Hello, I recently planted several plumeria cuttings. The soil has 1/3 miracle grow potting mix, 1/3 sand and 1/3 perlite. I also added BR-61 Fertilizer 9-58-8. This morning I noticed the worm shown in the in the picture below in one of the pots. Is this a worm indeed? Is this harmful to the plant? Is there a treatment to get rid of it?

It looks like the larvae of a fly. Do you have any gnats or larger flies hanging around the plants?

Hi Sooby! Thank you for your feedback! I live in Houston so there's always gnats and flies. Should I be worried about this in regards to the plant's health? I just planted this cutting 3 weeks ago, so I hope I do not have to treat it and stop it from growing.

The black head is typical of fungus gnat larvae, which can be detrimental to plants but it would depend how many there are and whether there is something else that looks similar which is harmless. If you have any potatoes to spare put a slice of one on top of the potting mix and if there are other fungus gnat larvae they will be attracted to it within a few days. If it attracts a lot then you may want to treat.

Thank you so much! I'll try that this week.

Hard to ID without any size reference.

Why are you using such a high phosphorous fertilizer?