Not sure if this is the right subforum, but as this does have to do with an apartment problem...
I have some plants- some are always kept indoors, some always in the balcony, and some others in the balcony during summer and indoors for autumn and winter. The problem though is that somehow the pots provide the ideal housing for some black flies. These are not houseflies or fruit flies, but very elusive little black coloured flies. They don't bite or do anything nasty, but having them hovering in the apartment is very unsightly. I live near agricultural lands which might explain their presence.
I tried getting rid of them, but it just became too much that I moved my plants to the balcony hoping that the flies would hate the cold and find some other conducive place. The problem though is that 1) those plants cannot survive in the cold (the tomatoes are wilting by the hour) and there was frost this morning 2) the flies seem to be staying put.
Any suggestions? I wish not to use insecticide as my apartment is more on the smaller spectrum and I usually work from home (i.e. breathing everything in doesn't sound like a good idea).
A similar (if not the same) problem has been described on this forum before - you may want to do a search, as there was some good information - but I think the solution was a layer of fine sand on top of the earth in the pot, as these flies, apparently nest/live in the earth and the sand prevents this.
[scroll down to the suggested similar threads at the bottom of this page - it may be one of them]
Wait for the snow and first real frost ... Take the plants out. Flies will extinct. Not sure if the plants will make it though. Perhaps they shall hibernate for a bit.
I've had that problem as well. I tried the sticky paper, sand and other methods, but nothing helped. In the end, I repotted my plants and then put sand on top, which finally got rid of them.
Are the tomatoes actually carrying fruit, or are you just bringing them through the winter in preparation of the next spring?
Tomato plants are very quick to take root. If there is something bad in the soil, it might be an option to throw it out but cut the plants off first, stick them in vases with water, give them a week or two or three to grow roots, and plant them in fresh soil from a trsutworthy source, also using all new pots etc. Make sure all the old pots, soil and anything else are gone long before to avoid any risk of contamination.
Will head to OBI tomorrow then (Landi is too far away) and find the sticky fly papers (hopefully, without poison).
I did The change here is that these are not houseflies or fruitflies and my poor plants are involved. I did notice that they didn't target my orchids nor another pot that had lots of pebbles- so the material in the pot does matter. The flies are also very tiny- the same dimensions as a fruitfly (and more agile), so a bit difficult to get hold of.
Most of the plants are outside now. There was frost this morning. It was indeed my hypothesis that the cold temperatures might force them to flee, but it seems they only burrowed into the soil...
Thanks, keksli. I'll have to do this if nothing else works.
They are carrying lots of fruit and plenty of flowers. One of the plants is from 2013... although I don't know how it would be as they are now in the balcony. Have wrapped them with plastic, but the leaves are wilting. It's quite tragic
I had this highly annoying problem (fungus gnats, Trauermücken) earlier this year and nuked the highly annoying, tiny and silent but still very noticeable gnats by using these tablets from Migros. Use them as directed (1 tablet per liter of water) until you've noticeably decreased gnat population. Then use 1 tablet per watering can (2.5l?) of water to water the plants until the gnats are gone completely.
Notes:
Let the tablets dissolve completely before watering: This takes time and warm-ish water. If you don't you'll end up with very concentrated stuff at the bottom of your watering can and diluted stuff at the top. I recommend filling the watering can and adding the tablets the day before you want to water the plants. When the tablets are fully dissolved, the water will smell slightly and there'll be some foamy stuff on top.
Make sure you don't overwater your plants, as those gnats love wet soil.
mother of vinegar. it attracts them. they also sell in migros/coop small plastics cups (with mother of vinegar) with a shape so that flies can get into them but not escape. it always helps with small flies but was not enough once when I got lots of pots of parsley, basil, etc.
Probably flies that live on grape vines but get homeless when the grapes are harvested. and start looking around for a new place.
Apparently there is a new Japanese variety that is spreading wildly; they spoil the wine so vineyards spray a lot of nasty stuff to contain them.. Consequently do not let your dog munch grass from around vineyards.
Usually they die out quite quickly but I noticed a couple hovering around my wine glass last night.
Thank you, glowjupiter! I think you identified the unwelcomed visitors!
Does it work on gnats?
Not sure. glowjupiter's solution seems to have identified the culprit.
I'll embark on the following mission tomorrow: A treatment of Anti-sciarides (Migros; for the larvae & eggs) + the fly paper (if I find these at Migros; for the adults) + Argile expansée (Migros; so that the adults are dissuaded and find elsewhere)
Hey, we had the same problem last month with the plants. At first we tried to solve it with the yellow sticky, but soon realized that it was simply not enough in our case.
However, the yellow sticky did help us identify the pot which was the culprit. We moved it to the basement, removed a cm of top soil from it (flies lay the eggs not too deep), and added a layer of aquarium gravel on the top to prevent easy access to the soil. That seems to have broken the cycle and fixed the problem. Also, make sure you are not over watering your plants like we were.
Thank you to all of your helpful pointers. The flies are almost history and the following is the winning formula I used.
1. Bio-weapons: Anti-sciarides (as recommended by glowjupiter). Got these from Migros and followed her instructions - i.e. completely dissolving the tablets in warm water and applying this on the pots (although not enough to drench the soil). As I was away for 5 weeks in December/January, I treated the plants before leaving and repeated after returning.
jacek, the cold treatment didn't work (the flies are very resilient). I ended up losing my poinsettia, rosemary, and all capsicums. Interestingly, one of the colocasias also may have fared too badly (although this was indoors).
amogles, I didn't get time to take care of the tomatoes before I left. I kept them outside, all wrapped up, but they did not make it.
If anyone were to encounter such flies: it's best if you act quickly (unlike me). It seems as if the larvae of these gnats feed on the roots (which may explain my colocasia) and the flies lay too many eggs. Given the warm room temperature and substratum, they are obviously too comfortable.
My flies were like tiny pin head size black beetles. They always flew to the windows and died on the floor. A few went into food cupboards and died there, but not into the packets of food.
Finally I realised they were coming from my indoor plant soil. I sprayed the earth surface with a standard fly spray, and they no longer surface.
Didn't know that (and I am not a coffee drinker too). The flies have returned though and I think the mistake was in opening the windows and doors for the fresh air.