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Blueberries: Leaves are unusually colored, spotted or necrotic (browning)

Leaves are:

Light green

Yellow:

Reddish-purple or maroon

Red or have red spots:

Purple or brown spots:

Purple-brown spots on leaves and stems

Whitish


Leaves are light green

Light green leaves may indicate a lack of nitrogen.

Nitrogen deficiencies are common in blueberries. Note the light green color (chlorosis) is uniform across the leaves with no particular pattern or mottling.  Other symptoms of nitrogen deficiency include reduced shoot growth, numbers of new canes and yield. Nitrogen deficient leaves may develop early fall color and then drop off.

Two blueberry plants. Plant on left has yellow-green leaves throughout, plant on right has dark blue-green leaves.

Nitrogen deficiency on ‘Bluecrop’ blueberry. Plant on the left did not receive adequate nitrogen fertilizer.

More blueberry nutrient deficiency information.

Leaves are yellow: Yellowing is interveinal, not associated with browning

Interveinal yellowing is caused by iron deficiency, but is symptomatic of high soil pH. A high soil pH (>5.2) results in the inability of the blueberry plant to use iron, causing a lack of chlorophyll production.

Blueberry leaves with dark green veins and pale yellow leaf tissue.

Iron deficiency symptoms develop first in young leaves. Lowering the pH with sulfur will usually correct the problem.

Small blueberry plant with yellow leaves with green veins. Some of the yellow leaves have bronze color along outer margins.

Leaves are yellow: Yellowing is interveinal, associated with browning

A number of causes can induce leaf browning in blueberries. Many of these are associated with factors contributing to overall cane death or dieback.

If canes are not dying but leaves on particular portions of the plant are turning brown, the cause could be

Herbicide injury from preemergent materials is usually accompanied by leaf yellowing or bleaching, followed by browning, and tends to be interveinal. More herbicide injury information.

Blueberry leaf with necrotic brown patches along outer leaf margins.

Sinbar (terbacil) herbicide damage.

 

Blueberry leaf with brown, necrotic tissue along outer margin of leaf.

Princep (simazine) herbicide damage

Botrytis Stem and Leaf Blight – This fungus affects leaves and shoots during damp, cool springs

More botrytis blight and fruit rot information

Blueberry leaves and fruit on bush. One blueberry twig is bendy and discolored, and fruiting cluster is wilted and salmon-tinged.

Blueberry blossoms with wilted appearance. Flower calyxes are purple-blue and blossoms are wrinkled and salmon tinted.

Mummy Berry Shoot Blight – Leaves become necrotic and are covered with powdery masses of gray spores during wet weather. More mummy berry information

Young blueberry shoot wilting near the tip. Stem just below the tip is purple-brown, and discoloration extends into adjacent leaves.

Wilted blueberry shoot with dark patch of discoloration along stem and leaf. Discoloration begins at leaf base and travels up leaf along veins.

These primary shoot blight infections occur when spores are rain splashed and wind carried from mushrooms cups developing from mummfied fruit on the ground under bushes.

Severely decayed blueberry with small fungal bodies emerging from surrounding ground. Fungus is mushroom-shaped but has a hole at the center of the cap.

Mummified blueberry and fruiting bodies of mummy berry fungus.

Severely decayed blueberry on ground surrounded by fruiting bodies of fungus. Fungus is semi-translucent, brown and salmon tinged when sunlight shines through it. Fungal bodies are unfurled, are Y-shaped with recurved edges.

Potassium Deficiency – K deficiency results in marginal leaf burn. It is not common, but has been observed in very sandy soils.

Blueberry leaves with dry, brown tissue along leaf edges. The border between healthy green tissue and browned tissue is sharp, but pattern of browning is irregular along leaf margin and may extend far into the leaf towards the central vein.

Potassium deficiency in blueberry with characteristic marginal leaf burn.

 Overfertilization – Overfertilization also causes marginal leaf burn. In young plants, too much fertilizer can lead to death.

Blueberry leaf with inter-veinal yellowing in main leaf body. Most of leaf is mottled, with leaf tissue alternating between deep blue-green along veins and pale yellow in inter-veinal margins. Edges of leaf are dry and orange-brown.

Drought Stress can cause browning of blueberry leaves. Water demand for blueberries is typically highest in the Northeast during the month of July when average precipitation is very low.

Blueberry bush viewed from above. Individual branches are entirely brown and leathery, while other branches are entirely healthy and green.

Blueberry shoots with dry, crispy leaves at top of branch.

Leaves are yellow: Yellowing is veinal, may be associated with browning

Veinal yellowing or bleaching is caused by injury from Solicam (norflurazon) herbicide. More herbicide damage information.

Close-up of blueberry leaf base. Veins at leaf base are white, but turn purple-red halfway towards the tip of leaf.

Leaves are reddish-purple or maroon

Possible causes:

Fall Reddening – Blueberry leaves develop a maroon color in autumn as a normal response to lowering temperatures. Less frequently, blueberry leaves may develop a reddish-purplish hue in spring if the weather is cold. This coloration disappears with the arrival of warmer weather.

Blueberry shoot with uppermost leaves shiny, unifrom red in color. Veins remain green.

Phosphorus deficiency causes purple coloration in blueberry leaves, but this is rarely observed in the field. Blueberries have a low P requirement. If the pH is too high (>5.2) for adequate P uptake, other nutrients likely will be unavailable as well.

Blueberry plant in pot of sand. Plant is short and has deep purple tinged leaves. Text on image says "minus P"

Leaves are red: Reddening is interveinal

Possible causes:

Magnesium deficiency, common in acid soils, causes interveinal reddening because chlorophyll production is reduced. Symptoms begin as an interveinal yellowing and progress to a bright red. Leaves at the bases of young shoots are most likely to exhibit symptoms first. Young leaves at the tips of shoots are seldom affected.

Blueberry leaf with maroon coloration and green veins. Red color is deepest at tip of leaf.

Viral diseases: A blueberry viral disease with similar symptoms is caused by two strains of the same virus. Blueberry scorch and Sheep Pen Hill disease (SPHD) are commonly found occurring on the West Coast and in New Jersey, respectively. Both are typically observed in spring when a blossom blight occurs. Blighted blossoms are retained through the summer but fail to develop into fruit. More blueberry virus information.

Blueberry leaf with blood red horizontal stripes.

Blueberry leaf scorch virus.

Blueberry leaf with blood red streaking in zebra pattern along entire leaf. Central and main veins are yellow and bordered by green tissue.

Leaves are red:  Red spots are on the upper leaf surface only

Red ringspot virus causes spotting on the upper leaf surface only and on young shoots.

 

Blueberry bush with leaves mottled in purple spots. Central vein remains green.

Blueberry leaf with circular purple-red spots on leaf surface. Some spots are merged to form blobby red areas.

Blueberry marked with red spots. Spots are mostly spherical in shape. Spots are most prominent along leaf margins, some spots are present on central vein.

Blueberry stem and leaves covered in red patchy disoloration.

 Purple-brown spots on leaves and stems

Gloeosporeum leaf spot

Gloeosporium infection, caused by the fungi Gloeosporium minus and Gloeocercospora inconspicua, causes necrotic lesions on leaves and succulent stems.

Defoliated blueberry bush with black twig tips. Black regions of twig extend halfway down twigs, below which healthy green tissue is visible. Healthy blueberry plant beside infected plant is in full leaf.

Gloeosporium infection causes twig dieback and canker.

Blueberry leaf with several rusty patches. Patches are on leaf tip and side. In background, dark brown canker is visible on branches.

Gloeosporium fungus can cause symptoms on leaves and branches, as well as fruit.

Blueberry leaves with red-brown spotty discoloration. Spots are either uniformly brown and leathery, or paler in center. Spots appear randomly distributed on leaf, with 2-3 patches per leaf.

More Gloeosporium leaf spot information

Leaves are whitish

Powdery mildew:

Powdery mildew can cover leaves with a whitish “film” more commonly seen on the undersides  but occasionally on the tops as well. Most commonly, though, mildew expresses itself as red or brown spots on the upper leaf surface.

Blueberry leaf underside with powdery mildew mottling along entire underside. Mildew is mostly gray but has some small black spots.

Blueberry leaf surface with semi-transparent white-gray patches. Patches most prominent along veins.

Blueberry leaf with angular and spherical spots on leaf surface. Spots are reddish-brown in color. No white discoloration is visible.

Green, shiny blueberry leaf with random pattern of circular and angular spots. Spots are red-brown and scattered across leaf without any discernible pattern.

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