Newly infected plants often exhibit
no symptoms at all, but those plants can transmit the virus to
healthy hostas if they come into contact
with sap from the infected hosta. It can take three or more years
for some plants to show symptoms. To compound the difficulty in
determining if any of your plants are infected, certain cultivars do
not show distinctive symptoms at all.
Trojan Horse Viruses
Given that hosta lovers are always on the lookout for new cultivars
with distinctive leaf colors and patterns, HVX is a cruel joke. Many
hobbyists, as well as professional plant breeders, collect seed and
grow the resulting seedlings in hopes of finding a hot new hosta. As
a matter of fact, before HVX was identified, infected plants with
unique leaf colors and patterns were thought to be new cultivars,
given names, and introduced to the marketplace. These include 'Breakdance,'
'Eternal Father,' 'Kiwi Watercolours,' Leopard Frog,' 'Lunacy,' and
'Parkish Gold.' Although they have been taken off the market, some
of those cultivars might still be found in people's gardens. All
plants with these names are thought to be infected and should be
removed and destroyed.
HVX is transmitted by spreading the sap of infected hostas to
healthy ones. The virus can be spread by inadvertently hitting
infected hostas with lawn mowers or string trimmers, by deadheading
or pruning off dead leaves with pruning shears, on your hands, by
animals feeding on hostas, and by propagating infected plants. There
is currently no evidence that insect feeding spreads HVX.
There is no cure for HVX, as is true for all virus diseases. Scout
your garden regularly and removed any hosta that shows suspicious
symptoms promptly. Burn it or tie it up securely in a trash bag for
collection - never toss it on the compost pile. Since viruses are
systemic, it is not enough to cut off dead or funny-looking leaves.
Thoroughly wash and sterilize pruning tools that you use on your
hostas before moving from one plant to the next. Clean and sterilize
shovels, too, after using them to dig out suspect plants. After
completely cleaning any soil or sap off, dip the pruners in
isopropyl alcohol and allow them to air dry, or dip them into a
solution of one part Clorox to nine parts water. Dry tools after the
Clorox dip to keep them from rusting.
What to Avoid
Shop for new hostas carefully, and avoid anything that does not look
normal. Even though some hostas have mottling patterns not caused by
virus, these will be spread evenly over the leaf, rather than
following the veins, as is true if they are infected. Cultivars that
have mottled leaves that are not known to be the result of HVX
include 'Cynthia,' 'Laella,' 'Kiwi Forest,' 'Wild Bill, and ' Xanadu
Paisley.' Be cautious about accepting unusual-looking hostas from
friends or at plant swaps. Introduce new hostas to your garden with
care. If possible, isolate them from your established beds and
observe them for at least a year before planting them in your
The only sure way to confirm that a suspicious looking hosta is
infected with HVX is by virus indexing through a certified
laboratory. This can be expensive, and is really meant for
professional growers rather than home gardeners. John Peplinski, the
director of Penn State University's Buckhout Laboratory, has not
seen any probable HVX samples come through his lab to date. (Penn
State's Disease Diagnostic Lab does not perform virus indexing).
Is the Soil OK?
There is no evidence that HVX survives in soil, so you can replant
the area with clean hostas after you a sure that all of the infected
plant's roots have decomposed. The virus is limited to hostas and is
not known infect other species of plants. Although all hostas should
be considered susceptible, several are reported to be resistant to
HVX, including 'Blue Angel,' 'Color Glory,' 'Frances Williams,' 'Bressingham
Blue,' 'Frosted Jade,' and 'Love Pat.'
There are excellent photographs of HVX symptoms on a number of
websites, including Michigan State University.
Mold on peonies
in the shade