Plant Disease Management Handbook

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Cedar (Cedrus spp.) - Needle Blight

Shoot blight on mountain hemlock.

OSU Plant Clinic Collection, 2010.

By M. Putnam

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Grape (Vitis spp.) - Eutypa Dieback

Older vines show wedge-shaped cankers in the trunk and cordons. This vine only had a small section of living vascular tissue seen on the right side of this image.

OSU Plant Clinic Image, 2013.

Photo of Grape (Vitis spp.)-Trunk Diseases

Dead spurs on a grape cordon indicate canker disease due to Botryosphaeria.

Melodie Putnam.

Cause Xanthomonas vesicatoria (formerly X. campestris pv. vesicatoria) is a bacterium that overwinters in plant refuse for up to 2 years and can be seedborne. The bacterium infects solanceous weeds such as black nightshade and ground cherry; some strains also infect pepper.

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Spruce (Picea spp.) - Schweinitzii root and butt rot

Fir, Douglas and True - Stem Decays (Heart Rots)

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Pear (Pyrus spp.) - Fire Blight

When these vigorously growing seedlings die from fire blight the tip turns down to form the Shepard's crook symptom.

Jay W. Pscheidt, 2008.

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Tomato (Lycopersicon esculentum) - Tomato Spotted Wilt

Cause The tomato spotted wilt virus, which is transmitted from plant to plant by thrips. This virus is a primary problem in greenhouses and can infect hundreds of weed, ornamental, and vegetable species, which then can harbor the virus. In Oregon, the problem has been found in potato fields.

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Oak (Quercus spp.) - Inonotus Root and Butt Rot

Oak (Quercus spp.)-White Pocket Rot (Piped Rot)

Annual conks appear on upper bole usually near knots, broken branches or pruning wounds.

Alan Kanaskie, 2015.

Decay is a white pocket rot of the heartwood of living trees.

Alan Kanaskie, 2015.

Cause Neonectria ditissima (formerly Nectria galligena), a fungus, occasionally causes a perennial target-shaped canker on the trunk and limbs of Oregon white oak. In response to infection, the tree forms a callus ridge around the initial canker. The following year the fungus invades the heathy tissue beyond the callus ridge, and the tree forms another callus ridge.

A perennial target-shaped canker on the trunk and limbs.

Alan Kanaskie, 2007.

Round to oval woody target-shaped cankers.

Alan Kanaskie, 2015.

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Oak (Quercus spp.) - White Pocket Rot (Piped Rot)

Oak (Quercus spp.)-Inonotus Root and Butt Rot

Annual conks appear on the base of the tree or large roots at ground level in summer and early autumn.

Alan Kanaskie, 2008.

The upper surface of conks weathers to black and deteriorates in winter to a dark-brown or black mass.

Alan Kanaskie, 2015.

Inonotus dryadeus, the bleeding conk, which definitely indicates decay!

Dave Shaw, 2009.

Cause Ganoderma applanatum (formerly Fomes applanatus), also called the "Artist's conk," is a common root and butt rot fungus on oaks and other hardwoods, especially Oregon white oak. Decay is a white-mottled rot of the trunk and large roots. Decay can extend more than 10 feet above ground.

Oak (Quercus spp.)-Ganoderma Root and Butt Rot

Perennial woody conks appear on the base of the tree or on trunk wounds.

Alan Kanaskie, 2016.

Conks are grey-to-brown on top, with a pure white underside (pore layer) that turns brown when scratched.

Alan Kanaskie, 2015.