Plant Disease Clinic


Cedar-apple rust

The Plant Disease Clinic provides plant disease diagnostic services to Virginia Cooperative Extension agents. Plant samples with problems caused by pathogens, including fungi, bacteria, viruses, and nematodes, in addition to plant samples with environmental or other abiotic problems may be submitted to the Plant Disease Clinic. Diagnosis is provided for any type of plant. Other services provided by the Plant Disease Clinic include mushroom identification and identification of non-weedy plants.

The Plant Disease Clinic is a member of the National Plant Diagnostic Network (NPDN) within the region of the Southern Plant Diagnostic Network. The mission of the NPDN is to enhance national agricultural security by quickly detecting introduced pests and pathogens.

Current Disease Update

The tiny dark objects on this rhododendron leaf are the spore masses or peridioles of the artillery fungus. (Photo credit: Bruce Watt, University of Maine,

Artillery Fungus

Artillery Fungus

The artillery fungus is common in home and urban landscapes where it decays organic debris and is most commonly associated with wood mulch. The genus of this fungus is Sphaerobolus, which translates to “sphere thrower”, and gives a clue regarding its unique adaptation. If not for the production of the sticky spore masses that it discharges forcibly about 15’ high and 20’ distant, this fungus would likely be overlooked because its fruiting body or spore-producing structure is less than 1/20 of an inch in diameter.

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