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Helping farmers find, destroy, and manage EFB


Symptoms of EFB

John Pinkerton, Ken Johnson, Jay W. Pscheidt

The stromata are at first white when they break through the surface and turn black by August. Stromata usually are arranged in single or double rows along the stem. Death of the cambium in the area of the canker results in a sunken appearance as the surrounding cambium continues to grow.

One of these black stroma may contain 50 to 100 flask-shaped perithcia. Each perithecium may contain 1,000 sacks or asci, each of which contains 8 ascospores. The ascospores reach maturity by the time fall rains begin in October.

The disease may be confused with Eutypella cerviculata, which produces smaller black fruiting bodies on dead branches. This fungus produces diagnostic black rings under the bark, which can be detected using a pocketknife. Cicada-egg-laying scars can also look somewhat like EFB but are not black and look stitched.

Mature, black stromata arranged in rows along an older branch. Note the dead twig near the center of the canker. This is the shoot that the fungus originally infected several years earlier.
More mature black stromata
Photo by Jay Pscheidt, 1988.

Another EFB look-alike is the ovaposition wounds produced by cicada insects when laying eggs.
Ovaposition wounds produced by cicada insects
Photo by Jay Pscheidt, 1995.

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Mature, black stromata arranged in rows. Note the sunken area where the stomata are located or the raised area next to the canker. Tree cells in the cankered area are dead and do not continue to grow.
Mature black stromata
Photo by Jeff Stone, 1988.

False Eastern Filbert Blight. The fungus Eutypella cirviculata also produces black stromata but on already dead limbs. It is not a pathogen. Use a pocket knife to scrape away the surface layers to reveal the black rings characteristic of this fungus. EFB cankers do not have these signs.
False Eastern Filbert Blight
Photo by Jay Pscheidt, 1989.

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