Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00000811
11/12/99
JUNIPERUS DISEASE PROBLEMS
Twig blight causes death and browning (Vis. 3) of twigs
tips. The disease may progress down the stem killing the
whole branch. Small lesions (Vis. 4) may be seen at the
base of dead tissue. Prune out dead branch tips.
Three rust diseases seen most often are cedar-apple rust,
hawthorn rust, and quince rust. The most common is
the first. On juniper, the disease forms (Vis. 2) galls
that form orange jelly-like horns (Vis. 1) in spring. The
horns are most likely to form following periods of rainy,
warm weather. Spores formed in the horns infect the
alternate host. The diseases are more serious on the
alternate host than juniper. A separation of a few hundred
yards will help control the disease. Prune out the spore
horns when seen in the spring.
Junipers are not tolerant of ice coatings. Expect dieback
when junipers are covered with ice for several days.
Removing the ice is impractical and it usually melts
before injury occurs.
Related information.
Pesticide Recommendations
Twig Blight of Juniper
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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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