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Description and
Diagnosis
Bacterial wetwood involves a
liquid that oozes and bubbles through the bark cracks
and wounds, also known as slime flux, inspired by the
slimy, foul smelling, brown appearance of the liquid.
The prime wounding agents are insect borers,
mechanical injury, and natural cracks and splits which
are rarely observed. This condition is common in oaks,
mulberry, sycamore, elm, ash and redbud. There are
several common types of anaerobic soil bacteria
(bacteria to which oxygen is
toxic) which cause of this infection. These bacteria
feed on substances in the wood, releasing fatty acids,
methane and carbon dioxide gases. These fatty acids go
rancid leaving the wood of the tree water soaked and
foul smelling.
The gaseous by-products create a
hydraulic pressure which forces liquids out of the
cracks in the bark which turns brown due to
oxidization. The bacteria do not cause any wood decay.
However, the liquid raises the internal pH (alkaline)
causing the infected wood to resist decay for a few
years. Bark tissue will degrade in some cases.
Infection is thought to enter the tree primarily
through root uptake, but contaminated pruning tools
have all so been reported to transmit this infection.
Slime Flux wounds do not close properly as tree tissue
involved in wound closure are killed by the infection.
Control
There is
no satisfactory control for bacterial wetwood. It does
cause die back of branches, but as previously
mentioned the raised pH prevents and delays decay
fungi from rotting out the heartwood of the tree.
Inserting drain tubes around the affected area is no
longer recommended. It only helps spread bacterial
population within and create wounds conductive to the
entry of other pathogens. As a radical effort and
with some success with early detection of one or two
wounds using a hatchet to expose the infection. Then
spray the area with Ammonium Chloride, (Consan 20, a
triple action microbial disinfectant), allowing the
wound to air dry as oxygen is also toxic to the
bacteria. Preventative measures such as avoiding
moisture stress, proper pruning and adequate
fertilization may invigorate trees. Do not disturb
soil around the base of the tree to prevent wounds
that the bacteria may enter.
ASIAN AMBROSIA BEETLES |
