CORTICIUM RED THREAD

Turf Affected:

Kentucky bluegrass, ryegrasses, and creeping red fescue.

Season:

Winter and early spring.

Conditions For Development:

Temperatures form 68 to 75 degrees F and long periods of rainfall.

Early Symptoms:

Irregularly shaped patches from 2 inches to 3 feet and appear water-soaked.

Late Symptoms:

The disease is confined to the leave and sheath only. The wet areas enlarge as the infected area drys out. Easiest to diagnose in the final stages because the leaves look like red threads.

DOWNY MILDEW

Turf Affected:

St. Augustine, Kentucky bluegrass, bentgrasses, ryegrasses, tall fescue and creeping red fescue.

Season:

Spring, early summer, and fall.

Conditions For Development:

Cool humid weather in the 60 to 70 degree range.

Early Symptoms:

White raised linear streaks that develop parallel to the mid-vein of the leaves.

Late Symptoms:

A fungal growth appears on the leaves and the tips of the leaf die. It can be confused with St. Augustine decline but it can be distinguished by less yellowing and more striping.

FAIRY RINGS

Turf Affected:

All lawn grasses.

Season:

Early spring to late fall.

Conditions For Development:

Introduced into new areas as bits of mycelium. Two to three years are required from the time of placement until the first-formed ring appears.

Early Symptoms:

Continuous circles of bands that are darker green and faster growing than the surrounding areas.

Late Symptoms:

Fruiting bodies of fungi appear. Usually called mushrooms, these structures may be quite abundant throughout the infected areas.

FUSARIUM BLIGHT

Turf Affected:

Kentucky bluegrass, bentgrasses, ryegrasses, tall fescue and creeping red fescue.

Season:

Spring and summer.

Conditions For Development:

High humidity with daytime temperatures ranging from 80 to 95 degrees F.

Early Symptoms:

Scattered light green patches 2 to 6 inches in diameter.

Late Symptoms:

Patches change within 2 days to a dull reddish brown, then tan and finally a light straw color.

FUSARIUM PATCH (Pink Snow Mold)

Turf Affected:

Kentucky bluegrass, bentgrasses, ryegrasses, tall fescue and creeping red fescue.

Season:

Late fall, winter and early spring.

Conditions For Development:

Cold wet weather. High humidity and temperatures from 32 to 45 degrees F. Snow cover provides an ideal environment for the development. Severe outbreaks can also occur during periods of prolonged rainfall and temperatures from 30 to 40 degrees F.

Early Symptoms:

Pale yellow irregularly circular patches.

Late Symptoms:

Affected areas change color to a whitish gray. Individual leaves take on a bleached appearance and feel slimy when wet. The borders may become covered with a dedicated network of "cobwebby" threads which will turn from white to a light pink.

GRAY LEAF SPOT

Turf Affected:

St. Augustinegrass.

Season:

Spring, summer and fall.

Conditions For Development:

Cool wet weather.

Early Symptoms:

Minute brown dots.

Late Symptoms:

Spots enlarge rapidly to form oval spots. The center becomes a depressed gray area with an almost black ring around the edges.

HELMINTHOSPORIUM LEAF SPOT

Turf Affected:

Kentucky bluegrass, bentgrasses, ryegrasses, tall fescue and creeping red fescue.

Season:

Late Spring and summer

Conditions For Development:

Warm wet weather. Most common when temperatures are ranging from 80 to 90 and there are extended periods of rain.

Early Symptoms:

Same as Melting-out.

Late Symptoms:

The infection of the sheath isn't as common as with melting-out. Most of the damage is done to the blade itself. It causes a rapid drying-out of the leaf tissue turning the leaf a light straw color.

MELANOTUS WHITE PATCH

Turf Affected:

Tall fescue.

Season:

Summer.

Conditions For Development:

Most frequently seen if the fescue is under 12 months old or is seeded to heavy.

Early Symptoms:

Circular off white patches.

Late Symptoms:

Patches may mat together and become closely pressed to the soil surface. Restricted to the leaf blades only.

MELTING-OUT

Turf Affected:

Kentucky bluegrass, ryegrasses, and tall fescue.

Season:

Late winter and early spring.

Conditions For Development:

When temperatures are between 55 to 70 degrees F, and extended periods of rainfall or overcast weather.

Early Symptoms:

Minute water-soaked areas.

Late Symptoms:

Areas turn dark pruplish-red, then turn brown and finally a dull white. Damage is mostly seen on the entire sheath of the grass causing the leaves to drop off.

NECROTIC RING SPOT

Turf Affected:

Kentucky bluegrass, bentgrasses, ryegrasses, chewing fescue, tall fescue and creeping red fescue.

Season:

Late winter, spring and fall.

Conditions For Development:

Cool wet spring and fall months.

Early Symptoms:

Irregular patches in shades of red, yellow or tan.

Late Symptoms:

Areas turn tan or brown. Patches are somewhat circular in shape. The thatch may decompose rapidly in the damaged area leaving depressions or a "sunken" area.

NEMATODES

Turf Affected:

All lawn grasses.

Season:

Late spring and summer.

Conditions For Development:

When soil temperatures are in the mid 50's, the population of hatched nematodes increases rapidly.

Early Symptoms:

Infected area begins to look under watered or under fertilized.

Late Symptoms:

Plants will lack overall vigor and will have difficulty with low soil moisture or high temperatures. Growth will be restricted in depth and density.