NRS (Necrotic Ring Spot) Fungus

Necrotic Ring Spot (NRS) is a persistent and damaging turfgrass disease that commonly affects Kentucky bluegrass lawns in Utah. Recognizing the signs, knowing the best time to detect it, and understanding effective treatments are crucial in combatting this challenging lawn ailment.

Necrotic Ring Spot manifests as circular or arc-shaped patterns of dying grass in lawns. These rings typically range from a few inches to several feet in diameter. Initially, the affected grass shows a darkening or browning, gradually transitioning to complete death, resulting in patches of straw-colored or tan grass. Often, a ring of dark green, healthy grass surrounds the affected areas, creating a noticeable contrast. As the disease progresses, the rings might merge, causing larger dead patches throughout the lawn.

NRS primarily emerges in the late spring to early summer when soil temperatures range between 65°F to 75°F, creating an optimal environment for the disease to thrive. Symptoms may persist through the summer and can even reappear in the following spring, especially if left untreated.

Proper lawn maintenance, such as adequate watering, regular mowing, and avoiding excessive nitrogen fertilization, can assist in reducing the severity of NRS. Applying fungicides during the early stages of the disease, typically in the fall or early spring, can help control the spread. Fungicides containing active ingredients like azoxystrobin, propiconazole, or flutolanil are effective against NRS. It’s essential to follow label instructions for application. 3. Enhancing soil aeration and reducing thatch buildup can create a less favorable environment for the disease to thrive. 4. In severe cases, reseeding or resodding affected areas might be necessary to restore the lawn’s health and appearance.

The most effective time to address Necrotic Ring Spot is during the fall or early spring. Applying fungicides or implementing cultural practices during these periods can help fortify the lawn against the disease before it reemerges in the following season. Remember, prevention is key in managing NRS. Consistent lawn care practices, proper irrigation, balanced fertilization, and timely fungicidal applications can significantly reduce the impact of this turfgrass disease. While battling Necrotic Ring Spot can be challenging, a proactive approach and a combination of appropriate strategies can aid in preserving the vitality and beauty of Kentucky bluegrass lawns in regions susceptible to this disease.

In the battle against Necrotic Ring Spot (NRS), there’s a ray of hope for Kentucky bluegrass enthusiasts. Some varieties of Kentucky bluegrass exhibit resistance or tolerance to this troublesome disease. Cultivars such as Midnight, Bewitched, and Award have shown greater resilience to NRS compared to other standard varieties. If your lawn suffers significantly from recurrent outbreaks of NRS, replacing the susceptible grass with these resistant Kentucky bluegrass species could be a strategic solution. By planting these resistant cultivars, homeowners can reduce the risk of the disease reoccurring and maintain a healthier, more vibrant lawn. The use of disease-resistant grasses provides a long-term strategy for managing Necrotic Ring Spot, offering a proactive measure to fortify your lawn against this persistent turfgrass ailment. As always, proper lawn care practices combined with planting resistant grass varieties can significantly bolster the resilience of your lawn against NRS.