Cedar blight, caused by _Phomopsis juniperovora_, is most severe on
eastern red and Rocky Mountain cedars. Other hosts include arborvitae,
cypress, and Atlantic white cedar. The disease ranges from the mid-West
to the Atlantic coast and south to Alabama where it is most common in
nurseries.
[Illustration: Needle symptoms on 1-0 eastern red cedar nursery
stock and 5 year old Arizona cypress.]
[Illustration: (cont.)]
Symptoms on red cedar resemble that of drought. The tips of branches are
killed back and sometimes entire trees will turn brown. The fungus forms
black fruiting bodies on needles and stem lesions. Fungus spores are
distributed by rainwater; nursery overhead sprinkling systems also
facilitate blight spread.
Control of cedar blight is initiated by removing and burning infected
nursery stock early in the season before infection becomes heavy.
Seedbeds should be well drained. Avoid introducing cedar stock to an
infected nursery. The location of cedars in the nursery should be
changed frequently and, where possible, cedar beds should be kept well
away from older cedar or cedar hedges. Seedlings growing in low-density
seed beds are more vulnerable to the blight; thus beds should be fully
stocked. Cedar mulch should never be used on cedar beds. Avoid wounding
nursery transplants. No economically feasible control is available for
forest stands.