Volutella Blight Causing Boxwood Dieback.

Volutella Blight Causing Boxwood Dieback.
Disease Digest
Authors
Joe Boggs
Published on
May 2, 2016
Landscapers and gardeners may be seeing scattered dieback on boxwoods this spring. One
candidate for the sectional dieback is Volutella blight. Both English and American boxwoods
are susceptible to this disease which is caused by the fungal pathogen, Pseudonectria buxi
(also called Volutella buxi).
Sectional Foliar Discoloration from Volutella Canker on Boxwoods
The fungus targets stems where it produces girdling infections. Symptoms first appear in the
spring and intensify with new growth. Leaves turn light yellow then brown and eventually drop
from infected stems. A close examination of the affected stems may reveal loose bark and
constricting girdling. A careful removal of the bark will expose chocolate colored phloem tissue
with a distinct transition zone between dead stem tissue and healthy green tissue. The disease
may be managed by pruning a few inches beneath the transition zone. Of course, sanitation
pruning may significantly disfigure heavily infected plants.
Sectional Dieback from Volutella Canker
NOTE: boxwood defoliation and dieback may also be caused by a number of other problems
including salt damage, winter injury, boxwood leafminer, and various root rots. "Box blight"
caused by the fungus, Cylindrocladium buxicola, should also be eliminated before making a
Volutella blight diagnosis. This highly destructive fungus typically causes a rapid decline of
entire plants rather than sectional dieback. If box blight is suspected, we urge that you send
affected plants to our OSU Extension, C. Wayne Ellett Plant and Pest Diagnostic Clinic, for
confirmation [ http://ppdc.osu.edu/ ].
Transition Zone Between Healthy and Cankered Stem Tissue
Tags
Volutella
Volutella on Boxwood