Which Soil Fungus Is this?

Question

I've been trying to save the last of the larger peace lilies I got for a while, and it looked like it was taking ok to splitting and pruning the dead sections (earlier issue : rootbound and overcrowded leaves), but it's broken out into mold all over the soil surface in both pots it was split to.

For right now plant A from the split still seems pretty healthy and plant B is weakened but still having new growth/recovery, so am trying figure out whether I can get ahead of this or if I should abandon.

Answer 1

There is what appears to be some sort of creature or larvae visible in the image - its on the right hand side of the picture, on the soil. It looks greyish white and has what looks like 3 pairs of legs at the front... but I can't see it clearly, so it may not be a creature at all.

Assuming you haven't kept the soil absolutely sodden with water, but have been watering sensibly, the mould is probably due to the potting soil, because it seems to have a lot of lumps in it, much of which is un-decomposed woody material. With lumpy potting soils, it's usually best to sieve out the larger pieces if you're going to use it for houseplants. You could pick off the larger pieces, but I doubt the mould will kill your plant anyway, though you may not be thrilled to have a pot full of mould covered soil in the house. But whatever that creature is, if it is a creature and its still alive, might be an issue for your plant. If you can find proper houseplant potting soil, then it might be worth decanting the plant, washing off the existing soil (in case that creature has burrowed into the soil and is nibbling the roots) and repotting into the new soil.

Answer 2

You might be a bit confused:

“Soil organisms show their greatest diversity of species and usually their largest populations in productive soils. The size of the microbial biomass usually shows direct correlation with the amount of plant growth…” - Soil Microbiology and Biochemistry by E.A. Paul and F.E. Clark, Academic Press, Inc.

The truth is that these spores that provide a Gardner with "living soil" are present in all forms of natural soil that has not been treated. Treated soil is treated for aesthetic purposes only and it is highly HIGHLY unlikely that this mold is doing anything but good things for you.

Mold on your surface dirt can actually be a sign of healthier dirt. Here is what I would do:

Rather than kill the fungus I would go to the garden center and pick up some Mycorrhizae powder. Pull up these guys and wash off their roots and before planting (in the same soil) spread some of this powder onto your roots and mix it into the soil.

This way we can be sure you are not going to loose all the great benefits of having a healthy "living soil" without having to worry weather or not the fungi in your soil is supposed to be there or not.