Slime flux explained

Slime flux
Causal Agents:Bacteria (Brevundimonas bullata, Paracoccus alcaliphilus, P. marcusii and Luteimonas aestuarii, and Pectobacterium carotovorum)
Hosts:Trees (elm, cottonwood, poplar, boxelder, ash, aspen, fruitless mulberry and oak)
Eppo Codes:ERWICA

Slime flux, also known as bacterial slime or bacterial wetwood, is a bacterial disease of certain trees, primarily elm, cottonwood, poplar, boxelder, ash, aspen, fruitless mulberry and oak. A wound to the bark, caused by pruning, insects, poor branch angles or natural cracks and splits, causes sap to ooze from the wound. Bacteria may infect this sap causing it to darken and stain the bark, eventually taking on a foamy appearance and unpleasant odor. This slimy ooze becomes toxic to the bark and eats into the tree. Additionally, the fermented sap attracts insects like flies, ants, and maggots.

Cause

Slime flux occurs when a wound is made in a tree trunk through things such as natural growth cracks, frost, insects, birds, lawn mowers, cat scratches, or pruning wounds, which causal bacteria can enter. Once inside the xylem, the internal pressure of the tree is raised, from the normal range of NaN1NaN1 up to 600NaN0, due to bacteria fermenting and emitting a gas mixture of methane, nitrogen, carbon dioxide, and oxygen. This accumulation of liquid and gas causes that part of the tree to have a damp, dark brown appearance known as wetwood.[1] Eventually, the pressure will cause the sap and gasses to burst through the xylem and out of cracks in the trunk and ooze down the side of the tree. This sap flux may be further infected by other pathogens once exposed to the air such as air-borne bacteria, yeast, and other fungi, at which point it is known as slime flux.[2]

Causal agents

Causal bacteria for the initial wetwood varies depending on the species of tree. The bacteria are commonly found in water and soils. Enterobacter spp., Bacillus spp., Pseudomonas spp.[3] Xanthomonas spp., Agrobacterium spp., Acinetobacter spp., Corynebacterium spp., Bacteroides spp., Clostridium spp., Edwardsiella spp., Klebsiella spp., Lactobacillus spp., Methanobacterium spp.,[4] Brevundimonas bullata, Paracoccus spp. and Luteimonas aestuarii have been isolated from wetwood in various tree species.[5]

Species of Prototheca have been isolated from slime fluxes.[6]

Treatment

There is no cure, but the bark of a tree is like skin. The wound should be disinfected with rubbing alcohol or a household bleach solution of one part bleach to nine parts water. The excess sap should be wiped from the tree to discourage hungry insects. With prompt and continuous treatment, the tree should survive. In the forest, practices that minimize wounding will reduce the spread of this disease. For urban trees, maintaining vigorous, healthy growing conditions (thorough watering, mulching around the base and adding compost to the drip line) and avoiding wounds will reduce the probability that trees will be affected by this disease. Removing bark from the affected area will reduce damage to an individual tree. Additionally, the “hungry insects” are most likely harmless. The main “pest” you will need to be concerned with are borers.

Background

Slime flux or more commonly known as Wet wood is a seepage of the wood that is unseen by the human eye. The seepage is typically a sour smell that comes from the trunk of the tree.

Significance

The slime flux disease causes a constant odor, and bleeding cankers on the base of the tree. Slime flux can eventually kill a tree. The bacteria and pathogens can spread to surrounding trees. Oozing liquid is a sign that there has been an earlier injury. In some cases, as the outer wound calluses over and the internal methane production decreases, the slime flux may stop in a year or two. In other cases slime flux may reoccur year after year.

Plants which may be affected

Plants which are known to be affected by slime flux!Family!Genus!Species!Notes
AltingiaceaeLiquidambar[7]
AsparagaceaeCordyline[8] In the United Kingdom, the Royal Horticultural Society noted an increase in the number of affected Cordyline following the cold winter of 2010/2011.
BetulaceaeBetula (birch)[9] [10] Paper birches are known to be affected.[11]
ElaeagnaceaeElaeagnusE. angustifolia (Russian-olive)[12]
CornaceaeCornus (dogwood)
FabaceaeCercis (redbud)
ProsopisMesquites are known to be affected.[13]
RobiniaR. pseudoacacia (black locust)
FagaceaeFagus (beech)
Quercus (oak)White oaks are known to be affected.[14]
JuglandaceaeCarya (hickory)
Juglans (walnut)J. cinerea (butternut)
MagnoliaceaeLiriodendron (tulip tree)
Magnolia
MalvaceaeTilia (lime, linden)
MoraceaeMorus (mulberry)[15]
NyssaceaeNyssaN. sylvatica (sourgum)
OleaceaeFraxinus (ash)
PinaceaeAbies (fir)
Pinus (pine)
Tsuga (hemlock)
PlatanaceaePlatanusPlatanus × hispanica (London plane)
RanunculaceaeClematis[16] In the United Kingdom, Clematis are the plants most commonly affected by slime flux.
RosaceaeMalus (apple; crabapple)M. domestica (apple)[17] (apple).[18]
Prunus (cherry; plum)
Sorbus
SalicaceaePopulus (poplar; aspen; cottonwood)[19] P. tomentosa[20] The majority of poplar species are known to be affected.
Salix (willow)
SapindaceaeAcer (maple)A. negundo (boxelder maple)[21] A. saccharinum (silver maple)
Aesculus (horse-chestnut)
UlmaceaeUlmus (elm)U. americana (American elm)[22] [23] U. parvifolia (Chinese elm)[24]

U. pumila (Siberian elm)[25]

The majority of elm species are known to be affected.

References

Notes and References

  1. Book: Jacobi. William R.. Diseases of Trees in the Great Plains. Ball. John. USDA Forest Service. 2016. 120–123. Wetwood (Slime Flux) and Alcohol Flux in Hardwoods.
  2. Hamilton. Douglas W.. September 1980. WETWOOD AND SLIME FLUX IN LANDSCAPE TREES. Journal of Arboriculture. 6. 9. 247–249.
  3. Murdoch . C. W. . Campana . R. J. . April 1983 . Bacterial Species Associated with Wetwood of Elm . Phytopathology . 73 . 9 . 1270–1273 . 10.1094/Phyto-73-1270.
  4. Schink. Bernhard. Ward. James C.. Zeikus. J. G.. 1981. Microbiology of Wetwood: Role of Anaerobic Bacterial Populations in Living Trees. Microbiology. 123. 2. 313–322. 10.1099/00221287-123-2-313. 1350-0872.
  5. Alizadeh. M.. Khakvar. R.. Babai-Ahari. A.. 2017-12-01. Isolation and characterization of bacterial agents associated of wetwood disease on elm trees in Iran. Acta Phytopathologica et Entomologica Hungarica. en-US. 52. 2. 157–168. 10.1556/038.52.2017.028. 1588-2691.
  6. Pore. R. S.. 27391222. 1986-05-01. The association of Prototheca spp. with slime flux in Ulmus amencana and other trees. Mycopathologia. en. 94. 2. 67–73. 10.1007/BF00437369. 1573-0832.
  7. Web site: September 1999. IPM : Reports on Plant Diseases : Bacterial Wetwood and Slime Flux of Landscape Trees. 2021-03-16. ipm.illinois.edu.
  8. Web site: Cordyline slime flux. 2021-03-15. rhs.org.uk. Royal Horticultural Society.
  9. Web site: Wetwood. 2021-03-15. The Morton Arboretum.
  10. Web site: Sanogo. Carmen. 23 April 1999. Bacterial Wetwood (Slime Flux) in Trees. 2021-03-15. hortnews.extension.iastate.edu.
  11. Web site: Pecknold. Paul C.. January 2016. Slime Flux. 2021-03-16. Purdue e-Pubs.
  12. Web site: Slime Flux. 2021-03-15. extension.usu.edu.
  13. Web site: Olsen. Mary W.. Young. Deborah J.. September 1998. Slime Flux or Wetwood. 2021-03-16. The University of Arizona Cooperative Extension.
  14. Web site: 2020-07-10. Slime Flux of Trees. 2021-03-16. Purdue Extension Forestry & Natural Resources. en.
  15. Web site: Heimann. Mary Francis. Hudelson. Brian. 19 May 2009. Bacterial Wetwood Plant Disease Diagnostics Clinic. 2021-03-15. pddc.wisc.edu.
  16. Web site: Clematis slime flux. 2021-03-15. rhs.org.uk. Royal Horticultural Society.
  17. Ogilvie. Lawrence. 1924-03-31. Observations on the "slime-fluxes" of trees. Transactions of the British Mycological Society. en. 9. 3. 167–182. 10.1016/S0007-1536(24)80019-0. 0007-1536.
  18. Ogilvie. Lawrence. Research Items . 113 . 691–693 . Nature . 2845 . May 10, 1924 . 10.1038/113691a0 . free .
  19. Web site: 2014-06-10. Bacterial Wetwood (Slime Flux). 2021-03-15. www.agr.gc.ca. Government of Canada.
  20. Zhou. Jianghong. Xia. Fei. Che. Shaochen. Wang. Jianhong. Zhang. Guofeng. 2020. Providencia rettgeri as the causal agent of the brown slime flux of Populus tomentosa. Forest Pathology. en. 50. 1. e12576. 10.1111/efp.12576. 213932836. 1439-0329.
  21. Web site: Vann. Stephen. Wetwood of Shade Trees. 2021-03-16. uaex.uada.edu.
  22. Web site: Jacobi. W. R.. December 2013. Bacterial Wetwood. 2021-03-16. Colorado State University Extension.
  23. Web site: Carter. J. Cederic. August 1945. Wetwood of Elms. 2021-03-16. IDEALS @ Illinois.
  24. Web site: Goldberg. Natalie P.. October 2006. Slime Flux. 2021-03-16. New Mexico State University.
  25. Web site: Mohan. S. Krishna. Colt. Wm. Michael. Barney. Danny L.. November 1990. Bacterial Wetwood and Slime Flux of Trees. 2021-03-16. University of Idaho Digital Collections.