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Download IPM for Weeds - San Diego Master Gardeners
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IPM for Weeds University of California Statewide IPM Program In this presentation…. • Definition of IPM • Tips on ID and biology Cultivation • Trouble weeds • Management • Prevention Competitive plants Mulches IPM for Weeds Why manage weeds? People don’t like the way weeds look • Crowd out desirable plants • Provide hiding places for pests Bee stings Burclover Tripping or fire hazards IPM for Weeds What is IPM? • Science-based • Combines several pest management methods • Focuses on long-term prevention • Pesticides used as a last resort • Keeps weeds at a level you can live with • You set your own goals Weed management with IPM Didn’t plan ahead IPM for Weeds How do you identify weeds? Broadleaves Wide leaves Branching veins Dallisgrass Sedges Yellow Leaves nutsedge in sets of 3 Triangular stems Oxalis Grasses Narrow leaves Large crabgrass Arranged in sets of 2 Parallel veins Round or flat stems IPM for Weeds Want more information on weed ID? • ID weed to species for most effective management approach Weed photo gallery www.ipm.ucdavis.edu Pest notes Key to weeds in lawn IPM for Weeds What makes some plants successful as weeds? • Competitive and invasive • Reproduce quickly Tubers Seeds Rhizomes Stolons IPM for Weeds Why are weeds invading? • Poorly maintained areas • Underlying problem IPM for Weeds Why are weeds invading? Maintenance problem Overwatered or Nutsedge waterlogged flower areas Annual bluegrass Crabgrass Nutsedge IPM for Weeds Why are weeds invading? Knotweed Maintenance problem Compacted soils or bare areas Spotted spurge IPM for Weeds Why are weeds invading? Maintenance problem Lawns low in nitrogen fertilizer White clover Black medic Burclover IPM for Weeds Why are weeds invading? Dandelion Maintenance problem Thin areas in lawns IPM for Weeds Why are weeds invading? Maintenance problem Lawns mowed too short Bermudagrass flower head Invading Bermudagrass IPM for Weeds Know the life cycle of your weed Control weeds before they spread Annual bluegrass Annual weeds Crabgrass Die Sprout Sowthistle Grow Flower Spotted spurge IPM for Weeds Know the life cycle of your weed Control before vegetative parts or seeds form Perennial weeds Bermudagrass Grow Overwinter Oxalis Mature Die back IPM for Weeds When should weeds be managed? • Before you plant, before weeds emerge, and before weeds mature Before planting Seed dispersal • Prepare site Don’t let Seed Before emergence weeds go • Plant competitive to seed or species develop • Apply mulch vegetative Seedling parts! Emergence • Cultivate Flower Maturing development • Mow weed IPM for Weeds Get weeds out before you plant • Dig out existing vegetation • Cultivate, irrigate, cultivate • Solarize the soil • Apply a nonselective herbicide for serious weed problems IPM for Weeds Give your plants a head start Soils • Must hold water and nutrients • Must have good drainage • Amend soil before planting Plants • Establish quickly • Choose vigorous plants adapted to local conditions • Plant ground covers to cover bare areas IPM for Weeds Prevent weeds with mulches Mulch: layer of material put on the soil surface around plants to prevent weed growth • Block light and suppress weed growth • Hold moisture in; reduce soil compaction and erosion • Improve soil Organic mulch Fabric mulch Rock mulch IPM for Weeds Organic mulches Before applying mulch, make sure the soil is weed-free • Apply to adequate depth and keep away from base of trees and shrubs • Break down and need to be replenished • More effective if applied over fabric Large or medium-sized mulches: apply 3 to 4 inches deep Fine mulches: apply 2 inches deep IPM for Weeds Rock mulches Advantages • More permanent than organic mulches • Do not need to be replenished much Disadvantages • Difficult to keep clean • Don’t add anything to improve soil • Make it hard to remove weeds Rock is most effective if placed over synthetic mulch or fabric barrier IPM for Weeds Synthetic mulches • Used under organic or rock mulches • Use landscape fabric; avoid plastic mulches • Landscape fabrics allow water and air to pass through and last a long time • Avoid sun exposure IPM for Weeds Synthetic mulches Put fabric down with U-shaped Cut X in fabric nails and overlap edges Dig planting hole Cover with Place plant in hole mulch IPM for Weeds Maintaining mulch • Replenish mulch as needed • Keep mulch at the proper depth • Remove weeds by hand • Avoid disrupting the mulch Some weeds may grow on top of mulches IPM for Weeds Pull them out • Remove weeds as you see them • Remove weeds before they set seed • Remove entire plant • Irrigate before hand-weeding • Grasp the weed by its base and roll it back and forth to loosen its roots IPM for Weeds Tools make weeding easier Perennial weeds Dig up and destroy roots, stems, tubers Dandelion knife Annual weeds Control with various hoes Hula hoe Hand tine Garden hoe IPM for Weeds Tools make weeding easier Adaptive gardening tool IPM for Weeds Control with hot water and flaming Hot water • Effective against annuals or young perennials • Treat foliage and stems Flaming • Effective against young annual weeds • Pass the flame over the leaves IPM for Weeds Weed-eating animals • Be careful not to use them around desirable plants • Protect them from dogs or other predators • Provide other food sources and water • Remove from areas where pesticides are applied • Dispose of animal waste Weed-eating geese IPM for Weeds Do you need herbicides? Herbicides are pesticides that control weeds • Hand-weeding and mulching usually provide adequate control • Use for special situations • Figure out the underlying cause • Use preventive methods • Choose one labeled for the weed and safe around desirable plants IPM for Weeds Herbicides can injure garden plants Preemergent • Before seedlings emerge Postemergent • After weeds emerge Selective • Kills specific types of weeds Nonselective • Kills most vegetation IPM for Weeds Herbicides can injure garden plants • When labels are not followed • When drift occurs • When roots are buried beneath treated areas Glyphosate injury Dicamba injury Special problem herbicides Glyphosate Dicamba 2,4-D 2,4-D injury IPM for Weeds Follow the label • Follow all directions • Use only the amount needed • Don’t overirrigate Wear proper clothing Make sure the product is labeled for your weed and is registered for the area where it will be used IPM for Weeds Applying glyphosate • Most common herbicide • Kills most weeds, but can damage desirable plants • Pre-mixed solutions may be too weak to control Place a funnel over perennials the spray nozzle to avoid drift Mix up your own solution • Use hand-held applicator or • Treat when weeds are actively growing low-pressure pump sprayer • Measure product and water • Small areas: dig up • Rinse the measuring propagules, irrigate, treat container • Large areas: treat, • If necessary, add surfactant irrigate, treat again IPM for Weeds Is your approach working? Weeds will decrease • Manage the area properly Competitive plantings Barriers Well-maintained mulches Drip irrigation or other low-output irrigation system • Remove weeds regularly As you see them Before they set seed IPM for Weeds Where can you get more information? www.ipm.ucdavis.edu County UC Cooperative Extension Offices www.ucanr.org IPM for Weeds Managing weeds in lawns New lawns • Prepare planting site properly • Select an adaptable grass plant www.ipm.ucdavis.edu Established lawns • Water, fertilize, and mow properly • Monitor and remove weeds by hand • Use herbicides as a last resort IPM for Weeds Managing weeds in annual beds Before planting • Cultivate, irrigate, cultivate • Solarize the soil Maintenance • Hand-weed • Mulch around plants • Plant cover crops on empty beds IPM for Weeds Managing weeds in landscape beds • Remove all weeds before planting • Plant competitive plants, eliminate bare ground • Put down a fabric barrier with mulch • Remove weeds by hand • Provide proper water • Use physical barriers Ground covers Fabric barrier with rock mulch Mowing strip IPM for Weeds Managing weeds around trees • Keep weeds and other plants away from the base of trees • Consider mulches Newspaper mulch 1. Wet newspaper and layer around tree 2. Place compost on top Remove weeds before mulching Use organic mulch with or without fabric barriers IPM for Weeds Managing weeds in hardscapes Sidewalk or driveway cracks • Use screwdriver or weed knife Weed knife • Apply less-toxic materials • Seal with crack filler or foam • Flame or treat with hot water Fence lines • Fences supported by concrete are best • In landscaped areas, mulch along fence lines IPM for Weeds IPM for Weeds Cheryl A. Reynolds, Mary Louise Flint, and Joyce F. Strand University of California Statewide IPM Program Funding of this project was provided by the Elvenia J. Slosson Endowment Fund and Cooperative State Research, Education, and Extension Service, USDA Advisory Committee: Bethallyn Black – UC Cooperative Extension Contra Costa County Pamela Geisel – UC Statewide Master Gardener Academic Coordinator Judy McClure – UC Cooperative Extension Sacramento County Cheryl Wilen - UC Cooperative Extension UC Statewide IPM Program Photography: Jack Kelly Clark, Cheryl Reynolds, Statewide IPM Collection Illustrations: Chris O’Connor Special thanks: Anita Clevenger, Susan Poirier, Bill Pierce, Ruth Ann Weber
