How to Identify Your Lawn or Plant Disease & Fungus Problem
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Anthracnose
Common Location: Both Lawn & Plants
×AppearanceDiseased lawns have irregular yellow to orange patterns in small freckle-like spots or circles up to one foot in diameter.
Also look for tiny spores that appear as black, saucer-shaped pads with black spines. -
Ideal Growth ConditionsThis fungal disease is worse in cool, wet weather.
Many plants can be infected, including trees, perennial shrubs, vegetables, fruit and flowers. -
Solutions
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Black Rot
Common Location: Plants
×AppearanceThese spots start as yellowish, irregular circles and later turn gray, brown and black.
Drops of gummy ooze sometimes appear. -
Ideal Growth ConditionsThe disease is known to infect fruit in tropical and temperate climates.
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Solutions
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Black Spot
Common Location: Plants
×AppearanceThe leaves yellow around the spots.
Black or purple lesions on the canes appear. -
Ideal Growth ConditionsThis disease weakens rose plants.
Its spores germinate between 65 and 85 degrees. -
Solutions
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Brown Patch
Common Location: Lawn
×AppearanceLook for circular brown patches and thinned turf. -
Ideal Growth ConditionsThis patch occurs at night in the summer when temperatures are above 68 degrees.
It’s troublesome for turfgrass. -
Solutions
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Brown Rot
Common Location: Plants
×AppearancePowdery tufts of brown-gray spores appear on flower shucks.
Brown spots, then tan spores, appear on fruit surfaces.
Infected fruit rots; flowers wither and die; and twigs get cankers. -
Ideal Growth ConditionsThe fungus is known to afflict stone fruit and orchards.
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Solutions
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Crown Rot
Common Location: Both Lawn & Plants
×AppearanceInfected leaves develop circular areas that turn reddish, then tan and finally straw-colored.
Dark brown to black rot appears on the roots, crowns and bases of stems, and light masses of fungal spores emerge. -
Ideal Growth ConditionsThe fungal disease often occurs on heavy soils with wet conditions.
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Solutions
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Dollar Spot
Common Location: Lawn
×AppearanceThe fungus leaves hourglass-shaped leaf spots that extend across the blade with bleached centers and brown, purple or black borders.
Cottony fungal growths are also common. -
Ideal Growth ConditionsDollar spot commonly infects bluegrass, ryegrass and fine fescues.
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Solutions
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Fusarium Patch
Common Location: Lawn
×AppearanceThe yellowish or reddish-brown patches are one to six inches in diameter with little white filaments attached to the grass. -
Ideal Growth ConditionsThis occurs in the absence of snow cover at temperatures below 59 degrees Fahrenheit, with less than ten hours of leaf wetness for several consecutive days.
It thrives in high-nitrogen soils that are low in phosphorous and potash. -
Solutions
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Leaf Smuts
Common Location: Lawn
×AppearanceThis fungus looks like powdery black spores.
Infected plants become stunted, turn yellow, then gray before black spores break through the leaf surface. -
Ideal Growth ConditionsThe disease infects Kentucky bluegrass and sometimes perennial ryegrass in spring and fall.
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Solutions
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Leaf Spot
Common Location: Both Lawn & Plants
×AppearanceThe disease leaves brown or black spots on leaves or tan lesions with dark borders.
It can cause reddish-brown rotting of sheaths and crowns, leading to wilting, yellowing or death of the foliage. -
Ideal Growth ConditionsIt commonly infects bluegrasses and Bermudagrasses.
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Solutions
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Melting Out
Common Location: Lawn
×AppearanceThe lower portion of the leaf blade and the plants’ crowns rot reddish brown, leading to wilting, yellowing or death of the foliage. -
Ideal Growth ConditionsThis fungus is associated with leaf spot.
It’s a danger to bluegrasses and Bermudagrasses. -
Solutions
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Necrotic Ring Spot
Common Location: Lawn
×AppearanceLook for patterned rings of dead turf in wide diameters, healthy green turf in the center and decayed roots and crowns. -
Ideal Growth ConditionsThis unsightly patch disease occurs in spring and fall.
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Solutions
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Powdery Mildew
Common Location: Both Lawn & Plants
×AppearanceThe infection displays blades that appear dusted with flour, with white to gray powder on leaves, and yellowing that leads to dry out and death. -
Ideal Growth ConditionsMany plants are at risk for this disease that’s common from July to September.
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Solutions
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Pruning Wounds
Common Location: Plants (Trees, Shrubs & Ornamentals)
×AppearancePruning wounds may become avenues for development of fungal diseases, such as grapevine trunk disease, cytospora and fungal canker.
A pruning seal helps protect trees and smaller plants from diseases that can enter through pruned areas. -
Ideal Growth ConditionsThere is a greater risk of infection when pruning during periods of extended rain events.
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Solutions
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Rust
Common Location: Both Lawn & Plants
×AppearanceRust fungi create reddish, yellowish or orange spores.
In mild cases, tiny, powdery pustules appear on leaf blades.
In severe cases, reddish dust will fall from leaves. -
Ideal Growth ConditionsIt’s common on Kentucky bluegrass and perennial ryegrass in early fall.
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Solutions
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Scab
Common Location: Plants
×AppearanceSymptoms include a tan discoloration followed by a light bleaching of the leaf.
Sometimes light spores or dark reproductive structures create more scab. -
Ideal Growth ConditionsThis fungal disease is known to impact ornamental trees (flowering, crabapple, flowering pear, hawthorn), plants (pyracantha) and fruit (apple and mayhaw).
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Solutions
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Spring Dead Spot
Common Location: Lawn
×AppearanceIt appears in small, circular dead areas up to several feet in diameter, while rotting roots look dark. -
Ideal Growth ConditionsA terror to Bermudagrass, this disease enjoys springtime weather, especially in the southern U.S.
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Solutions
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Summer Patch
Common Location: Lawn
×AppearanceFirst, the disease shows up as circular patches or rings, with off-colored turf that tends to sink in the turf stand.
Over a week-long period, the turf turns yellow or straw brown and eventually collapses to the soil surface.
Roots turn black and rotten. -
Ideal Growth ConditionsSummer patch occurs when soil temperatures are above 65 degrees.
It commonly affects Kentucky bluegrass and annual bluegrass. -
Solutions
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Take-All Patch
Common Location: Lawn
×AppearanceCircular patches (eight to 24 inches in diameter) form on wilted plants that collapse and turn orange tan.
Infected plants also have rotted roots. -
Ideal Growth ConditionsThe patch grows when the soil is wet, pH is less than 6.5 and temperatures are below 63 degrees Fahrenheit.
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Solutions
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Zoysia Patch
Common Location: Warm-Season Lawn
×AppearanceLook for large circular and semi-circular bleached or yellow patches with orange-bronze borders. -
Ideal Growth ConditionsIt’s most prevalent is early spring during wet and mild weather conditions.
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Solutions
Disclaimer:
*Product label only provides directions for use against Black Rot on grapes.
References:
https://extension.uga.edu/publications/detail.html?number=C891&title=turfgrass-diseases-quick-reference-guide#Fairy
https://www.gardeningknowhow.com/plant-problems/disease/crown-rot-disease.htm https://www.extension.purdue.edu/extmedia/bp/bp-115-w.pdf
https://ipm.ucanr.edu/home-and-landscape/anthracnose/pest-notes/#gsc.tab=0
Richard Latin. 2011. A Practical Guide to Turfgrass Fungicides. APS Press (Second Edition). 336 Pages.
A Compendium of Turfgrass Diseases. 2023. APS Press (Fourth Edition).