Plants infected with viruses exhibit a variety of symptoms including: mosaic, ringspots, stem lesions, rosette (witches broom), "oak leaf" pattern, stem pitting, stunting, flower break, and more.

Hosta virus X (HVX) is fairly common on hosta. HVX is most easily diagnosed on gold hosta cultivars where abnormal green stripes appear parallel with veination of leaves. Canna yellow mottle virus is very prevalent on the Tropicana series of canna. Symptoms included stunted plants, necrotic streaks in leaves, and muted variegation.

Rose rosette is a viral disease transmitted by eriophyid mites. Virus diseases may be difficult to diagnose unless you are familiar with symptoms associated with specific virus diseases.

Do not propagate plants with symptoms of a viral disease. In production, remove and discard infected plants. For impatiens necrotic spot, monitor and manage thrips populations in greenhouses.

Remove Roses with symptoms of rose rosette. Break up mass plantings by using a non-host as a barrier between smaller plantings. Remove multiflora rose near rose plantings. Pruning and control of the vector is being evaluated.

For chemical control recommendations, consult the Insect and Plant Disease Control Manual, UT Extension Publication 1690, found here. Please contact your local Extension office for specific pesticide recommendations.