Spring Dead Spot of Bermudagrass can turn your once-green haven into a patchy nightmare in the early stages of the growing season. While it's definitely not a death sentence for a lawn, it is unsightly and unwanted in most settings. Understanding the contributing factors and underlying activity that lead to this disease can keep you from asking, "Why do I have brown spots in my lawn?"
The Basics of Spring Dead Spot: Let's grasp the basics before delving into the connection. Spring Dead Spot is a fungal disease primarily affecting maintained turfgrasses. This disease that takes a grip on your lawn in the fall, as mild soil temperatures arrive (~70 °F), though no visual signs are present at this time. Weakening the plant ahead of the onset of winter, affected turf succumbs to frost and freeze damage that would otherwise not affect the grass. Once green-up begins, the now dead turf presents as bleached circular patches. In light to moderate cases, these patches will heal as the growing season progresses.
Disease ID: Spring Dead Spot of Bermudagrass presents as bleached and dead patches of turf that can measure from inches to several yards across. Within the patches, plant parts (rhizomes, roots, crowns, stolons) exhibit signs of rot, with portions appearing black. Patches are perennial but may not be consistent in size and location, and weed encroachment in dead patches is common due to reduced competition.
Late Season Nitrogen and the Perfect Storm: Late-season nitrogen applications, while seemingly beneficial for promoting growth and color into late fall, can inadvertently create a welcoming environment for the fungus responsible for Spring Dead Spot. Here's how:
Extended Nitrogen Availability: Late-season nitrogen extends its availability into the dormant winter period. While grasses may not actively grow during this time, the fungus remains active beneath the surface, utilizing this extra nitrogen as a nutrient source.
Fungal Feast: The fungus responsible for Spring Dead Spot thrives on nitrogen-rich environments. The surplus nitrogen becomes a feast for the fungus, enabling its persistence and resilience through the winter months.
Prevention Strategies: Now that we understand the connection, let's explore preventive measures:
Optimal Timing: Schedule nitrogen applications earlier in the growing season, avoiding inputs that can linger into dormancy. It is generally accepted in our area that September 15th is the deadline for fall Nitrogen inputs
Balanced Nutrition: Ensure a well-balanced fertilization approach, considering your lawn's specific needs without overloading it with excess nitrogen.
Soil Testing: Conduct regular soil tests to determine nutrient levels and adjust your fertilization strategy accordingly. A data-driven approach can make all the difference.
Timing and balance are your allies in the battle against spring dead spots. By being mindful of late-season nitrogen applications, you can take a significant step toward preserving your lawn's health and beauty.
Remember, a healthy lawn results from strategic care and a comprehensive understanding of its unique needs. Stay tuned for more insights on lawn care, and let's keep your outdoor space thriving!
For more information on this disease, Oklahoma State University Extension has an excellent fact sheet by Nathan R Walker publicly available. https://extension.okstate.edu/fact-sheets/spring-dead-spot-of-bermudagrass.html