Turf: Diseases & Fungus
Turf disease and fungus can be prompted by high moisture,
humidity, or heat. As spores are transferred (either wind, foot traffic,
water, mower, etc), funguses and diseases are prone to infect new portions
of a lawn or uninfected plants. Sometimes fungus can be corrected by taking
just a few simple steps, and sometimes a fungicide is warranted. Below
is information about common funguses to this area.
Anthracnose on turf can cause yellowing and thinning of the lawn, usually
starting with the older growth then spreading to the newer growth. The
lesions are round or oval, reddish-brown, and usually outlined...
Visually, brown patch is circular patches (a few inches to a few feet
in diameter) of dead, brown grass sometimes outlined by a ring of violet.
This disease appears during high humidity and high temperatures...
Dollar spot begins as small irregular light brown or straw colored patches.
Dollar spot is active during moist warm weather and can spread forming
large areas of infected turf. The leaf of the grass displays lesions...
Gray leaf spot generally affects tall fescue and rye grass - though it
has affected other cool seasoned grass types as well. The beginning stages
of Gray leaf spot are small lesions which mimic the look...
Gray snow mold appears on lawns when snow melts in spring and patches
of straw colored turf a few inches to a few feet in diameter can be seen.
The orange sclerotia is the key to identification. As snow...
Kentucky Bluegrass, Fescue's, and Bentgrass can be affected by Necrotic
Ring Spot. This disease begins as light green patches scattered throughout
the lawn, though as the disease grows...
Pink snow mold can affect lawns in autumn, winter and spring. Unlike gray
snow mold, pink snow mold does not require the insulation of snow to start
the pathogen (although snow cover indeed...
Powdery mildew appears in shaded areas that have little to no air circulation.
A white, fine powder forms on the blade of the grass sometimes covering
the whole blade. Kentucky Bluegrass is...
Pythium Blight, also referred to as cottony blight or grease spot, is
a rapid spreading disease that occurs during very humid weather patterns.
Within a matter of days, pythium blight can wipe out a lawn...
Red thread infects grass blades and leaf sheaths. The fungus is distinguishable
by thread-like strands or web-like areas of coral-pink to blood-red on
the tips of brown grass blades...
Rust is favored by warm and humid conditions and develop most frequently
on grasses subject to drought conditions, low nitrogen fertility and shade.
The disease first appears on grass leaves as small...
Summer patch affects Kentucky Bluegrass, Annual Bluegrass and Fescue's.
The disease appears during summer and is related to necrotic ring spot
where rot is caused to the root and crown of the plant...
Fungicides may be used as a preventative or corrective
measure; they can work by either preventing or interfering with the germination
process of the fungal spores or destroy the fungus outright. Contact fungicides
will not be absorbed by the plant’s tissue and will only remain
active on the surface of the plant in the location applied. This is beneficial
since it rarely leads to the fungi building a resistance against the fungicide
since the residual does not last long. Penetration fungicides may also
be an option. This sort of fungicide not only penetrates the leaf of the
plant (in which it can then travel to other portions of the plant) but
may also be used as a contact fungicide. Penetration fungicides can be
used to protect new growth from potential fungus attacks (especially if
susceptible, such as perennial rye grass).
Other sites that provide a wealth of information on Turf
diseases and funguses:
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