"Dog vomit fungus" is one of those oddities of nature that just makes you say "eeewwww!" Even if you've never had it in your garden before, it's pretty safe to say that you'll know it when you have it; its nickname couldn't be more fitting. It is most likely to show up during warm, wet periods, sometimes seeming to pop up out of nowhere overnight. It often grows in wood mulches or along the sides of untreated wood, and sometimes in lawn grass.
What Is Dog Vomit Fungus?
The scientific name for dog vomit fungus is Fuligo septicai. It is also known by another nickname—"scrambled egg fungus"—because the fruiting body (the part you see) is light-yellowish in color and looks a bit like scrambled egg curds. The frightful appearance of this fungus may cause concern that it's harming garden plants, but it is actually really interesting (if you have kids, they'll get a kick out of learning more about this oddball organism).
Fuligo septicai is a type of slime mold and is most often found in moist, shady areas and on materials such as mulch, rotting logs, leaf litter, and untreated lumber. Dog vomit fungus and other slime molds are saprophytic, which means that they feed on decaying organic materials. They are not diseases and won't really harm your plants. Occasionally, they'll grow on plants that are growing in mulch, and if a large enough colony forms, they may smother the plant.
This is uncommon, however, and you'll usually just find the mold in the mulch itself.
Life Cycle of Dog Vomit Fungus
Slime molds like dog vomit fungus produce spores that are wind-borne. They are highly resistant and can survive even during hot, dry weather. The spores can remain viable for several years, waiting for conditions to be favorable for growth.
When warm, moist conditions are present, the dormant spores absorb moisture and crack open to release a swarm sphere. It is shortly after this stage that gardeners see the tell-tale, disgusting-looking fungus appear.
Controlling Dog Vomit Fungus
The best way to get rid of dog vomit fungus is to break it up and dry it out. Fungus that is growing in mulch or leaf litter can simply be raked out and disposed of. It is best not to dispose of it in your compost pile, unless you practice hot composting or you want more of the fungus to show up in your garden later.
Dog vomit fungus growing along lumber or tree stumps can be scraped away with a trowel or small shovel and disposed of. If you have it growing in your lawn or in plants, gently rake it out as best you can. A strong jet of water will help to dislodge any of the remaining fungi still clinging to the plants (although it may pop up again later.)
If dog vomit fungus continues to be a problem, you may want to consider switching from wood-based mulches to something inorganic, like gravel. But in most gardens, it doesn't pop up often enough to be a real issue. And because it typically doesn't harm plants, you may opt to let it be and simply hope for drier conditions in the future so you won't have to see it again anytime soon.