Cryptomeria is known as an ornamental tree in the US, it is however the main timber tree species in Japan. It is a favorite for builders, often placed as an accent plant on the corner(s) of a house...and often planted too close. Don’t confuse this with the leyland cyprus - similar in look as well as in landscape function (fast growing screen). Two common diseases for the cryptomeria include Cercospora Blight and Root Rot.
Cercospora Blight, also known as Leaf Spot, appears as brown needles that often start at the the base of the tree. When disease pressure is high, the entire tree may turn brown. One of the best management practices is to make sure there is enough space between trees to decrease the duration of leaf-wetness and to reduce humidity levels. No specific fungicide as demonstrated to be effective once the disease is present. We have had success with our Deep Root Treatment to increase their vigor.
The second common disease is Root Rot (Armillaria) which is caused by a fungus. Symptoms are growth reduction and yellowing of the needled die-back. However, symptoms are not apparent and large trees may survive the infection for several years before showing any signs. Light brown mushrooms often appear at the base of the tree and in nearby soil. The disease spreads through the movement of contaminated soil or by wind-blown spores (when mushrooms are produced). It is important recognize this disease because trees infested by it are more at risk of uprooting. However, and as already mentioned, symptoms are not always that obvious. There are no treatments for root rot, however, when a tree that had it is removed or blown over it is important to remove the roots (or the mulch from the stump that was ground) as all the spores are present in them.
