Sciarid flies

I have noticed quite a lot of these little pests in my propagator this week and have tried an experiment to get rid of them.

I have put three drops of Manuka and three drops of Lemongrass essential oils on a cotton wool pad and wiped it on the edges of the pots and then left it in the propagator and closed the lid. When I opened it up again a few hours later two sciarid flies flew out and there was no sign of any left inside. I tapped the pots to see if any were hiding but couldn't see any.

It will be interesting to see if any have come back tomorrow, or how long it keeps them away.

Both these essential oils are insect repellant, so they would probably work on their own.

I also have some insectivorous plants on the greenhouse staging, butterworts are the best for catching sciarid flies, there are also two kinds of sundew and a saracena (pitcher plant).

I've never had them inside my propogator yet, but had loads in the greenhouse pots and trays.
I'm never really sure if they do any harm or not?

Never thought of using oils to deter them...I used to let the compost dry out a bit, for some reason I thought that they liked really moist conditions..but maybe that was something else..

I love the carniverous plants, but always assumed them to be hard to look after.
Though I grow , and look after literally hundrds of plants, mainly from seeds, i'm useless with indoor pot plants, lost count of how many I've killed.
I bought a jasmin a few weeks ago, put it in the sunlounge, forgot to water it, but could still see buds on it every time I walked by, so thought it o.k. Went to check it last week, and the plant , leaves, buds had all dried out..they crumbled in my fingers...So there it sits, mocking me, yet another failure.

You are right that the flies like moist conditions, but you can't really let seedlings dry out much can you especially with the bottom heat in the propagator. The eggs they lay in the soil hatch into tiny see-through larvae which eat roots. I don't think they actually kill anything as they are so small, but they will set the seedlings back quite a bit.

I also found a slug in the propagator which was chomping its way through a tray of nicotiana. I wondered why none had germinated all down one side of the tray.

I know what you mean neglecting house plants, mine usually look rather sorry for themselves. I have been making a special effort for the past year and water them with diluted 'worm wee' from the wormery. I don't know the analysis for it, but it makes everything flower. I would have thought it was more nitrogen than potassium, but it works anyway. I sometimes spray them with a seaweed feed too which seems to perk them up. I might even go overboard and pot some of them up this year - they have been in the same pots for years, poor things.

I've abandoned the experiment and decided to put yellow sticky traps in the propagator - I can see how many flies I've caught and I haven't caught any beneficial insects as the propagator lid is closed most of the time while the seedlings are tiny.

One surprising thing I have seen this week is some small centipedes in the plant pots in the propagator, so nature is solving the problem for itself as they are eating the sciarid fly larvae. Isn't nature wonderful - we just have to be patient.

Fascinating thread thanks Pat. I love the outcome - that given a little time nature finds the balance.