Montana s Noxious Weeds: Integrated Weed Management MODULE 5
Integrated Weed Management Begin with the end in mind... Kill the weed Yes, but not the whole story Healthy plant community that meets management objectives Whitetop infestation Diverse, native plant community
4 Golden Rules 1. Know what you want to do with your property Landowner may need to change the way things are done or change what h/she want to do with the land 2. Promote healthy vegetation Healthy, desirable plants use available plant resources (water, nutrients, sunlight) and keep them from being used by weeds 3. Implement good land use practices Overgrazing or excessive soil disturbance related to construction are invitations to weeds 4. No one weed control method works alone Strategically combining control methods will lead to success
Integrated Weed Management (IWM) Combination of multiple management tools to reduce a weed population to an acceptable level Eradication may/may not be possible depending on degree of infestation Large scale sulfur cinquefoil infestation
Weed Management Integrated Weed Management Prescribed fire Revegetation Prevention Biocontrol Hand pulling Mowing Grazing
Before you implement IWM... Inventory Simple map of property Map weed patches Weed identification Note distinguishing features Consult guidebook Get help! County Extension agent or weed coordinator mtweed.org, weedawareness.org MSU Schutter Diagnostic Lab, diagnostics.montana.edu
IWM Methods Preventative any action that stops weeds from establishing Mechanical physical activities that destroys or inhibits weed growth Chemical application of chemical that is toxic to plants Biological use of natural enemies to limit weed growth and reproduction Cultural any technique that involves maintaining field conditions so that weeds are less likely to grow (e.g. maintaining competitive vegetation, proper grazing, revegetation, fertilization, irrigation)
Prevention Most effective IWM tool Examples Limit disturbance Weed seed-free forage, seed, soil, gravel Washing vehicles and equipment Cleaning clothing, shoes, pets, livestock Scouting for new weeds Education
Mechanical Taprooted weeds Annual weeds Small infestations Examples Hand-pulling Digging Hoeing Tillage Mowing
When and Where to Use Hand-pulling and digging Small infestations Tap rooted weeds Prior to seed production Easiest when soil is moist Sensitive areas (near water or sensitive plants) Mowing For species that spread by seed only, mow when they begin to flower For species that spread vegetatively, repeat mowing throughout growing season Prior to herbicide application
Chemical Rhizomatous and taprooted weeds Annual, biennial, perennial weeds Larger infestations that are accessible for spraying equipment Examples Glyphosate (Roundup) 2,4-D Dicamba Aminopyralid (Milestone)
Key Considerations Herbicide selection Where and when to apply herbicides Sprayer calibration Mixing and handling herbicides Storing and disposing of herbicides Useful brochure on herbicides and noxious weeds: http://store.msuextension.org/publications/agandnaturalresources/eb0214.pdf
Biological Classical Introduction of natural enemy of weed, usually an insect, that feeds exclusively on the weed Examples Leafy spurge flea beetles Spotted knapweed root-feeding weevil Grazing Use of livestock that will eat weeds Usually sheep or goats
When and Where to Use Large infestations Sensitive areas (near water) or steep terrain Time is not an issue Integrate with herbicides to control perimeter of infestation If grazing, must be carefully managed
Cultural Focused on shifting balance between weeds and other vegetation Maintaining competitive vegetation Examples Proper grazing Revegetation Fertilization Irrigation Prescribed fire
Revegetation When is it needed? No remaining desired vegetation Newly disturbed sites Integrate with weed control Choose appropriate species Management goals Precipitation Soil type Elevation
IWM Example Spotted Knapweed Matt Lavin, Flickr
biomass (kg/ha) Integrated Management Reduced Knapweed 12 = No grazing = Grazing with sheep 8 4 0 Non-sprayed 1 qt/a 2,4-D treatment Sheley et al. 2004. Integrating 2,4-D and sheep grazing to rehabilitate spotted knapweed infestations. Journal of Range Management 57:371-375.
Grass Cover (%) Integrated Management Increased Grasses 40 30 20 = No grazing = Grazing with sheep 10 0 Non-sprayed 1 qt/a 2,4-D treatment Sheley et al. 2004. Integrating 2,4-D and sheep grazing to rehabilitate spotted knapweed infestations. Journal of Range Management 57:371-375.
Another IWM Example Spotted Knapweed 4 different studies in western Montana Integrated revegetation with various spotted knapweed control methods (chemical, biological, mechanical) Sampled 2, 6, and 15 years after seeding
Knap weed biomass (ln g m -2 ) Seeded grass biomass (ln g m -2 ) Seeded Grass Reduced Invader after 15 years 7 6 5 4 3 2 Seeded grass biomass increased from ~26 lb/a in Year 2 to 1760 lb/a in Year 15 1 0 6 5 4 3 2 Highest seeding rate decreased spotted knapweed biomass by ~86% 1 0 (Rinella et al. 2012) 0 1250 500 12500 1250 500 0 12500 1250 500 0 Year 2 Year 6 Year 15 12500
Non-seeded Seeded
Resources People and Organizations County Extension Office County Weed District Office Montana Noxious Weed Education Campaign (weedawareness.org) Montana Weed Control Association (mtweed.org) Montana State University Schutter Diagnostic Lab (diagnostics.montana.edu) Montana Department of Agriculture (http://agr.mt.gov) NRCS field offices Shantell Frame-Martin (shantell.frame@montana.edu) Jane Mangold (jane.mangold@montana.ed)
Resources Publications http://store.msuextension.org/publications/agandnaturalresources/eb0159.pdf
Module 5: Assessment