Hawkweed Control in Alaska. Steven Seefeldt

Transcription

1 Hawkweed Control in Alaska Steven Seefeldt

2 Background Hieracium About 800 species world wide

3 Background Hieracium About 800 species world wide Hierax = hawk. It was thought that the great vision of hawks was due to their supposed addiction to these plants

4 Background Hieracium About 800 species world wide Hierax = hawk. It was thought that the great vision of hawks was due to their supposed addiction to these plants Certainly the eye of a hawk is needed to distinguish the host of species Lewis J. Clark

5 Background Native Hieracium species in AK albiflorum White umbellatum Narrow leaved tristi Alpine scouleri var. albertinum Western

6 Background Introduced Hieracium species in AK aurantiacum Orange caespitosum Meadow murorum Wall lachenalii Western/common pilosella Mouse ear sabaudum New England

7 Orange Hawkweed Norman Melvin

8 Orange Hawkweed

9 Meadow Hawkweed

10 Meadow Hawkweed

11 Wall Hawkweed

12 Wall Hawkweed

13 Western/common Hawkweed

14 Western/common Hawkweed

15 Mouseear Hawkweed

16 Mouseear Hawkweed

17 New England Hawkweed

18 New England Hawkweed

19 Red = western/common Yellow = mouseear Blue = Meadow

20 Red = narrow leaved

21 Hawkweed reproduction Flowers from rosettes, typically get one stalk Each stem with multiple flower heads Each head with multiple seeds Seeds dispersed by wind and easily carried on vehicles, animals and clothes Many species have stolons

22 Orange Hawkweed in Alaska First identified in Juneau in 1961 Starting to become more widespread

23 Orange Hawkweed management Information from the south Mechanical methods not effective Mowing increases vegetative spread Plowing spreads Digging difficult

24 Orange Hawkweed management Information from the south Mechanical methods not effective Mowing increases vegetative spread Plowing spreads Digging difficult No biological agents

25 Orange Hawkweed management Information from the south Mechanical methods not effective Mowing increases vegetative spread Plowing spreads Digging difficult No biological agents Herbicides Must have surfactant to get past leaf hairs Must apply during rosette stage

26 Talkeetna Weed Pull Methods: 2 x 2 meter plots 8 treated plots, 8 control plots Pre-treatment % cover estimates Hand pulled each treated plot (biomass of orange hawkweed including roots and stolons)

27 Post-Pull (6/25/2007) End of the day Post-Pull (8/6/2007) 6 weeks after pull Post-Pull (8/6/2007) 6 weeks after pull

28 Orange Hawkweed management Herbicides used in the south 2,4-D 2,4-D Banvel Dicamba Transline Clopyralid Curtail Clopyralid + 2,4-D Redeem R&P Clopyralid + triclopyr Milestone Aminopyralid

29 Greenhouse Study Clopyralid + Triclopyr (Redeem R&P) Aminopyralid (Milestone) Clopyralid (Transline)

30 Greenhouse Study

31 Greenhouse Study

32 Greenhouse Study Used 6 herbicide rates 1, 1/2, 1/4, 1/8, 1/16 and 0 times the full label rate Sprayed 10 plants at each rate when at the 8 leaf rosette stage Visually rated damage after 3 weeks Cut plants at ground level, dried and weighed Experiment conducted twice

33 Greenhouse results Redeem

34 Greenhouse results - Milestone

35 Greenhouse results - Transline

36 Greenhouse results 1 First trial First trial 1 Second trial Second trial Weight (grams) /16 1/8 1/4 1/ /16 1/8 1/4 1/ Re Mi Tr 0 Re Mi Tr

37 Field Trials Four sites, Talkeetna (hay fields) and Homer (wood lot and abandoned field) Plots 6 x 30 feet Milestone at 105, 52, and 26 g ai/ha, Transline at 420, 210, and 105 g ai/ha plus a control Three replications of each of the above treatments Randomized complete block

38 2007 Field Trials Pre-treatment Measurements: Two ¼ x ¼ m sub-plots per plot % cover estimates of orange hawkweed, grasses, and forbs Post-treatment Measurements: Rate plots visually based on herbicide damage, 0% (no damage) to 100% (dead) after three weeks End of season harvest ¼ x ¼ m sub-plots and separate by cover type Rate plots visually the following year

39 The work in Homer, AK Control area Biomass harvest Milestone 1x

40 Visual Injury Milestone 1YAT Percent injury H 07 H 08 T 07 T08 Herbicide rate (1 = 105 g ai/ha)

41 Visual Injury Transline 1YAT Percent injury H 07 H 08 T 07 T 08 Herbicide rate (1 = 420 g ai/ha)

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44 Impact on Grasses Percent dry weight Herbicide rate Milestone Transline

45 Impact on broadleaves Percent dry weight Herbicide rate Milestone Transline

46 % injury of high rate on other plants Species Milestone Transline Wild celery (Angelica lucida) 100 tolerant Paper birch (Betula papyrifera) tolerant Daisy (Chrysanthemum spp) Dandelion (Taraxacum officinale) Fireweed (Chamerion angustifolium) Wild geranium (Geranium erianthum) Nootka lupine (Lupinus nootkatensis) Hempnettle (Galeopsis tetrahit) tolerant Spruce (Picea spp) tolerant Willow (Salix spp) tolerant Common yarrow (Achillea millefolium)

47 Other plant tolerant of transline Aspen (Populus tremuloides) Norwegian cinquefoil (Potentilla norvegica) Cow parsnip (Heracleum maximium) Sheep sorrel (Rumex acetosella) Sitka burnet (Sanguisorba canadensis) Beauverd spirea (Spiraea stevenii)

48 Conclusion Two herbicides are promising for use on orange hawkweed but they must be used at the recommended label rates based on greenhouse and field research

49 Conclusion Two herbicides are promising for use on orange hawkweed but they must be used at the recommended label rates based on greenhouse and field research Grasses increased as orange hawkweed decreased

50 Conclusion Two herbicides are promising for use on orange hawkweed but they must be used at the recommended label rates based on greenhouse and field research Grasses increased as orange hawkweed decreased Milestone is best if grasses are desired

51 Conclusion Two herbicides are promising for use on orange hawkweed but they must be used at the recommended label rates based on greenhouse and field research Grasses increased as orange hawkweed decreased Milestone is best if grasses are desired Transline is best if plant diversity is desired

52 Warnings From the book Wild Flowers of the Pacific Northwest by Lewis J. Clark Pg 561 Introduce into one s garden with peril

53 Acknowledgements ARS Jeff Conn, Joseph Kuhl, Dan Hall, Erin Carr, Nan Werdin-Pfisterer, Trista Saunders, Jennifer Kapla, Steve Lillard, Zachary Behr, Katie Mohrmann, and Katie DiCristina AK - Caleb Slemmons, Gino Graziano, Steve Hicks, Jen Vaughan, and Emily Perchuzel Weed pullers of the Youth Conservation Corps and Talkeeta citizens Four land owners