Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00001197
11/12/99
PSEUDOTSUGA DISEASE PROBLEMS
Armillaria Root Rot kills trees by girdling them at the soil
line. Infected trees will show yellowing then death of the
needles. Other symptoms include patches of resin on the bark
at the root/trunk junction. White fungus patches form under
the bark in the infected area. Stressed trees will be more
susceptible.
Douglas-fir is especially susceptible to Rhabdocline
Needlecast. Yellow spots form on infected needles in the
fall. These become brown the following spring and then fall
in the summer. The new growth becomes infected in the spring
and so fungicides, if used, must be applied at 7 to 10 day
intervals beginning at bud break and continue until the buds
are fully open.
Swiss Needlecast will cause infected needles to turn yellow,
then brown and finally to drop off the tree. Yellow needles
may be found in either fall or spring with the browned
needles falling in the fall. Usually older needles on the
lower part of the tree are most affected.
Related information.
Pesticide Recommendations
This information is for educational purposes only. References
to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU
Extension. Reprinting cannot be used to endorse or advertise
a commercial product or company.
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
heatley@msue.msu.edu . Please read our
disclaimer for important
information about using our site.