Question
I own 1 house plant called an Areca Palm. Ive had it for about 1 month and for the past couple of days i have had probably 20 house flies in my small apartment. they are not small gnat-like flies they are normal looking flies that you would see everyday. I couldn't figure out why soo many were in my house, considering I never leave windows and doors open. Even if I did, its quite a large amount to be in here just from coming in from outdoors. So I think they are breeding in my house and the only place I can think of where they are laying their eggs is in my palm. Am I right? and how can I rid of any egg laying without having to throw my plant away or harming it?

Answer
Hi Sarah,

Fungus gnat larvae feed on decaying organic matter in soil. Flies do not. Unless there is some kind of food substance (compost, for example) in the potting soil, then the flies are coming from some other source. If there is food substance in the soil, then the soil should be replaced with a sterile, peat-based potting mix

Although I have seen fungus gnats in plants many times, I have never seen houseflies living on plants.

Will Creed