They’re back. While visiting a landscape yesterday, I could smell the unmistakable odor of the foul smelling stinkhorn mushroom. The landscape’s owner pointed them out to me but my nose had already detected them. They were coming up all over a side bed mulched with wood chips. The homeowner, knowing how this fungus operates, was doing the only control practice other than removing the fungi’s food source (the wood mulch). The control practice is removal of the individual mushrooms while they are in the “egg” stage.
Stinkhorns are mushrooms that smell like rotted meat. It’s their putrid odor that motivates residents to seek advice on control measures. But with the exception of the objectionable smell, stinkhorns are really not a problem.
Mushrooms are the reproductive part of a fungus. They grow from fine root-like structures called mycellia, which normally go unseen. Mycellia can live for years in wood, other organic matter, or the soil.
The stinkhorn fungus is a decomposer and is considered beneficial because it helps breakdown decaying plant material. This fungus helps compost grass, straw, wood chips or similar organic matter on the soil surface. It seems to prefer wood.
Stinkhorn fungi start as white, egg-like structures that are anchored to the soil by a root-like network. Only the top of the egg-like structure can be seen. The mushroom emerges from this egg. Based on the type of stinkhorn, the fruiting structure (mushroom) will be stalk-like or globular, lattice-like in shape. Mushrooms vary in color but most are pink to orange. They also vary from 2 to a little over 6 inches in height and from 1/2 to 3 inches in width. All possess foul odors.
Various insects, including flies, are attracted to the scent of stinkhorn mushrooms. Flies feed on the spore slime. After dining, they depart and transport spores for this fungus to other locations.
Stinkhorn fungi do not cause disease, in spite of their occurrence near declining trees and shrubs. Their colonies may extend in all directions around the visible mushroom and they persist for a number of years until their food source is exhausted.
Mushrooms from the stinkhorn fungus are produced during cool, moist weather (fall through spring0.
Realize that this fungus is beneficial in that it is a decomposer. There are no legal, effective, practical chemical control options. Hand-pick the “egg” stage before it ruptures and put it in a zipper bag in the garbage. Small or new colonies may be eradicated through complete removal of mulch to the depth of the native soil. No guarantees with this method.