Blueberry Leaf Mottle
(Blueberry leaf mottle virus – BLMV)
Damage: Leaves are mottled and may be malformed or strap-like. The top of bushes die back with weak regrowth occurring only at the crown.
Disease: BLMV is spread by pollen and carried by bees. It is present in Michigan.
Blueberry Red Ringspot
(Blueberry red ringspot virus – BRRV)
Damage: Circular red rings or blotches, 4-6 mm in diameter, develop on one-year-old and older stems. Older leaves develop reddish brown circular spots, 3-5 mm in diameter, in mid to late summer.
Disease: The disease is caused by BRRV and it is not known how it spreads. It is present at low incidence in Oregon and the Eastern US. ‘Bluecrop’ is resistant to this disease.
(Blueberry shoestring virus – BSSV)
Damage: New and one-year-old stems show red streaks, 3-20 mm long, more on the side of the stem exposed to the sun. Leaves are elongated and strap-like (shoestring appearance), and may be reddish in colour. Blossoms have reddish streaks. Berries are reddish purple instead of blue. Yield is reduced.
Disease: BSSV is spread by the blueberry aphid, Illinoia pepperii, which is not present in BC. The virus has a latency period of 4 years before infected bushes show symptoms.
Damage: Bushes are severely stunted and bushy. Leaves may be spoon-shaped or cupped downward with chlorotic margins and chlorosis between the veins. Chlorotic areas turn bright red in late summer. Yield is reduced.
Disease: This disease is caused by a phytoplasma and is spread by leafhoppers. It is present in Eastern Canada and the Eastern US.
(Tobacco ringspot virus – TRSV)
Damage: Symptoms vary among cultivars. Leaves may be small, misshapen, crinkled and have small necrotic spots, 2-5 mm in diameter. Young twigs may have small brown necrotic patches. Yield is reduced. Symptoms are similar to those of ToRSV.
Disease: TRSV is spread by dagger nematodes (Xiphinema spp.) from infected to healthy roots in the soil. It causes plant decline in Oregon and the Eastern US.
(Tomato ringspot virus – ToRSV)
Damage: Leaves are cupped and misshapen or elongated and have pale yellow or brown circular spots of 2-5 mm in diameter. Stems may have brown, circular spots of 2-5 mm in diameter. Some shoots may appear normal, others may have misshapen leaves. An infected bush can be completely defoliated.
Disease: ToRSV is spread by dagger nematodes (Xiphinema spp.) from infected to healthy roots in the soil. The virus spreads slowly, causing plant decline in expanding circular patches in the field. It is present in Washington, Oregon and Michigan. It has been detected in BC on raspberries but not on blueberries.