Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00000308
11/12/99
CATTLEYA DISEASES PROBLEMS
American anthracnose starts at the tips of the leaves and
spreads towards the bases. The diseased areas are dark
colored and decayed. Many spore pustules develop in the
decaying leaves and stems.
Black rot causes infected leaves to turn purplish brown or
black. If the pseudobulb is infected before the leaf, the
part above the infection dies.
Leaf blight symptoms are purplish brown or black leaves.
A number of leaf spots attack this species of orchid.
Basal rot invades the root collar then extends into the
leaves. Infected leaves wilt, discolor, and break off,
usually at the base. The base of the stem may be covered
with a thick fungal growth.
Petal blight causes spots on the petals. The spots may be
bordered by pink rings. If the spots enlarge, the petal
may fall off.
Abnormal flower colors may be due to a virus disease
called cattleya flower break. The virus is carried by the
green peach aphid.
Related information.
Pesticide Recommendations
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This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
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