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AUTHOR
Tim R. Murphy
The University of Georgia
Crop and Soil Sciences

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TABLE OF CONTENTS
  1. Turfgrass Weed Biology and Identification
  2. Why do we control weeds in turfgrasses?
  3. Weeds
  4. Turfgrass Weeds
  5. Control vs. Eradication
  6. Developing a Weed Management Program
  7. Why are weeds an annual problem?
  8. Characteristics of Most Weeds
  9. Characteristics of Most Weeds
  10. Characteristics of Most Weeds
  11. Characteristics of Most Weeds
  12. Weed Competition
  13. Weed Competition
  14. Weed Identification is a Key Step in Control
  15. Traditional Plant Identification is Based on Recognizing Floral and/or Reproductive Features
  16. Mowing Removes Identification Characteristics of Many Turf Weeds
  17. Identifying Turf Weeds Depends on Primary Vegetative Structures
  18. Leaf
  19. Leaf Arrangement
  20. Shape of cotyledons or true leaves
  21. Leaf margin
  22. Major vegetative parts of grasses used in identification
  23. Stolons and Rhizomes
  24. Tubers and Rhizomes
  25. Tubers and Rhizomes
  26. Bulbs
  27. Weed Life Cycles
  28. Summer Annuals
  29. Summer Annuals
  30. Crabgrass
  31. Goosegrass
  32. Common lespedeza; Prostrate knotweed
  33. Prostrate spurge
  34. Chamberbitter, cannonball weed, gripeweed
  35. Winter Annuals
  36. Winter Annuals
  37. Annual bluegrass Poa annua L.
  38. Common chickweed
  39. Lawn burweed (spurweed)
  40. Henbit
  41. Hairy bittercress
  42. Biennials
  43. Shiny cudweed; Purple cudweed
  44. Warm-Season Perennials
  45. Warm-Season Perennials
  46. Dallisgrass
  47. Kyllinga; Sedge
  48. Virginia Buttonweed
  49. Purple Nutsedge - Cyperus rotundus
  50. Yellow Nutsedge - Cyperus esculentus
  51. Nutsedge: purple vs yellow
  52. Cool-Season Perennials
  53. Cool-Season Perennials
  54. Perennial ryegrass; Wild garlic
  55. Wild garlic
  56. Dandelion
  57. Wild violet; Ground ivy
  58. Identify the Weed Problem
  59. "Weeds of Southern Turfgrasses"
  60. "Color Atlas of Turfgrass Weeds"
  61. Turfgrass Web Pages
  62. UGA



SLIDE CONTENTS
  1. Turfgrass Weed Biology and Identification Tim R. Murphy The University of Georgia
  2. Why do we control weeds in turfgrasses?
  3. Weeds Compete with desirable plants for sunlight, moisture and nutrients Reduce yields or quality of harvested product
  4. Turfgrass Weeds Reduce quality - leaf width, shape, color differences Reduce density - out-compete turfgrasses, can lead to erosion Decrease aesthetic value or utility of the turfgrass. - difficult to mow, disrupt uniformity of playing surfaces, safety considerations, attract insects
  5. Control vs. Eradication Control Process of limiting a weed infestation to a level that is beneficial (economics, aesthetics, safety, etc.). Eradication Elimination of all plants and plant parts of weed species from an area.
  6. Developing a Weed Management Program Prevent weed introduction Properly maintain turfgrasses Identify weeds and learn life cycle Initiate control practices Preventive Cultural Mechanical Herbicides
  7. Why are weeds an annual problem? Seed and vegetative structure dormancy Prolific seed producers Spread of seed (wind, birds, humans, etc.) Turfgrass culture selects tolerant species Monoculture Mowing
  8. Characteristics of Most Weeds High reproductive output Some weeds produce 1000’s of seeds per plant Bimodal reproduction (more than one way to reproduce) Dandelion – seeds and taproot fragments Virginia buttonweed – seeds, stem fragments, roots
  9. Characteristics of Most Weeds Discontinuous germination or sprouting Weed seeds can remain dormant in the soil for many years and germinate sporadically. Crop and turf species are bred to NOT have dormancy – hence all seeds germinate at the same time.
  10. Characteristics of Most Weeds Highly dispersible Weeds must be able to colonize and invade. Ability to Withstand Environmental Extremes Ability to survive unexpected events. Annual bluegrass and smooth crabgrass are found throughout the entire United States. (tremendous genetic diversity)
  11. Characteristics of Most Weeds Earliness Many weeds germinate early and grow faster and taller than desired turf. Thus they are capturing resources (light, moisture, nutrients) also needed by the turf. Various weed species found at any time of the year.
  12. Weed Competition Competition will occur if there is one limiting resource needed by two or more plants. Weeds compete for the following resources. Light Water Nutrients Space
  13. Weed Competition Weeds efficiently compete because of: Early germination Rapid seedling growth Large leaf area Extensive root systems
  14. Tubers Thickened portions of rhizomes or roots, serving for food storage and also for propagation (yellow nutsedge example) Rhizomes Underground stems that can emit roots from the lower side and leafy stems from the upper side (green kyllinga ex.)
  15. Tubers and Rhizomes Weeds that produce tubers include purple nutsedge, yellow nutsedge and Florida betony. Rhizomatous turfgrasses include bahiagrass, bermudagrass, Kentucky bluegrass, tall fescue and zoysiagrass. Rhizomatous weeds include dallisgrass, nimblewill and kyllinga species.
  16. Bulbs Short, vertical, underground organs for food storage or reproduction on which specialized leaves prominently develop (wild garlic)
  17. Weed Life Cycles Weeds are classified as… Annuals (summer and winter) Biennials Perennials (warm-season and cool- season)
  18. Summer Annuals Germinate in spring or early summer Produce seed in the summer Die with cold weather or frost Live for only ONE growing season!
  19. Summer Annuals Grass Broadleaf Crabgrass species Spotted spurge Foxtail species Common lespedeza Goosegrass Prostrate knotweed Sandbur Sedges: annual sedge
  20. Southern crabgrass Smooth crabgrass
  21. Goosegrass
  22. Common lespedeza Prostrate knotweed
  23. Prostrate spurge Milky sap
  24. Chamberbitter, cannonball weed, gripeweed
  25. Winter Annuals Germinate in fall or early winter Over-winter (very slow growth) during coldest months Actively grow and produce seed in the spring Die in summer as temperatures rise Live for only ONE growing season!
  26. Winter Annuals Grass Broadleaf Annual bluegrass Chickweed species Henbit Lawn burweed Speedwell species Knawel Hop clover
  27. Annual bluegrass Poa annua L. Boat shaped leaf tip
  28. Common chickweed
  29. Lawn burweed (spurweed)
  30. henbit Henbit
  31. Hairy bittercress
  32. Biennials Germinate in fall or spring when conditions are favorable Usually found in rosette stage in 1st Yr Produce seed and die in the 2nd growing season
  33. Shiny cudweed Purple cudweed
  34. Warm-Season Perennials Germinate in spring or summer Can produce seed in the first summer Can produce seed or reproduce by vegetative means indefinitely (survive for many years due to underground structures such as taproots, rhizomes, tubers, bulbs and aboveground structures such as stolons)
  35. Warm-Season Perennials Grass Broadleaf Dallisgrass Virginia buttonweed Bahiagrass Smutgrass Sedge / kyllinga species: green and false-green kyllinga, purple and yellow nutsedge
  36. Dallisgrass
  37. Kyllinga Sedge spp.
  38. Virginia buttonweed
  39. Purple Nutsedge – Cyperus rotundus Introduced, native to Eurasia S. East U.S., CA and AZ Ranked world’s worst weed Forms chains of interconnected tubers Prefers medium to fine-textured soils Highly adapted to compacted soils
  40. Yellow Nutsedge – Cyperus esculentus Native to North America Found in all of U.S. Ranked 16th worst weed in world Forms tubers Commonly found in sandy soils Thrives in non-compacted soils
  41. Cool-Season Perennials Germinate in fall or winter Can produce seed in the first spring Can produce seed or reproduce by vegetative means indefinitely (survive for many years due to underground structures such as taproots, rhizomes, tubers, bulbs and aboveground structures such as stolons)
  42. Cool-Season Perennials Grass Broadleaf Perennial ryegrass Ground ivy Tall fescue In. mock strawberry Dandelion Wild violet Yellow woodsorrel White clover Grass-Like: Wild garlic
  43. Perennial ryegrass clumps Wild garlic
  44. Wild garlic bulbs and bulblets
  45. Dandelion Dandelion
  46. Wild violet Ground ivy
  47. Identify the Weed Problem READ textbooks and periodicals Keep a diagnostic tool kit - hand lens, etc. Know the life cycle of the pest (What temp. does a specific weed seed germinate?) Is the weed the cause or effect of the problem? Confirm your diagnosis
  48. ACES - ANR-616 UGA-CES $14.00
  49. www.amazon.com * 214 weed species *575 color photos *Control info for each weed $88.00
  50. Turfgrass Web Pages www.georgiaturf.com or .org 437 photographs of 193 weeds Control recommendations Popular articles Links to turfgrass organizations, GA automated weather network