Getting rid of Tiny flies

[Andy Hamilton]

Having a bit of a nightmare at the moment. We are strating to get taken over by tiny flies. It was ok in the summer as we had a carnivourous plant foolishly gave it away. I have been looking for another to help eradicate all the flies but florists do not stock them in the winter.

The flies are the tiny sort about the size of mustard seeds. They seem to have taken up residence in my window box. I had to take this inside becaue of frost, so I guess the heat from the central heating does not help. They seem to be eating away at some of the plants, and I have found tiny little grubs in some of my other pots. I am going to start planting my seedlings soon, so I desperately need some help on this one.

[jennywren]

I think the only organic way to get rid of them is to change the compost in all of your pots (and scrub them out too). I had an infestation like this once in my greenhouse. I think it's caused by keeping the compost a bit too damp, which then gives the flies the ideal conditions to breed in.

[FluffyMuppet]

They sound like fungus gnats (sciarid flies). The flies themselves are harmless, although annoying. They can't fly well and have a tendency to drown themselves in any available body of water or the dregs of cups of tea. Their larvae will damage seedlings by nibbling away at the roots.

All the available information says that keeping pots on the dry side will discourage them, but I've never had much luck with that. Yellow sticky traps work really well if you can stand the ick factor, although you will need to persevere as after the first flush of adults have committed sticky suicide there will still be grubs hatching out.

I have read that they will be attracted into carnivorous pitcher plants, and have actually bought some seeds to give that a go. They are too small to trigger the traps on a Venus Fly trap.

If your plants are in imminent danger of death then I have had some success with changing the compost, as jennywren says, but I also washed the roots of the plants to make sure the grubs were gone. They don't swim well :)

[Andy Hamilton]

Cheers both of you, it was actually a pitcher plant that I was after that was what I had last summer and it worked a treat. Will try and get some seeds myself rather than buy the plant this year, where did you buy them from?

I managed to kill some with the cider I brewed that is still a bit too sugary for drinking, have loads swimming around upsidedown in a mug of it. nice

I will have to get scrubbing then do you suggest anything to use such as disinfectant?

[Wombat]

G'Day Andy,

When I was doing plant propgation as part of the Farm Tech certificate we always used dettol to clean up our pots and equipment. It may be worth a go!

[FluffyMuppet]

I bought my pitcher plant seeds from eBay (http://stores.ebay.co.uk/Supreme-Seeds_ ... ayZ2QQtZkm), but while I was waiting for them to be delivered I also bought a kit for growing carnivorous plants from Homebase, which has seeds for Venus Fly Traps, Sundews (I think, it's a themed 'scary plant' kit so they call them something else) and Pitcher plants.

I wouldn't have thought disinfecting your pots was really necessary to get rid of the fungus gnats, hot soapy water should be fine, but you can get plant-friendly disinfectants (Citrox, I think it's called, from the Organic Catalogue). The 'classic' garden disinfectant is Jeyes Fluid, which I think is pretty heavy going, but anything should be OK as long as you rinse well.

[Andy Hamilton]

Right pots are clean and ready to grow again.

Now this has given me a new dilema, I have a bin bag full of compost in my flat. I can't chuck it out with the rubbish as it is known as garden waste and they wont touch it.

Is is ok to put it on my allotment without fear of the flies ruining all of my plants. I think there is going to be a frost tonight I would have thought that would kill off the little blighters. Or am I better off just chucking it in the 'green' waste area on the allotment?

Fluffymuppet/emma how are your carnivourous plants getting on?

[FluffyMuppet]

Fungus gnats won't thrive outside in this cold weather, so putting the compost on your allotment should be fine. They like it indoors because the warmth and humidty lets them breeed all year round

It's also only the larvae that do any damage and then generally only to young plants.

My carnivorous plant seeds are still in the fridge - one set said they needed to be in there for a month (which is nearly up I think) and the other said 3 months, so they've got a way to go.

And you can just call me Muppet, to distinguish me from the other Emma 8)

[FluffyMuppet]

Just as an update, from my original carnivorous plants set, only 2 pitcher plant seeds ever germinated. They're now making slow progress on the windowsill.

My other set of just pitcher plant seeds needed a longer period of cold stratification, which they finished a few days ago, so I am still waiting for them to germinate.

In the meantime, I bought a sundew (Drosera) from a local garden centre last week which is living among the plants at work - and eating lots and lots of fungus gnats. In fact, it was so successful that this weekend I have bought another one to live at home - it's still settling in to its new surroundings.

The garden centre has a lovely display of very large pitcher plants - some of which are hanging in hanging baskets and have pitchers about 8 inches tall! Very impressive, but I don't have a suitable home for one that big at the moment.