The Impact of Oak Wilt

Transcription

1 Oak Wilt

2 The Impact of Oak Wilt Oak wilt is one of the most destructive tree diseases (Young, 1949). this disease has the potential of becoming one of the worst diseases to attack the forests of the state. (True and Gillespie, 1961). Oak wilt is now one of the most serious forest diseases in the country (Johns and Phelps, 1992). Ceratocystis fagacearum, the cause of oak wilt, is a fungus with the potential to be one of the most destructive of all tree pathogens. (Gibbs and French, 1980).

3 The Impact of Oak Wilt

4 The Impact of Oak Wilt First confirmed in Dallas in Likes areas with growing population and native oak trees.

5 County Impact / Oak Hill Quad Do Not Publish

6 Shady Hollow Estates Overview Not intended to be accurate; not for real estate use.

7 Shady Hollow Estates NW, NE Not intended to be accurate; not for real estate use. Not intended to be accurate; not for real estate use.

8 Shady Hollow Estates SW, SE Not intended to be accurate; not for real estate use. Not intended to be accurate; not for real estate use.

9 Active Lost Cavern Not intended to be accurate; not for real estate use.

10 Active Edwards Hollow Not intended to be accurate; not for real estate use.

11 Active Black Mesa Not intended to be accurate; not for real estate use.

12 Oak Wilt Fungus Caused by fungus Ceratocystis fagacearum Produces different kind of spores Relies on insects for transportation Produces fungal mats only on Red Oaks

13 Ceratocystis fagacearum A fungus with two forms Above Ground Form Below Ground Form

14 Oak Wilt Above Ground

15 Fungal Mats Produced only on Red Oaks. Spore mats form under bark. Multiple mats per tree. Produce a sweet odor like rotting melons attracting beetles Trees killed in late summer may produce mats the following spring

16 Beetle Spread

17 Beetle Spread Attracted to sweet smelling odors such as ripe fruit, fresh wounds on trees, and fungal mats.

18 Beetle Spread

19 Prevent Oak Wilt! Don t prune branches on oak trees February 1 June 30. Use paint on all cuts or wounds to oak trees. Don t move any firewood until it is wellseasoned Destroy all red oaks that are dead or dying near an Oak Wilt disease center.

20 Pruning Avoid pruning in the Spring. Paint wounds yearround.

21 Firewood Cover infected red oak logs with clear plastic. Leave covered through the summer. Fungus is killed by high temperatures >36 o C DontMoveFirewood.org

22 Oak Wilt Below Ground

23 Local Spread

24 Root Grafting Root Grafting can take place between separate trees. Roots must grow, touch, and graft. Inter-species grafting is uncommon, but not impossible.

25 Local Spread

26 The Impact of Oak Wilt Oak species most affected by oak wilt in Texas Q. texana (buckleyi) Spanish Oak Q. marilandica Blackjack Oak Q. nigra Water Oak Q. virginiana Live Oaks Q. fusiformis Q. glaucoides (laceyi) Lacey Oak Q. polymorpha Mexican White Oak Q. sinuata var. breviloba Shin Oak

27 Oaks are Affected Differently

28 The White Oaks Bur Chinkapin Post Lacey White Shin

29 The Live Oaks Escarpment Coastal

30 The Red Oaks Blackjack Spanish (HP) Shumard (HP)

31 Diagnosis and Management

32 Diagnosis Pattern of disease in the population Pattern in individual trees Foliar symptoms Taking samples

33 1. Pattern of Disease Live Oak Center

34 2. Pattern in individual Trees Diseased Live Oak Diseased Red Oak

35 3. Foliar symptoms Live Oak Symptoms Red Oak Symptoms

36 Below Ground Containment Trenching to halt oak wilt spread through connected root systems [at least 4 feet deep and 100 feet from symptoms]. Roguing = removal of diseased trees within trenched area.

37 Trenching 54 and 60 inch rock saw used in recent years.

38 Preserving High Valued Trees

39 Fungicide Injection Used on trees under disease pressure on advancing margin of disease centers. Only treat trees within 150 feet of Oak Wilt disease center. Expose root flares & inject on root flares. Does not contain disease.

40 Fungicide Advantages of Macro-Injections at Root Flare Bark is thinner below soil line. Increases the number of potential injection sites. In case of future injections, spreads out the wounding. Research demonstrated distribution of fungicide.

41 Fungicide 2015 International Society of Arboriculture BMPs

42 Fungicide Fungicide Injection equipment Trees being injected Double helix bit Green T

43 Final Product

44 Key Points for Communities Constant Education Prevent Oak Wilt Don t prune oaks Feb 1- June 30 No Spring Cleanup Days Use paint on all cuts or wounds to oaks Destroy all red oaks that die of Oak Wilt Don t move any firewood until well-seasoned Plant native, non-oak tree species Trench when Centers are Small

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46 For More Information Texas A&M Forest Service Clay Bales (512) Texas A&M Forest Service Website: