Insect and Disease Fact Sheet Compliments of
New Century 
1-877-79TREES
Phomopsis and Kabatina
Tip Blights of Junipers
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Phomopsis tip blight and Kabatina tip blight
are two common diseases of junipers found in most states east of the Mississippi.
Both: diseases are caused by fungi and the damage they cause on nursery
stock, transplants and certain juniper varieties in the landscape can be
sever; however, most establighed junipers in the
landscape are seldom killed. The disease is most serious on younger plants
and becomes less serious as plants get older. There are many varieties of
juniper that vary from very susceptible to highly resistant. Junipers are generally
considered as low maintenance because they are relatively free of major diseases
and insect pests; however, these diseases can adversely affect the
appearance and health of these trees in certain locations and under the
proper environmental conditions. Although Phomopsis
and Kabatina blights cause almost identical
symptoms, aspects of their development and control do differ. Therefore, it
is important to distinguish between the two diseases. |
Close-up of Phomopsis tip blight on
juniper. |
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Close-up of Phomopsis tip
blight on juniper. |
Symptoms and
Causal Organisms Phomopsis tip blight caused by the
fungus Phomopsis
juniperovora, damages new growth and succulent
branch tips of junipers from mid-April through September. Older, mature
foliage is resistant to infection; therefore, most blighting occurs on the terminal
4 to 6 inches of the branches. Affected foliage first turns dull-red or brown
and finally ash gray. Small gray lesions often girdle branch tips and cause
blighting of foliage beyond the diseased tissue. Small, black,
spore-containing fungal fruiting bodies develop in the lesions. Use a hand
lens to view these diagnostic fungal structures more easily. Spores
of the Phomopsis fungus are produced, throughout
the summer, and infection can occur whenever young
foliage is available and moisture or humidity is high. Most infections usually
occur in |
April through early June and again in late August through
September.
Very few infections occur in mid-summer or during the winter months. Repeated
blighting in early summer can result in abnormal bunching (witches' broom) and
discoloration of the foliage, stunting of young trees or shrubs, or in severe
cases plant death. Be cautious in diagnosing witches brooming
and stunting because similar damage can be caused by the dwarf tip mite. With
juniper problems, it is always a good idea to have problem diagnosis confirmed
by a diagnostic laboratory.
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Kabatina tip blight, caused by the fungus Kabatina
juniperi, first appears in February and March; and
well before symptoms of Phomopsistip blight
appears. The terminal 2 to 6 inches of diseased branches throughout the
juniper turn dull green first, then red or yellow. Small ash-gray to silver
lesions dotted with small, black fruiting bodies of the fungus are visible at
the base of discolored tissue. The
brown, desiccated foliage eventually drops from the tree in late May or
June. Foliar blighting occurs only in
early spring; it does not continue through the summer. Blighting is also restricted to the branch
tips and does not cause extensive branch dieback or tree death. Be cautious in diagnosing witches brooming and stunting symptoms because similar damage can
be caused by the dwarf tip mite. |
Severe infection
of Phompsis tip blight on juniper. |
With juniper problems it is
always a good idea to have problem diagnosis confirmed by a diagnostic
laboratory. The primary infection period for the Kabatina
fungus is thought to be in autumn even though visible symptoms are not apparent
until late winter or early-spring. Infection often is associated with small
wounds on branch tips caused by insect feeding or mechanical damage.
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Control
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Appearance of Phomopsis tip
blight on juniper. |
Information obtained through the Ohio State Extension Factsheet HYG-3056-96
Insect and Disease Fact Sheet Compliments of
New Century
1-877-79TREES