Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00001428
11/12/99
TAGETES DISEASE PROBLEMS
Botrytis blight causes the flowers to turn brown and
decay especially in wet weather. A gray mold forms on the
fading flowers. Pick off and destroy the infected
flowers.
The same wilt which attacks China Aster may infect
marigold, particularly French and dwarf types. Infected
plants wilt and die. Remove and destroy infected plants.
A leaf spot causes oval to irregular, gray to black spots
on the leaflets. The spots may be speckled with black
fruiting bodies. The disease starts on the lower leaves
and progresses upward. Varieties of African marigolds are
most susceptible.
Stems infected with wilt and stem rot turn brown and
shrivel at the soil line. The foliage wilts and the plant
dies. African types are most susceptible. Remove and
destroy infected plants.
Aster yellows is becoming more of a problem on marigold.
Control the insects which carry the disease. There is no
chemical control. On China Aster, sprouts (Vis. 1) in the
leaf axils and greenish flowers (Vis. 2) are the main
symptoms.
Related information.
Pesticide Recommendations
Botrytis Blight
Fungal and Bacterial Leaf Diseases
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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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