Monday, July 13, 2020

Slime Mold Sounds Nasty But Good

Horticulture Hotline 07/13/20
By Bill Lamson-Scribner

Many people are coming in to Possum’s with pictures and texting me pictures of a black film over the leaf blades of grass. What you see is the fruiting body of a fungus that is decomposing thatch and other organic matter in the soil. When the fungus tries to reproduce, it sends it’s spores up the leaf blade of the grass where it is higher up in the air, so the wind will catch a spore more easily. With the spore up in the air, it will travel further also. This fungus is called slime mold. Very nasty looking, but beneficial since it is helping to control thatch.

Slime mold does not hurt the grass, except for the shading of the sun from the leaf surface where photosynthesis takes place. This shading is usually not an issue because these spores disappear very quickly. The weather was perfect for this mold to want to reproduce. Overcast, rainy and humid days are ideal conditions for this fungus.

 Since slime mold’s main purpose is to decompose organic matter in the soil and it really does not damage the grass, I have never recommended any chemical control for slime molds. I do suggest you spray it off of the leaf blades of your grass with a hose if you can’t stand it. In a commercial setting or golf course (read and follow product label), you could use Protect DF.

All grasses are a susceptible host, but remember the spores are just using the grass like a ladder for a little elevation. Slime mold is helping to break down thatch and other organic matter, which is a good thing. I would leave it alone and let mother nature lend me a hand in controlling thatch.

I know I have to get back to those biting insects, but the rains we had and basically the time of year, brought up a whole different set of issues. Gray leaf spot on St. Augustine grass, chinch bugs, army worms, large flying roaches trying to get out of the heat at a cousin’s house (no one ever has roaches themselves – always a friend or a cousin), and those nasty flies by the grill (s) and garbage cans have come on strong.

With all the rain and the fact that many people just fertilize in the spring because they do not realize how long our growing season is, I’m seeing some mighty hungry grass, shrubs and trees.

Always read, understand and follow product label. The product label is a Federal Law.