Dr.Bonsai

Your cypress is most likely a species of Chamecyparis, something like a Hinoki Cypress? These are actually false cypress, the most common "cypress" used for bonsai.

Although they are generally considered low-maintenance and largely disease-free, Chamecyparis and juniper are both occasionally affected by blight. This is a fungal growth that attacks only the new growth on the tree, with the older growth being resistant.

Your description of the problem suggests that you may have Kabatina tip blight. Phomopsis is another type of tip blight, but it leaves a darker nodule.

In any case these control methods will help:
[*]Make sure that the foliage is not allowed to remain wet overnight.[*]Prune out any affected branch tips. [*]If the growth is dense at points, prune to improve ventilation

If it is truly a Kabatina/Phomopsis blight, then application of a copper-based fungicide to the foliage might be beneficial. Infection typically occurs in the summer months through insect vectors or mechanical damage, and the symptoms appear much later. So, this may be why you haven't seen any improvement, despite the fact you have already begun a fungicide treatment.

The following articles have more information on tip blight:

http://ohioline.osu.edu/hyg-fact/3000/3056.html

http://www.forestpests.org/southern/Diseases/phmbsis.htm

http://www.na.fs.fed.us/spfo/pubs/fidls/phomopsis/phomopsis.htm

http://fhpr8.srs.fs.fed.us/idotis/diseases/phomopbl.html

Adobe PDF format:

http://www.utextension.utk.edu/spfiles/sp277b.pdf

Good luck,

Dr. Bonsai