Slime flux disease and Globe Willow
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Slime flux disease and Globe Willow

Question:

I need help! I have frothy, smelly, sappy stuff coming out of my globe willow trees. I'm guessing it's slime flux, but I'm not sure. Anyway, what is the best thing to do? A book says to put a drainage tube underneath it, some other stuff I found on the internet said not to do that, some say to cut the limb off and disinfect the tools, and I remember something about washing it down with a Clorox solution. Will the trees die? What can I do about it? How can I prevent its spread to other trees?

Answer:

The problem you described on globe willow is very likely slime flux as you suspect. This bacterial disease of trees is also known as "wet wood" disease. Globe willows are one of several fast-growing trees subject to this disease.

It is not possible to cure the problem, but it may be managed to some extent. It is debilitating to the tree, so the first thing to do is minimize stresses imposed on the trees by environmental and cultural factors. Don't let them suffer for lack of water, provide adequate nutrition (don't over-fertilize), and prune properly (no topping or extremely heavy pruning— just remove weak, damaged and dead branches, and winter prune only limited amounts of healthy wood if necessary to thin crowded branches).

The "flux" of stinky stuff is due to gas pressure produced by bacteria (Erwinia) inside the tree forcing sap through cracks in the trunk. This gas and the fermentation of sap causes the foul odors and dripping, fermented, sap. The insertion of a drain tube to release the gas pressure is an old and discredited recommendation; it does much more harm than good. If the dripping sap is causing problems on the lawn or surfaces below the tree, the offending material may be washed away with a strong jet of water. Scrubbing the tree trunk with a ten percent chlorine bleach solution at the site of the dripping sap will help to delay the redevelopment of the odors by removing yeasts and other organisms that ferment the fluxing sap to produce the odors temporarily from the bark. These organisms will reestablish in the area of the flux in a relatively short time, and it may be necessary to scrub again. This is probably most important when a party is planned the next day or so; the rest of the time washing with a jet of water frequently is easier and usually sufficient.

Irrigation or good rainfall seems to aggravate the situation. This is to be expected and not a reason to reduce watering.

"Will the tree die?" Yes, but then all trees ultimately die. This will speed its demise but is not necessarily an immediate death threat. Provide proper care for the tree as long as it looks good. When the necessary level of care becomes too much trouble or when the appearance of the tree is bad enough, remove the tree and replace it with another tree. At this time replace it with a slower-growing but more resistant tree. Other trees subject to slime flux are mulberry, cottonwood, ash and many of our other fast-growing trees. These should be avoided. The slower-growing trees are more likely to resist the problem. By planting them before removing the ailing tree, you can allow it to develop some size and cast some shade before removing the other tree.

To prevent the spread of slime flux, clean pruning tools between pruning cuts. However, if a tree is susceptible to the problem, wind-broken branches and improper pruning cuts will allow entry. The wisest course is to plant those trees which are more resistant to the disease.

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Curtis W. Smith, Ph.D., is an Extension Horticulture Specialist with New Mexico State University's Cooperative Extension Service. New Mexico State University is an equal opportunity/affirmative action employer and educator.

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