Asked January 18, 2021, 1:06 PM EST
Hello! I recently purchased a potted pothos from a local big box store. The tag indicates it came from Michigan nursery as well. I’ve been keeping it quarantined as I do all new plants, especially as the last couple days I’ve noticed new foliage blackened/failing to unfurl & dark spotting under leaves, so I was concerned about thrips. I went to examine it more closely last night, prune damaged areas and apply some horticulture oil to the foliage and insecticidal pellets to the soil as a precaution. However, after removing some foliage and getting a better look at the potting soil, I saw what I thought was mold/fungus - flat green across the surface and more raised, fuzzy white around the edges of the pot, almost like webbing. I decided to drench with 1:2 water & 3% hydrogen peroxide & intended to follow with a systemic fungicide. Before I could get to that part, I noticed little black worm shaped things popping out all over. I was able to get one out intact by touching it with fly trap sticky paper & it was certainly a larvae/maggot but nothing I’ve ever seen before. Black, thin and tapering at its ends, unsegmented, totally smooth - almost like a tiny leech. The white webbing I thought was mold also looked to contain what I assume are the pupae of this... thing. I tried searching and Mycetophilid fungus gnat larvae seems to fit the description of the larvae and the environment I found them in - green coating, white webbing along edges. I’ve never heard of this before and I’m not seeing a ton of information. Can you advise on how to treat & whether they spread plant pathogens? The pothos in question is currently isolated & grounded to my basement for traumatizing me - I’ve had plenty of plants with fungus gnats, but they were cute & cuddly in comparison to these things.
Ingham County Michigan