Now that spring has finally arrived, landscape contractors across the country are gearing up to start their lawn maintenance routines. Between laying down new turf grass, spreading fertilizer and setting a mowing schedule, there’s a lot that goes into managing a healthy yard. In fact, keeping up with lawn maintenance is one of the best ways to prevent weed growth, grass diseases and pest control issues, according to the Environmental Protection Agency. Considering grass diseases have the potential to completely destroy a new or seasoned lawn, it’s crucial for landscapers to understand the warning signs and to take action to stop their spread as soon as possible.
Identifying grass diseases
While there are many different types of grass diseases, the most common have similar symptoms and treatment strategies. As highlighted by the University of California, grass diseases need three components to flourish and spread: A disease-causing pathogen, a suitable environment and a susceptible host. Although there’s not much landscapers can do to eliminate harmful pathogens, they can make a major impact by keeping lawns appropriately watered, mowed and aerated. It’s also important to choose a turfgrass species that is well suited to the local climate, as this may help prevent sudden disease outbreaks caused by temperature fluctuations and weather-related events.
Here’s a quick breakdown of the five most common grass diseases identified by Turf Magazine:
- Brown patch: This grass disease (named rhizoctonia solani) mainly affects cool-season turf lawns in the early summer, when nighttime temperatures reach 65 to 70° F. The turfgrass species most at risk are tall fescue, Kentucky bluegrass and perennial ryegrass, though brown patch can quickly spread to adjacent turf. This grass disease is caused by a fungus (Rhizoctonia) and is usually cured by laying down a strong fungicide.
- Large patch: While similar to brown patch, this grass disease mainly targets warm-season turfgrass including zoysiagrass and bermudagrass. In most cases, this lawn care issue pops up in spring or autumn, when overcast skies and moist weather creates the perfect conditions for the disease to spread. Large patch generally starts as small blotches and quickly grows into massive, off-colored brown spots. Controlling this type of grass disease often requires applying fungicides that contain azoxystrobin and/or propiconazole.
- Pythium blight: This foliar disease is classified as a water mold and is particularly harmful to newly seeded turfgrass. Generally speaking, pythium blight forms due to poorly drained soil and humid conditions, and leaves behind a “gray, water-soaked appearance,” according to Turf Magazine. Once symptoms have appeared, it may already be too late for landscaping contractors to prevent their spread using fungicides.
- Pink snow mold: This grass disease is most common in areas with cool, humid weather, such as the Pacific Northwest. Despite its name, the trademark pink hue is only present for a short period of time and the disease can grow in any season, not just the winter. Under wet conditions, pink snow mold will leave behind a “white mycelium,” per Turf Magazine, while dry weather often leads to brown or bleached patches of turfgrass. Combating pink snow mold can be difficult unless landscapers catch the symptoms early and apply a strobilurin fungicide.
- Necrotic ring spot: While less common than other grass diseases, necrotic ring spot can be one of the most difficult to manage when maintaining a Kentucky bluegrass lawn. This disease starts as a dormant outbreak in early summer before growing into circular patches of tanned or browned turf later in the season. The best way to prevent necrotic ring spot is to proactively spread fungicide in the late spring, though frequent irrigation may also help the turf recover.
Grass disease prevention
Once a grass disease has taken hold of a lawn, it can be extremely challenging to manage without using some form of pesticide or fungicide. As such, landscape contractors should focus on preventative lawn maintenance that can stop turfgrass diseases before they grow out of control. According to the grass seed and fertilizer manufacturer Pennington, landscapers should take the following steps to keep lawns healthy and disease-free:
- Keep soil PH at appropriate levels for specific turfgrass species
- Fertilize turfgrass in late spring/early summer
- Water lawns consistently to promote growth and resilience
- Cut grass to recommended heights with a clean, sharp mower blade
- Dethatch lawns and aerate soil to promote drainage
- Apply pesticides and fungicides to combat severe infestations
Ultimately, the best lawn maintenance plan is one that considers the individual needs of different turfgrass species and can be adapted accordingly. For more information on common grass diseases and how to prevent them, check out this handy guide from the University of California’s Integrated Pest Management Program.