Tech Notes Issue 13

Spider Mitesare Active inEarly Spring

Mites can cause damage to both cool andwarm season turfgrasses during the winter months. Their needle-like mouthparts pierce the plant or leaf sucking out the plant juices. Although mite damage for themost part is sporadic, symptoms can appear speckled with a purplishshade or ableached straw color. Severely damaged plants may appear stunted or killed. A potential sign of mite damage occurs in early spring when the turf fails to green up (more on mites in a future issue).

Photograph: A few mites can produce significant webbing.

Pink Patch Appears on Low FertilityGreens During Cool Wet Weather

Pink patch caused by the pathogen Limonomyces roseipellis can occur on cool season turfgrasses including fescues, ryegrass, and blue grassbut is most frequently found on bent grasses.

Symptoms like those of red thread, often are more or less circular, pinkish red to tan patches, 5 to 10 cm in diameter.Pink patch spreads much slow than red thread and is less severe. Damage isg enerally superficial. Individual leaves affected by pink patch become covered with a growth of fungal mycelium. The pink patch fungus does not produce red fungal threads or pink cottony masses of mycelium as does red thread.

Pink patch was once considered a form of red thread disease. The pink patchf ungus and the red thread fungus are similar in appearance, and often develop together. The disease is more severe in turfgrass maintained with low nitrogen fertility. The fungus grows at temperatures from 4 to 32 C. Mild temperaturesa re often ideal especially if there is abundant moisture. The pathogen has a slow rate of growth and is more severe on slow growing stands of turfgrass.

The disease is usually managed by increasing the growth rate of the turfgrass. An adequate fertility program should reduce the appearance and severity of pink patch. Chemically, many of the fungicides that control red thread will also control pink patch.

Photograph: Pink patch symptoms on creeping bentgrass green. The photograph was taken during early spring.