Diseases often target the most important part of the turfgrass plant: the crown. If the turfgrass plant were a person, the crown would be the brain. It’s the part of the plant that makes growth decisions and is where roots, shoots, and stems originate from. Plus, it also serves as the plant’s energy storage center, stockpiling carbohydrates to help it recover from wear and stress.

Since virtually every function of the plant relies on a healthy crown, protecting it is vital. Unfortunately, there are quite a few diseases that can harm it, including:

  • Pythium blight
  • Summer patch
  • Dollar spot
  • Leaf spot and melting-out diseases
  • Necrotic ring spot

We’ll cover each of these diseases—including how to identify and control them—below.

Pythium Blight

Pythium blight is a fungal disease that targets the leaves and crowns of many turfgrass species, including creeping bentgrass, fescues, and perennial ryegrass. It thrives when air temperatures and humidity are high, targeting moist, compacted soils. The disease causes sunken, discolored spots to appear on the lawn. Infected turf will appear waterlogged and slimy before dying and turning brown.

Since Pythium blight can spread and kill turf at a rapid pace, preventative fungicides should be used. Some powerful Pythium-fighting options include ArmorTech CYA 345, Mefenoxam 2AQ, and Serata.

Summer Patch

During periods of heat stress, the fungus Magnaporthe poae starts harming the roots, stolons, and crowns of Kentucky bluegrass and fine fescues. This fungus causes summer patch, a disease that causes turfgrass to wilt and turn yellow or straw-colored. These patches then grow up to three feet in diameter. By the time symptoms set in, the disease will have already taken hold. When the patches begin to darken, this means the roots have died. 

Properly irrigating and aerating your customers’ turf will go a long way in preventing summer patch, but since the disease becomes unmanageable before symptoms even appear, preventative fungicides should also be used. Summer patch treatment should begin when soil temperatures reach 60°F at two inches of depth. When it comes to product options, broad-spectrum fungicides like Tourney EZ, Lexicon, or Pillar SC will provide excellent control.

Dollar Spot

Dollar spot is a fungal disease that causes small, tan lesions to appear on grass blades. These lesions grow into circular patches that range from one to three inches in diameter—about the size of a U.S. silver dollar. These spots then merge over time to create larger patches, and these damaged areas can die if they’re left untreated. This disease prefers temperatures ranging from around 60–90°F and affects many different warm- and cool-season varieties.

Lawns with nitrogen deficiencies are especially susceptible to dollar spot, so ensure that your customers’ lawns are properly fertilized and watered. Applying nitrogen is an important step since dollar spot is a low-nitrogen disease, but fungicide applications will be the key to effective control. Consider a broad-spectrum fungicide like Pillar SC or Lexicon, and be sure to discuss other options with your ATS rep. If you have visited a dollar spot-affected property, be sure to clean off your mowers and shoes to prevent the fungus from being spread from lawn to lawn.

Leaf Spot and Melting-Out Diseases

Leaf spot is a fungal disease that causes small, dark lesions to form on grass blades. These lesions then expand and develop a light, tan center, and dark-colored border. These spots are often surrounded by a yellowish halo. As the disease progresses, the spots will merge together and cause further damage, killing turf in severe cases.

A similar disease known as ‘melting out’ can also occur. This disease affects the crown and other vital areas near the base of the plant, causing a red-colored rot to appear, which can kill the turf.

Both of these diseases primarily target Kentucky bluegrass and bermudagrass lawns. Avoid heavy nitrogen applications since excess nitrogen can promote disease growth on susceptible turf. Although these two diseases can kill infected grass, Fame SC will provide preventative control of both leaf spot and melting out.

Necrotic Ring Spot 

Necrotic ring spot targets cool-season lawns in the spring and summer, creating sunken, circular patches of dead turf. Kentucky bluegrass is relatively resilient compared to other turf types and can tolerate some infection.

That being said, during periods of environmental stress—especially heat stress—plants cannot survive, and the disease’s characteristic dead patches and rings will appear. The center of these patches may look healthy enough, but the ring around it will appear bleached. When it comes to control, Tourney EZ is an excellent curative option.

No matter the disease, your Advanced Turf Solutions rep is here to answer your questions and provide you with the products and advice that will help you make your customers’ lawns healthier. Need a rep? Click here to get connected in seconds.