Comprehensive Spotted Knapweed - Bedstraw Control Project

Final Report for FNE04-518

Project Type: Farmer
Funds awarded in 2004: $7,836.00
Projected End Date: 12/31/2007
Matching Non-Federal Funds: $12,750.00
Region: Northeast
State: New York
Project Leader:
Expand All

Project Information

Summary:

FNE04-518
Comprehensive Knapweed and Bedstraw Control Project
Bob Huot- Huot-Kinne Farms
339 Spurr St. New Berlin, NY 13411
607-847-8124
humpix@doghows.org

2. Goals
A. To find ways to control knapweed and bedstraw without using traditional chemicals.
B. To create strategies that could realistically be used by area farmers.

3. Farm Profile
Background
Huot-Kinne Farms is located on 215 acres in Columbus, NY. The farm has 80 acres of hay land, 25 acres of pasture, and the rest wooded or unused. Dairy replacement heifers and hay are the primary products of the farm. There are generally 5-10 cows grazing in the pasture. Hay is used on the farm or sold. The farm has decreased the number of replacement heifers over the past few years, and at peak production was raising dozens of animals.

Problem
In 2002, the farmer, Bob Huot, noticed that his heifers did not want to eat a rather woody plant in the baled hay: knapweed. Knapweed has infested fifty percent of the hay and pasture lands. In evaluating the fields, smooth bedstraw was also identified as a persistent problem.

Knapweed Centaurea spp.
• Poor Livestock Forage
o Spiny stems and leaves
o Becomes woody as it matures
• Invasive
o Capitalizes on disturbed ground
o Competes with desirables
o Spreads through seeds
• Spotted knapweed is allelopathic
• Two species- Spotted (maculosa) and Brown (jacea)

Bedstraw Galium mollugo
• Devalues Pasture Land
• Reduces Hay Quality
Control of Knapweed (Centaurea spp.) and Bedstraw (Galium sp.) is an increasing problem on the farm, in Chenango County, in New York State and perhaps the Northeastern U.S. Pasture and hay lands are becoming choked with these weeds, reducing grazeable acres and devaluing the hay crop. Knapweed, because of its spiny stems and leaves, creates undesirable hay bales and forage that discourages livestock consumption. It is the belief of the grower, and local specialists, that the presence of knapweed is cutting down on hay intake and affecting animal performance. Bedstraw is a perennial nuisance that devalues pastureland and reduces hay quality severely. At the start of the project it appeared that little was known on how to effectively control invasive knapweed plants in the Northeast. Knapweed has been a problem in the Western U.S. for years, and many publications are available on the different control measures in the West. None of these control recommendations had ever been comprehensively tested in the Northeast. Bedstraw has been a major problem in the Northeast and continues to cause problems for farmers, as they are without good control measures that have been widely and fully tested.

Weed control is a perennial management issue for farmland in the Northeast. Many farms do not carry the capacity of animals to control weeds through grazing or to warrant the proper pasture management practices. But, many of these farms want to provide the best possible feed for their animals as economically possible while producing a good quality product. Often the goals of these farms include environmentally and socially sound management objectives that aim to limit the use of chemical pesticides.

Currently, the two management techniques most often recommended for bedstraw and knapweed control are herbicide spraying and mowing. Mowing is an excellent management practice for overall sword health, but the timing and frequency of mowing for knapweed and bedstraw control are unspecified. Herbicides have many advantages and drawbacks, and many farmers are looking for alternatives to chemical herbicides.

4. Participants
Phil Metzger- USDA/NRCS Central New York Resource Conservation and Development, Technical Advisor- Project leadership, data collection, assisted in reporting.
Rebecca Hargrave- Cornell Cooperative Extension Chenango County, Cooperator, Project leadership, data collection, assisted in reporting, outreach activities.
Stacie Edick, Data collector
Headwater Youth Conservation Corp- Data collectors
BOCES New Visions- High School Class- Data entry

5. Project Activities
To determine the best management options for knapweed and bedstraw control, traditional weed management techniques with new and weed specifics options were compared.

Plot Description and Management

Eight separate treatments were established: See Map in Appendix A. (The complete report including appendices and charts is available from the Northeast SARE office in Burlington VT)
• Insect Biocontrol- Field 1
• Herbicide (split in to sub-treatments)
o One targeting bedstraw – Field 2
o Another targeting knapweed- Field 3
• Lime- Field 4
• Animal Grazing- Field 5
• Mowing Once a Season- Field 6
• Mowing Twice a Season- Field 7
• Mowing Thrice a Season- Field 8
• Control- Field 9

Biocontrol

This field had a heavy infestation of both knapweed and bedstraw at the start of the project: 27% and 8% respectively.

Two types of insects were introduced in the summer of 2006 to help control knapweed the Blunt Flowerhead Weevil Larinus obtusus and the Knapweed Root Weevil Cyphocleonus achates.
No other management practices occurred in this plot (no mowing or grazing).

Objectives for this field were to see if the insects would establish and feed on the knapweeds, and to determine if they were having an effect on the weed population.

Herbicide
The herbicide treatment was split into two sub-fields, upper and lower. The herbicides were sprayed according to label directions in the fall:
• Dicamba for Knapweed- Lower half
• Crossbow for Bedstraw-Upper half
Both sub-fields were mowed once a year (June) with the adjacent field.

The objective of the herbicide treatments was to compare the results to other treatments: standard recommendation versus non-standard.

Animal Grazing
Managed grazing in an area can have a profound effect on non-tolerant weeds. 3-4 cows were penned in an area with moderate knapweed and bedstraw levels (12 and 10% cover) each summer for three years. Not only was the grazing damaged measured, but also damage to the weeds from trampling and turning of the surrounding soil.

Lime
The pH of one of the infested fields was ~ 5.6, which is slightly low for optimum grass growth. To determine if raising the pH affected the percent cover of weeds lime was added in 2004 and 2005 (approximately 2 tons/acre). The pH was raised to ~ 6.3.

Many farmers feel that by raising their pH the grass can out compete the knapweed, we hoped to answer this question.

This plot was otherwise untreated- not mowed or grazed.

Mowing
Mowing is a sound method to control weeds and promote grass vigor. One large field was divided into 4 sub-fields, 3 mowing treatments and a control.
The three mowing sub-plots:
• Once- early summer
• Twice- early and mid summer
• Three Times- early, mid and late summer

The objective with these treatments was to determine the effects of different timings and frequencies of mowing.

Control Plot
The control plot was the edge of the mowed treatments. This field was unmaintained, no mowing or grazing, and was used as a baseline for comparison.

Monitoring
Monitoring took place twice per year in June and October resulting in data collected from Fall 2004 to Spring 2007.

A dart with a 3 foot tape attached to it was randomly thrown within each field or sub-field and measurements taken around the dart point.

The following observations were recorded resulting in general population trends for knapweed & bedstraw and other relevant learning:
1. Dart entry point (landed in): soil or litter or plant (recorded plant type)

2. Area around dart entry point (approximately 3 foot radius): condition of soil surface – bare or covered & any signs of insects, small or large animals

3. Distance to nearest perennial and the type, age & condition

4. Percent Cover – Knapweed, Bedstraw, Grass, Forbs (e.g. 25% Knapweed, 10% Bedstraw 45% Grass, 20% Forbs)

6. Results
Treatment Results & Control Recommendations:

Data was taken in the spring and the fall. Overall spring readings tended to be higher than fall readings. The fluctuations between seasons made it hard to compare fall with spring data, therefore fall data was compared against fall data and spring against spring. See additional charts in Appendix B. (The complete report, including charts and appendices is available from the Northeast SARE office in Burlington VT)

Biocontrol – Utilized flower weevils and root weevils
Spring: 17% decrease
Fall: 1% decrease

Results: Observed on idle land – flower weevils not only increased but spread within a 2 year time frame. No data on root weevils. Time period of study (2 years) was inadequate to determine if knapweed was affected significantly.

Recommendation: More information is needed to determine if flower weevils can become part of other treatment options such as livestock and mowing. Consult Cornell Cooperative Extension for types and rates. Be sure to check with State rules on introducing insects.

Herbicide
Herbicide Upper (Crossbow – bedstraw herbicide.)
Spring: 96% increase
Fall: 84% decrease

Results: Crossbow showed mixed results in knapweed control.

Herbicide Lower (Dicamba – knapweed herbicide)
Spring: 5% increase
Fall: 76% decrease

Results: Dicamba, a fall applied herbicide, appeared to reduce knapweed.

Recommendation: Combine with mowing. Treat in October, with one spring mowing per year to control seed development. Also encourage desirable forage with liming and fertilizing.

Lime
Spring: 18% increase
Fall: 3% decrease

Results: No significant impact. Everything appeared to do better.

Recommendation: Advantage of liming is to help desirable forage competitive with unwanted plants. Intensive soil management may have a positive result.
Consult Cornell Cooperative Extension and use standard rates.

Grazing & Animal (Bovine) Impact
Spring: 69% decrease
Fall: 80% decrease

Results: Proved to be an effective control of Bedstraw. Vigorous growth of grasses from grazing and animal impact appeared to out-compete other plants.

Recommendation: An effective control. Must use cows / other livestock at high stocking rates so hoof action and overgrazing results. This creates the desired herd effect.

An animal behavior study to train animals to eat Bedstraw would be something to consider.

Mowing
Mowed Upper (3x)
Spring: 37% decrease
Fall: 86% decrease

Mowed Center (2x)
Spring: 33% decrease
Fall: 2% decrease

Mowed Lower (1x)
Spring: 11% decrease
Fall: 68% decrease

Results: Mowing appears to control and reduce knapweed effectively.

Recommendation: Begin mowing 2 to 3 times per year. At a minimum you must mow once per year. Timing: Mow field as Knapweed begins to flower and always prior to seed development. Late spring and late summer mowings were found to be more effective that late spring followed by mid-summer mowings.

Secondary Treatment: Introduce flower weevils, root weevils, etc, as a supplemental treatment. Consult Cooperative Extension for acceptable types and rates.

Control
Spring: 7% increase
Fall: 10% decrease

Results: Not definitive

Recommendation: Leaving land idle is not a good management strategy because pasture / hay land condition would decline as Knapweed has shown a proclivity to generally increase in idle fields.

Overall Recommendations on controlling Knapweed
1 – Do not plow infested fields as this appears to encourage spreading.

Options for heavy infestations:
2 – Graze at very high stocking rate if you have livestock. Temporary fencing allows for rapid movement of animals and lets you virtually “nuke” the ground through very high stocking rates.

3 – Mow 2 to 3 times per year as flowers appear and prior to seed development. Late spring and late summer mowings were found to be more effective that late spring followed by mid-summer mowings.

4 – Improve overall field fertility by applying lime, animal manure and/or organic fertilizers to improve competitiveness of desirable species.

5 – Spray with Dicamba or comparable herbicide according to Cornell Cooperative Extension and manufacturer’s guidelines. Apply in fall and mow in spring to control seed development.
Approximate cost – $8 – $12 per acre, plus cost of chemical ($17 / ac.)

Farm Scenarios for addressing Knapweed infestation
Early signs of infestation – a small number of Knapweed plants are present in field(s).
Key Strategies:
Livestock Farms – Do not allow the fields that contain Knapweed to go un-grazed. Encourage intensive grazing of Knapweed plant areas by livestock, early in the season. When Knapweed plants are young livestock find them palatable. Return animals to these areas upon re-growth of Knapweed plants. Do not allow plants to flower and develop seed. Use mowing if necessary. If unable to graze closely see Non-Livestock Farms below.

Non-Livestock Farms – Do not allow the fields that contain Knapweed to go un-mowed. Knapweed spreads rapidly in idle fields and can quickly become the dominant plant. Mowing 2 to 3 times per year will help keep Knapweed in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor.

Moderate infestation – moderate amounts of Knapweed plants spread throughout the field(s) or heavy infestations in small areas of fields.
Key Strategies:
Livestock Farms – Encourage intensive grazing of Knapweed plant areas by livestock, early in the season. When Knapweed plants are young livestock find them palatable. Return animals to these areas upon re-growth of Knapweed plants. Do not allow plants to flower and develop seed. Use mowing if necessary. Consider introducing Knapweed appropriate biological control agents such as Knapweed Flower Weevil and Knapweed Root Weevil, particularly in heavy infestation areas. Consult Cornell Cooperative Extension for appropriate regulations and rates of introduction. If unable to graze closely see Non-Livestock Farms.

Non-Livestock Farms – Do not allow the fields that contain Knapweed to go un-mowed. Knapweed spreads rapidly in idle fields and can quickly become the dominant plant. Mowing 2 to 3 times per year will help keep Knapweed in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor. Consider introducing Knapweed appropriate biological control agents such as Knapweed Flower Weevil and Knapweed Root Weevil, particularly in heavy infestation areas. Consult Cornell Cooperative Extension for appropriate regulations and rates of introduction. Consider spot spraying heavy patches of Knapweed with appropriate herbicide. Always consult Cornell Cooperative Extension and manufacturer’s label for guidance on herbicide use.

Heavy infestation – high numbers of Knapweed plants throughout field(s).
Key Strategies:
Livestock Farms – Apply very high stocking rate grazing of fields with Knapweed plants early in the grazing season. When Knapweed plants are young livestock find them palatable. Additionally, the ground should show heavy animal impact from livestock herd effect. Return animals to these fields upon re-growth of Knapweed plants. Do not allow plants to flower and develop seed. Use mowing if necessary. Consider if unable to graze closely see Non-Livestock Farms.

Non-Livestock Farms – Do not allow the fields that contain Knapweed to go un-mowed. Knapweed spreads rapidly in idle fields and can quickly become the dominant plant. Mowing 2 to 3 times per year will help keep Knapweed in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor. Consider introducing Knapweed appropriate biological control agents such as Knapweed Flower Weevil and Knapweed Root Weevil, particularly in heavy infestation areas. Consult Cornell Cooperative Extension for appropriate regulations and rates of introduction. Consider spot spraying heavy patches of Knapweed with appropriate herbicide. Always consult Cornell Cooperative Extension and manufacturer’s label for guidance on herbicide use.

Biocontrol
Spring: 35% increase
Fall: 40% decrease

Results: Mixed results on idle land; weevils not applied for Bedstraw control.

Recommendation: Not applicable.

Herbicide
Herbicide Upper (Crossbow – bedstraw herb.)
Spring: 16% decrease
Fall: 27% increase

Results: Crossbow showed mixed results for Bedstraw control.

Recommendation: Mixed results data did not show Crossbow as being particularly effective in this study.

Herbicide Lower (Dicamba – knapweed herb.)
Spring: 64% increase
Fall: 83% increase

Results: Dicamba is not labeled for Bedstraw control. It appears that the Dicamba reduced competition and encouraged Bedstraw.

Recommendation: Not applicable.
1 qt. per acre.
$23.50 per acre for herbicide. $8 – $12 per acre.

Liming
Spring: 10% increase
Fall: 149% increase

Results: No significant impact. Everything did better when raising pH from 5.6 to 6.3.

Recommendation: Lime can be part of an overall improved fertility program to promote competition from desirable forage to out compete Bedstraw.

Grazing & Animal (Bovine) Impact
Spring: 98% decrease
Fall: 100% decrease

Results: Proved to be the most effective control of Knapweed.

Recommendation: Must use cows / other livestock at high stocking rate so hoof action and overgrazing results. This creates the desired herd effect. Additionally, if grazed young appears to be attractive forage and animals thrived (anecdotal evidence from farmer/grazier Troy Bishopp). Once the plant matures animals are much less likely to graze. An animal behavior study to train animals to eat Knapweed would be something to consider.

Mowing
Mowed Upper (3x)
Spring: 55% decrease
Fall: 38% increase

Mowed Center (2x)
Spring: 59% decrease
Fall: 23% increase

Mowed Lower (1x)
Spring: 57% decrease
Fall: 142% increase

Results: Frequency of mowing didn’t seem to make a difference; however mowing does help when applied once or twice per year.

Recommendation: Mow fields once or twice per year and combine this with raising fertility of field to encourage desirable forage species. Late spring and late summer mowings were found to be more effective that late spring followed by mid-summer mowings.

Control
Spring: 58% decrease
Fall: 49% decrease

Results: Bedstraw population reduced most likely due to increase in other plants, which were more competitive in un-mowed conditions.

Recommendation:
Leaving idle is not a good management strategy because pasture / hay land condition would generally decline. Other plants appeared to out compete Bedstraw.

Overall Recommendations on controlling Bedstraw:
1 – Do not plow infested fields as this appears to encourage spreading of various undesirable plants.

Options for heavy infestations:
2 – Graze at very high stocking rate if you have livestock. Temporary fencing allows for rapid movement of animals and lets you virtually “nuke” the ground through very high stocking rates.

3 – Mow at least once per year as flowers appear and prior to seed development.

4 – Improve overall field fertility by applying lime, animal manure and/or organic fertilizers to improve competitiveness of desirable species.

Farm Scenarios for addressing Bedstraw infestation
Early signs of infestation – a small number of Bedstraw plants are present in field(s).
Key Strategies:
Livestock Farms – Do not allow the fields that contain Bedstraw to go un-grazed. Encourage intensive grazing of Bedstraw plant areas by livestock, early in the season. Return animals to these areas upon re-growth of plants. Do not allow plants to flower and develop seed. Use mowing if necessary. If unable to graze closely see Non-Livestock Farms below.

Non-Livestock Farms – Do not allow the fields that contain Bedstraw to go un-mowed. Mowing annually will help keep Bedstraw in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor.

Moderate infestation – moderate amounts of Bedstraw plants spread throughout the field(s) or heavy infestations in small areas of fields.
Key Strategies:
Livestock Farms – Encourage intensive grazing of Bedstraw plant areas by livestock, early in the season. Return animals to these areas upon re-growth of plants. Do not allow plants to flower and develop seed. Use mowing if necessary. If unable to graze closely see Non-Livestock Farms.

Non-Livestock Farms – Do not allow the fields that contain Bedstraw to go un-mowed. Mowing annually will help keep Bedstraw in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor.

Heavy infestation – high numbers of Bedstraw plants throughout field(s).
Key Strategies:
Livestock Farms – Apply very high stocking rate grazing of fields with Bedstraw plants early in the grazing season. Additionally, the ground should show heavy animal impact from livestock herd effect. Return animals to these fields upon re-growth of plants. Do not allow plants to flower and develop seed. Use mowing if necessary. If unable to graze closely see Non-Livestock Farms.

Non-Livestock Farms – Do not allow the fields that contain Bedstraw to go un-mowed. Mowing annually will help keep Bedstraw in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor.

Overall Field & Farm Planning Recommendations:
Focus on your goal for the field, farm and family.

Just focusing on killing a pest plant may indeed kill the plant but doesn’t guarantee a high quality pasture / hay field, if indeed that is your desire. In fact without a change in management you are likely to get the same result (infestation of undesirable plant(s)) down the road. Focus on your goal for the field: if it is high quality forage then look at control methods and management that results in meeting that goal. Said another way, focus on attaining high quality forage not just killing the problem plant, or, manage toward what it is you want not what you don’t want.

Also, realize that the goal of particular fields should lead toward your farm/family goal for the entire farm. The establishment of a farm/family goal gives you a direction to make decisions towards. This holistic view will more likely result in actions that provide the desired impacts and results.

7. Conditions
Field conditions varied from year to year. A big factor each season was the amount of rainfall. 2006 was a very wet summer, which could be the cause of the increased growth rate seen that year: see Charts 6-13 in Appendix B.

8. Economics
There were no real economic differences. Knapweed and bedstraw are still problems being managed. Hay production is up slightly, but did not effect overall farm income.

9. and 10. Assessment and Adoption
Farmer Statement – Bob Huot:

I started with the hope that with assistance from J. Rebecca Hargrave, Cornell Cooperative Extension of Chenango County, and Phil Metzger, USDA – Natural Resources Conservation Service / Central NY Resource Conservation & Development Project, Inc., we could develop methods to control Knapweed and Bedstraw. We chose a number of methods, observed and recorded the impact of those approaches. My goal was to improve both hay and pasture quality.

What became clear to me was the complexity of the systems we were dealing with. Our report is just scratching the surface. We have a few relatively clear and positive outcomes but more time and data is needed. For example, in some of the control areas (contiguous areas left alone) there seemed to be a reduction in the number of Knapweed and Bedstraw plants, so why do anything? Well, they were being pushed aside by even more aggressive, less desirable plants like briar cane and golden rod, so, to just count Bedstraw and Knapweed plants does not give the real picture. Another example: We chose the herbicide Dicamba to kill Knapweed and it worked but that allowed more Bedstraw to encroach. Conclusion: No action is isolated. Each act is part of an interactive whole.

So, based on the information we’ve gathered over the past three years, we are putting together a plan for my farm to improve the quality of both hay and pasture. This means establishing a higher percentage of desirable grasses and reducing the weed population. By mowing, spreading the knapweed weevils, no till seeding, lime and fertilizers and in some cases herbicide application, we can make these improvements. See Appendix D for Farm Plan.

I will continue to observe and record, in a general way, the results of these practices.

Note: Another control approach was tried with a late seeding (August 2005) using a no-till drill with Alice Clover and Baradana Orchard Grass. We got no rain for a month after the seeding, subsequently little new grass survived. Currently we have observed that the results are the same, no new grass.

11. Outreach
Numerous articles were written and presentations given during the course of this grant. Appendix E has copies of the clippings from the Cornell Cooperative Extension of Chenango County Newsletter, October-November, 2005; the Oneonta Daily Star, June 28, 2004; and the Small Farm Quarterly, October 10, 2005.

Presentations were given at Graze-a-palooza in March 2007, Hamilton, NY; and Turning Goldenrod into Green, January 2006.

Two Factsheets, ‘Knapweed Management for Northeast Farms and Grazing Lands’, and ‘Bedstraw Management for Northeast Farms and Grazing Lands’ were written and will be available on the Cornell Cooperative Extension of Chenango County website http://www.cce.cornell.edu/Chenango

12. Report Summary
The Comprehensive Knapweed and Bedstraw Control Project goal was to determine the best traditional and non-traditional management options for knapweed and bedstraw control.

Eight different treatments were evaluated and compared them against a control field. An herbicide targeted at bedstraw, another herbicide targeted at knapweed, three mowing frequencies, bovine grazing, pH adjustment, and biocontrol knapweed predatory insects (knapweed seedhead and root weevils) were tested. Each was set in its own field and random plot samples were collected each spring and fall from within each field.

Animal grazing was found to be the most successful treatment followed by herbicide application and mowing. Knapweeds and bedstraw are difficult to control with just one method, so a multi-year, multi-pronged attack is recommended for adequate management. The farm should be evaluated and farm and field management goals and current levels of infestation assessed before choosing treatment options.

Huot Hills Farm – Comprehensive Knapweed Control Plan

The following recommendations represent a field by field comprehensive plan to control the aggressive infestation of Knapweed on the Huot Hills Farm. See map following text for field locations.

Field I – Biocontrol methods were used for two years in a small portion of this field, which had a heavy infestation of Knapweed at the eastern end near the new pond. It was too early to tell if the treatment was impacting the Knapweed population, however it was clear that the flower weevil was thriving and spreading, even beyond the field where it was applied.

Prescription: (1) Scout all of field to determine how prevalent Knapweed is to determine course of action. Depending upon the level of Knapweed infestation in the remainder of this field the proposed treatment is as follows:
If remainder of field is similarly heavily infested – (2) Do not allow this field to go un-mowed. Knapweed spreads rapidly in idle fields and can quickly become the dominant plant. (3) Mowing 2 to 3 times per year will help keep Knapweed in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. (4) Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor. (5) Monitor spread of Knapweed flower & root weevils from eastern end of field. (6) Consider introducing additional Knapweed weevils in other heavily infested areas. Consult Cornell Cooperative Extension for appropriate regulations and rates of introduction. (7) Consider spot spraying heavy patches of Knapweed with appropriate herbicide. Always consult Cornell Cooperative Extension and manufacturer’s label for guidance on herbicide use.

Field II – This field was treated with a three different mowing frequencies (once, twice, three times) annually for three years. It showed mostly heavy infestation. Areas with more frequent mowing appeared to reduce the Knapweed population.

Prescription: (1) Scout the remainder of this field to determine level of Knapweed infestation. Depending upon the level of infestation in the remainder of this field follow the proposed treatment: If remainder of field is similarly heavily infested – (2) Do not allow this field to go un-mowed. Knapweed spreads rapidly in idle fields and can quickly become the dominant plant. (3) Mowing 2 to 3 times per year will help keep Knapweed in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. (4) Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor. (5) Consider introducing Knapweed appropriate biological control agents such as Knapweed Flower Weevil and Knapweed Root Weevil, particularly in heavy infestation areas. Consult Cornell Cooperative Extension for appropriate regulations and rates of introduction. (6) Consider spot spraying heavy patches of Knapweed with appropriate herbicide. Always consult Cornell Cooperative Extension and manufacturer’s label for guidance on herbicide use.

Field III – Scout this field to determine level of Knapweed infestation to determine course of action. Depending upon the level of Knapweed infestation in the remainder of this field follow the proposed treatment as stated below.

Field IV – Scout this field to determine level of Knapweed infestation to determine course of action. Depending upon the level of Knapweed infestation in the remainder of this field follow the proposed treatment as stated below.

Field V – Scout this field to determine level of Knapweed infestation to determine course of action. Depending upon the level of Knapweed infestation in the remainder of this field follow the proposed treatment as stated below.

Field VI – This moderate to heavily infested field was treated with herbicides in the southern end. Dicamba did a reasonable job reducing the Knapweed population.

Prescription: (1) Scout the remainder of this field to determine level of Knapweed infestation. Depending upon the level of Knapweed infestation in the remainder of this field follow the proposed treatment: If moderately infested – (2) Do not allow this field to go un-mowed. Knapweed spreads rapidly in idle fields and can quickly become the dominant plant. (3) Mowing 2 to 3 times per year will help keep Knapweed in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. (4) Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor. (5) Consider introducing Knapweed appropriate biological control agents such as Knapweed Flower Weevil and Knapweed Root Weevil, particularly in heavy infestation areas. Consult Cornell Cooperative Extension for appropriate regulations and rates of introduction. (6) Consider additional spot spraying of heavy patches of Knapweed with appropriate herbicide. Always consult Cornell Cooperative Extension and manufacturer’s label for guidance on herbicide use.

Field VII – Lime was applied for three years in a small portion of this field, which had a heavy infestation of Knapweed at the northern end. Additionally, biocontrol methods (flower & root weevil) were used for two years in this small portion of the field.

Prescription: (1) Scout all of field to determine how prevalent Knapweed is to determine course of action. Depending upon the level of Knapweed infestation in the remainder of this field the proposed treatment is as follows: If remainder of field is similarly heavily infested – (2) Do not allow this field to go un-mowed. Knapweed spreads rapidly in idle fields and can quickly become the dominant plant. (3) Mowing 2 to 3 times per year will help keep Knapweed in check and enhance the environment for grasses and broadleaf plants that flourish under this type of management. (4) Improving fertility with animal manure and/or organic fertilizers and lime will also help desirable plants to improve vigor. (5) Monitor spread of Knapweed flower & root weevils from eastern end of field. (6) Consider introducing additional Knapweed weevils in other heavily infested areas. Consult Cornell Cooperative Extension for appropriate regulations and rates of introduction. (7) Consider spot spraying heavy patches of Knapweed with appropriate herbicide. Always consult Cornell Cooperative Extension and manufacturer’s label for guidance on herbicide use.

Field VIII – Scout this field to determine level of Knapweed infestation to determine course of action. Depending upon the level of Knapweed infestation in the remainder of this field follow the proposed treatment as stated below.

Field IX – Scout this field to determine level of Knapweed infestation to determine course of action. Depending upon the level of Knapweed infestation in the remainder of this field follow the proposed treatment as stated below.

Research

Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.