Written by Ron Vanderhoff
Category: Insects, Diseases & Rodents
I received another call yesterday from a Costa Mesa gardener named Joe. He seemed a bit desperate. He wasn’t quite sure whether he should call a nursery, a hazmat team, a veterinarian or The Extraterrestrial Society.
In one of his garden beds this morning appeared a large, slimy blob that looked like -- how to put this gracefully? -- dog vomit. The blob was several inches across, pale yellow, and appeared to be growing. In other words, it was repulsive.
I tried to calm him down. He sounded like he had dead-bolted the front door and closed the blinds. I suspect there may have been weapons nearby. For the next few minutes I was able to talk him down.
Joe had stumbled across an organism called a slime mold. They’re hard to ignore. When one is found, gardeners tend to be both embarrassed and fearful at the same time. The first time you see one, you might think somebody spilled some sort of poisonous goop or the egg foo yung might have fallen out of the Chinese take-out bag. In Joe’s case, aliens surely had settled into his garden.
There are more than 700 species of slime mold in the world, but the one that Joe was describing is affectionately known as Dog Vomit Slime Mold – no kidding.
Slime molds are most often seen growing on top of mulch, in flower beds or in grass lawns, but can appear nearly anywhere. The patch may be just a few inches or as much as two feet across. When first noticed, the blob is yellow in color, soft and slowly expanding across the surface of whatever it is growing on; like a giant amoeba. Then, as the weather warms, the growth transforms itself into a tan colored, cushion-like mass about an inch thick and the consistency of a slice of bread. With further aging, the crust becomes more firm and small liquid, blood-colored droplets form on the surface. The transition from a mushy yellow blob to crusty brown slime can occur very quickly, usually in one to two days.
Slime molds are strange and primitive organisms. Interestingly, there are 13 separate sexes in a slime mold’s world and one slime mold can mate with any of the other 12 sexes. Slime molds have also caused all sorts of classification problems for scientists. When Carl Linnaeus first developed a classification system for all of the world’s life forms he considered there to be only two kinds of life - plant and animal.
But over the past 250 years things have expanded considerably. Eventually, a five-kingdom model of classification emerged, incorporating plants, animals, fungi, algae and bacteria. But now biologists are considering adding a sixth kingdom, which would include that slimy blob in Joe’s garden.
Slime molds are essentially harmless things, but admittedly are ugly. They aid in the breakdown of organic debris. Slime molds feed on bacteria, fungi and other dead organic matter. Chemical control of slime mold isn't necessary and eventually every gardener will interface with a slime mold or two. If they really bug you, consider simply raking over the developing mass before it develops any further. Better yet, as I instructed Joe, unlock the door and open the blinds. Just avoid this little patch of the garden for a couple days and the hideous little creeping blob will go away by itself.
Questions from Readers September 5.
Several emails came to me about last week’s article on the first discovery of Asian Citrus Psyllids in Orange County. Most wanted to know what to do, but several people thought they had located infestations on their backyard citrus, only to find that they were looking at whiteflies, scales or aphids. One person brought a ziplock bag full of houseflies to the nursery, certain that they were Asian Citrus Psyllids.
Lynn, Costa Mesa
As I mentioned in last week’s column, the most important thing a home gardener can do is to obey the quarantine on the movement of backyard citrus fruits, foliage and plants. Meanwhile, citrus plants that are sold in any Orange County garden center or nursery and citrus fruit sold at grocers and farmers markets will all be certified by the County Agricultural Commissioner as free of the pest. Tonight I am meeting with state and local agriculture officials in Irvine to learn more about this new pest and the citrus quarantine. I’ll keep you posted of any new developments.