A few months after an infected branch dies, fruiting bodies (pycnidia) appear near the base of dead needle fasicles. Asexual spores (conidia) ooze out of these pycnidia during wet weather from April to October. These spores are transported by rain splash and wind to nearby branches, spreading the infection in individual trees and onto adjacent trees. Fruiting bodies (apothecia) appear in early summer on branches that have been dead for 1 to 2 years (see below). The apothecia are also commonly found at the base of dead needle fasicles and are often found in association with the pycnidial stage.
In the European strain, the windblown ascospore stage is rarely found and the infection period of the conidial spore stage is longer than in the North American strain, making it more difficult to control.Management Guidelines
The best way to prevent the introduction of the dangerous European strain into the Lake States is to make sure that infected nursery stock, Christmas trees, or other infected material is not introduced.
In the Field
- Pick red pine planting sites where Scleroderris canker is not present.
- If the planting site is in a Scleroderris canker hazard area, select a species for planting that is immune or has a low susceptibility. Hard pines are highly susceptible, but spruces, cedars, firs, and larches are more resistant to infection.
- Avoid geographic depressions, such as frost pockets, where the disease is most damaging.
- Select planting stock from a nursery outside of the range of Scleroderris canker or from a nursery that has an effective fungicide control program.
- Do not plant infected seedlings.
- In high-value stands, prune lower branches on infected and healthy trees.
- Do not ship infected red pine Christmas trees into areas where Scieroderris canker is not present.
- Abide by all quarantine laws designed to prevent the introduction of the European strain into areas where it is not present.
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Trees "R" Us, Inc. is a professional tree service for the Chicago's North Shore, North and Northwest suburbs. Tree trimming, tree removal, stump grinding, fertilizations, tree disease treatments and prevention as well as plant health care are just a few of our high quality, professional services. Contact us today for a free analysis or quote at www.treesrusinc.com or at 847-913-9069.
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