Montana Pesticide Education Program http://mtpesticides.orgWhat is considered a weed?Weeds are Indicators of Site ConditionsNoxious Weeds in MontanaSlide 6Weed ManagementControl MethodsSlide 11Slide 12Slide 13Stages of Weed DevelopmentSlide 15Slide 16Slide 17Managing Landscape WeedsSlide 19Herbicide CharacteristicsSlide 21Slide 22Slide 23Herbicides and Plant CharacteristicsSlide 25Herbicide EffectivenessClimatic FactorsBull Thistle (Cirsium vulgare)Canada Thistle (Cirsium arvense)Poison Hemlock (Conium maculatum)Purple Loosestrife (Lythrum salicaria)Weed treatment in riparian areasSlide 33Slide 34Slide 35Slide 36Slide 37Now what?Then...Slide 40Montana Pesticide Education Montana Pesticide Education ProgramProgramhttp://mtpesticides.orghttp://mtpesticides.orgResidential Weed Residential Weed ManagementManagementResidential Weed Residential Weed ManagementManagementWhat is considered a weed?•Any plant growing where it is not wanted.•Obnoxious Weeds–Toxic Weeds–Invasive and Noxious weeds are the most troublesome.•Rapidly dominate the site•Very difficult to controlWeeds are Indicators of Site Conditions•Salty Soils–Shepherds Purse, Russian Thistle•Acid soils – Very Acid Soils–Horsetail – Hawkweed & Knapweed•Badly drained soils–Horsetail•Deep shade–Ground ivy, chickweedNoxious Weeds in Montana•Landowners are responsible for controlling the spread noxious weeds on their property•Cat 1 = established & widespread•Cat 2 = recently introduced and rapidly spreading•Cat 3 = Not yet detected or in few locationsCategory 1Category 2Noxious Weeds in MontanaCategory 3Weed Management•Buy clean seed for wildflowers or lawns; don’t plant weeds!•Clean yard equipment before using it in another area•Get weeds along streams under control•Use mulch materials or weed mats•Pull weeds early – before they go to seed!Prevention is the most effective practice of all!Control MethodsMechanical•Mowing, hand pulling, burning, solarizingCultural•Shading, site preparation, plant appropriate competitive vegetationBiological•Parasites, predators, and pathogens; typically a slow process – not for urban Chemical•Repeated application•Plants must be growing•USE ACCORDING TO LABELWeed Biology/Life CyclesExploit Weed Weaknesses•Monocots: parallel leaf veins, growth points at/below soil levelGrasses–Grass family •Cheatgrass, quackgrass–Sedge family •Nutsedge–Lily family•Wild onion, death camasDicots: net-like leaf veins, diverse Dicots: net-like leaf veins, diverse growing pointsgrowing pointsMany othersBroadleaf–Composite family •Dandelions, thistles, knapweed–Mustard family •Shepherd's purse, lambsquarter, whitetop–Carrot family•HemlockStages of Weed Development•1. Seedling–Tender, vulnerable•2. Vegetative–Great uptake of water and nutrients•3. Seed production–Reduced uptake, energy directed to flowers, fruit•4. Maturity–Little uptake or energy production•Annual weeds: live one year –Summer annuals: seed & die by winter.•Pigweed, lambsquarter, black medic–Winter annuals: germinate in late summer, overwinter, produce seed, die the next season.•Chickweed, curly dock, cheatgrass, black medicBiennial weeds: broadleaf plants with a 2-year life cycleHoundstongue, mullein, burdock, bull thistle– mature, seed and die in second year– vegetative growth first year (Rosette)•Perennial weeds: live 3 or more years–most persistent –difficult to control–propagules•rhizomes, stolons, bulbs, tubers–wide range of dicots and monocotsManaging Landscape Weeds•Maintain competition – grazing management•Prevent seed production•Prevent seed germination•Limit emerged weeds early•Limit susceptible stages of mature weeds.Chemical designed to control weeds. Plant, soil and weather conditions influence herbicidal activity.Herbicide CharacteristicsContactSystemicHerbicide Herbicide CharacteristicsCharacteristicsPersistentNonPersistentHerbicide Herbicide CharacteristicsCharacteristicsSelectiveNonSelectiveHerbicide Characteristics•Application in relation to plant development–Pre-plant•Before crop is planted–Pre-emergent•Before weeds emerge–Post emergent•After weeds emergeHerbicides and Plant Characteristics•Growing points•Leaf shape and orientation•Wax and cuticleHerbicides and Plant Herbicides and Plant CharacteristicsCharacteristicsLeaf hairsLeaf hairsDeactivationDeactivationLife cycle stageLife cycle stageHerbicide Effectiveness020406080100seedling vegetative flowering mature% controlClimatic Factors•Relative humidity•Light•Precipitation•TemperatureBiennial2-5 feet tallFlowers purple July-SeptemberReproduces by seedSeed can be viable for 10 yearsBull Thistle (Cirsium vulgare)Control: hand pullcut or mow before going to seedherbicides? When?PerennialFlowers light pink-purpleGrows 1-4 feet tallHas deep horizontal rootsReproduces through creeping roots, some seedCanada Thistle (Cirsium arvense)Control:pull by hand (small plants)apply herbicides; spot-spraying young plants is very effectiveControl: hand pull or dig* (small plants)apply herbicides in early spring or late fall*be sure to wear gloves & properly dispose of all plant materialBiennialGrows to 10 feet tallTiny white flowers & purple-mottled stemsAll parts of plant are highly poisonous (if eaten)Reproduces by seedPoison Hemlock (Conium maculatum)Control: cut, dig, or hand pull (small plants) cut and remove the flowering spikes to prevent new seedlingsapply herbicides when actively growing at full to late floweringPerennialFlowers purple on spikesStems are square; plant can be 6-8 feet in heightReproduces by seed and rootsPurple Loosestrife (Lythrum salicaria)Weed treatment in riparian areas•Select the most effective treatment methods for the site•If herbicides are used, be sure the label allows application adjacent to or in the water•Consider wipe application or hand removalSensitive areasWhere is this water going?Non-target vegetationHerbicides in a Residential SettingDriftAnimals & kidsConcerns over chemical useMovement of contaminated soil and vegetationHose EndSprayers For Urban/Residential UseSkid MountATV & Lawn TractorBackpackHand HeldSpot Treatment < 1/10th acreUp to 1 acre> 1 acre depending on tank size & GPAGeneral PrecautionsPrevent DriftCalibrate Your Sprayer Add the
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