Sciarid fly help

Hi I have a young mango tree (about 35cm tall) that I have been growing for 8 months or so in my bedroom. I have what I think is sciarid fly living in the compost for many months now and they mainly only stay around the mango tree. I put a fairly thick layer of perlite on top of the compost months ago and this helped a bit but not much. I end up just clapping them to death when they fly out of the pot but this is becoming extremely annoying. I also put up a sticky tape trap thing but this only catches a few.

The mango tree did get a fungal disease which I treated but it keeps sprouting new tiny leaves but they keep falling off which might be due to the larvae attacking the roots and stunting it's growth.

I have had some ideas about getting rid of them but I'm not sure if they would damage the plant but at this point I might just grow another mango tree from seed and just see if this works on the infected one. I was thinking of taking the perlite off and putting vaseline on the compost to stop the larvae coming out and adults laying eggs. I would do it as close to the stem as possible but not touching it as it might burn it or damage it.

Or I have a Resolva bug killer spray which I could try diluting with water and use it as a soil soak.

Or putting a clear bag around the whole plant to see if it suffocates the flies but this will probably not work although it would stop the flies laying eggs in my other plants. I'm running out of ideas to try so any ideas will be very appreciated.

 

I've been battling these flies indoors on and off for the last three years, until I discovered a way to get rid of them. I accidently re-introduced them earlier this year by bringing a plant in from my greenhouse. The measures I took were drastic for my plants but you are welcome to try it as it does work.

Firstly, the flies I have were introduced by B&Q's Verve multi-purpose compost. If you were using this try a different compost and buy it elsewhere, this also applies if it wasn't Verve you used. Store the new compost away from any other compost or plants until you're ready to use it.

I removed all my indoor plants from the soil, rinsed the roots thoroughly in tepid water and then placed them in buckets of water for two weeks indoors. This is the length of time the flies live for and the larvae will drown if there are any around the roots. The flies will only produce more if they have access to soil. All plants indoors must be put through the process at the same time to make sure they are all clear. Discard any of the old compost and wash out the pots thoroughly.

After two weeks the flies should have died and it should now be safe to re-pot the plant/s, but do this indoors so that flies aren't re-introduced from any soil outside. I can't guarantee your plants will survive but all mine did, including a temperamental Ficus Benjamina that likes a very dry soil.

 

Thanks that does sound good but I don't know if my ginger plants would survive but I could put them out in my porch cos I don't think the flies like them. I tried sowing some cape sundew plants hoping they would eat the flies but they haven't even germinated :(
I might get rid of these things eventually

 

Thanks I've been watering from the bottom of the mango only once a week thinking that would discourage them. I've also tried using diluted peppermint tea to water it but that only reduces the numbers a little bit