Mike...these are fungus gnats, not fruit flies! Look at the FAQ for the forum. Your best bet is a systemic insectide (actually, your best bet is keeping the soil dryer, but you need to get rid of them). You can repot them all or, just remove the top 1", which I know will help. Then don't overwater!!! Peroxide and alcohol may damage the bulbs. I wouldn't use it all the time!!! Fungus gnats will kill young bulblets, so get them under control NOW!!

What other adventures have you had? Last time was it mites?? How did that work out for you!
:-)
Kristi

Mike you can check to see if they are fungus gnats, just put slices of raw potato about 1/4 inch thick, sticking half into the soil. After about 4 hrs, you will see the larvae of the fungus gnats. This will not get rid of them, but it is a good way to monitor them. To get rid of them you need to use "BT" that is sold under the name "gnatrol", or fly strips. Last year I thought this was a way to get rid of them, I bought a 5 lb bag of red potatoes, sliced them and put them in all my plants. It did not get rid of them, but I had potatoes all summer and fall. I never knew it was so easy to grow potatoes. Barbra

I sedomly have problems with these flies, usually they don't stay long.
I guess this has to do with my method of watering - always from below. The substrate up to 2-5cm below the surface stays dry all the time. In addition to prevent the flies from entering the soil I put gravel for fishtanks on top. I haven't seen these flies for a long time and I have never used chemicals in my flat.
I heard that you can kill them by flushing the pots with very strong coffee, but I don't know how much that harms the plants. Their larvae feed on dead material but are known to harm the plant roots when they don't find enough to eat.

Barbara, interesting tip about the potato! Guess the larvae crawl up onto it?? OR, do the eggs hatch that fast? These gnats seem to appear from out of nowhere so I wouldn't doubt that they have a very short lifecycle!

The tip about coffee is good as well. I guess I use the systemic outside for the NBF...but we had to resort to it inside (we buried that layer with another inch of soil) when my coworker refused to do anything with the gnats and we had them floating in our coffee throughout the office. My poor coworker...she got up from her desk and came back just a couple of minutes later and had 10 in her hot cocoa!

YES...we've had the discussion about using it inside, but again, we covered it with soil. No one died but the gnats!!
K