Wow! Slime Flux!
Posted: 08/04/2011 Filed under: Nature, Science 2 Comments »
A couple weeks ago, walking past an oak tree by our driveway, I smelled vinegar, strongly.
“Huh. Weird,” I thought as I walked into the house. ”Is something fermenting?”
That afternoon, Matt and I noticed a fleet of yellowjacket wasps hovering, landing, and crawling across two lightened spots on one of the tree’s roots. ”Are they nesting?” we mused, but didn’t get close enough to inspect.
A couple days later, we did look closer, and saw not only yellowjackets but also carpenter ants and other wasps visiting the spots, sometimes tussling with each other. ”Could yellowjackets be raiding an ant nest, or vice versa?” we wondered.
We looked even closer and realized that the light patches on the tree root were oozing a white liquid, which was apparently the insect attractant. ”I’ll bet you that white stuff is the source of the vinegar smell,” I thought.
So I consulted Google and got an answer right away: my bet was right!
Turns out, our tree has a case of a plant disease called, sexily, slime flux. It is caused by a bacterial infection often associated with heat stress. (And what U.S. plant — or person – hasn’t been experiencing heat stress recently, really?) The infection usually begins in a natural crack or in a damaged area of the tree.
There are two types of slime flux — alcoholic and acidic — and the acidic type results in a vinegar odor as the bacteria ferment the tree’s sap.
Some sources say there’s nothing to be done to help the tree; others say to wash the wound with diluted bleach. Maybe my horticulturist father can offer advice (hint, hint)?
[Update: Originally, we identified the tree as a sweet gum. There are sweet gum branches hanging down all around at eye level. There are sweet gum seedlings sprouting up at its base. But if from the start we'd taken two seconds to follow the trunk upward to double- check its own true leaves, we would have seen that it was instead an oak, and that all that sweet gum evidence was from the real sweet gum tree growing right beside it. Whoops. Apparently, our natural history observation skills have become a bit rusty since Bennett was born! *blushing*]
There are two groups of things often diagnosed as “slime flux.” One is wetwood disease, the other are bleeding cankers. Both can cause sour odors and ooze.
Wetwood disease can be seen on trees, especially elms, where a branch has been cut or broken off and (usually) white discoloration streaks down the trunk beneath the wound. It is an internal disease, usually bacterial, and normally little can be done. They used to drill holes into the trees and insert a pipe to relieve the pressure, but doing this can actually speed the deterioration of mechanical support in the tree by drying it out. If the wood is too wet, decay fungi can’t grow, so draining the wetness out allows the rot to begin.
Cankers are diseases of the bark and cambium. Many times they can be temporary and do not kill the tree. A couple of reference books that I have (I lean pretty heavily on Dr. Alex Shigo’s opinions) offer that chemical treatments or physical “surgery” and removal of the canker can do more harm than the canker itself.
I’d say, “Hold your nose and see what happens.”
Hortdad
Thanks, Dad! We will stay upwind and keep our fingers crossed that they are quick-healing cankers (they seem to align best with the canker description)!