Heterobasidion root disease management

Preventing Heterobasidion root disease is crucial. If you are thinning a plantation within several miles of a confirmed location, consider either (1) thinning when temperatures are forecast to be below 32˚ F, or (2) applying an appropriate fungicide on freshly cut stumps. These actions are critical if you are within a mile of confirmed Heterobasidion root disease. Spores of Heterobasidion can travel long distances, and the closer a confirmed location is to the thinning site, the greater the risk of infection.

Spores are less likely to be released and germinate at freezing temperatures, so thinning in late December, January, and early February is a good way to avoid Heterobasidion root disease. However, there is a moderate to high risk when thinning in winter if temperatures rise above freezing and there is little snow pack.

green colored stumpsIf thinning during spring, summer, or fall, you can use a fungicide on stumps to prevent Heterobasidion root disease. Cellu-Treat® is registered for this purpose in Minnesota. It can be applied by backpack sprayer or through sawbars on mechanical harvesters. One source for ordering this fungicide is the manufacturer's website. Landowners can apply this fungicide on their own land without a license. Any person hired to apply Cellu-Treat® must be licensed as a commercial pesticide applicator by the Minnesota Department of Agriculture. Learn how to obtain a pesticide applicator license by visiting the Minnesota Department of Agriculture website or by calling 651-201-6615.

In theory, Heterobasidion spores could move around on soil and woody debris from an infested site. This has never been documented, but as a cautious approach, logging equipment arriving at a plantation must be free of soil and woody debris. Likewise, equipment must be free of logging debris before leaving a site.

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