Watch Out, Jacksonville: 3 Vicious Winter Lawn Diseases

Winter is when your lawn usually goes dormant. One thing that doesn’t sleep however, is lawn disease. Even though many lawn diseases happen in warmer weather, you’ll want to make sure to watch out for these three common winter lawn diseases and take care of them before it causes too much damage to your Jacksonville yard.

Snow Mold

1. Snow Molds (Gray and Pink)

The fungi that cause snow molds attack the grass during the winter, either under snow cover or during cold winter rains. These diseases are often more common when snow starts falling on ground that isn’t too completely frozen or on turf that is not fully dormant. The injury usually appears in the spring as circular to irregular spots of dead, matted grass.

Patches of snow mold range from 3-12 inches in diameter. However, individual patches frequently coalesce and appear as large, irregular, blighted areas in the lawn. Weblike growths of fungus are often visible when the matted patches of grass are wet.

Grass infected with pink snow mold usually appears white to salmon in color whereas grass infected by gray snow mold appears white to gray. Since it is not unusual for both types of snow mold to be found in the same area, diagnosis based solely on color can be inaccurate.

Gray snow mold normally attacks leaf blades and usually only occurs after prolonged snow cover. Grass infected with gray snow mold usually recovers as growth resumes during warm spring weather.

In contrast, pink snow mold can invade leaf blades, roots, and crown tissues so it often causes more serious damage. Pink snow mold can occur with and without snow cover and grass infected with this disease may not recover when temperatures warm in spring.

The effects of snow mold can be minimized by raking the affected patches to remove matted grass and plant debris in the spring. This procedure also helps to stimulate new growth. Over-seeding can be helpful to fill in affected areas.

Red Thread on a blade of grass

2. Red Thread

Lawns infected with red thread frequently have a reddish-pink cast in early morning or when wet. These colorful patches can vary in size from several inches to several feet in diameter.

When examined more closely, the symptomatic grass blades appear to be covered with a pinkish, gelatinous growth when the grass is wet or pink, cotton candy-like threads when the grass is dry. Infected grass blades may turn brown, but infection is usually limited to the blades.

Red thread is most common on perennial rye grasses and fine-leaf fescues although it can occur on most turf grasses.

Red thread is usually more common on lawns that are stressed by drought, soil compaction, low temperatures, or inadequate fertility so any steps to minimize stress and maximize vigor are helpful. Watering should be infrequent but deep. It is helpful to mow when your grass is dry and to mow affected portions of the lawn after the healthy portions to help minimize spread of the fungus.

Dollar Spot on a lawn

3. Dollar Spot

Dollar spot is characterized by small, circular, brown spots on the leaf blades which can turn nearly white. The spots may remain separate or coalesce into larger irregular areas which often have hourglass shapes. Dollar spot can occur in the early summer, late summer, and early winter when humidity levels are high and cool nights follow warm days.

It is helpful to maintain adequate fertility since dollar spot is often found on nitrogen-deficient lawns. Infected lawns should be mowed when the grass is dry to minimize spread of the fungus to healthy grass. Watering to maximize vigor is helpful but it should be deep rather than frequent, shallow watering.

Need help tending to your lawn? Visit our Jacksonville lawn care page for more info! In addition to Jacksonville, we also provide lawn care service in Orange Park, Ponte Vedra Beach, and Saint Augustine.