Hosta Virus X difficult to detect
Perennial hostas have long been a shade garden favorite, The leafy plants are hardy and both heat- and drought-tolerant. Until recently, they had few insect and disease problems.
Now, however, an untreatable disease called Hosta Virus X is slowly but surely spreading nationwide, said Jennifer Smith, horticulturist with K-State Research and Extension. It typically moves when hands or tools touch an infected hosta and then a healthy one.
"Your best defense against bringing the virus into your garden is to know what a variety is supposed to look like. Any variation from that can be a Hosta Virus X symptom," Smith said. "But, that's not as easy as it sounds. Today, healthy hostas are available in a wide range of sizes, textures, leaf colors and shapes."
The disease even fooled plant breeders for a while. Evidently, the "new and unusual" characteristics of some recent hosta releases are actually Hosta Virus X symptoms. The suspect varieties include Breakdance, Eternal Father, Kiwi Watercolours, Leopard Frog, Lunacy and Parkish Gold.
Discovering that took time because hosta varieties vary widely in how they react to being infected, Smith warned. Leaf symptoms can be mosaics and lines, small brown lesions, mottling and blotches. Sometimes, plant tissues pucker or twist. But, a few varieties look unchanged.
"I avoid buying hostas that appear to be unhealthy in any way. I won't touch those with characteristics that could be symptoms. I'm always suspicious if one or two hostas look different from their kin," she said.
So far, the only way to prevent the disease's spread is to remove and burn or otherwise destroy infected hostas. For gardeners who want to be sure first, any local K-State and Research and Extension office can submit a sample to be tested at K-State for a small fee.
"For Hosta Virus X, though, you've got to submit a whole, live plant," Smith said.