Large Patch Disease: Control with Two Fall Fungicide Applications
Large Patch Disease is a significant concern for those maintaining warm-season turfgrasses like Centipedegrass, Zoysiagrass, St. Augustinegrass, and Seashore paspalum. As the cooler months approach, the threat of this disease increases, particularly in transition zones and areas with cooler spring weather. Understanding how to control Large Patch Disease with targeted fungicide applications in the fall is crucial for maintaining a healthy lawn.
In this article, we will discuss the factors that contribute to the development of Large Patch Disease, identify the symptoms, and offer cultural and chemical control strategies to keep your lawn looking its best.
Topic | Details |
Susceptible Turfgrasses | – Centipedegrass, Zoysiagrass, St. Augustinegrass, Seashore paspalum. |
Ideal Conditions for Disease | – Develops when soil temperatures drop to ~70°F. |
Symptoms | – Reddish-brown lesions on leaf sheaths. – Blighted rings (5 inches to 10 feet). – Yellow patches with possible orange rings. – Leaves detach easily from stems. – Limited recovery at spring green-up. |
Development Factors | – Excessive nitrogen in fall and spring. – Poor soil drainage. – Over-irrigation. – Excessive thatch. – Low mowing heights. |
Cultural Control Practices | – Avoid nitrogen in fall/spring. – Improve soil drainage. – Water only to prevent drought. – Control traffic to avoid compaction. – Mow at recommended heights. |
Management Tips | – Apply modest nitrogen in summer. – Delay spring nitrogen until disease is inactive. – Promote sunlight and air circulation. – Avoid overwatering and reduce thatch. |
Chemical Control | – Apply fungicides preventatively in fall. – Monitor soil temperatures (Centipede/St. Augustine: 80°F; Zoysia: 70°F). – Two applications, 28 days apart, provide season-long control. – Use at least 2 gallons of water per 1,000 sq. ft. during application. |
Susceptible Turfgrasses
Large Patch Disease primarily affects specific types of turfgrasses, making it essential to know if your lawn is at risk. The turfgrasses most susceptible to this disease include:
- Centipedegrass
- Zoysiagrass
- St. Augustinegrass
- Seashore paspalum
These grasses are particularly vulnerable in regions where the weather conditions in late fall and early spring are favorable for disease development. Large Patch Disease typically thrives when soil temperatures drop to around 70°F, often during periods of extended leaf wetness. Regular lawn disease and fungus control can help mitigate the impact of these conditions.
Recognizing the Symptoms of Large Patch Disease
Identifying Large Patch Disease early can help prevent severe damage to your lawn. The symptoms are most noticeable in the spring as the grass begins to green up. Look out for the following signs:
- Reddish-brown or black lesions on the basal leaf sheaths
- Blighted rings of turfgrass, ranging from 5 inches to 10 feet or more in diameter
- Patches that appear reddish-brown to yellow, sometimes with an orange ring around them
- Leaves that easily detach from the stems
- A stark contrast between blighted patches and healthy, dormant turf in winter
- Limited recovery of affected areas during spring green-up
Infected warm-season grasses rarely show leaf spots, but they may have rotted leaf sheaths near the soil surface, causing the leaves to pull free with little resistance. For more detailed information, visit the NC State Extension page.
Factors That Contribute to Large Patch Disease Development
Several environmental and cultural factors can increase the likelihood of Large Patch Disease developing in your lawn. Understanding these factors can help you take preventative measures:
- Excessive nitrogen in the fall and spring
- Poor soil drainage and waterlogged areas
- Over-irrigation leading to prolonged leaf wetness
- Excessive thatch accumulation
- Low mowing heights that stress the turf
By being mindful of these factors and considering professional lawn and landscape maintenance services, you can reduce the risk of Large Patch Disease and keep your lawn healthy and vibrant.
Cultural Control Practices for Large Patch Disease
While fungicides play a crucial role in controlling Large Patch Disease, cultural practices are equally important. Implementing these strategies can help you manage the disease more effectively:
- Avoid nitrogen applications in the fall and spring to prevent rapid, susceptible growth.
- Improve soil drainage by avoiding planting in low-lying, saturated areas or installing subsurface drainage systems.
- Irrigate wisely by watering only when necessary to prevent severe drought stress.
- Control traffic on the lawn to avoid compaction and aerify regularly to maintain soil drainage.
- Mow at recommended heights to reduce stress on the turf and keep thatch under control. Consider using a professional lawn mowing service to ensure optimal mowing practices.
These cultural practices are the foundation of a healthy lawn and can significantly reduce the impact of Large Patch Disease.
Management Tips for Large Patch Disease
Proper lawn management is essential for preventing and controlling Large Patch Disease. Here are some expert tips to keep your lawn disease-free:
- Apply nitrogen sparingly during the summer and avoid it altogether in the fall. A fertilization service can help tailor the correct nutrient regimen for your lawn.
- Delay spring nitrogen applications until Large Patch Disease is no longer active.
- Vertical cut zoysiagrass after it has fully greened up, followed by a light nitrogen application to aid recovery.
- Promote sunlight and air circulation by trimming back overgrown areas and improving drainage.
- Avoid overwatering and keep thatch levels in check to reduce disease risk.
Integrating these tips with regular lawn treatment can help maintain a healthy, disease-resistant lawn.
Chemical Control: Fungicides for Large Patch Disease
Preventative fungicide applications are a key component of controlling Large Patch Disease. Timing is critical, especially in the fall. Here’s how to use fungicides effectively:
- Monitor soil temperatures to determine the right time to apply fungicides. For Centipedegrass and St. Augustinegrass, apply fungicides when soil temperatures drop to 80°F for five consecutive days, typically in September and October. For Zoysiagrass, wait until soil temperatures drop to 70°F for five consecutive days, usually in October and November. You can use the Soil Temperature Maps to track soil temperatures in your area.
- Apply fungicides twice in the fall, spaced 28 days apart, to achieve season-long control. In severe cases, continue applications every 4-6 weeks as long as soil temperatures remain above 50°F.
- Use at least 2 gallons of water per 1,000 square feet during application, with higher volumes improving the fungicide’s effectiveness.
For best results, consider integrating these chemical controls with professional lawn care services that include targeted weed control and fungicide applications.
Fungicides for Control
Selecting the right fungicide is essential for effectively managing and controlling Large Patch Disease in your lawn. The table below provides a comprehensive list of recommended fungicides, categorized by their effectiveness and active ingredients.
These products can be found at major retailers, such as big box stores, Site One, Triangle Chemical, landscape supply stores, and Amazon. By following the label instructions meticulously and choosing a product suited to your lawn’s specific needs, you can maintain a healthy, disease-free lawn throughout the season.
Product Name | Active Ingredient(s) | Effectiveness |
Headway G | Azoxystrobin, Propiconazole | Excellent |
Quali-Pro Strobe Pro G | Azoxystrobin, Propiconazole | Excellent |
Pillar G Intrinsic Fungicide | Pyraclostrobin, Triticonazole | Excellent |
Fame Granular Fungicide | Fluoxastrobin | Excellent |
Heritage G | Azoxystrobin | Good |
Scott’s Disease EX | Azoxystrobin | Good |
Ferti-lome Liquid Systemic Fungicide II Containing Banner RTS2 | Propiconazole | Good |
Bonide Infuse Systemic Disease Control Lawn & Landscape RTS2 | Propiconazole | Good |
Bayer BioAdvanced Fungus Control for Lawns RTS2 | Propiconazole | Good |
Bayer BioAdvanced Fungus Control for Lawns Ready to Spread Granules | Propiconazole | Good |
Anderson’s Turf Products Prophesy 0.72G Fungicide | Propiconazole | Good |
Spectracide Immunox Fungus Plus Insect Control for Lawns RTS | Propiconazole | Good |
Ferti-lome F-Stop Lawn Fungicide | Myclobutanil | Good |
Lesco Eagle 0.39% Granular Turf Fungicide | Myclobutanil | Good |
Lebanon Eagle 0.62G Specialty Fungicide | Myclobutanil | Good |
Ferti-lome F-Stop Lawn & Garden RTS2 | Myclobutanil | Good |
Monterey Fungi-Max Multi-purpose Fungicide Concentrate | Myclobutanil | Good |
Spectracide Immunox Multi-Purpose Fungicide Spray Concentrate | Myclobutanil | Good |
This streamlined table provides a clear overview of fungicide options to help you select the best product for controlling Large Patch Disease in your lawn.
Conclusion: Protect Your Lawn from Large Patch Disease
Large Patch Disease can be a significant challenge for warm-season turfgrasses, but with the right combination of cultural practices and well-timed fungicide applications, you can protect your lawn from this damaging disease. By staying vigilant and taking action when soil temperatures begin to drop in the fall, you can keep Large Patch Disease at bay and enjoy a healthy, beautiful lawn year-round.
Don’t wait until it’s too late—call us today or fill out our estimate request form to ensure your lawn stays in top shape! Our team of lawn care experts is here to help you manage Large Patch Disease and maintain the lush, green lawn you deserve with comprehensive lawn care services that cover all aspects of turf health.