Hey guys I have a styrofoam grow box which sits on the grass beneath one of my benches . I moved it the other day and noticed a patch of white fiberous fungi or something, I've just now noticed it on the surface amongst some fert pellets... is this the good type (micorrhiza or something along those lines) or is it a problem?
The first photo shows some highly rhizomorphic mycelium, typical of a saprotrophic basidiomycete. That is to say it looks as though it is likely a mushroom producing fungi that is more concerned with breaking down the dead organic matter in the soil than attacking the living tissue.
The second photo shows hyphae (the thin threads) containing sporangia (the small bulb like lump visible on the tips of some of the threads) and is likely in the phylum Zygomycota, so a non-mushroom producing fungus.
Neither are likely to directly harm your plant but a highly organic mix could become hydrophobic (repel water) if the particles in the mix become completely colonised.
Its good stuff don't worry. All natural organic breaking down of microbs. Will not hurt trees or soil. Once the sun and air get to it it will naturally die.
Cheers
Kirky