Septoria Canker of Poplar |
| USDA Forest Service. 1979. A guide to common insects and diseases of forest trees in the northeastern United States. Northeast. Area State Priv. For., For. Insect and Disease Management., Broomall, PA. p. 123, illus. |
Septoria canker of poplar is caused by the fungus Septoria musiva. Certain native hybrids, particularly those bred from black poplar, balsam poplar, or cottonwood, and certain foreign hybrids (especially "Russian poplar"), are highly susceptible.
The fungus causes brown leaf spots with yellowish or white centers. These spots may affect as much as half of the leaf tissue. Cankers are formed in twigs of the current season's growth. The fungus does not girdle stems, but the cankers may allow entry of other fungi that do girdle stems, such as Fusarium.
Small, black, asexual fruiting structures develop on both cankers and leaves. In summer, under favorable conditions, asexual spores are spread to other places on the tree or to other nearby trees. S. musiva overwinters in tiny, black, flask-shaped sexual fruiting bodies on branches and fallen leaves. The sexual spores are shot into the air during periods of high humidity in the spring. They infect new leaves as the buds are opening. They also may infect young shoots and form cankers.
Damage; blotches on Balm-of-Gilead leaves
Minnesota Department of Natural Resources Archives, Minnesota Department of Natural Resources |
Damage; defoliation of Balm-of-Gilead trees
Minnesota Department of Natural Resources Archives, Minnesota Department of Natural Resources |
[ Contents ]
[ Previous ]
[ Next ]
[ Home ]
|
