Hosta Virus X
Host Plants: Hostas are the only known plant to be infected by this virus.
Pathogen: The disease causing organism is a virus particle in the potex group. (That’s where the X comes from.) The virus particles are so small they only can be seen with an electron microscope. This virus can only reproduce inside living hosta cells and once inside the plant they remain there for the life of the plant.
Symptoms: Stunted growth, leaf distortion and various patterns of leaf discoloration are common symptoms of this disease. The symptoms vary among different cultivars. Rarely will Hosta Virus X kill a plant, but it can make plants unsalable.
Spread: Unlike many plant viruses, insects are not known to spread this disease. Any type of a mechanical injury that moves plant fluids, however, can transmit this virus. Thus, virus spread can occur from pruning tools when cutting off old leaves or removing flower scapes. Other possible means of spread in the landscape include string trimmers, shovels and even manual transmission, if hands become contaminated with sap from infected plants.
Control: There is no cure for infected plants. The best means for avoiding this disease is to carefully inspect all plants before they enter the nursery or landscape. Unfortunately in recent years a large percentage of certain varieties of hostas available from wholesalers were infected with this virus. Check with your source of plants and see if they have a testing program - or consider having suspect plants tested yourself. A test for hosta viruses will cost at least $25, so testing will be most appropriate when deciding weather to discard a large number of plants.
Some of the hosta cultivars that are most often found to be infected in nurseries and garden centers include Gold Edger, Gold Standard, Golden Tiara and Sum and Substance. Watch these cultivars especially carefully for virus symptoms, and discard suspicious plants.
(Photos by Margery Daughtrey, Plant Pathologist, Cornell University, Long Island Research and Extension Center.)
Brian Eshenaur 10/2006
Hosta Virus Testing
How To Submit Samples for Virus Testing:
Collect symptomatic leaves, stems, or entire plants. Wrap in plastic. It is very important that these samples do not dry out during shipment. Do not add extra water to the bags.
Ship samples immediately after collection.
Ship samples by overnight delivery or mail early in the week to insure
fast delivery. Plant samples often begin to decompose if left in the
post office over the weekend.
Submit payment with samples.
Two Labs that offer testing for HVX
Cornell Diagnostic Laboratory
Plant Disease Diagnostic Clinic
329 Plant Science
Ithaca, NY 14853
Contact for pricing.
Univ of Minnesota Plant Clinic
Plant Disease Clinic
495 Borlaug Hall
1991 Upper Buford Circle
University of Minnesota
St. Paul, MN 55108-6030
Specify that you want them tested for Hosta Virus X.
The price at the University of Minnesota’s lab is $25.00 for the first sample and $5.00 for each additional. Make checks payable to the University of Minnesota.