Effective Ways to Get Rid of Lawn Weeds

Credit: Lane Tredway: Pyriculria grisea: fescues, kikuyugrass, ryegrasses, St. Augustinegrass: irregular blighted patches of grass with bleached spots with dark margins on leaves; ryegrass develops a fishhook appearance: daytime temperature levels of 8595F; high humidity or rainfall; overwatered and overfertilized grass: irrigate effectively; don't overfertilize; minimize shading; increase air movement: fungicides are offered, however cultural controls are more useful Fusarium patch damage to bentgrass grass.

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McCain: Microdochium nivale: yearly bluegrass, bluegrasses, fescues, ryegrasses, zoysiagrass: circular patches of 12 inches that can expand to 12 inches; leaves initially appear watersoaked, then reddish brown, and lastly bleached; minute, gelatinous spore masses often seen on dead leaves; white or pinkish fungal threads might be seen in morning; more common in Central and Northern California: regularly cool temperature levels (4065F) and damp conditions; high nitrogen applications in fall; neutral or alkaline soil pH; pathogen survives in grass residues: minimize shade and improve soil aeration and water drain; water appropriate length of time; prevent excess nitrogen, especially in fall; maintain soil pH between 6.56.7.

Credit: M. Ali Harivandi: Bipolaris spp. and Helminthosporium spp.: bermudagrass, bluegrasses, fescues, kikuyugrass, ryegrasses, zoysiagrasses: circular to elongated brownish areas with brown centers and dark brown or purple borders on leaf blades, sheaths, and stems; crowns and roots regularly have a dark brown rot; crown-infected plants may pass away in hot, windy weather condition, leaving thinned areas throughout the grass; spores are windborne: warm temperature levels (7090F) for bluegrasses, ryegrasses, and fescues; cool temperatures (6070F) for bermudagrass and zoysiagrass; high humidity; low clipped turfgrass; most severe with excess nitrogen fertilization or deficiency: reduce shade; enhance soil aeration and water drainage; prevent dry spots and too much nitrogen fertilizer; preserve as high a cutting height as possible: fungicides offered but typically not called for Pythium blight (grease spot), triggered by Pythium sp., on a ryegrass and bluegrass yard.

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Ali Harivandi: Pythium spp.: all lawns: small, circular areas (26 inches) that run together; blackened leaf blades rapidly wither, turn reddish brown, lie flat, stick together, and appear greasy; roots may be brown; in damp conditions, masses of fungal mycelium may appear: low spots that remain wet; warm temperatures (8095F daytime, > 68F night time); endures as spores in soil for long periods: minimize shading; improve soil aeration and water drain; water proper length of time; prevent mowing wet grass and applying high levels of nitrogen during hot, damp weather condition: fungicides available but primarily avoided by cultural practices in California Patches of tall fescue turfgrass infected with Rhizoctonia blight.

Treating Fungal Lawn Quickly

Credit: Arthur H. McCain: Rhizoctonia solani AG 2-2LP: bermudagrasses, kikuyugrass, St. Augustine grass, zoysiagrass: very first appears as small, irregular brown patches or rings that can enlarge to many feet in diameter; centers might recover leading to rings of diseased turf; leaves and sheaths become watersoaked, wilt, turn light brown, and die; plants take out easily from soil with rotten stolons, in light problems, roots typically not infected and plants typically recuperate; soil-inhabiting fungi that forms fine, fungal threads in soil or on turfgrass: excess thatch and mat along with cool temperature levels (6070F); wet soil conditions: decrease shading and enhance soil aeration and water drain; water appropriate length of time to a depth of 46 inches; prevent excess nitrogen in the fall; maintain thatch less than 1/2 inch: fungicide helpful if illness serious in previous Red thread damage to grass foliage.

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McCain: Laetisaria fuciformis: bentgrasses, bermudagrasses bluegrasses, fescues, ryegrasses: red thread might kill turfgrass in patches that are 28 inches in size, or the disease may take place over large locations without eliminating the plants; pink web of fungal threads bind the leaves together; search for pink, gelatinous fungal crusts projecting from the leaves to assist recognize this disease: common under conditions of mild air temperatures (6075F) and extended durations of leaf wetness; typically appears on plants deficient in nitrogen during periods of cool or warm temperature levels if there is adequate moisture (e.g., excess irrigation or rains): appropriate watering and fertilization can reduce the incidence; sufficient nitrogen generally can prevent this illness from taking place; prevent drought tension by watering turfgrass based on evapotranspiration needs of the turfgrass; provide adequate air flow; minimize shading: fungicides hardly ever necessitated other than in serious cases Rust damage to bluegrass foliage.