Cedar Leaf Blight, Cedar Twig Blight, Berckman’s Blight Coryneum berckmanii, C. thujina (fungus), Seridium cardinale (Leyland cypress)
Effects Oriental arborvitae, Italian and Monterey and Leyland cypress.
Found in the Western Coastal U.S.
Contrubuting factors include; Rain or foggy, cool weather or infested pruning tools.
The Blight on Small branches become reddish-brown, many dropping; larger limbs girdled. Twigs with black pustules of fruiting structures (acervuli). Foliage becoming gray. Dead twigs become entangled at base of tree.
The Cankers on twigs and branches girdled, with cankers first appearing on lateral twigs; slightly sunken, dark, resinous, rough, with black spore pustules. Yellowing and browning of foliage with gummy ooze at cankers.
Infection is first evident in upper part of tree during moist spring. Following initial infection, acervuli produce spores which drop to lower branches or are spread in windblown rain and fog or by birds and insects. Repeated infection leads to death of tree.
Cypress Cedar Branch Canker
Seridium cardinale (Leyland cypress)
As with Monterey cypress, disease development on Leyland cypress has been closely tied with hot, dry summer weather.
The most noticeable symptom of Seridium canker is yellowing or browning of the foliage on one or more top or lateral branches. This discoloration may appear at any time of the year but is most likely to be seen in the spring. Disease development often continues until a considerable portion of the tree is killed.
The spores are spread to healthy foliage and branches of adjacent Leyland cypress by splashing water and contaminated pruning tools.