Experiment causes black soldier fly larvae colony to crash!
Okay, maybe the blimp image is a little extreme, but it’s difficult to get attention on the internet these days. 😛 The good news is that bringing my BSF colony (Hermetia illucens) back into balance shouldn’t be all that difficult. In the past when I’ve run into problems I’ve corrected them by lessening the amount of food scraps that I introduced into the unit, and that is what I’m doing currently.
BSF larvae can eat almost anything
BSF grubs will consume almost anything organic except high cellulose materials like woody stems and grasses. They will quickly eat just about anything that has available calories including food waste that would probably be toxic to humans, like decomposing fish for example. The fact that they are able to efficiently digest such a wide range of material is what makes BSF larvae such a powerful tool for processing waste.
About those decomposing fish…
I help my neighbor manage the small pond behind his house. Recently several of his fish died and I did him the favor of removing them a few days after they floated to the surface. The fish weighed about 5 pounds (2.3 Kg) total and by the time I removed them they were already very stinky. Instead of disposing of them like a normal person I decided to see how quickly my BSF would process them. I’m happy to report that my small colony completely consumed the fish within about 2 days. I am unhappy to report that after I added the decomposing fish to my BSF unit it began attracting blow flies and house flies.
Black soldier fly grubs produce an info-chemical that repels pest flies, but there are limits as this test illustrates. The odor of these decaying fish was a powerful attractant to undesirable flies and it overpowered the repellent properties that are normally very effective in a BioPod.
I’m currently using a homemade BSF unit (not any more!) because BioPods are not yet available. My homemade unit is a less efficient design and I’m sure that this made my recent problem worse than it would have been. My unit doesn’t deal with liquids as well as a BioPod so the problem was less contained than it would have been with the commercial product. I will be happy when the first BioPods arrive.
And now the good news
Even the extreme imbalance created by adding these decaying fish to my colony can be corrected with a little time and care. Of course I’m more cautious about sanitation while the pest flies are present, but in reality I don’t need to do much other than stop feeding the colony and let the other flies cycle through. It’s now been about 5 days since I added the fish and my colony is almost back to a balanced state again.
You can avoid this type of problem easily
My test with the decayed fish was something that most people would not have tried, but I’m involved in testing the limits of this technology. If you use BSF larvae to process your normal household food scraps it’s very unlikely that you’ll experience anything like the crash I just created. You can even add food that is somewhat spoiled and you shouldn’t have a problem like my recent experience.