Plant Disease Management Handbook

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Blueberry (Vaccinium corymbosum) - Scorch

Blueberry (Vaccinium corymbosum) - Shock

Image related to Blueberry (Vaccinium corymbosum)-Virus Diseases

Mosaic on 'BlueRay'.

Bob Martin.

Blueberry Mosaic Virus symptoms may just be green and yellow patchy mottling of the leaves.

Jay W. Pscheidt, 2012.

Blueberry Mosaic Virus causes light green to yellowish mottling on the leaves.

Photo by Ralph S. Byther

Scorch on the cultivar 'Elliott'.

Bob Martin.

The branch on the left side shows both the initial shock symptom but it also recovering with new growth.

Jay W. Pscheidt.

Fruit-drop problem on 'Bluecrop'. Top left, reddish coloration of leaves and corolla in early season, red coloring is ephemeral, gone after bloom. Top right, fruit drop to the ground about three weeks before harvest. Lower left, cluster of 'Bluecrop' just prior to harvest on plant with Fruit Drop Symptoms. Lower right, cluster on 'Bluecrop' just prior to harvest on healthy plant.

Bob Martin.

The bushes with the fruit-drop problem are not laden with fruit and are upright in this photo.

Bob Martin.

See:

Raspberry (Rubus spp.) - Ascospora Dieback

Image related to Blueberry (Vaccinium corymbosum)-Twig Canker

Grey-white cankers with reddish margins.

OSU Plant Clinic Image, 2008.

See:

Cranberry (Vaccinium macrocarpon) - Upright Dieback

Image related to Blueberry (Vaccinium corymbosum)-Twig Blight

This dieback can been seen progressing into last year's wood of this 'Liberty' blueberry (unlike bacterial blight that typically does not go into 2nd year old wood).

Maryna Serdani, 2011.

Branch dieback on 'Draper' due to Phomopsis.

OSU Plant Clinic collection, 2012.

Note discoloration of this 'Bluecrop' wood in cross section.

OSU Plant Clinic Image, 2014.

Cross section of this 'Draper' blueberry showing discoloration of vascular system well into the xylem.

OSU Plant Clinic image, 2012.

See:

Blueberry (Vaccinium corymbosum) - Fusicoccum Canker (Godronia Canker)

Image related to Blueberry (Vaccinium corymbosum)-Stem Canker

'Draper' blueberry with bot canker.

OSU Plant Clinic Image, 2013.

Cankers on this 'Duke' blueberry.

OSU Plant Clinic Image, 2013.

Cankers girdle the stem of this 'Duke' blueberry.

OSU Plant Clinic Image, 2013.

Cause Silver leaf is not new to the PNW as it has been a minor problem on stone fruit for many years. It is a disease where the fungus, Chondrostereum purpureum, invades cut or wounded stems and limbs of a wide variety of plants. This fungus was confirmed for the first time in 2014 by the OSU Plant Clinic on 'Draper' and 'Liberty' blueberry with silver leaf symptoms although samples with these symptoms had been received since 2009.

Image related to Blueberry (Vaccinium corymbosum)-Silver Leaf

Scattered plants in field develop silvery leaves and stand out from other bushes. Sometimes called ghost plant due to the way it looks.

Lisa Jones, 2014.

The top surface of young leaves turns silvery as the epidermis separates from the rest of the leaf.

Lisa Jones, 2014.

The heartwood of infected stems near the base of the bush may turn brown or exhibit purple to brown concentric rings of discoloration.

Lisa Jones, 2014.

Extensive wood rot of the 'Draper' blueberry.

OSU Plant Clinic Image, 2014.

Fruiting bodies (basidiocarps) may develop in the fall on the surface of dead or dying branches.

Jay W. Pscheidt, 2014.

Healthy leaf on the left and silver leaf to the right on this 'Topshelf' cultivar.

OSU Plant Clinic Image, 2016.

Cause The blueberry shock virus (BlShV), which is pollenborne. Transmission occurs when pollinators, especially foraging honeybees, transfer infected pollen to flowers on healthy plants. The cultivars Berkeley, Bluegold, Bluetta, Cargo, Duke, Liberty, Aurora, Pemberton, Reka, and Elliott are particularly susceptible and the virus spreads rapidly through a field. In 'Bluecrop', 'Bluejay', 'Mini Blue', 'Calypso', 'Legacy', 'Perpetua', 'Reka', and 'Toro' the virus spreads very slowly in the field.

Note the green stems but with blighted flowers. The healthy comparison stem is in the center of the picture.

Photo by Jay W. Pscheidt, 1992.

Image related to Blueberry (Vaccinium corymbosum)-Shock

The bush without leaves on the right is showing shock for the first time. Other plants in the area appear healthy.

Jay W. Pscheidt, 2004

Leaf spots are seen when bushes recover and grow new foliage even the year after inital symptoms are observed.

Jay W. Pscheidt, 2007.

Bud on the left are healthy but buds on the right have died due to Blueberry shock virus. Sometimes you can find secondary infection by Pseudomonas in these dead buds.

Jay W, Pscheidt, 2008.

See:

Blueberry (Vaccinium corymbosum) - Virus Diseases

Blueberry Cultivar Susceptibility

Image related to Blueberry (Vaccinium corymbosum)-Scorch

Notice the flower blight caused by this virus.

Dept of Horticulture, OSU

Symptoms of scorch on 'Berkeley'.

Bob Martin.

Flower and shoot dieback from Blueberry scorch virus on 'Elliott'.

Bob Martin.

Line patterns, often called oak leaf patterns, are common in some virus infected plants.

Bob Martin.

Cause Phytophthora root rot, caused primarily by the oomycete Phytophthora cinnamomi, is a soilborne disease affecting blueberry in the Pacific Northwest. It is primarily a warm weather pathogen and does not survive well where soils freeze deeply or repeatedly in winter. This fungus-like organism has an extremely wide host range and infects a large number of tree and shrub species in the Pacific Northwest including other ericaceous plants (such as rhododendron and madrone) and many conifers.

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What looks like nutrient deficiency or high soil pH is due to lack of roots from root rot.

Wei Yang

Phytophthora sp. was isolated from these roots.

Maryna Serdani, 2011.

Poor growth on top and rotted roots below. Plant was easily pulled out of ground.

Jay W. Pscheidt, 2016.

See:

Blueberry Cultivar Susceptibility

Infections are rarely seen in the field.

Jay W. Pscheidt, 2010.

Image related to Blueberry (Vaccinium corymbosum)-Ripe Rot (Anthracnose)

Note the sporulation of the fungus on the side of this berry.

Photo by Jay W. Pscheidt

Infections can be seen on these Spartan blueberries.

Bernadine C. Strik

Cause Paratrichodorus renifer. Stubby-root nematodes are migratory ectoparasites, and therefore found only in soil. This nematode is commonly found in blueberry plantings throughout the PNW but more frequently in Washington and British Columbia. This nematode has been shown to seriously damage blueberry cuttings by severely stunting the young root system. In microplot experiments, this nematode caused 40% yield loss of blueberry 'Chippewa.'