1. Master Gardener Training - Weed Identification and Management Jeffrey Derr Professor of Weed Science Virginia Tech

2. Additional information - Weed identification Books Weeds of the Northeast – Cornell Press Weeds of Southern Turfgrass, Georgia Cooperative Extension Service Weeds of the South - University of Georgia Press Color Atlas of Turfgrass Weeds – John Wiley & Sons

3. Additional information Pest Management Guides Home Grounds and Animals http://pubs.ext.vt.edu/456/456-018/456- 018.html Herbicide labels

4. Additional Information – Weed ID Websites www.ppws.vt.edu/ipm/weeds_container_nurseries.html www.turfweeds.net www.ppws.vt.edu/weedindex.htm Virginia Tech Weed ID websites

5. What is a weed?

6. Prickly pear cactus Purple loosestrife

7. What is a weed? Plant out of place, growing were it is not needed or wanted Purple loosestrife (Lythrum) Prickly pear cactus Bamboo English ivy

8. Why control weeds?

9. Reasons to Manage Weeds Competition - leading to reduced crop growth and yield (quantity, quality) for water (drought years) nutrients (especially nitrogen) –cannot correct with extra N light (viny weeds) pollination (dandelion blooms) – reduced crop pollination)

10. Reasons to Manage Weeds Harbor insect and disease pests (dandelion and tomato ringspot virus, buckhorn plantain/aphids) Attract bees (problem for those allergic to bee stings) Interfere with harvest (rash - poison ivy, spines - brambles) Allelopathy (natural herbicides) - juglone – black walnut Provide cover for rodents

11. Reasons to manage weeds Adversely affect human health – rashes (poison ivy), poisonous if eaten (black nightshade), allergies (common ragweed), thorns (greenbrier) Reduce aesthetic value of lawns and gardens Block visibility along highways Block water flow in ditches

12. Weed names Common names – differ across state, country (stickweed, wiregrass, silver crabgrass, etc.) Weed scientists used an approved list of common names for the US (horseweed, bermudagrass, goosegrass) Scientific name – used throughout the world Eleusine indica (goosegrass)

13. Weed life cycle Annuals Summer - grass, broadleaf, sedge, other monocots Winter – grass, broadleaf Biennials – broadleaf Perennials – grass, sedge, other monocots, broadleaves

14. Summer annual grasses Large crabgrass Giant foxtail Goosegrass

15. Microstegium (Japanese stiltgrass)

16. Winter annual grasses Italian (Annual) ryegrassAnnual bluegrass

17. Annual broadleaves Summer common lambsquarters, smooth pigweed, common ragweed, ivyleaf morningglory Winter vetch, horseweed, fleabane, common chickweed, henbit

18. Summer annual broadleaves Common ragweed tall morningglory Common lambsquarters Smooth pigweed

19. Winter annual broadleaves Vetch Common chickweedHorseweed Henbit

20. Biennials Musk thistle Wild carrot

21. Perennial Monocots Perennial grasses clump - tall fescue, orchardgrass creeping - quackgrass, bermudagrass, johnsongrass Perennial sedges – yellow nutsedge Other perennial monocots – wild garlic

22. Bermudagrass Perennial grasses Quackgrass Johnsongrass

23. Yellow and Purple Nutsedge Perennial sedges (rhizomes, tubers)

24. False Green Kyllinga – perennial sedge

25. Other monocots Wild garlic (perennial)

26. Perennial broadleaves Simple – dandelion, buckhorn plantain Creeping - bindweed, brambles, poison ivy, horsenettle, hemp dogbane

27. Dandelion Buckhorn plantain Simple perennial broadleaves

28. Creeping perennial broadleaves Poison ivy Horsenettle Hedge bindweed

29. Perennial broadleaf weeds Hemp dogbane Black locust

30. Turf Weed Control Biological – none available Cultural Chemical

31. Integrated Pest Management Determine management level – high, medium, low Scouting – identify weed problems late spring for winter annuals late summer for summer annuals, perennials Determine weed infestation level/need for renovation Evaluate control options – nonchemical vs chemical Chemical treatments – broadcast, spot-treatment

32. Cultural Control of Weeds in Turf Use the best adapted turf species for the site Proper mowing heights : 3-4 inches for tall fescue Maintain appropriate pH, nutrient levels, irrigation Correct compaction, shade, and drainage problems Control insects and diseases Reduce stress – drought, excess salts, etc.

33. Biorational Products for Turf Corn gluten By-product of corn milling 60% protein Preemergence herbicide Annual weed control, esp crabgrass No postemergence effects ~ 10% nitrogen Herbicidal components Various products Safe Lawn, WOW!, A-Maize-N, Organic Weed and Feed, etc

34. Chemical Control in Turf Preemergence herbicides – primarily for annual weeds Postemergence herbicides – primarily used for perennial weeds

35. Crabgrass control in turf Preemergence Pre + Pre Postemergence Pre + Post

36. Preemergence Crabgrass Herbicides – at seeding or newly-seeded cool-season turf Tupersan (siduron) Tenacity (mesotrione) – best applied by a lawn care company Drive (quinclorac) – certain formulations are for commercial applicators only

37. Preemergence Crabgrass Herbicides – established cool-season turf Barricade (prodiamine) Dimension (dithiopyr) pendimethalin (Halts, Pre-M, Pendulum, etc.) bensulide (Bensumec, etc.) Team (trifluralin + benefin) Dacthal (DCPA) Balan (benefin) Tupersan (siduron)

38. Preemergence Crabgrass Herbicides – established warm-season turf Barricade (prodiamine) Dimension (dithiopyr) pendimethalin (Halts, Pre-M, Pendulum, etc.) bensulide (Bensumec, etc.) Team (trifluralin + benefin) Dacthal (DCPA) Balan (benefin)

39. Postemergence crabgrass herbicides – cool season turf Dimension (pre-tillering of crabgrass) Drive/products containing quinclorac Acclaim Extra (fenoxaprop) Tenacity (mesotrione)

40. Annual Bluegrass control Preemergence crabgrass herbicide in late August (probably will not be able to overseed) No postemergence controls for homeowners

41. Preemergence Control of Annual Broadleaf Weeds Depends upon the herbicide Preemergence control possible for: Spotted (Prostrate) spurge Common chickweed Henbit Others

42. Preemergence broadleaf control Gallery, Green Light Portrait (isoxaben) Preemergence crabgrass herbicides

43. Bermudagrass Suppression in Tall fescue Suppression/Need repeat treatments Acclaim Extra + Turflon, some other chemicals Or 2-3 applications of Roundup and reseed Proper mowing height Overseeding

44. Yellow nutsedge control in Cool-season turf Postemergence control - SedgeHammer - Dismiss - Basagran -Also used for kyllinga control

45. Wild Onion, Wild Garlic Control 2,4-D ester

46. Broadleaf Control Chemicals 2,4-D, 2,4-DP, MCPP, MCPA, dicamba, triclopyr, clopyralid, fluroxypyr Usually use combinations such as 2,4-D + MCPP 2,4-D + MCPP + dicamba Leaf, root absorbed Sprays and granular forms

47. Spray versus Granular application Spray generally provides better control since these chemicals are absorbed by leaves as well as roots Granular formulations – reduce potential for leaf uptake, apply when dew is present Granules – no spray drift, still can injure ornamentals through root uptake

48. Dandelion Buckhorn plantain

49. Oxalis (woodsorrel)

50. Ground ivy Triclopyr or a dicamba based product

51. Wild Violet Control in Turf Postemergence control - triclopyr based product

52. Lespedeza - Use a triclopyr based product

53. Virginia buttonweed Repeat applications of a turf combination broadleaf herbicide - (Trimec, etc.)

55. Ornamental Bed Weed control Cultural Control Chemical control

56. Cultural Control in beds Hand-weeding, tilling, hoeing Mulches –Organic : pine bark, pine straw, hardwood bark, etc –Inorganic – rocks –Black plastic –Landscape fabrics

57. Mulches 2 to 4 depth Avoid mulch with a sulfur or ammonia odor (sour mulch) Free of weed seed Control annual weeds Rock mulches better than bark mulches for weed control Bark mulches can support weed growth

60. Black plastic Controls annuals and suppresses perennial weeds (inhbits water movement, gas exchange) Lacks porosity Best fit is annuals, vegetable gardens Consider fabrics for long-term use

61. Black plastic Improves weed control over mulch alone Lacks porosity (water, gases cannot readily move through) Encourages surface rooting Does not hold mulch well

63. Landscape fabrics Allow for water, gas exchange Sacrifice on weed control compared to solid black plastic Shoot penetrate upward through fabric Root penetration downward through fabric Keep totally covered with 1 inch mulch Rock mulches better for weed control

66. Chemical Weed Control in Ornamentals Preemergence herbicides Postemergence herbicides

67. Annual Flower beds Site prep – control perennial weeds prior to planting Rototill Transplant Irrigate Apply granular trifluralin (Preen Garden Weed Preventer, Treflan, etc) Irrigate Mulch

68. Woody ornamental beds Wider choice of preemergence herbicides than in annual beds (ie Snapshot) Apply prior to mulching

69. Postemergence Herbicides - Ornamentals A) Selective herbicides grasses - Segment, Fusilade/Ornamec (Grass-B-Gon), Envoy, Acclaim yellow nutsedge – Basagran, SedgeHammer woody orn directed spray broadleaves - none

70. Postemergence Herbicides - Ornamentals B) Nonselective herbicides Contact – Reward – Scythe, acetic acid based products (BurnOut, etc) Contact/systemic- Finale Systemic – glyphosate (Roundup, etc)

71. glyphosate (Roundup, others) Off patent, many producers nonselective systemic leaf, bark absorbed inactivated upon contact with soil use under good soil moisture wiper or shielded spray applications

72. Yellow nutsedge perennial sedge cultural control - landscape fabrics chemical control preemergence – Pennant Magnum, Tower postemergence – SedgeHammer, Basagran, Roundup, Finale, Reward

73. Bermudagrass control Postemergence control in broadleaf ornamentals and nongrass monocots like liriope Fusilade/Ornamec/Grass-B-Gon Segment Envoy

74. Poison ivy perennial broadleaf postemergence control - nonselective glyphosate, Finale Triclopyr (Brush-B-Gon)

75. Weed Control in Vegetable Gardens Cultural Hand-weeding, hoeing, cultivation Mulches – grass clippings (do not use from a lawn recently treated with a post broadleaf herbicide) Newspaper + grass clippings Black plastic

76. Weed Control in Vegetable Gardens Rototill in spring to control chickweed and other winter annuals

77. Weed Control in Vegetable Gardens Chemical Control Trifluralin (Preen Garden Weed Preventer, others) See PMG and label for which species can be treated at seeding, which at transplanting Glyphosate for site prep or after final harvest