Friday, June 5, 2009

"Dog Vomit" Slime Mold

There’s been a bumper crop of slime molds in landscape beds this year, and we’ll see them throughout the summer and into the fall. By far the species most often noticed is Fuligo septica, a.k.a. the “dog vomit” slime mold. Despite the unpleasant name, it is completely harmless to humans, animals and plants.

Slime molds spend most of their lives as amoeboid cells or inconspicuous plasmodia that creep slowly through soil, leaf litter, mulch, etc. A plasmodium feeds by engulfing bacteria, spores, and bits of organic matter. It eventually moves out to a more exposed location on top of mulch, pine straw, a stump, a low-growing plant, or even the foundation of a building. There it stops moving and transforms into a fruiting (spore-producing) body. This is when Fuligo septica first gets noticed as a bright yellow, frothy mass a few inches to up to a foot in diameter. It quickly fades to a dull orange and then a light tan as its surface dries to a crust. After a few days it breaks apart to release its dark-colored spores, which blow away to start the life cycle anew. Within a week or two, all that’s left is a dusting of leftover spores and bits of gray or yellowish crust.

Control measures for Fuligo septica are neither effective nor necessary. If considered intolerably unsightly, they can be removed by hand or washed off with a hose, but there's a good chance that new ones will pop up at a later date, though probably not next year, unless new mulch is applied.

Written by: Mike Munster, Department of Plant Pathology


Anonymous said...

This shows up in my yard every year in early fall (September). I live in Phoenix, Arizona--where I wouldn't expect anything like this since it is so dry. It spreads quickly and kills any desert plants that it engulfs. It is always near the foundation of the house in a shaded area, and it smells foul. I dig it out and it comes back.

Artizona said...

I have this growing in my yard and I would like to eliminate it. Is there any way? It has destroyed several cacti and keeps coming back when I dig it out. It is only near the foundation of the house in September and October, but it spreads rapidly after a rain. I live in Phoenix--normally a very dry climate.

Diane Turner said...

Artizona, I think you should call your local Extension office in Phoenix. I know they can help you with this problem. Call 602-827-8200