Hosta Virus X

I finally have some time and the Hostas are fully leafed out so here goes...
Hosta Virus X is a virus that infects Hostas (not too surprising) and will eventually kill the plant. Hostas have always been pretty tough and reliable with slugs as about the only pest that bothers with them, and there are even varieties that are highly slug resistant. And then this virus was discovered a little more than 10 years ago and it has been difficult to control in nurseries and greenhouses.

Due to the variations in symptoms, this virus is often overlooked and may not be diagnosed before the virus spreads. There were even some varieties that were named as a new cultivar because of the interesting variegation, when they actually tested positive for the virus. Some of the symptoms are; mottling of the leaves, stunted or abnormal growth and collapsing leaf tissue. Here is an example of Gold Standard that tested positive for HVX.
We received these plants from a nursery last spring. The symptoms started showing soon after the leaves emerged. The Johnson County K-State Extension office tested these and others that were in the same shade house. Every plant that tested positive or was showing symptoms was destroyed along with the pots.

The virus spreads by infected sap transfered to an open wound on another plant and can be easily spread during pruning or even walking through a shade house where there are infected plants. With this virus it is very important to catch it early and destroy the plant. There is no chemical or method to kill or control HVX, which is a major issue on the growing side. Most reliable growers test their cultures and do not propagate infected tissues.

There do seem to be some varieties that are more succeptable to infection and some that are highly resistant and everything in between. Some varieties have been called 'Immune' but there is no evidence yet that they cannot become infected. This is a Gold Edger that was showing symptoms at the same time as the Gold Standard, but had been in the shade house for several years.It seems that the gold or yellow varieties are pretty easily infected, but it may be that the symptoms just show up a little easier on that particular color of leaf.

Here is a list of varieties that seem to be more succeptable:

Birchwood Parky’s Gold Blue Cadet Color Glory Diamond Tiara El Nino, Fan Dance Gold Edger Gold Standard Golden Prayers Golden Tiara Goldrush Harvest Glow Hydon Sunset Janet Kara Krossa Regal Little Aurora Louisa Lunacy Montana Chirifu Moonlight Sport Opipara Pacific Blue Edger Paradise Joyce Queen Josephine Regal Slendor Richland Gold Rim Rock Royal Standard Stiletto Striptease Sun Power Sum & Substance Undulata Albomarginata Wide Brim Yellow Splash Rim.

It seems like a huge list but these are varieties that have had some plants test positive.
One more much smaller list, these are the varieties that were named as and marketed as new varieties but were actually infected plants:

'Blue Freckles'

'Breakdance'

'Dotted Fantasy'

'Eternal Father'

'Kiwi Dreadlocks'

'Kiwi Watercolours'

'Leopard Frog'

'Lunacy'

'Pamela Ann'

'Parkish Gold'

'Strip Show'

'Tye Dye'

There is a lot of information out there on this disease, but the most important thing is stopping it from spreading as much as possible. If you are seeing symptoms but are not sure, the K-State Extension office will test the plant at a small cost. They need the roots and leaves and it needs to be a fresh specimen. Here is their website for more information: http://www.oznet.ksu.edu/DesktopDefault.aspx?tabid=24