Regulations (pertaining to the Great Lakes)
In 2011, the Great Lakes Indian Fish & Wildlife Commission ranked S. alba to be a low priority for regulation and control (Falck et al 2012). There are no known federal or state (within the Great Lakes region) regulations for this species. Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
Control
Biological
To our knowledge, no research into possible biological control organisms for this willow has been attempted in North America or anywhere else. Candidates for insect control are generally not sufficiently specific to avoid damage to native willows.
Physical
Like most river trees, willows resprout vigorously from cut stumps, and will usually grow back into a tree eventually. Repeated cutting of new stump shoots can eventually kill the trees. But given their large root systems, cutting would presumably be needed to be done several times per growing season for several years in order to starve the roots. Mowing or weed-whipping might be useful for seedlings. (GLIFWC 2013). Small seedlings can be hand-pulled, while larger trees may require a weed wrench or machinery to remove the root systems.
Chemical
Given willows’ tendency to resprout from the roots, multiple applications will likely be needed for control.
The nonselective herbicide glyphosate (available commercially as "Roundup" and "Rodeo") is commonly used for treating woody invasives such as crack willows. Tryclopyr (Garlon 3A or equivalent amine formulation) is also effective against broadleaf and woody plants, and has the advantage of leaving grasses and sedges intact. Recently Roundup has been shown to be highly toxic to both adult frogs and toads and their tadpoles, probably due to the surfactant (polyethoxylated tallowamine, or POEA) in this glyphosate formulation (Relyea 2005). Because of this and other as yet unknown effects of various herbicide formulations on the environment, herbicide should be applied as precisely as possible and only when needed, using only the amount needed to get the job done. Any attempt to control crack willows or other invasive plants in aquatic habitats must be done using Rodeo or other herbicides formulated for use over water. Permits are required for herbicide application over water in many states, including Wisconsin, Michigan and Minnesota. (GLIFWC 2013).
Triclopyr amine is best used on young willows (seedlings) that are actively growing. 2,4-D LV ester can be applied when leaves are fully developed and growing (amendable to aerial application). Metsulfuron is used on fully leafed-out brush.
Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.