IPM for Weeds

1. IPM for Weeds University of California Statewide IPM Program

2. In this presentation…. • Definition of IPM • Tips on ID and biology • Trouble weeds • Management • Prevention Cultivation Competitive plants Mulches IPM for Weeds

3. 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

4. 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

5. How do you identify weeds? Broadleaves Sedges Yellow nutsedge Leaves in sets of 3 Wide leaves Triangular stems Oxalis Branching veins Dallisgrass Grasses Parallel veins Narrow leaves Round or flat stems Large crabgrass Arranged in sets of 2 IPM for Weeds

6. Want more information on weed ID? Weed photo gallery • ID weed to species for most effective management approach www.ipm.ucdavis.edu Key to weeds in lawn Pest notes IPM for Weeds

7. What makes some plants successful as weeds? • Competitive and invasive • Reproduce quickly Tubers Seeds Rhizomes Stolons IPM for Weeds

8. Why are weeds invading? • Underlying problem • Poorly maintained areas IPM for Weeds

9. Why are weeds invading? Annual bluegrass Maintenance problem Crabgrass Overwatered or waterlogged areas Nutsedge flower Nutsedge IPM for Weeds

10. Why are weeds invading? Knotweed Maintenance problem Compacted soils or bare areas Spotted spurge IPM for Weeds

11. Why are weeds invading? Maintenance problem Lawns low in nitrogen fertilizer White clover Black medic Burclover IPM for Weeds

12. Why are weeds invading? Dandelion Maintenance problem Thin areas in lawns IPM for Weeds

13. Why are weeds invading? Bermudagrass flower head Maintenance problem Lawns mowed too short Invading Bermudagrass IPM for Weeds

14. Know the life cycle of your weed Control weeds before they spread Annual bluegrass Annual weeds Crabgrass Sprout Die Sowthistle Grow Flower Spotted spurge IPM for Weeds

15. 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

16. When should weeds be managed? • Before you plant, before weeds emerge, and before weeds mature Before planting Seed dispersal • Prepare site Don’t let weeds go to seed or develop vegetative parts! Seed Before emergence • Plant competitive species • Apply mulch Seedling Emergence • Cultivate • Mow Flower development Maturing weed IPM for Weeds

17. 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

18. 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

19. 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

20. 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 Large or medium-sized mulches: apply 3 to 4 inches deep • Break down and need to be replenished • More effective if applied over fabric Fine mulches: apply 2 inches deep IPM for Weeds

21. 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

22. 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

23. Synthetic mulches Dig planting hole Put fabric down with U-shaped nails and overlap edges Cut X in fabric Cover with mulch Place plant in hole IPM for Weeds

24. 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

25. 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

26. Tools make weeding easier Perennial weeds Dig up and destroy roots, stems, tubers Annual weeds Dandelion knife Control with various hoes Hula hoe Hand tine Garden hoe IPM for Weeds

27. Tools make weeding easier Adaptive gardening tool IPM for Weeds

28. 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

29. Weed-eating animals Weed-eating geese • 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 IPM for Weeds

30. 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

31. 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

32. Herbicides can injure garden plants • When labels are not followed • When drift occurs • When roots are buried beneath treated areas Glyphosate injury Dicamba injury 2,4-D injury Special problem herbicides Glyphosate Dicamba 2,4-D IPM for Weeds

33. Follow the label • Use only the amount needed • Don’t overirrigate • Follow all directions 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

34. Applying glyphosate • Most common herbicide • Kills most weeds, but can damage desirable plants • Pre-mixed solutions may be too weak to control perennials Place a funnel over the spray nozzle to avoid drift Mix up your own solution • Treat when weeds are actively growing • Small areas: dig up propagules, irrigate, treat • Large areas: treat, irrigate, treat again • Use hand-held applicator or low-pressure pump sprayer • Measure product and water • Rinse the measuring container • If necessary, add surfactant IPM for Weeds

35. 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

36. Where can you get more information? www.ipm.ucdavis.edu County UC Cooperative Extension Offices www.ucanr.org IPM for Weeds

37. 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

38. 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

39. Managing weeds in landscape beds Ground covers • Remove all weeds before planting • Plant competitive plants, eliminate bare ground Fabric barrier with rock mulch • Put down a fabric barrier with mulch • Remove weeds by hand • Provide proper water • Use physical barriers Mowing strip IPM for Weeds

40. Managing weeds around trees Remove weeds before mulching • Keep weeds and other plants away from the base of trees • Consider mulches Use organic mulch with or without fabric barriers Newspaper mulch Wet newspaper and layer around tree Place compost on top IPM for Weeds

41. 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

42. 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