Control programs can include manual, mechanical, chemical, biological and cultural components. Landowners and land managers should evaluate their site, the life cycle characteristics of the invasive species and the best available science to determine which control method or combination of methods will be most effective and economical.

Employing a combination of prevention and control measures is an effective way for landowners and land managers to manage invasive species. This approach is often referred to as integrated pest management (IPM) and can include pulling, cutting, targeted pesticide use, biological controls and native species reintroduction.

Where eradication of the invasive species is not realistic, control strategies must strike a balance between the ecological impacts of allowing invasive species to spread and the economic realities of control measures. Not all control methods are practical, effective, economically feasible or environmentally sound for every situation. It’s recommended that landowners and land managers consult the most recent science or refer to invasive species websites.

Another website that may be useful in deciding whether the prescribed fire is a viable management technique is the Nature Conservancy’s Global Invasive Species Team [exit DNR] website. The website features Invasive Plant Species Summaries which give information regarding the management of various invasive species.

Spot treatment with fire: Sometimes large-scale burns are either inappropriate or cannot be done because of high fuel moisture or a lack of fuel to carry a fire. In such situations, spot-treating plants that are vulnerable to fire may be preferred. A propane torch with a long wand works well in these situations and can be used to treat individual plants or small groups of plants.

This technique works especially well on seedlings and young saplings and is generally less labor-intensive than hand-pulling and less expensive than herbicide treatments. Spot burning often only top-kills more mature plants.

To burn invasive plants with a propane torch, the operator passes the flame over the plant for less than one second, which is enough time to boil the water in the plant. Boiling the water within the plant will cause it to droop immediately and die within a couple of hours.

Some municipalities will not allow other types of prescribed burning but will approve burn permits for spot-treating plants with a propane torch. Be aware, however, that propane torches are dangerous to use, and there are several safety hazards that should be observed.

• Wear fire safety gear (Nomex fire suit, hard hat with face shield and Nomex ear/neck protector, leather gloves and leather boots).
• Make sure that the pressure relief valve on top is pointing away from the person carrying the pack. This valve is designed to release pressure by venting gas. If the tank overheats, the vented gas can ignite and will burn the applicator if the valve is pointing inward.
• Always be cautious where you set the torch down because the tip of the torch gets very hot. Cool it down with water, if possible.
• Do not use propane torches on dry vegetation or when windy conditions exist unless you have made adequate preparations to contain a runaway fire.

• Basal bark – Apply herbicide (generally in an oil carrier) in a ring, at least 6″ wide, to the base of a woody stem, typically the bottom 12-24 inches. For trees that root sucker, treat the exposed root collar as well. Spray to the point of run-off, but not beyond. The herbicide will penetrate the stem and move to the roots. The best timing is in the fall and early winter. Do not treat wet bark. Herbicide solutions may vary based on the diameter of the plant. Always apply in accordance with the herbicide label.
• Bundle and cut – Bundle together all the stems of a plant (typically grass). Cut the stems above where they are bundled, and apply herbicide to the cut stems.
• Cut-stump treatment – Cut all stems of a plant near its base and apply herbicide to the exposed cambium (outer) layer and down the sides of the root crown. Water-based herbicides should be applied immediately after the stem is cut. Oil-based herbicides can be applied later. The best timing is in the fall and early winter. Applications can be made using a sponge paintbrush, spray bottle or a backpack sprayer. Adding a dye to the solution helps keep track of what cut stumps have been treated.
• Foliar spray – Apply herbicide directly to the leaf surfaces of the plant. Use care to avoid applying to any non-target plants. Use special formulations near open water. A variety of sprayers can be used, including handheld, backpack, and mounted sprayer units for off-road vehicles and trucks. A surfactant may be needed when applying herbicides to fuzzy or waxy leaves.

All herbicide label formulations are listed as percent active ingredient (a.i.); this is the chemical that kills the plant. When an herbicide is purchased it will contain a certain amount of active ingredient. You will need to know the percent a.i. in your herbicide of choice to determine the amount of carrier (i.e. water or oil depending on the herbicide’s formulation) you need to add.

For example, if the herbicide you purchased contains 41% glyphosate, but you need a solution of 1% a.i. you would need to add roughly 3.12 ounces of your original 41% herbicide to a gallon of the carrier. [e.g., 1 (% a.i. in solution) x 128 (oz in a gallon) / 41 (% a.i. in herbicide) = 3.12 (oz of herbicide)]

ADDITIONAL RESOURCES

• Herbicide Effectiveness on Invasive Plants in Wisconsin [PDF exit DNR] by Mark Renz, University of Wisconsin – Extension
• Factsheets for invasive weed management [exit DNR] by Brendon Panke and Mark Renz, University of Wisconsin – Extension

• Sheep, goats and cattle – kudzu, thistle (bull, Canada, and musk), wild parsnip
• Sheep and goats – garlic mustard, spotted knapweed, cypress and leafy spurge, white and yellow sweet clover, tansy, yellow starthistle, reed canary grass
• Goats and cattle – giant and Japanese knotweed
• Goats – black locust, common buckthorn, honeysuckle (all species), Japanese barberry, multiflora rose, autumn and Russian olive, Oriental bittersweet, crown vetch

• Forest Health Herbicide Information
• Control Info – Center for Invasive Species and Ecosystem Health [exit DNR]
• Emerald Ash Borer Control – DATCP [exit DNR]
• Spongy Moth Control – DNR/DATCP/UW Extension site [exit DNR]
• Feral Hogs – Oklahoma Department of Wildlife Conservation
• Invasive Animal Management – Conservation Commission of Missouri [exit DNR]
• Purple Loosestrife Biocontrol Program