Fungus gnats

[CarterBeatsTheDevil]

I've got a collection of cacti and succulents which I absolutely love and am very proud of. My husband has a rubber plant which developed fungus gnats (different room). He didn't want to treat them and now all the plants in my room (about 14) have fungus gnats. They all got them at about the same time so I didn't have time to isolate one in particular.

I know lots of people don't necessarily bother to treat them but when you have 14 infested plants that's a lot of tiny flies knocking around.

I've scattered diatomaceous earth in them and dried them out, but I couldn't leave them without water any longer (they'd been left for 4 weeks) and having watered them a week ago two of them are already showing signs of infestation again. They were very well drained. Is this just eggs from the last batch? Do I just keep going with the diatomaceous earth after every water?

Stickies still clear!

I was about to start a new thread on this. Will try most of these suggestions- thank you! Tiny flies are so irritating but I'm not sure which plant was the original culprit.

The nematodes were the clincher, I think. Nematodes and stickies for the adults. The diatomaceous earth does sort of work but it is messy and causes white tide marks in the soil. Good luck!

Just ordered some nematodes. Never even heard of them but 🤞🏻 they do the trick

Same here. After repotting I put either stones, slate chips or decorative glass pebbles on top. Definitely works.

I'm still not winning with some plants I took as cuttings last year, I've tried putting stones on top of the soil, cinnamon, chilli powder and upside down matches but they're still flying about!!

Fungus gnats like damp soil and decomposing stuff, ad their name implies, they eat the fungus gowing on it. They need a wet environment, so are you overwatering?

If you can, dry the soil out, that's 90% of the problem.

Otherwise, look on eBay for 'hypoaspis'. You'll get a bottle of soil filled with tiny mites. These eat the fungus gnat larvae. One pot of 2000 costs about £10 and can cure easily 50 plants. Just sprinkle this soil onto the tops of the plant's soil.

Alternatively, buy nematodes if your soil has to be kept wet. Look for Steinernema feltiae (no other species with similar names!). Dissolve these in water and water your plants.

Neither of the above mites/nematodes will go elsewhere, they will only live in your plants!

It's not an instant fix (maybe a week or two). The adults will linger for a while and lay eggs again on any plant with untreated soil.

@Girliefriendlikespuppies Bastards. Time to bring in the predators!