As you may know from another thread, I'm get eaten alive by the fruit flies inside my house, with windows and doors closed

I have no idea where they come from.I have all window gaps closed off and all sink drains closed.

The only thing that is open are the shower drains, which don't have a drain trap.

I have set up fruit fly traps around the house, and the one in the bathroom get plenty, as well as the one below the table lamp in the living room, while other rooms only catch a few.

So my latest guess is that they come out of the shower drains which end up in a big drain pipe that runs around the perimeter.

I don't feel like replacing the drains in the shower, as that would mean breaking tiles etc.

Where the shower drains end up in the manholes in the big drain around the perimeter, is easily accessible.

Would it work if I stick such a drain trap on the pipe where it exits in the manhole?

A running P trap would be better for you

you can make it yourself with 4 elbows and a piece of pipe

A running P trap would be better for you

you can make it yourself with 4 elbows and a piece of pipe

rinning p trap.jpg

And how would I do that with a shower?

You can fit it in the manhole

You can fit it in the manhole

Isn't that exactly what I picture in the OP?

I would think it doesn't make a difference if the end piece is horizontal or vertical, my only question actually is if it will be effective when in the manhole, because there is about 25 meter running pipe between the shower and the drain trap.

Studied the fruit fly in medical genetics at ucsf......drosophila melancastor.sp? Doesnt bite humans.......maybe u have ants or bed bugs...

Studied the fruit fly in medical genetics at ucsf......drosophila melancastor.sp? Doesnt bite humans.......maybe u have ants or bed bugs...

They don't bite, but they come sit on you face, fly straight into you nose or come sit on other parts of your body.

I'm not aware of it at night, though it will happen for sure, but right while I'm sitting at my computer. I see them fly in front of my eyes, and they dive like a Japanese plane at Pearl Harbor.

If you studied fruit flies you will know if the picture below are fruit flies or something else.

Not drosophilla....sp?...... god its been three decades since my last run in with the little bastards.......slipped and fell and broke six generations of test tubes.......

could be an asian fruit fly....anyways there called fruit flys cause they eat fruit....

They look like a real young aaian honey bee........sad they plant there hive in arupid places.....places that dont last long......check around.

Entering the name in Google it indeed looks like a Drosophila melanogaster

http://en.wikipedia.org/wiki/Drosophila_melanogaster

God im getting old....i remember shit but cant see it........good thing i didnt become a surgeon. .....

You can fit it in the manhole

Isn't that exactly what I picture in the OP?

I would think it doesn't make a difference if the end piece is horizontal or vertical, my only question actually is if it will be effective when in the manhole, because there is about 25 meter running pipe between the shower and the drain trap.

No they are not the same.

The trap you have in the op is designed to be fitted to a sink.

Depending on the diameter of the pipe running from your shower it may or may not be possible to purchase a trap with the same diameter,

If you can get a trap the same size you will be fitting it in the opposite direction that it is designed to work, With a 25 meter run you could be making more problems for yourself.

Before digging up the garden / floor, are you sure the little chaps are arriving via the shower drain?

A quick and easy mitigation would be a saucer upside down over the drain (add a little Vaseline to the edge for a good seal if you wish), if they stop coming, you've got your source.

Remove the saucer before showering of course.

I often wonder why Thais build without drain traps.

Even without a bug problem, the smell is enough to get me to install my own traps!

Before digging up the garden / floor, are you sure the little chaps are arriving via the shower drain?

A quick and easy mitigation would be a saucer upside down over the drain (add a little Vaseline to the edge for a good seal if you wish), if they stop coming, you've got your source.

Remove the saucer before showering of course.

This is my catch from just 2 days in the trap I set up in the bathroom. The traps elsewhere in the house have much less victims, so they must originate from somewhere in the bathroom.

You can fit it in the manhole

Isn't that exactly what I picture in the OP?

I would think it doesn't make a difference if the end piece is horizontal or vertical, my only question actually is if it will be effective when in the manhole, because there is about 25 meter running pipe between the shower and the drain trap.

No they are not the same.

The trap you have in the op is designed to be fitted to a sink.

Depending on the diameter of the pipe running from your shower it may or may not be possible to purchase a trap with the same diameter,

If you can get a trap the same size you will be fitting it in the opposite direction that it is designed to work, With a 25 meter run you could be making more problems for yourself.

Sorry but I don't get your point. The picture I added was just a picture I got from Google, to indicate what I have in mind, but of course I have to construct it myself with elbows because the size of the drain is 2".

So the question is still, will it work at the end of a 25 meter drain pipe.

A trap at the end of a 25m drain pipe might not preclude the smells but should stop the flies if that's how they are getting in.

A trap at the end of a 25m drain pipe might not preclude the smells but should stop the flies if that's how they are getting in.

I luckily don't have smells in the bathrooms, but those fruit flies are a real nuisance.

I have placed a a plastic cup with Vaseline on the walls and bottom upside down over the shower drain and another floor drain, but so far haven't caught a single fly in the Vaseline, while they are at the same time flying around in the bathroom as if there is no tomorrow.

I have also emptied the adjoining dressing room and put all the clothes in the sun, because many of them I didn't wear long time have signs of moist.

I also notice that my antique cupboards in the living room are full of moist. Relative humidity in the living room is 70% at the moment.

Is this extreme high and if so how to solve it?

The swimming pool is at the side of the living room, but I actually rarely keep windows open to prevent heat entering.

Good or bad?

I think i found where the fruit flies enter. They go straight through the insect screen, which isn't broken by the way.

Around midday I put a fly trap in my son's bathroom, which hasn't been used for over 2 weeks as he's on holiday, so no damp conditions there.

I locked all the drains and the bathroom, and within an hour I had caught at least 5, so they must have been present. After that it slowed down.

Then late afternoon when the sun went down and was right on the small bathroom window, I went inside the bathroom and it was as if war of the fruit flies had started. Inside the trap several were crawling around and so was in the bathroom itself.

It only could have come through the insect screen from the small window, which had the evening sun shining on it. I closed the window and an hour later there seemed to be a truce.

Mr Google confirmed me later that they indeed go straight through insect screens.

Interesting times ahead if you can't even aerate the bathrooms.

You could try spraying the screen with a bug killer. Might put them off.

You could try spraying the screen with a bug killer. Might put them off.

I was thinking of hanging a piece of Camphor in front of the screen.