Weeds - PowerPoint PPT Presentation

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  1. Weeds • What is a weed? • A weed is a plant out of place

  2. What Do Weeds Do? • Compete with crops for resources • Interfere with crop quality and quantity • Reduce aesthetics of landscape • Affect function of turfgrass • Displace native flora

  3. What Do Weeds Do? Ragweed pollen causes hay fever • Cause allergies • Harm people • Harbor insects and plant pathogens

  4. Weeds -- How Did They Get There? • Every shovel full of soil contains thousands of weed seeds -- waiting for an opportunity • Often we just provide the weeds with the opportunity and environment to flourish

  5. Wind People Rain runoff Birds and other animals Garden cultivation Mowing Topsoil or compost addition Purchased plants Weed Seed Are Spread By:

  6. Invaders - weed dispersal • Wind • Surface water • Birds & animals • Activities of man • site prep, cultivation, planting

  7. How we introduce and move weeds • top soil • organic amendments • equipment • plants

  8. And, sometimes we intentionally introduce weeds Multiflora rose Crabgrass Kudzu

  9. More Plants (weeds) Intentionally Introduced Water hyacinth Bamboo Japanese knotweed

  10. The First Step in Weed Management is Identification!Weed Identification – Its More Than Knowing a Name!

  11. Why is it Important to Identify Weeds? • So you know • when it germinates, • how it spreads, • And, so you can determine the most appropriate control measure(s) -- herbicides, cultivation, mulches, etc.

  12. How do you correctly identify a weed? • Compare to a photo • Remember weeds can appear different due to site conditions • Easiest to do when plant is flowering • Keys to Identification • Send a sample to the local Cooperative Extension office

  13. Identification Resources • For Piedmont and Coastal Plains • Identifying Seedling and Mature Weeds in the Southeastern US • Weeds of Southern Turfgrass • Mountains • Weeds of the Northeast • Weeds of Southern Turfgrass

  14. How to order: • Identifying Seedling and Mature Weeds in the Southeastern US (AG-208) • Publications Office, Box 7603 NCSU, Raleigh, NC 27695-7603 $10.00

  15. How to order: • Weeds of Southern Turfgrass • Publication Distributions Center IFAS Building 664 P. O. Box 110011 University of Florida Gainesville, FL 32611 (352-392-1764) $8.00 + $3.00 shipping

  16. How to order: • Weeds of the Northeast • Cornell University Press P. O. Box 6525 Ithaca, NY 14851-6525 607-277-2211 $29.95 plus $5 shipping

  17. Some Web-Based Weed ID Resources • www.ces.ncsu.edu/depts/hort/weeds • www.ppws.vt.edu/weedindex.htm • www.rce.rutgers.edu/weeds/ • axp.ipm.ucdavis.edu/PMG/weeds_common.html • www.psu.missouri.edu/fishel/ • www.ppws.vt.edu/newss/weedid.htm • www.griffin.peachnet.edu/cssci/TURF/turf.htm

  18. How to send a sample for ID • Fresh samples: moisten sample; wrap in DRY paper towel; put in a zip-lock bag and mail on Monday or Tuesday to the appropriate specialist

  19. How to send a sample for ID • If you cannot send it right away (or if you get the sample on Thursday or Friday: Lay flat on between newspaper; press. • Mail the dried, pressed sample to the appropriate specialist

  20. Use the Sample Submission Form • http://intra.ces.ncsu.edu/depts/cs/weedforms/2weedide.pdf or • http://www.cropsci.ncsu.edu/turffiles/weedid/weedid.htm • http://www.cropsci.ncsu.edu/aquaticweeds/weed_id/aquatic.htm

  21. Classification of Weeds

  22. Weed Classification • Ways weeds are classified • Lifecycle • Seed leaves • Growth habit • Susceptibility to herbicides

  23. Lifecycles • Annual • Biennial • Perennial

  24. Life cycle of an annual weed Plant dies Seed Seedling Plant sets seed Plant flowers

  25. Life cycle of a winter annual weed Summer Fall Plant dies Seed Seedling Plant sets seed Plant flowers

  26. Common winter annual weeds

  27. Life cycle of a summer annual weed Spring Fall Plant dies Seed Seedling Plant sets seed Plant flowers

  28. Common Summer Annual Weeds J. Derr J. Neal J. Neal J. Neal

  29. Life cycle of a biennial weed Seedling Plant dies Seed Second Season First Season Plant sets seed Plant flowers Over-winters as a rosette

  30. Common Biennials • Bull Thistle • Queens Ann’s Lace • Mullein J. DiTomaso R. Uva J. Neal

  31. Life cycle of a perennial weed Roots/ rhizomes spread Seedling Seed Plant Over-winters Plant Flowers Plant sets Seed New plant

  32. R. Uva R. Uva J. Neal J. Neal J. Neal Some common perennial weeds

  33. Perennial Weeds Reproduce By: Seeds Tubers Bulbs Rhizomes Stolons

  34. Types of Perennial Weeds • Simple perennials • Creeping perennials • Rhizomes • Stolons • Creeping roots that produce shoots • Tuberous perennials • Bulbous perennials

  35. Simple Perennials • Spread by seed • Tap root or hardy fibrous root system • Examples: dandelion, plantain, dogfennel, pokeweed Tap root

  36. Creeping Perennials Stolon • Reproduce and spread by • Underground stems (rhizomes) • Above-ground stems (stolons) • Creeping fleshy roots that produce new shoots • Many also reproduce by seeds or other means. Rhizome

  37. Tuberous Perennials • Tubers are swollen, modified stems that are often resilient to controls, spread by cultivation, and may persist in the soil for years. • Tubers form on rhizomes Tubers J. Neal

  38. Bulbous Perennials • Persist through the dormant season as a bulb • Wild garlic and wild onion produce bulblets, aerial bulblets, and seeds R. Uva

  39. Weeds Are Also Classified By: • Cotyledons (Seed leaves) Dicot (two seed leaves) Monocot (one seed leaf)

  40. Monocots • One seed leaf when plant emerges • Long narrow leaves • Parallel veins

  41. Grasses Onions Garlic Sedges Rushes Lilies Dayflower Monocots -- Examples

  42. Grasses • Rounded or flattened stems and nodes • Have fibrous root systems • Some have fibrous roots, rhizomes or stolons for reproduction • Growing point is below surface

  43. seedhead blade Grasses are identified by: ligule sheath auricles midrib collar stolon bud leaf crown rhizome

  44. Vernation or Leaf Bud Rolled in the bud Folded in the bud

  45. The Scotts Co. The Scotts Co. The Scotts Co. Ligules Absent Membranous Hairy

  46. Ligules Absent Membranous Hairy

  47. The Scotts Co. The Scotts Co. The Scotts Co. Auricle Absent Present Clasping

  48. The Scotts Co. The Scotts Co. The Scotts Co. Seedheads Panicle Branched spike Spike

  49. Seedheads Panicle Branched spike Spike

  50. Grass-Like Weeds • Sedges: Sedges have triangular “stems”. Grasses have flat or rounded “stems”. • Annual and perennial species • Most common and difficult to control are yellow and purple nutsedge • Wild Garlic and wild onion: hollow leaves have a pungent onion-like or garlic-like aroma • Wild garlic is the most common