Do flies hibernate.

[joe90]

After such a long wet period finally some sunshine, but what’s this, my conservatory is full of flies!!,! And I mean many hundreds. There is a slight design flaw in that where the sloping roof fits the timber there is a tapered gap that flies can get into. I meant to fill this with foam strip but forgot last year. It would appear the flies have “hibernated” in this gap and come out into the warm. There are no flies outside to indicate they are coming in from out there.

 

answers on a post card to........

[jamieled]

Cluster flies can do this. Do they seem a bit dozy?

[SteamyTea]

Some do, some don't

https://sciencing.com/list-of-insects-that-can-hibernate-12335399.html

[Jeremy Harris]

Sounds very much like cluster flies.  They hibernate in tiny gaps, typically around the outside of windows and doors.  I had thousands of them inside my garage last year, all banging their heads on the window, trying to get out.

[ProDave]

Cluster flies get past the first seal in our Rationel windows, so when you open them for the first time in the spring a whole load of half asleep dopey flies fall in and you spend the next 10 minutes chasing them out.

[Delicatedave]

We moved in in Oct, cleared the loft Nov, it's March and if I open the loft hatch for a few hours the bedroom window sill will have flies tried to get out. Don't have clue where they are in the loft, it's be vacuumed to to bottom. Don't want to use chemicals so hoping it'll fade away.

[joe90]

Thanks one and all, yes, sounds like cluster flies, must fill the gaps and keep vacuum ing.

[Jeremy Harris]

2 hours ago, joe90 said:

Thanks one and all, yes, sounds like cluster flies, must fill the gaps and keep vacuum ing.

 

 

They can get in through extremely thin gaps, and even seem to be able to get past the flap type outer window seals.  They are also creatures of habit, and will often over-winter in the same place, year after year (no one seems to know why, as they don't live that long).  I believe that there are some deterrents available, a bit like using diluted peppermint oil to keep spiders away.  Once the cycle is broken it seems that there's half a chance that they won't come back again in the Autumn.

[joe90]

I have bought fly papers on line to help (if they arrive !).

[Gone West]

We have flies hibernating under the roof tiles and in the winter when the sun shines they come out and provide a good meal for the pied wagtails.

[Jenni]

For cluster flies we find regular use of foggers helps. 

For big flies we've had great success with "Red Top" catchers. 

[ragg987]

Spring has sprung. And with the warmth and sunshine the flies have exploded. This has occured for the last 3 years now - start in spring, buzz around until autumn and then vanish.

 

They congegrate on our west, east and south-soffit boards and render at the top of our 2-storey house. I get the impression that they may be sheltering behind the render carrier boards and now that the sun is out they want out too!

 

Any ideas how to tackle this, given i would have limited access to behind the render boards? A google search suggest these can get through tiny spaces so sealing may not be effective, and I guess if sealed tight might encourage a damp space?

 

I have a few of the red-top catchers out and they are of extremely limited use - they catch maybe a few hundred and there are thousnads of these things.

[Matt60]

On 20/04/2021 at 17:39, ragg987 said:

Spring has sprung. And with the warmth and sunshine the flies have exploded. This has occured for the last 3 years now - start in spring, buzz around until autumn and then vanish.

 

They congegrate on our west, east and south-soffit boards and render at the top of our 2-storey house. I get the impression that they may be sheltering behind the render carrier boards and now that the sun is out they want out too!

 

Any ideas how to tackle this, given i would have limited access to behind the render boards? A google search suggest these can get through tiny spaces so sealing may not be effective, and I guess if sealed tight might encourage a damp space?

 

I have a few of the red-top catchers out and they are of extremely limited use - they catch maybe a few hundred and there are thousnads of these things.

 

I've had these is a couple of houses and contrary to what I have found online, you can get rid of them but you need to be consistent over 2/3 years. Cluster flies are also sometimes referred to as field flies which is many ways is more accurate. They spend the summer on the fields and over-winter inside. They give off quite a distinctive smell and it is this smell that let the new ones know where to bed down. Once you break the cycle and get rid of the smell, you're in business.

 

The following is a result of my own research and trial and error and it's worked for me. I don't claim to be an expert, but the following did work.

 

If you have them in at the moment (you probably do, not quite warm enough yet) then you need to get rid of the ones you do have. You can either use a Henry hoover to hoover them up (this will make it stink and eventually clog the whole tube up with fly guts), do not use your main vacuum cleaner for this. I warn you... I bought a load of copy Henry hoover bags of eBay for this purpose but you'll still need to soak the whole tube section in hot soapy water to get it clean - don't bother while it still works and until you've cured the problem. It's not a nice job.

Or

Use a "Bug Bomb" - I used to buy mine on eBay. I used to put mine on a baking tray (just in case) light it and leave it in the loft. It will kill any insect and doesn't produce enough smoke that you need to tell the fire brigade or anything like that. This is a good system as it gets the whole lot dead in one hit. 

However, you still have the smell that attracts the others and so you are going to have to hoover them up and get them binned - see the above issue and advice.

Then

What I did was got concentrated lavender floor cleaner and diluted it into what was still a very strong solution. My issue both times was a loft and so I loaded this in to a pump pressurised garden sprayer and sprayed it between the roof membrane layers and around the soffits and anywhere else I thought they might be getting in. I also soaked the roof trusses etc. I then burnt fistfuls of lavender josticks, particularly from the autumn onwards as the weather cools and they come off the fields. Once the summer was finished I'd use a small bug bomb and hoover up all the bodies. 

 

If you keep doing this and are diligent about it you can pretty much cure it in about 2/3 years. The first time I done it resulted in about a 90% reduction from what must have been 100k flies. Basically; bug bomb, hoover the bodies and dispose, and then kill the smell with lavender based products as they don't like lavender. Don't bother trying to seal up the gaps, you're wasting your time. Oh and don't let them freak you out, they are not normal flies, they don't go for rotting flesh and turds. Their eggs are laid in the grass and hatch out of the ground I believe.

 

Anyway, Good luck!

[ragg987]

Really appreciate this. I need to figure out how to tackle behind render carrier boards. A company I spoke to suggest I dust insect powder into the void using a pressure pump. They also said breaking the cycle is key as the flies leave a pheromone that draws them back.

 

I'm going to try this and will report back.

[joe90]

Just as an update (as I started this thread) in my conservatory there was a gap between glass and inside frame of about 6mm, I believe the flies laid eggs in this gap and during the spring they all hatched, hence clouds of flies. I scraped out this gap with a piece of stiff wire and inserted a length of 10mm foam, no flies since, will see what next spring brings.