Dog Vomit Fungus pretty much says it all. We get several calls every year when it’s warm and moist asking, “What the heck is this yellow stuff in my mulch?” and “How do I get rid of it?”
“Dog Vomit Fungus” goes by the scientific name of Fulgio septicai, and is a Slime Mold. It usually occurs in warmer weather and moist conditions. It feeds on decaying organic matter. This is the reason we see it most often in mulched areas, where the mulch is breaking down. It’s not uncommon to see it growing on or around the stems of plants. The fungus is not harming those plants. There is a slight chance of it smothering smaller plants, but this usually does not happen.
Dog Vomit Fungus is spread by spores through the air. After it goes through the slimy yellow phase, it will crust over and turn light brown. If it is disturbed at this point, the spores will puff up like dust and be distributed by the wind. Spraying it with water at this point will only result in increasing the spread of the spores.
Control of Dog Vomit Fungus
There are 2 main ways of controlling the Fungus, drying it out or removing it. While it’s in the slimy phase, use a rake to spread it out. Exposing the fungus to the air will help to dry it out before the spores are produced. The second way to control it is to just remove the mass. Be careful to dispose of it away from your garden areas to reduce the chances of it popping back up. Remember that excessive moisture started the cycle. Try to insure that those areas have a chance to dry out more thoroughly. Therefore if you use irrigation, you might dial it back a bit in that area.