Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00000980
11/12/99
NARCISSUS DISEASE PROBLEMS
Blue mold is a storage problem and is worse on injured
bulbs. The disease is most likely in moist storage
conditions. This disease is caused by Penicillium sp.
Crown rot covers bulbs with layers of coarse white mold.
Remove infected plants and avoid infested soil for 2 to 3
years.
Basal rot causes a decay starting at the roots or bases of
the scales, and spreads upwards inside the bulb. The
plants are dwarfed and the blossoms abnormal. The disease
is caused by Fusarium oxysporum.
Fire causes spotting and rotting of flowers in humid
weather. The disease spreads and rapidly destroys the
leaves. The symptoms on leaves are dark reddish,
elongated, brown spots. Rake up and destroy old foliage.
The causal organism is Sclerotinia polyblastis.
Leaf spot causes large spots or blotches on the leaves.
The leaves wither and die. The bulbs lack nourishment due
to the premature death of leaves. Remove and destroy
plants with diseased foliage.
Smolder rots the foliage and flowers in cold, wet seasons.
The leaves are stuck together when they emerge and
infected bulbs rot in storage. Remove and destroy
infected plants.
Root rot causes leaf yellowing and stunting and withering
of plants. The roots have yellowish or brown discolored
stripes and decayed regions. The bulbs remain sound.
This disease is more of a problem where narcissi have been
planted for several years.
Leaf scorch causes blighted leaf tips to be separated from
healthy portions by a yellow area. The secondary
infection on the lower leaves is minute, water-soaked or
yellowish spots, which become raised, scabby and reddish.
The flower stalks and flowers may be spotted.
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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