Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00000768
11/12/99
ILEX DISEASE PROBLEMS
Tar spot may occasionally cause small yellow spots on the
leaves in summer. Eventually the spots turn reddish
brown with narrow yellow borders. Leaves may not drop
prematurely but the infected areas drop out leaving holes
in the leaves. Gather up and destroy badly infected
leaves.
Many different fungi cause leaf spots on holly. Reduce
the injury caused by leaf spots by keeping trees healthy.
Should a leaf spot become serious, identify the causal
fungus before spraying. Dispose of diseased leaves.
Cankers caused by several different fungi lead to sunken
areas on stems and plant dieback. Keep trees healthy and
prune out infected branches.
Spine spot is small gray spots with purple margins and is
caused by spines of one leaf puncturing an adjacent leaf.
Chlorosis symptoms are light green or yellowish leaves
with darker green veins. This problem is due to a high pH
leading to iron deficiency. Use acidifying fertilizers
and chemicals to bring down the pH. Sprays of iron chelate
will green up plants until the pH can be lowered.
Hollies scorch during the late winter due to rapid and
wide temperature fluctuations. Shade plants during the
winter to prevent the problem.
Purple blotches on the leaves are caused by some
environmental factor such as nutrient deficiencies,
drought, and winter injury.
Related information.
Pesticide Recommendations
Cankers
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.
For more information about this data base or its contents please contact
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