Invasive Plant Control Database

Welcome to the Invasive Plant Control Database

This website contains information on how to control many invasive plants common to the Midwestern United States. Information was collected from both scientific literature and expert opinions and summarized by the Midwest Invasive Plant Network (MIPN), in partnership with the Mark Renz lab from the University of Wisconsin-Madison. Methods that are uncommon, do not provide sufficient control, or lack information for determining effectiveness on target species are omitted. For each species, information was reviewed by four individuals, including two identified as experts on control of that species. Information is searchable by several fields to improve the user’s ability to find pertinent information. To view the search feature, you must first select an invasive plant. Additionally, users have the option of entering personal experiences with managing specific species (see “add new case studies” under search results). These case studies will be visible to all users once verified by MIPN staff.

We make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability, or availability with respect to the information or products on the website. Any reliance you place on such information is therefore strictly at your own risk. References to pesticide products on this website are for your convenience and are not an endorsement or guarantee of one product over another.

Step 1: Select Plant

Step 1: Select a species by choosing a common or scientific name from the list, or by typing a name in the search box.

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Step 2: Select Search Parameters

Step 2: Select search parameter(s) of interest. If no parameters are selected all control methods will be displayed. For effectiveness ratings, methods that meet or exceed the criteria selected will be displayed.

Under the Search Results you will find

  • Plant Identification information – information on species identification, including photographs and a current distribution map.
  • Ecological Threats – threats posed to natural ecosystems by this species.
  • Case Studies – Detailed success (and failures) on how to control specific species contributed by experienced personnel.
  • Non-chemical and chemical control methods that fit the selected search criteria. Please note you are responsible for using pesticides in accordance with the label directions and state and federal laws. Herbicide availability and registered uses vary from state to state. Contact your state department of agriculture for information on the correct use and licensing required for any pesticide application.

You may reset the search criteria or the species you have selected at any time by selecting the corresponding links on the right hand side of the page.

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Search Results

Centaurea stoebe (spotted knapweed)

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Non-Chemical controls
New (Type)Description
Type -
Mowing

User Type -
Novice

Effectiveness -
in season
year after treatment
Mow once annually at the flowering stage for 3 years to suppress populations. Mow as low as possible. Plants may resprout, but it is unlikely that they will be able to produce viable seed. While mowing has been reported as an effective means of suppression there is no data on how many years of mowing are required to control a population.
Type -
Prescribed burning

User Type -
Professional

Effectiveness -
in season
year after treatment
Spring burns can kill germinating seedlings and can suppress above-ground growth of established plants depending on fire intensity. Summer burning, when knapweed has begun to flower, is the most effective timing for suppressing knapweed. However, summer burning can adversely affect desirable species. At least 3 years of annual burning are needed for the suppression of established knapweed populations. Fire may benefit other species well-adapted to this management (e.g., prairie grasses), resulting in improved competition with knapweed. A hand-held propane torch can be effective for treating seedlings.
Type -
Removal

User Type -
Novice

Effectiveness -
in season
year after treatment
Pulling plants is an effective individual plant treatment if soil conditions allow for the removal of the top 3" of the taproot. For hand cutting, cut through the entire taproot with a sharp shovel or spade 3" below the surface and remove plant and attached root. If flowers are present, bag material and dispose of it in a landfill to avoid potential for seed spread. Pulling or cutting will rarely control large populations, but is recommended for small establishing infestations in sensitive areas or when integrated with other management activities.
Type -
Grazing

User Type -
Novice

Effectiveness -
in season
year after treatment
Grazing with sheep or goats can suppress populations if done twice a year. For best results, initiate grazing when rosettes are present and repeat when plants have regrown and are in the bolting to bud stage. Spring applications of herbicides can reduce the population of unpalatable adult plants and increase the effectiveness of grazing.
Type -
Biocontrol

User Type -
Novice

Effectiveness -
in season
year after treatment
There are 13 common agents for biological control of knapweed. Commonly recommended agents are Agapeta zoegana (root mining moth), Cyphocleonus achates (root mining weevil), Urophora affins, U. quadrifasciata (seed head flies), Larinus minutus, and L. obtusus (seed head weevils). A successful biological control program should include at least one seed head agent and one root mining agent. Biological control agents rarely eliminate entire populations, instead they reduce the cover and seed production. Contact your local department of agriculture for information on permits for the release of biological control agents.
Chemical controls
New (Type)IngredientsDirections
Type -
Foliar

User Type -
Professional

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
aminocyclopyrachlor + metsulfuron

Common product name:
Streamline
Rate -
(broadcast) 4.75 - 5.5 oz/A (aminocyclopyrachlor: 1.9 - 2.15 oz a.i./A + metsulfuron: 0.6 - 0.87 oz a.i./A)
(spot) 0.2 - 0.4 oz/gal (aminocyclopyrachlor: 0.08 - 0.16 oz a.i./gal + metsulfuron: 0.03 - 0.05 oz a.i./gal)

Timing -
Apply to rosettes in fall or spring or to plants in the bolting stage.

Caution -
Do not apply directly to water or to areas where surface water is present. Avoid using Streamline in areas where soils are permeable, particularly where the water table is shallow as groundwater contamination may result. Streamline remains in the soil for months depending on application rate and has the potential to contaminate surface runoff water, especially on poorly draining soils or areas with shallow groundwater. Maintenance of a vegetative buffer strip is recommended between the areas Streamline is applied and surface water features. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants. Do not compost treated plants as herbicide can persist through composting process.
Type -
Foliar

User Type -
Professional

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
dicamba

Common product name:
Banvel; Clarity
Rate -
(broadcast) 16 - 32 fl oz/A (0.5 - 1 lb a.e./A)
(spot) Equivalent to broadcast rates.

Timing -
Apply to rosettes in fall or spring or to plants in the bolting stage.

Caution -
Do not apply directly to water or to areas where surface water is present. Use of this chemical in areas where soils are permeable, particularly where the water table is shallow, may result in groundwater contamination. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants. Rates > 16 fl oz/A (0.5 lb a.e./A) may cause stunting and discoloration of sensitive grasses, such as smooth brome.
Type -
Foliar

User Type -
Professional

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
aminopyralid

Common product name:
Milestone
Rate -
(broadcast) 5 - 7 fl oz/A (0.08 - 0.1 lb a.e./A)
(spot) Equivalent to broadcast rates.

Timing -
Applications to rosettes in fall or spring or to plants in the bolting stage are the most effective, but applications can control plants that are in the flower bud stages.

Remarks -
14 fl oz/A can be used as long as less than half of the area is treated. Depending on the volume of solution applied per acre, typical mixtures for spot treatments are 2-8 mL Milestone per gallon of water. This herbicide can provide residual control of germinated spotted knapweed seedlings. Length of residual control is dependent on site specific factors such as amount and timing of precipitation, regrowth of desired plants, and the rate applied.

Caution -
Do not apply directly to water or to areas where surface water is present. Remains in soil for up to one year depending on application rate. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants. Do not compost treated plants as herbicide can persist through composting process.
Type -
Foliar

User Type -
Professional

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
dicamba + diflufenzopyr

Common product name:
Overdrive
Rate -
(broadcast) 6-8 fl oz/A (dicamba: 0.02-0.03 lb a.e./A + diflufenzopyr 0.01 - 0.012 fl oz a.e./A)
(spot) Equivalent to broadcast rates.

Timing -
Apply to rosettes in fall or spring or to plants in the bolting stage.

Caution -
Do not apply directly to water or to areas where surface water is present. Use of this chemical in areas where soils are permeable, particularly where the water table is shallow, may result in groundwater contamination. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants. Rates > 16 fl oz/A (0.5 lb a.e./A) may cause stunting and discoloration of sensitive grasses, such as smooth brome.
Type -
Foliar

User Type -
Professional

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
picloram

Common product name:
Tordon K; Trooper 22K
Rate -
(broadcast) 10 - 32 fl oz/A (0.15 - 0.5 lb a.e./A)
(spot) Equivalent to broadcast rates.

Timing -
Applications to rosettes in fall or spring or to plants in the bolting stage are the most effective, but applications can control plants that are in the flower bud stages.

Remarks -
This herbicide can provide residual control of germinated spotted knapweed seedlings. Length of residual control is dependant on site specific factors such as amount and timing of precipitation, regrowth of desired plants, and the rate applied.

Caution -
Do not apply directly to water or to areas where surface water is present. Use of this chemical in areas where soils are permeable, particularly where the water table is shallow, may result in groundwater contamination. Remains in the soil for over one year depending on application rate and has the potential to contaminate surface runoff water during this timeframe. Maintenance of a vegetative buffer strip is recommended between the areas picloram is applied and surface water features. Overspray or drift to desirable plants should be avoided as even minute quantities of the spray may cause severe injury to plants. Do not compost treated plants as herbicide can persist through composting process.
Type -
Foliar

User Type -
Professional

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
dicamba + 2,4-D

Common product name:
Outlaw; Weedmaster
Rate -
(broadcast) 64 - 96 fl oz/A (dicamba: 0.5 - 0.8 lb a.e./A + 2,4-D: 0.7 - 1.1 lb a.e./A)
(spot) 0.8% (dicamba: 0.009 lb a.e./gal + 2,4-D: 0.011 lb a.e./gal)

Timing -
Apply to rosettes in fall or spring or to plants in the bolting stage.

Caution -
Do not apply directly to water or to areas where surface water is present. Use of this chemical in areas where soils are permeable, particularly where the water table is shallow, may result in groundwater contamination. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants. Rates > 16oz/A (0.5 lb a.e./A) may cause stunting and discoloration of sensitive grasses, such as smooth brome.
Type -
Foliar

User Type -
Professional

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
imazapyr

Common product name:
Arsenal; Stalker (Aquatic: Habitat; Imazapyr 2sl)
Rate -
(broadcast) 64 - 96 fl oz/A (1.0 - 1.5 lb a.e./A)
(spot) 0.5 - 1% (0.01 - 0.02 lb a.e./gal)

Timing -
Apply to rosettes in fall or spring or to plants in the bolting stage.

Caution -
Use product labeled for aquatic use if potential exists for solution to contact surface waters. Applications can result in bare ground as imazapyr is not selective and can remain in the soil for several months to over a year depending on application rate. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants.
Type -
Foliar

User Type -
Novice

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
glyphosate

Common product name:
Roundup Pro; many others (Aquatic: Rodeo; AquaNeat)
Rate -
(broadcast) 0.5 - 1.5 lb a.e./A
(spot) For a 3 lb a.e./gal product. 1 - 2% (0.03 - 0.06 lb a.e./gal)

Timing -
Apply to rosettes in fall or spring or to plants in the bolting stage.

Caution -
Use product labeled for aquatic use if potential exists for solution to contact surface waters. Applications can result in bare ground as glyphosate is not selective. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants.
Type -
Foliar

User Type -
Novice

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
2,4-D

Common product name:
Many (Aquatic: DMA 4 IVM; 2,4-D Amine 4)
Rate -
(broadcast) 1 - 2 lb a.e./A
(spot) For a 3.8 lb a.e./gal product. 1 - 2% (0.04 - 0.08 lb a.e./gal)

Timing -
Apply to rosettes in fall or spring or to plants in the bolting stage.

Remarks -
This herbicide offers moderate control when used as the only control method, but can be a useful when paired with other control methods. This herbicide will not provide any residual control of germinating spotted knapweed.

Caution -
Use aquatically labeled product if potential exists for solution to contact surface water. Use of this chemical in areas where soils are permeable, particularly where the water table is shallow, may result in groundwater contamination. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants.
Type -
Foliar

User Type -
Professional

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
aminocyclopyrachlor + chlorsulfuron

Common product name:
Perspective
Rate -
(broadcast) 4.75 - 5.5 oz/A (aminocyclopyrachlor: 1.9 - 2.15 oz a.i./A + chlorsulfuron: 0.75 - 0.87 oz a.i./A)
(spot) 0.2 - 0.3 oz/gal (aminocyclopyrachlor: 0.08 - 0.12 oz a.i./A + chlorsulfuron: 0.03 - 0.05 oz a.i./A)

Timing -
Apply to rosettes in fall or spring or to plants in the bolting stage.

Caution -
Do not apply directly to water or to areas where surface water is present. Avoid using Perspective in areas where soils are permeable, particularly where the water table is shallow as groundwater contamination may result. Perspective remains in the soil for months depending on application rate and has the potential to contaminate surface runoff water, especially on poorly draining soils or areas with shallow groundwater. Maintenance of a vegetative buffer strip is recommended between the areas Perspective is applied and surface water features. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants. Do not compost treated plants as herbicide can persist through composting process.
Type -
Foliar

User Type -
Professional

Effectiveness -
in season
year after treatment
Active Ingredient (A.I.):
clopyralid

Common product name:
Transline
Rate -
(broadcast) 10 - 16 fl oz/A (0.25 - 0.4 lb a.e./A)
(spot) 0.2 - 0.4% (0.005 - 0.01 lb a.e./gal)

Timing -
Applications to rosettes in fall or spring or to plants in the bolting stage are the most effective, but applications can control plants that are in the flower bud stages.

Remarks -
This herbicide can provide residual control of germinated spotted knapweed seedlings. Length of residual control is dependent on site-specific factors such as amount and timing of precipitation, regrowth of desired plants, and the rate applied.

Caution -
Do not apply directly to water or to areas where surface water is present. Use of this chemical in areas where soils are permeable, particularly where the water table is shallow, may result in groundwater contamination. Remains in soil for up to one year depending on application rate. Overspray or drift to desirable plants should be avoided, as even minute quantities of the spray may cause severe injury to plants. Do not compost treated plants as herbicide can persist through composting process.