Question: Is this a slime mould?

By | 04/01/2019
A slime mould on grass in a lawn.

I was sent these lovely photographs from a reader in December 2018 regarding a strange growth on her grass. She briefly writes:

Is this slime mould?

Erika
A white slime mould amongst clover on a lawn.
A white slime mould amongst clover on a lawn.

Thank you Erika for the question and the brilliant pictures.

Yes, that is a great example of a slime mould. If you have a look at a photographs of this dog sick slime mould you will see that it is very similar. That one appeared on my test lawn in the summer of 2018.

Your slime mould may be a similar species (mucilago crustacea). That is difficult to be sure from the pictures alone.

Slime moulds appear in a few hours and then tend to turn black and fade less than a day later.

What is a lawn slime mould?

A slime mould is not a plant or animal. It is a collection of single-celled organisms called Protozoa. When the environmenal conditions are correct they bloom and spore in huge numbers. This is the structure which becomes a slime mould. Once they release their spores for the next generation, they collapse and die.

They can vary in size and colour, but are most often yellow or white like yours.

If you look you can see that it is an intricate structure. It grows up and around the grass leaves which support it. Notice how it is enveloping the grass leaves, but they remain unharmed.

Will it harm my lawn?

Slime moulds do not harm grass. They grow up in and around the grass leaves and find their food by smothering bacteria, spores and tiny organic matter as they grow. They may leave an unsightly black “splodge” on the grass. This can be easily removed with a rake or the mower. No harm will come of the grass.

If it looks unsightly and you would like to get rid of it, then you can squirt it with a jet of water to wash it off.

Thanks for sharing!

Kris Lord

If you have a picture of a curiosity on your lawn, let me know!

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