#Pythium blight series

Fungicides should be applied to Pythium blight when the grass is in the вЂњgreasy,вЂќ dark green stage of infection. Fertilizing and watering sparingly (watering once a week at long intervals is preferable), and aerating the soil to prevent the buildup of thatch and loosen compacted soil is recommended.Дuring long summers, fungicides may be required to get rid of Pythium blight.

Pythium thrives in densely growing, lush grass, and prefers the permanently damp conditions provided by lawns whose soil drain poorly. Overfertilization and overwatering can often be blamed for the appearance of Pythium blight. Are damaging to the roots and crowns of grass, which can, if left untreated, end up killing off patches of grass вЂњpermanentlyвЂќ (until new grass seeds germinate in the infected area). Both Pythium aphanidermatum and Pythium spp. While Pythium aphanidermatum forms the gray mycelium or fruiting bodies that give the вЂњcottony blightвЂќ variety of Pythium blight its name, Pythium spp.does not. After the infected grass dries and the disease becomes less visible, yellow patches in the same shapes as the former вЂњgreasyвЂќ patches are left behind. The wet or вЂњgreasyвЂќ patches may then develop gray mold. Pythium blight starts off looking more or less normal, like dark, damp patches of grass running along already damp areas of the lawn. It can generate new spores and infect new plants within 2 hours of the arrival of sufficiently warm, damp weather conditions. Mycelium, or the gray mold created by the fungus Pythium aphanidermatum, is capable of surviving in soil and dead or cut grass blades. For this reason, they are often found growing in lines that follow indents in the lawn where water drainage occurs, or the mowing pattern on the lawn. Pythium blightвЂ™s fungal spores can be easily transported by wind, water and by mowing the lawn. The spots are water-soaked and dark-coloured early in the morning. This disease causes greasy, brown circular spots that are initially about 2 cm to 5 cm in diameter and then rapidly enlarge in size. During the past three years, the failure of fungicide treatments against the disease has been observed in several locations in Northern Italy. Pythium Blight appears suddenly during hot, humid weather. If extensive damage appears, turf seldom responds to fungicide treatment (See the section Chemical Controls for Turfgrass Diseases).There are over 20 species of fungus that result in Pythium blight, the most common being Pythium aphanidermatum. Pythium blight is one of the most important turf grass diseases. Fungicide control of Pythium root rot is less consistent than control of foliar blight. Leaves within affected areas are matted, orange or dark gray in color, and greasy in appearance. During extended periods of warm, humid weather, a preventive fungicide program is advised. (water mold/oomycete) Hosts bentgrass, bluegrasses, fescues, ryegrasses Overview Pythium blight first appears as small, sunken, circular patches up to 1 foot in diameter during hot, humid weather. Increasing the mowing height and other practices that promote root growth may lessen the damage from Pythium root rot. Increase air movement by reducing shading, selective pruning or fans. Remove thatch with frequent verticutting and avoid overfertilization. Avoid late day watering and overwatering new plantings.

Symptoms of Pythium root rot mimic melting out and anthracnose and there is no foliar mycelium.Д¬ontrol and Management: Diagnosis should be confirmed by a diagnostic laboratory as soon as possible. It also can cause crown and root rots which generally occur in early spring or late fall when soils are cool and excessively wet or saturated.

Pythium may cause seedling blight and poor stand development in perennial ryegrass overseedings. Hybrid bermudas are more susceptible to pythium than common bermudagrass. When disease is very active, fungal mycelium grows profusely over affected plants so that diseased areas have a cotton-like appearance. On close-cut turf, pythium blight may appear as streaks that follow water drainage or mowing patterns. Roundish, dark, greasy to slimy patches of matted grass, from two to 12 inches in diameter, appear suddenly.

#Pythium blight series

Host Grass: Hybrid Bermuda( Cynodon dactylon), Common Bermuda, Bentgrass( Agrostis palustris), Fescue, Perennial Ryegrass (Lolium perenne), Poa Series (Poa sp.)Д¬ause and Sym p toms: Disease is favored during rainy, foggy weather and in low lying areas where air circulation is poor. Pythium Blight, Cottony Blight, Greasy Spot (fungus вЂ“ Pythium aphanidermatum )