Butternut (Juglans cinerea) decline question.

Ed ceengr at usit.net
Sat Jan 22 19:08:37 EST 2000

Mike the Tree Doctor <mlamana at bestweb.net> wrote in message
news:68hi4.652$Ug3.59671 at newshog.newsread.com...
> Ed:
>My impression from speaking with a couple of pathologists is that
> hypovirulence may be becoming more prevalent in the wild. Any thoughts??
> Mike the Tree Doctor
> www.treedoctors.com

Under the right conditions for the tree and continued cycles of blight,
hypovirulence reportedly spontaneously appears.  The right conditions for
the tree would be an ideal site plus being released from competition in full
sun.  This may occur in areas of clear-cut so it may very well be more

I haven't seen much of it, but according to Dr. Anagnostakis at the
Connecticut Agricultural Experiment Station (CAES), hypovirulence is much
more prevalent in the south.  Swollen blight cankers on American Chestnuts
may indicate some resistance by the tree and/or a weakened version of the

Hypovirulence does not always allow an American Chestnuts to survive and may
revert to killing cankers without warning.  Killing and hypovirulent strains
of the blight may exist on the same tree resulting ultimately in its death.
Hypovirulence can be innoculated into some cankers and change them to
hypovirulent cankers, but not all strains of blight will convert.  However,
American Chestnuts with some resistance, combined with hypovirulent blight
can result in timber size trees.

Griffin, G. J.  2000.  Chestnut Blight Control and American Chestnut
Restoration. Journal of Forestry.  accepted for February publication will
have more details.

Ed Greenwell
ceengr at usit.net

More information about the Plantbio mailing list