Fungus gnats ?

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  #1  
Old 08-13-13, 07:55 PM
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Fungus gnats ?

The best I can tell these are fungus gnats. I've looked at many charts and that species seems to be the closest. These things are only 3/16" of inch long. Most are smaller. What a job trying to catch one on scotch tape to get a picture.

They seem to like moisture although I haven't found them in any of the sink traps.

What do you think ?
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Old 08-14-13, 05:54 AM
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A common breeding place for fungus gnats is in over-watered house plants; especially the pots with spanish moss on the top.

Slowly scratch into the surface of the soil to look for a ďjumpingĒ movement. This is what they do.

What about floor drains in basement, laundry drains, sump pump pits, etc?
 
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Old 08-14-13, 08:48 AM
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There is a shower stall with drain but no insects spotted in the shower. No floor drains or sump pit. Laundry is into a standpipe next to a laundry sink.

We're going to check the plants.

If they were coming from a particular area, like a drain, would they have a tendency to be flocking there ?
 
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Old 08-14-13, 03:43 PM
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Yes. Typically with the small flies you will see a greater density of them as you get closer to the nest/breeding site.

If you have central air, does the condensation drain go under the slab by any chance?
 
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Old 08-14-13, 10:34 PM
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Yes...I have central air but the condensate drains into the laundry sink in the basement.

The house is a split level with basement.... no slab.

The flies are concentrated in the kitchen. I found a few in the basement one day and then no more. Like I said I have a shower stall in a lower bathroom but haven't seen one anywhere near that bathroom. One day there were a few in the upstairs bathroom and then they were gone. A few were spotted in an upstairs bedroom.

We do have several plants and one does have spanish moss but I haven't seen any activity near any of the plants or in the soil. I've sprayed the soil with a soap mixture.

I tried tape on the kitchen drain but didn't see anything on it. They don't seem to be hanging around the sink.....just all over the kitchen.

I think what's happening is when I start to chase them in the kitchen they travel around the house. I've noticed they fly very fast and erratic but not very far.

I'm getting pretty good with the dustbuster

Any other thoughts ?
 
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Old 08-15-13, 04:32 AM
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I had a squirrel get into my chimney and die. Didn't know at first until it really started to decompose, however, all of a sudden I had flies everywhere. I could vacuum every hour and still not keep on top of them. Apparently they don't live long. Anyway, I stoked a good hot fire and kept it going for a bout a day and cooked what every was in the chimney. Then had someone help with getting the carcass out (I have a weak gag mechanism).

Check the refrigerator drip pan to see if you have any excess water under it that may provide a breeding ground for your winged friends.
 
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Old 08-15-13, 05:00 AM
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The drip pan is a good suggestion.

Do you have a garbage disposal? If so, there may be gunk on the underside of the rubber fingers; maybe you can get them out to clean them as well as the disposal itself.

Do you have a dishwasher and do you use it on a regular basis? Iíve found fly issues with dwís on occasion when they arenít used or donít work but there is still water inside them and the drain line.

Trash compactor? Oftentimes I find them with trash stuck to and on top of the ramming device (?) that then stays in the compactor.

Iím feeling safer to say it is a kitchen related issue based on your description so weíre making progress.
 
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Old 08-15-13, 08:31 AM
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Trash compactor - no
dishwasher - yes and it's relatively new and used every day. Hi heat cycle.
disposer - yes - I've been covering the drain opening at night. Tried the tape....nothing.

Drip pan I haven't checked.

The fireplace has a gas insert with a dedicated vent line thru chimney as well as custom screen around flue opening.


Thanks all for the feedback.
 
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Old 08-15-13, 09:01 AM
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When we had a gnat problem I first suspected all the things like drains, dishwasher, etc. Did all the cleaning, bleach, hot water etc. No help...looked at the plants (we have quite a few) and never saw any larva but some gnats on the surface...tried all the sprays and stuff..would eliminate them for a few days but always came back. Finally bought gnat-trol and used as directed, gone in less than a week. It's not cheap and I had to order from Amazon, but it works.
 
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Old 08-15-13, 06:28 PM
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I took all the plants outside. I'll get gnat-trol and treat them out there. There were only 5 plants and I didn't spot a single fly on or near them.

I still haven't found their source. Fridge tray was clean.

Early this morning didn't see any. Around 9:30 they started gathering in kitchen. Vacuumed up about 20.

Got home tonight and the kitchen was open for business again. They were all over.....maybe 30. I've been spraying them with soapy water which kills them quick as well as dustbusting them.

When I left this morning I put clear bowls over all the drains. Nothing on/in them tonight when I returned.

I'm a great believer in the Raid dry fumigating bombs. I've used them in the past with excellent results. Since they're a dry fog that is produced by a heating process they don't leave a messy residue on everything. Come Saturday if I don't see a decline in the amount of flying flies I'll bomb the house.

It's funny.... I bought several packs of those yellow sticky flytraps and these things are so small they land on them and then take back off. Of 4 traps I think there is a total of 9 flies on them.
 
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Old 08-16-13, 07:27 AM
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I think weíve looked at the simple and common issues causing fungus gnats. Iím wondering if something more unusual is going on such as a slow leak into flooring, insulation, or some other type of decaying organic matter.

I like how youíre doing/checking things so as to keep track of results or non-results. Good way to solve/identify a problem.

Is your residence on a slab? I may have missed that point earlier, sorry.
If so, there my be an unusual issue from underneath and they are coming up an expanison joint or such.

Another thought I just had: Toilets. Where the toilets are fastened to the floor and the gasket material. Sometimes the material decomposes and/or shrinks to allow gaps. Try closing all bathroom doors and keeping them that way to isolate the flys (maybe) or you could try taping around the toilet floor junction to include where the toilet bolts to the floor.

Another thought after second cup of coffee: Behind and under dishwasher. Check for very slow leak that may be leaking enough to decay matter but not enough to run out on the floor before it dries.

Day off today so Iíll keep drinking coffee and thinking...
 
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Old 08-16-13, 09:15 AM
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Check for leaks behind counters and dishwasher....hadn't really done that.

The house is a split level with a basement. However, we put an addition on the back many years ago that is an enclosed porch. There is a crawlspace under it. It's basically sand, rocks some boards and used as storage. Our ground here is primarily sand and we are high in elevation in town. Absolutely no outside water issues. All downspout lines are removed away from the house.
The crawlspace is open to the basement by a screened window and several other holes in block for services. I'm going to check out there.

One toilet is a year old and looks pretty sealed. I'll try taping the other one.
 
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Old 08-21-13, 07:34 PM
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I still have uninvited house guests

They were on the decline and then came back in force. I've been keeping the basement door closed. They appear to be in two distinct areas: the basement near the laundry sink and in the kitchen. I do find a few stragglers around the house but just a couple.

I started running my dehumidifier in the basement a week after I turned on the central air. The ducts were sweating so bad they were dripping everywhere. I thought maybe they took a hold in the ductwork. Haven't found any in there. They seem to like to land on the ductwork. Checked/flushed the condensate drip pan inside the furnace and it was clean. They aren't in the sink or the washer stand pipe. They mostly stay on the ceiling.

In the kitchen they hang around the sink and countertop. They also like the ceiling in the kitchen. The kitchen is connected to a porch that is fully windowed. They don't appear to be attracted to light as they don't go out there.

There are no live plants in the house now. Funny thing.... I came home last night and there were several flying around the doorway.... outside the house.

Everything is clean. I checked everywhere for a wet place for them to reproduce and didn't find anything.
 
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Old 08-22-13, 06:10 AM
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I have heard of flies, beetles, etc breeding in large volumes in the manure/sludge that gets spread on fields. Generally it doesnít happen but occasionally the conditions will exist so that an overpopulation exists outside and finds its way inside. That doesnít explain why you see them in the basement though.

Is the basement laundry sink underneath the kitchen?
 
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Old 08-22-13, 08:15 AM
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Pretty sure problem is solved. I bombed the basement with dry fog late last night. This morning I didn't see any right away. I'm walking around the basement and I see them in the corner....landing everywhere. I've got shelves there with canned goods, bowls, plates, serving stuff, etc. I'm looking everywhere on the shelf and I found a bowl with "what I don't know" in it.

Needless to say..... it looked like feeding time at the zoo.

Thanks for the help and I'll be posting again if the visitors aren't departed.
 
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Old 08-22-13, 04:10 PM
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Well done PJmax!!! Thanks for keeping us posted on your progress. I learned something from our exchanges.
 
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