it was probably the larva of the gnats eating the leaves

Go to the beach, or go to Home Depot and buy some sand. Take a cup or scoop and spread a layer of 1/2" to 1" of the sand over the top of the soil in your potted plants. The sand serves as a barrier that traps existing gnats and larvae underneath. It kills them all. It also serves as a barrier to keep the gnats out as well. I've dealt with this problem on multiple occasions. I think every damn bag of soil must be infested with the gnats or larvae, because it seems that every time I buy a bag of soil and pot my plants, over the course of the next few weeks my home ends up infested with gnats. This solution, of course, will change the look of your plants. But, it's kind of a nice look. It's clean and if you put a few shells and rocks in the sand, it's kind of a nice designer look. I've included a link to a photo I took. I just did this yesterday after getting fed up with all the gnats. Works like a charm. You will notice, after putting this layer of sand on the soil, that over the course of the next week or so, the gnats will be gone. Believe me. This works. Every plant in my house has a layer of sand spread on the top of the soil. Any time I have done it, the gnats were gone shortly afterward. Here is a link that might be useful:

kimmsr, Disagree with you, simply based on experience. I used to have lots of grubs in my very moist compost before using BT. Rarely see a grub of any kind anymore, using the same methods/materials with the addition of BT. http://www.nysaes.cornell.edu/ent/biocontrol/pathogens/bacteria.html States: Primary hosts: caterpillars; some BEETLE and fly larvae. Also states: "Over 90 species of naturally occurring, insect-specific (entomopathogenic) bacteria have been isolated from insects, plants, and the soil, but only a few have been studied intensively". So I give credit to BT. I put some good soil in my new compost piles, which has had applications of all commercial BT strains, so I can't say which one (if any) are at work against grubs. Doesn't matter to me. So I give credit to BT, et al. - and don't have names for the other 86 or so insect-specific (entomopathogenic) bacteria spoken of, OR other such non-specific bacteria that may not have been identified yet. http://ohioline.osu.edu/hyg-fact/2000/2500.html : 'Grubs' is a 'generic' term, used for larvae of a large group of beetles called SCARABS. The most important species are: Japanese beetle, Popillia japonica Newman; May or June beetles, Phyllophaga spp.; northern and southern masked chafers, Cyclocephala spp.; and black turfgrass ataenius, Ataenius spretulus (Haldeman). Other, more localized, white grub pests are: European chafer, Rhizotrogus majalis (Razoumowsky); the Asiatic garden beetle, Maladera castanea (Arrow); and the green June beetle, Cotinis nitida (Linnaeus). Option 4: Biological Control - Milky Diseases - Several strains of the bacterium, Bacillus popilliae (bacterium is extracted from Japanese beetle grubs and is most active against this species), have been found that attack white grubs...Unfortunately, recent studies in Kentucky and Ohio indicate that the currently available products have NOT PERFORMED WELL IN OUR SOILS. (caps are mine). Goes on to say that parasitic nematodes are a up to 80% effective, but "...do not appear to be effective from one season to the next". So you can take exception with me if you want to - your opinion is just as valid as mine - but now let's hear from YOU about your EXPERIENCE with grubs... Robert

Nothing in your bin will hurt your worms (except on rare occasion). When you do see something seem to be prospering better than the worms, it is telling about the environment of your bin. Go to happydranch.com and click on their invertebrate page. Lots of good information there. I doubt you can see springtails but check out potworms. Keep a good 3" layer of shredded paper on top of your food at all times. The newspaper that is under your bin can be shredded and added to your bin also, or put in an outdoor compost pile.