Notes on Blueberry Diseases
Blueberry stunt
Identification
Blueberry stunt is caused by a phytoplasma, a viruslike pathogen. The
phytoplasma causes stunting of new growth, which is plainly visible in
the summer. At this point, the leaves may also show signs of yellowing
around the edges and in between lateral veins, and are cupped slightly
downward. By autumn however, the chlorotic regions turn bright red. Infected
plants will appear bushy after several years because of shortening of
the internodes.
Blueberry stunt is vectored by the sharp-nosed leafhopper. Adults are
small (5 mm), brown with white flecks and a pointed head. Nymphs are yellow
with red to brown markings.
Period of activity
The disease is found in sapwood. Bushes are infected for life.
The disease is spread by the sharp-nosed leafhopper. Infections coincide
with peaks of leafhopper activity. Leafhoppers can be present from petal
fall through to late summer and often peak in numbers after harvest. There
are two generations per year.
Monitoring and thresholds
Use yellow sticky traps to monitor for sharp-nosed leafhoppers. Continue
to monitor after harvest for this pest.
Management notes
Purchase virus-tested planting stock from an accredited nursery. Remove
and destroy infected bushes.
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