Bullet Turfgrass Diseases

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Dollar Spots

Dollar spot affects small, circular areas of turf, about 1 to 5 inches in diameter. Spots may merge to form large, irregular areas. Leaves appear water-soaked initially, then brown and often exhibit a reddish band extending across the leaf. Lesions on leaves often have a distinctive "hourglass" shape with necrosis on the outer edges of the leaf blade and healthy tissue in the middle.

 

 

Fairy rings are circular or semi-circular and can range in size from a few centimeters up to many meters in diameter. Symptoms can be variable, depending on the species of fungi, and include: 1) dark green rings with no dead turf; 2) dark green rings with a thin ring of dying or dead turf inside or outside the green ring; 3) rings of dying and dead turf with a hardened hydrophobic layer of soil that is difficult to irrigate; and 4) rings of mushrooms without a visible effect on the turf. Weeds commonly invade infested areas.

 

Fusarium blight first appears as small, circular, grayish green areas, ranging from a few inches up to a foot in diameter. Some plants in the center of the circles may survive, giving them a donut appearance. The crown or basal area of the dead stems is affected with a reddish rot and is hard and tough.

 

Powdery mildew causes grayish white, powdery growth to develop on the leaf surfaces.  All turfgrasses are susceptible to powdery mildew, but it is most severe on Kentucky bluegrass and fescues. Powdery mildew is most injurious in shady areas with high humidity and poor air circulation with temperatures at about 65°F

 

 

Pythium blight, also known as grease spot, kills turf in small, roughly circular spots (2 to 6 inches) that tend to run together. Blackened leaf blades rapidly wither and turn reddish brown. Leaf blades tend to lie flat, stick together, and appear greasy. Roots may be brown and rotten. All grasses are susceptible toPythium blight.

Lush grass with high nitrogen nutrition appear to be more susceptible.

Rust begins as small yellow spots on leaves and stems that form elongated, reddish brown or orange pustules. Theturfgrass quality is reduced because of poor color and reduced plant vigor. Rust survives as dormant mycelia in infected plants; it may spread to turf from infections on other grasses and woody ornamentals. The disease is more severe in turf deficient in nitrogen.