I'm sorry but I still have serious reservations on the effectiveness of using nematodes. First, the larvae are generally nowhere near the soil. The adult fly lays eggs deep into the bulb foliage, sometimes actually tunneling under the paper sheath of the bulb itself to deposit her eggs. They hatch and the maggots immediately start working their way into the bulb itself, where they remain over winter. It is not until they begin to pupate in early spring that they move into the soil and by then it is far too late for nematodes to be of any value. Beneficial nematodes need warm soil temperatures to regenerate and start feeding, usually around 50F. This generally does not occur in the Puget Sound area until late May, so the timing of this control may be off slightly as well as questions about its effectiveness. And at $20 something a pop for the nematodes, it is kind of an expensive proposition that may or may not have any benefit. Again, after more than 30 minutes of online research, I didn't turn up a single hit that posed nematodes as a control agent for this problem. FWIW, the flies are typically present in this area in late spring. Promptly removing the dried, spent foliage, especially of early blooming narcissus, should go a long way to control bulb fly damage.

petalpatsy, I have been keeping black soldier fly larvea for over 10 years now, and you are not supposed to have a foul muck. If that is your experience you are not managing your liquids. I get the most amazing compost from my grubs and i get just as much as if it where in an aerobic pile. Except i get if faster. Because the grubs break stuff down within hours versus weeks you have to deal with moisture issues. But in no way do you get only muck as a result. The best grub composters have a living layer of soil/bacteria on the bottom that can handle excess moisture. That is precisely the issue with a lot of these DIY buckets that don't allow for liquid drainage and aeration. Now... that living layer of soil I have is AMAZING... man is it fertile. It doesn't smell and it's not MUCK. it's jam packed with micro organism (also aerobic bacteria by the way) it's dark and has a coffee grind consistency. Depending on the age (+1 year) it's in my ways similar to finished compost and if it's younger (it's has a more humus consistency). If you brew a compost tea for this material, you'll notice that the tea starts to bite a little bit and the material is slightly acidic (my plants in texas love this with our high alkaline soils). If you are having muck you have gone anaerobic and it stinks... but i assure you that's not what you supposed to be having. grub composting is also an aerobic process. Here is a link that might be useful: BioPod Forum

Mlkbskt, Blowfly larva are disgusting looking little creatures. Google it and you can find images of them. I only used to do nest checks like you, with a quick peek to see the babies are ok until I cleaned out a Bluebird nest last year and found a bunch of full sized blowfly larva underneath it. I was amazed all those babies fledged from that infested nest. I now use the spatula method (have a spatula dedicated to bird houses) and take a peek underneath the nest to see if I can see anything. But if the blowfly larva are small, you probably won't even see them that way. And if they are really large, they are ready to pupate and have already done their damage. A little fly just flies in there and lays her eggs. That is where they come from. There is really nothing you can do to prevent it from happening. It is a really gross job, and I always wear latex gloves to do it. Glad to hear your nest was so clean. My nests haven't been infested with blowfly larva too often. I've read it is more likely if the weather is very wet, which it had been around here.

Fly larvae are very difficult to get rid of especially due to the fact that you are limited to what you can incorporate into the grow medium without adverse effects to your plant. Most adult flies are not the main concern to your plants well being, in fact, they may be beneficial. Although, many fly larvae can impose a great threat to any plant's root system, especially during the vegetative state! In this matter I urge you to check out some beneficial nematodes, which are a natural predator to 257+ different fly larvae yet pose almost no threat to plants. Depending on your climate there are a few different species to fit best...with a little research I'm certain you will find what works for your plants. Good luck and I hope this helps...happy gardening!