Archive:Poplar/Septoria Canker

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From: Ostry, Michael E.; Wilson, Louis F.; McNabb, Harold S., Jr.; Moore, Lincoln M. 1988. A guide to insect, disease, and animal pests of poplars. Agric. Handb. 677. Washington, DC: U.S. Department of Agriculture. 118 p.

Importance

Cankers weaken branches and main stems. Multiple cankers girdle trees, causing top dieback, breakage, and tree death. Secondary organisms enter trees through cankers, causing stain and decay. Highly susceptible clones cannot be coppiced because this disease harms new shoots.

Look For:

• Depressed areas on stems and branches that look water-soaked. Often new cankers have orange or black margins.

• Rough, ash-gray area with a central crack on stem.

• Large, rough cankers on stems and branches. Fruit bodies are usually only found on first-year cankers.

Old Canker

Biology

The fungus overwinters in fallen infected leaves and young cankers. In the spring, ascospores from leaves are windblown and rainsplashed to leaves, stems, and branches, where infection takes place. Secondary infections throughout the summer are caused by conidia, produced in leaf spots, and rainsplashed to adjacent leaves and branches.

Dieback associated with stem canker.

Cankers on stump sprouts.

Monitoring Inspect plantations and nurseries for leaf spots and cankers beginning in midsummer. Trees of all ages are affected. New cankers are more numerous on the younger portions of trees.

Control:

• Remove infected leaf debris before spore release in the spring to reduce inoculum within plantings and minimize new infections if there are no other nearby sources of inoculum.

• Plant only resistant clones

• Plant only disease-free nursery stock.

• Harvest highly susceptible clones early and replace them with resistant clones.

Young branch canker.

Branch canker with characteristic malformation of affected area.

For Additional Information:

McNabb, H. S., Jr.; Ostry, M.E.; Sonnelitter, R.S.; Gerstenberger, P.E. 1982. The effect and possible integrated management of Septoria musiva in intensive short-rotation culture of Populus in the north central states. In: Zavitkovski, Jerry; Hansen, Edward A., eds. Proceedings, North American poplar council meetings; 1982 July 20-22; Rhinelander, WI. Manhattan, KS: Kansas State University: 51-58.

Moore, Lincoln M.; Ostry, Michael E.; Wilson, Louis F.; Morin, Michael J.; McNabb, Harold S., Jr. 1982. Impact of Spetoria canker caused by S. musiva on nursery stock and first-year plantation coppice. In: Zavitkovski, Jerry; Hansen, Edward A., eds. Proceedings, North American poplar council meeting; 1982 July 20-22; Rhinelander, WI. Manhattan, KS: Kansas State University: 44-50.

Ostry, M. E. 1987. Biology of Septoria musiva and Marssonina brunnea in hybrid Populus plantations and control of Septoria canker in nurseries. European Journal of Forest Pathology. 17: 158-165.

Ostry, M. E.; McNabb, H. S., Jr. 1983. Diseases of intensively cultured hybrid poplars: a summary of recent research in the north central region. In: Hansen, Edward A., comp. Intensive plantation culture: 12 years research. Gen. Tech. Rep. NC-91. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station: 102-109.

Ostry, Michael E.; McNabb, Harold S., Jr. 1986. Populus species and hybrid clones resistant to Melampsora, Marssonina, and Septoria. Res. Pap. NC-272. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station. 7 p.

Ostry, M. E.; McNabb, H. S., Jr. 1985. Susceptibility of Populus species and hybrids to disease in the north central United States. Plant Disease. 69: 755-757.

Palmer, Marguerita A.; Schipper, Arthur L.; Ostry, Michael E. 1980. How to identify and control Septoria leaf spot and canker of poplar. St. Paul, MN: U.S. Department of Agriculture, Forest Service, Norht Central Forest Experiment Station. 6 p.

Thompson, G. E. 1941. Leaf spot diseases of poplars caused by Septoria musiva and S. populicola. Phytopathology. 31: 241-254.

Stem Canker.

Water-soaked appearence of stem.