Diseases – Blueberry Field Guide

Phomopsis Canker

(Phomopsis vaccinii).
Damage: Individual branches turn reddish-brown, called “flagging”, and die, and leaves may fall soon after Large (5-15 cm), reddish brown, oval-shaped lesions can be seen on 1-3 year-old stems.
Disease cycle: This fungus over- winters on cankers on stems. Spores are released from cankers during periods of rainy weather and splash onto adjacent stems mostly in the spring. Lesions may take 1-3 year to fully girdle and kill individual branches.

Phomopsis Stem Canker On DraperSiva Sabaratnam, BCAGRI

Armillaria Root Rot

Armillaria Root Rot.

(Armillaria spp.)
Damage: Infected bushes have small, pale leaves and die within 1-2 years. At the late stages of disease, entire foliage turn brown. Root-like fungal growth (called rhizomorphs),dark brown to black when matured or pale white when young, can be found attached to roots or crown or under the bark. White fungal mats can be seen on the stem underneath the bark when scraped away at the crown just below or at the soil line.
Disease cycle: This fungal disease is common on trees and woody species, and may attack blueberries planted on recently cleared of forest land. Wood bark and other woody plant materials used as planting medium for blueberry propagation or as mulch in the field may harbour the fungus.

Armilaria Root RotSiva Sabaratnam, BCAGRI

Armilaria Root RotSiva Sabaratnam, BCAGRI

Armilaria Root RotSiva Sabaratnam, BCAGRI

Armilaria Infected CrownSiva Sabaratnam, BCAGRI

Armillaria RhizomorphsSiva Sabaratnam, BCAGRI

Rhizomorph Of Armilaria On Infected CrownSiva Sabaratnam, BCAGRI

Sooty Blotch

Unidentified causal agent
Damage: Grey to black blotches form on the surface of green stems and twigs, giving them a sooty appearance.
Disease cycle: The organism grows below the cuticle on plant surfaces. It does not appear to harm the plant.

Sooty BlotchCarolyn Teasdale, ES Cropconsult

Silver Leaf

(Chondrostereum purpureum).
Symptoms: Leaves have a silvery appearance. Infected branches have a brown discoloration in the heartwood. Infected plants die within 1-3 years.
Disease cycle: Growth of bracket-like fungus, 5-7 cm wide, emerges from dead branches and pruning wounds at plant base and releases spores. Spores are spread by wind and rain during spring and winter. It can also spread by transplants generated from stem cuttings of infected plants.

Silver Leaf On Phomopsis Infected Draper PlantSiva Sabaratnam, BCAGRI

Silver Leaf DraperSiva Sabaratnam, BCAGRI

Silver Leaf DukeSiva Sabaratnam, BCAGRI

Root and Crown Rot

(Phytophthora cinnamomi).
Damage: Patches of bushes in a field look weak, have small yellow leaves, and few blossoms or berries. Infection often occurs in low areas of the field with poor drainage. Roots are soft and brown, may lack feeder roots.
Disease cycle: This fungus-like organism thrives in warm, wet soils.

Root RotSiva Sabaratnam, BCAGRI

Root Rot DeclineSiva Sabaratnam, BCAGRI

Mummy Berry

(Monilinia vaccinii-corymbosi)
Symptoms: Individual leaf and flower clusters turn brown and droop. A bluish-grey fuzz is visible on the petiole or flower stem. Infected berries become pink and puckered, then turn hard, white, and shrivelled and drop to the ground late in the season.
Disease cycle: This fungus over- winters in infected berries (mummy berries) that fell to the ground the previous season. Primary infection occurs when spores (ascospores) are released from the sprouting apothecia (fruiting structures of the pathogen) from mummy berries in early spring and blown onto new flower and leaf buds. Secondary infection occurs when bees carry the secondary spores (conidia) from primary infections to open blossoms.

Mummy Berry AphoteciaCarolyn Teasdale, ES Cropconsult

Mummy Berry AphoteciaCarolyn Teasdale, ES Cropconsult

Mummy Berry AphoteciaCarolyn Teasdale, ES Cropconsult

Mummy Berry Fruit Infected LeafCarolyn Teasdale, ES Cropconsult

Mummy Berry Leaf InfectionCarolyn Teasdale, ES Cropconsult

Mummy Berry Leaf InfectionCarolyn Teasdale, ES Cropconsult

Mummy Berry Leaf InfectionCarolyn Teasdale, ES Cropconsult

Mummy Berry Leaf InfectionCarolyn Teasdale, ES Cropconsult

Mummy Berry Flower InfectionCarolyn Teasdale, ES Cropconsult

Mummy Fruit InfectionCarolyn Teasdale, ES Cropconsult

Mummy Berry Fruit InfectionCarolyn Teasdale, ES Cropconsult

Mummy Berry Fruit InfectionCarolyn Teasdale, ES Cropconsult

Mummy Berry Fruit InfectionCarolyn Teasdale, ES Cropconsult

Godronia Canker

Godronia cassandrae ( Fusicoccum putrefaciens).
Damage: Small (2-7cm), reddish brown, oval-shaped lesions develop on one-year-old stems, usually at the base of a bud. Older infections girdle stems and die, and the leaves turn reddish-brown, mostly attached to the stem e, giving a “flagging” appearance. Lesions may take 1-3 years to fully girdle and kill individual branches
Disease cycle: This fungus over- winters on canker lesions on stems. Spores are released from young canker lesions during cool, wet weather in the spring but mostly in the fall and cause new infections.

Godronia Canker Young LesionsSiva Sabaratnam, BCAGRI

Godronia CankerCarolyn Teasdale, ES Cropconsult

Godronia Canker Old LesionsSiva Sabaratnam, BCAGRI

Godronia Canker FlaggingCarolyn Teasdale, ES Cropconsult

Godronia FlaggingCarolyn Teasdale, ES Cropconsult

Godronia Canker In A Duke FieldSiva Sabaratnam, BCAGRI

Godronia Factsheet English

Godronia Factsheet Punjabi

Crown Gall

(Agrobacterium tumefaciens)
Damage: Hard, tumour-like growths are present on the roots, crown, or stems. Individual branches or entire plant may be killed.
Disease cycle: Crown gall is caused by a bacterium that enters the plant through wounds. The disease can be spread by infected pruning shears, farm equipment or plant wounds.

Crown Gall On Blueberry RootsSiva Sabaratnam, BCAGRI

Crown GallSiva Sabaratnam, BCAGRI

Botrytis Blight and Fruit Rot

(Botrytis cinerea)
Symptoms: Infected twigs turn silvery and brittle. Infected flowers wilt, turn brown and develop a grey fuzzy mould on the surface. Green berries develop small, soft, purple patches. Ripe berries become soft and develop grey mould on the surface. Symptoms on flowers and berries are present all season, particularly following periods of cool rainy weather. Symptoms on twigs are present year round.
Disease cycle: The fungus overwinters on dead branch tips and debris on the ground. Spores are released in cool, wet weather and are carried by the wind. The fungus may remain latent on the berries until ripening.

Botrytis Twig BlightSiva Sabaratnam, BCAGRI.

Botrytis Blossom RotCarolyn Teasdale, ES Cropconsult