The Seasonal Lawn Fungus Brown Patch

Brown patch is a fungal disease of turf grass, which is caused by the fungus species called Rhizoctonia. This turf grass infection is widespread in mid to end of the summer season, while there prevails extended spans of high temperature and humidity. On the turf grasses of cold seasons in U.S.A, brown patches are quite common. The disease is very harmful to some particular grass species; Bentgrass, Tall fescue, Annual bluegrass and ryegrass. Brown patch is also commonly known as a foliar disease; it exerts no effects on the roots or crowns of turf plants.

Symptoms of the harmful lawn fungus brown patch

Lawn Fungus

Lawn Fungus

The symptoms of this harmful lawn fungus, brown patch differ according to the different maintenance or caring practices executed on the turf grass (fertilizing, mowing, watering, etc). Signs on turf grasses, which remain wet for long spans and are typically mowed will form a typical purplish-gray outlined ring, known as ‘smoke outline or ring’, which ranges about 50cm in diameter. Cut grasses, which do not remain wet for elongated spans may start to show patches, which may range about a feet or more in their diameter. It may also possess a ‘frogeye’ form. Colorless mycelium over turf grasses covered with dew in the early morning period. If you take a closer glance at the leaf blades of the grass, (commonly on the species of Tall Fescue), irregularly shaped grazes, tan to brown in their colors.

The fungal disease cycle

The Rhizoctonia species survive in temperature varying 70 degree F to 90 degree F but may thrive in freezing temperature conditions as well. Brown patch is quite common when temperature at night does not drop much; not lower than 68 degree F while there are extended spans of high humidity and leaves remain wet for elongated spans. The Rhizoctonia species possess fungi of two particular groups, by which the turf plant is very often affected at different spans throughout the year.

Mostly, Rhizoctonia solani may form brown patches in the month of June or towards the early July. When temperature rises and humidity increases, the Rhizoctonia solani will be transformed Rhizoctonia zeae. It has been verified that brown patch is prominent on tender and lush turf grass, which contain extreme amounts of nitrogen or those that are maintained with moderate levels of the gas. The species is capacitated to survive in the land for years, without exerting any affects on the turf grass. During the cold season, the species will prevail on soil or grass tissues and convert themselves into resting components, known as sclerotia.

Chemical treatment of lawn fungus

The lawn fungus can be removed by the use of some useful, chemical fungicides. These include Dithiocarbamates, Carboximides, Phenylpyrroles, Nitriles, Antibiotics, QoIs, Dicarboximides, DMIs and Benzimidazoles.  These chemical fungicides are quite effective on treating fungal diseases of turf grasses. However, these fungicides need to be applied in the correct proportion, so that it tends to be harmful only for the fungus and not for the grasses instead. Quality and original fungicides are to be used in proper amounts to remove grass fungus.

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