Black spot rose

Black spot symptoms are irregular black spots often
surrounded by a yellow halo. As infection progresses, leaves
eventually drop. The disease spreads quickly from one plant to
the next so it is important to remove infected leaves as soon as
they show. Leaf drop contributes to the spread of the disease
by harboring spores and results in weakening the plant and
increasing susceptibility to winter injury, drought, dieback andse
stem cankers. Flower production will be reduced if the disease
is allowed to spread.
Prevention is the best control for black spot. Leaf litter
should be removed from the area since the spores will overwinter
on infected leaves. Protective fungicidal sprays are
advised. The fungus grows beneath the protection of the leaf
cuticle, making control difficult once the spores have germinated.
Weekly sprays from the time the plant leafs out in the
spring until autumn are advised. Spray both the upper and low
leaf surfaces. Proper pruning will remove spores overwintered
in small cane lesions