Roses may suffer from various disease that can affect
their growth & appearance. Here are some of the common
diseases to watch for in your garden, but remember to
always read the label for recommended
dosages and warnings before you use any product:
Blackspot
Symptoms:
A rounded dark lesion on the foliage that defoliates
the plant from the lower leaves up. Appears in the
summer. Spread by splashing water.
Treatment:
Spray copper or Neem in the spring and lime sulfur
in the winter. Baking soda works — somewhat.
Also: in the winter after pruning, when roses are bare,
gather up and dispose of all the foliage from the ground.
Powdery Mildew
Symptoms:
Irregular whitish lesions that deform the young soft
foliage. Appears first in spring. An airborne fungus.
Treatment:
It is controlled by Orthenex. The organic method is 1T baking soda, 1T vinegar,
1 T vegetable oil to a gallon of water other good sprays neem oil, horticultural
oils or utra fine oil (spray on cool days).
Downey Mildew
Symptoms:
Irregular purple-black lesions
on the canes and foliage. Defoliates quickly. Appears
when nights are cool and days are warm.
Furry growth may develop on under surfaces during humid weather.
Treatment:
Spray with copper, copper sulfate or Aliette.
Rust
Symptoms:
Rust appears on leaves and other green parts of
the plant as powdery pustules of orange aeciospores
usually confined to the lower leaf surfaces. In early
spring, spores may go unnoticed. Check underside
of leaves to monitor this problem.
Treatment:
Remove infected
leaves during growing season or spray with ultra
fine oil or Neem.
