Texas Live Oak Decline
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Ceratocystis fagacearum (Bretz) Hunt
Contents |
Importance
"Live oak decline" is a major disease that kills thousands of high value live oaks annually in Texas. Live oaks in Louisianna, Mississippi, and Florida have shown symptoms similar to those observed in Texas.
Identifying the Fungus
The primary pathogen, C. fagacearum, can be identified by isolating it from infected sapwood and by observing that through a microscope. Cultures are gray to tan and exhibit a fruity odor. Blunt, cylindrical microscopic spores are produced. Black, flask-shaped fruiting structures may develop.
Identifying the Injury
The initial symptoms are chlorotic leaf mottling, leaf browning, and defoliation. Later, the tree develops small leaves, water sprouts, twig and limb dieback, and eventually the tree dies. Cankering fungi also cause dieback and death after trees are stressed by wilt.
Biology
Live oak trees in Texas are infected by C. fagacearum, and develop initial symptoms mainly during the spring and fall. The fungus spreads through root grafts and by insect vectors. Dieback from canker fungi develops mainly during the summer months.
Control
Control procedures are the same as for oak wilt.
References
J. D. Solomon, F. I. McCracken, R. L. Anderson, R. Lewis, Jr., F.L. Oliveria, T.H. Filer, and P.J. Barry
