Leaves are:
Yellow:
- Yellowing is interveinal, not associated with browning
- Yellowing is interveinal, associated with browning
- Yellowing is veinal, may be associated with browning
- Yellowing is splotchy, may be accompanied by splotches of pink and pale green.
Red or have red spots:
Purple or brown discoloration or spotting:
- Purple-brown spots on leaves and stems
- Purple-brown mottling may accompany crinkled leaves
- Leaves turn purple-brown at margins and are unusually narrow
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.](https://blogs.cornell.edu/berrytool/files/2016/12/BB-nitrogen-opt-q5ivig.jpg)
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.
Iron deficiency symptoms develop first in young leaves. Lowering the pH with sulfur will usually correct the problem.
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
- Botrytis Stem and Leaf Blight
- Mummy Berry Shoot Blight,
- Potassium Deficiency
- Overfertilization
- Drought Stress
Herbicide injury from preemergent materials is usually accompanied by leaf yellowing or bleaching, followed by browning, and tends to be interveinal.
![Blueberry leaf with necrotic brown patches along outer leaf margins.](https://blogs.cornell.edu/berrytool/files/2016/12/bbsinbar-opt-1jh3106.jpg)
![Blueberry leaf with brown, necrotic tissue along outer margin of leaf.](https://blogs.cornell.edu/berrytool/files/2016/12/bbsima1-opt-1ws1gvz.jpg)
![Row of tall berry bushes with green leaves and ripening berries. The leaves closest to the outside of the planting, beside the tractor path, display bleaching and discoloration. Leaves further inside of the bush are healthy and green. Discolored leaves are either entirely yellow, or have a thick yellow border on the outer margins.](https://blogs.cornell.edu/berrytool/files/2020/11/Clomazonecommand-on-juneberry-300x216.png)
Botrytis Stem and Leaf Blight – This fungus affects leaves and shoots during damp, cool springs
More botrytis blight and fruit rot information
Mummy Berry Shoot Blight – Leaves become necrotic and are covered with powdery masses of gray spores during wet weather. More mummy berry information
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.](https://blogs.cornell.edu/berrytool/files/2016/12/bb05-mummyberry-opt-1syhsw5.jpg)
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.](https://blogs.cornell.edu/berrytool/files/2016/12/bbkdef-opt-1t4ns0v.jpg)
Overfertilization – Overfertilization also causes marginal leaf burn. In young plants, too much fertilizer can lead to death.
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.
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.
Yellowing is splotchy, may be accompanied by splotches of pink and pale green.
Blueberry mosaic associated ophiovirus causes leaf discoloration in mosaic patterns. Leaves may be crinkled. The discoloration can vary on a single branch, from bright green leaves with irregular scatterings of pale-yellow splotches, to bright pink and yellow splotches interspersed with pale green spots.
![mosaic virus blueberry Blueberry bush with healthy green leaves on most branches. One branch has mottled leaves. Leaves lowest on branch have yellow splotches throughout the leaf with no discernable pattern. Leaves higher up branch are green, pink, and yellow in an irregular mosaic pattern.](https://blogs.cornell.edu/berrytool/files/2021/06/IMG_0072-225x300.jpg)
![blueberry mosaic virus Close-up of a blueberry leaf with alternating pink and yellow splotches. The splotches have a stained-glass effect due to yellow borders around every strip of color.](https://blogs.cornell.edu/berrytool/files/2021/06/IMG_0073-300x225.jpg)
More information about blueberry mosaic associated ophiovirus.
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.
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.
Leaves are red: Reddening is interveinal
Possible causes:
- Magnesium deficiency
- Viral diseases – Blueberry Scorch and Sheep Pen Hill Disease.
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.
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.](https://blogs.cornell.edu/berrytool/files/2016/12/bb11scorch-opt-2ifw61o.jpg)
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.
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.](https://blogs.cornell.edu/berrytool/files/2020/09/Gelosporium1-225x300.jpg)
![Blueberry leaf with several rusty patches. Patches are on leaf tip and side. In background, dark brown canker is visible on branches.](https://blogs.cornell.edu/berrytool/files/2020/09/Gleosporium2-225x300.jpg)
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.
Purple-brown mottling may accompany crinkled leaves
Ringspot viruses, such as tomato rinspot and tobacco ringspot virus, are so named for the spotting and mottling that can arise on infected leaves. Occasionally, infected leaves may become crinkled without obvious discoloration. Before suspecting a virus, confirm that other causes of leaf discoloration are not to blame. Viruses can only be definitively confirmed with a lab test.
More ringspot virus information
![Crinkled blueberry leaves with few black-purple spots. Spots are uniform in color or may have green center. Unspotted sections of leaves are green. Spots do not have obvious pattern of distribution on upper leaf surface,](https://blogs.cornell.edu/berrytool/files/2016/12/bbpatr1-opt-15jsah8.jpg)
![Blueberry leaf with mottled purple-brown discoloration along leaf margins and interveinal areas. Leaf veins are red and weakly boredered in green. Leaf is slightly crinkled.](https://blogs.cornell.edu/berrytool/files/2016/12/bbtobr1-opt-1bfmzim.jpg)
Leaves turn purple-brown at margins and are unusually narrow
Blueberry Shoestring Virus
Blueberry shoestring virus can cause straplike deformation in leaves accompanied by brown-purple discoloration. Before suspecting a virus, confirm that other causes of leaf discoloration and deformation are not to blame. Viruses can only be definitively confirmed with a lab test.
![Blueberry stem with thin, blackened leaves that have straplike or stringlike appearance. Healthy leaves on same branch are much wider than symptomatic leaves.](https://blogs.cornell.edu/berrytool/files/2016/12/bbshoestring-opt-1vt031k.jpg)