Monday, June 2, 2008

Hosta

Hostas are a great plant with many cultivars, or sports, used in landscaping a shady area. While they do get a fragrant usually white or lavender flower, they are mostly grown for their foliage. The leaves can be ovate or elongate, small or large, and can range in color from blue to chartreuse as well as variegated.

While hostas are generally disease-free I recently became aware of a hosta disease called Hosta Virus X or HVX, for short. This disease manifests itself as blotching, called ink bleed, on the leaves and unusual leaf corrugations. It was discovered in 1996 and is spreading. It is transmitted mechanically, by using secateurs, scissors or even spades when cutting or dividing infected plants and then using those same tools on uninfected plants. Infected plants may not immediately show the symptoms of the disease until stressed by some environmental factor, such as drought or cold.

There is no cure for the disease. It is not necessarily fatal but plants that are highly susceptible can die. Unusual blotching or leaf corregations does not mean your plants are infected since several things may cause that to happen including cold weather but if you see any unusual blotching on your hostas it may be best to remove the plant and throw it away. Do not put it on the compost pile. Clean your tools with a solution of 10% bleach water after using them on each plant. Do not buy hostas if you don’t know where they came from. The virus is not thought to spread via the soil so you can replant in the same area although researchers do recommend waiting a few weeks so that any remaining plant material from the infected plants dies completely.
Hostas that appear to be more susceptible to HVX seem to be the gold or chartreuse colored varieties, in particular Sum and Substance and Gold Standard. Some varieties, or sports, that have been recently named are not actually new varieties but plants with HVX. The University of Arkansas web site has a chart listing highly susceptible, somewhat susceptible and sports known to be infected with the virus.
For more information here are some Web sites to go to: www.uaex.edu/Other_Areas/publications/PDF/FSA-7548.pdf
http://www.oznet.ksu.edu/library/plant2/EP132.pdf

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