Flies in soil

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Freeranger
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Flies in soil

Post by Freeranger »

Can anyone advise about flies in our garden soil, please?

I've just been digging dense buttercups out of a patch of garden (much to the bemusement of the bumblebees) and have been bitten all over. The area is in Scotland, highish (325m,c1100ft) mostly shaded to dapply, clay, permanently moist as at a low spot, near a stream, and quite rich in nitrogen and plant matter. Weather is warm. Plants doing well in the spot include willow, miscanthus, nettles buttercups and snowdrops and a shrub I think might be doizia.

These are not midges but smaller, and swarm just above the surface as I dig. I'm not sure if they're being released or are attracted to the bare earth. After a bit of sun on the soil and a breeze, they disperse. They don't seem to be over the areas I've done already.

Can anyone tell me what they are, and how I get rid? They're bitey little beasties and I come up in lumps. I'd like to stuff as much ground cover into this bed as possible, but am not sure if that will make it worse again. Maybe I should leave it exposed for a while. Any thoughts welcome.
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lancashire lass
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Re: Flies in soil

Post by lancashire lass »

Freeranger wrote:mostly shaded to dapply, clay, permanently moist as at a low spot, near a stream, and quite rich in nitrogen and plant matter.


Freeranger wrote:These are not midges but smaller, and swarm just above the surface as I dig. I'm not sure if they're being released or are attracted to the bare earth. After a bit of sun on the soil and a breeze, they disperse. They don't seem to be over the areas I've done already.


just going off the above description of the soil and activity, I think these might be fungus gnats/sciarid flies see this link to the RHS advice sheets

You are probably more familiar with them on seed trays filled with damp humid compost when it is warm indoors and they become a bit of a nuisance leaving dead flies on windowsills, but generally they are attracted to the mould and compost than in the living plants (tiny seedlings might succumb but generally fully grown plants are not affected) They can be seen in the vegetable garden when digging up mouldy potatoes (or rather you might notice the worm like larvae) or rotted onion bulbs (when the roots are withered and the bottom of the onion is soft and mouldy) but they are only attracted to the fungus and mould rather than be the actual cause of problems. If anything, they are actually doing a good thing in the compost heap not to mention a food source for predator insects and small birds, but their sheer numbers means they are in your face (they could be attracted to the carbon dioxide as you breathe which is probably how they look for presence of moulds)

As for biting, it's possible there are other insects like midges around but you might just be noticing the large numbers of the other flies? If you are convinced the flies you are describing are the ones responsible for biting, I'm afraid I'm at a loss as to what they could be sorry.
Freeranger
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Re: Flies in soil

Post by Freeranger »

Hmm - food for thought there, LL. Thank you. We do have this type of fly around the windows so it is a possible suspect.

You may well be right about the biting as it is quite hard to tell. Maybe I've just made wrong assumptions. I guess the lush, shady spot might just be a home for loads of midges too.

If I go for the well-stuffed cottage garden look will that tend to encourage them back, do you think? Maybe I should try and keep it a bit more open. I don't want to spoil things for our lovely bird and bat life, but there is a balance in all things....
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