. 

Fungicides will help in controlling Entomosporium leaf spot. Use it about every two weeks when the weather keeps the area wet and the temperature is not hot enough to dry out the plant leaves quickly. Spring and Fall are prime time for this fungus to develop. If you continue to have problems with this disease year after year, consider replacing your plants with a different species.

​Vinca, aka periwinkle, is a super popular plant during Louisiana summers. The flower is everywhere you look and for good reason. The flower looks fantastic in Louisiana landscapes. It does well in hot weather and in drier conditions. Unfortunately wet weather and cool temperatures become the perfect environment for Phytophthora blight, the vinca killer. This disease is always present in the soil, but can affect vinca when conditions favor it for too long. It spreads easily by rain splashing onto neighboring vinca, causing crown and root rot. It can wipe out an entire planting in no time.

Here are some best practices for planting vinca: 

• Stick with newer varieties like Nirvana for example.
• Use thin a thin layer of pine straw mulch to prevent soil splashing.
• Do not plant vinca two years in a row in the same place.
• Rotate in a different flower every other year to reduce the active disease presence.
• Use periwinkle in pots with good drainage. Change the soil next year if you want to plant periwinkle again.
• Less is more when using irrigation. Vinca will die much sooner by over-watering than under-watering.

In the previous few years, boxwoods have been repeatedly damaged by an unknown source. Raj Singh, a plant pathologist from LSU AgCenter, noticed this and identified the cause as the fungus Colletotrichum. It causes random die-back of twigs and a black discoloration of the stem. There are currently no official recommendations for treatment for the fungus. Considering this, take extra care to sanitize your pruning equipment to prevent the spread of the disease to healthy plants. If you suspect your boxwoods have been infected, please contact your AgCenter extension. Removal of infected plant matter may help prevent the spread of this new pathogen.

It is the middle of the summer and your crepe myrtles leaves are starting to discolor. They are developing brown spots and the leaves change from their natural green to yellow, orange and red. Crepe myrtle leaves will start to fall and your tree will start to look pretty shabby. So what is causing this problem?

Cercospora Leaf Spot is a fungus that causes all the problems mentioned earlier. While it won't severely damage your tree at first, it will return each year can start hurting your tree.  The fungal spores spread from splashing water during warm wet weather. Trees in humid areas with little air flow are more severely affected.

Buy a fungicide labeled for Cercospora Leaf Spot. Treat your tree as specified on the label starting in early summer when you first notice new spots. Most products have a short control period. If so, you will need to retreat your tree every one to two weeks, depending on the product label. Thinning the branches on the crepe myrtle will lead to better airflow and reduce the chance of Cercospora Leaf Spot recurring.

GreenSeasons offers fungus control and professional pruning in the greater Baton Rouge, greater New Orleans, Slidell, Prairieville, Walker, Denham Springs, Gonzales, Baker, Zachary, Hammond and Covington areas. If you need fungus control or professional pruning, click here for a free quote and we will give you a call. 

If you would simply like some advice on fungus control or pruning, please contact us and we will be more than happy to help.