Black Soldier Fly Blog

Here are selected emails I’ve received and my best shot at the answers.

1. BSF in a tumble composter, separating BSF from soil
2. How to initially attract BSF (in Kentucky)
3. BSF grubs disappearing from homemade unit
4. How to maintain colony while harvesting BSF grubs
5. Processing pet waste
6. Concerned about BSF grubs in compost and possible “infestation” from adult BSF
7. Difficulty establishing BSF in Michigan
8. What to feed to a BSF colony
9. Limitations of feeding manure-raised BSF grubs to animals
10. Trouble shifting BSF from compost pile to BioPod
11. Protecting BSF grubs while establishing a colony
12. What to do with harvested grubs if you don’t have animals to feed
13. Containing BSF that are migrating out of a worm bin
14. Starting in an non-native area, concerned about BSF pestering neighbors

1) BSF in a tumble composter, separating BSF from soil

I bought my first composter in June. It is a tumble
composter that I added a bacterial accelerant to
and mixed greens and browns into. I think I used a little too many
wet greens as I now happen have a well established BSF colony! I
have three questions – first is should I continue tumbling, or do I
leave new food scraps on the surface? Second, do BSF eat corn husks?
And lastly, how might I separate the newly processed soil from the
BSF so I can use it in a garden? Thanks!

I don’t think that continued tumbling will hurt the BSF grubs, but if the scraps get buried more than 6 or 8 inches the larvae might not eat them.

BSF can’t process cellulose so I doubt they’ll target the corn husks right away, but It’s possible that they might work on the husks once they decompose some.

If you’re worried about the BSF larvae causing problems in the garden I can’t imagine what harm they would do. They aren’t designed to eat living plants or fresh vegetables so I don’t see any problem with adding them along with the compost. Having said that, if you want to separate the larvae you could put fresh food scraps in one corner of your unit and that should concentrate them for manual removal. They are especially fond of coffee grounds. You could also try this method: Collecting the immature larvae The dark brown larvae are the final larval stage and they don’t eat so you can’t attract them with food. If the walls of the container are damp or at less than a 45° angle the mature larvae will migrate out on their own. The mature larvae could also be added to the garden without a problem.

2) How to initially attract BSF in Kentucky

How, specifically, do I get started with black soldier
flies? I don’t recall seeing them in my area (W. KY) but that doesn’t
mean they’re not here. How do I target attracting them in order to
get a colony started? Thank you!

Probably the simplest way to start a BSF colony is to start a traditional compost pile and make sure that you always have some amount of fruit and/or vegetables present in it. Most of the people who accidentally discover BSF do so in their compost piles. I would also ask anyone I know who might have a compost pile if I could check it occasionally. If you know someone at a feed store that might be a good source. The store might not want to admit it but BSF often get into open or damp grain stores. Alternatively you can maintain some kitchen scraps in a bucket until they show up. That’s how I started. Here are a few links to my early experiences:

http://blacksoldierflyblog.com/2008/05/24/my-first-black-soldier-fly-colony/

http://blacksoldierflyblog.com/2008/05/24/first-attempt-to-attract-bsf/

My neighbor inadvertently started a colony in a bucket of dried seed corn that had partially filled with rainwater. Basically if they’re in your area they will eventually find rotting food. The more consistently you make food scraps available, the more likely you are to get BSF. I’m almost sure there are BSF in KY, especially if it tends to be humid during the summer.

3) BSF grubs disappearing from homemade unit

Hello…We have a homemade “Biopod”(with curving ramps)&
twice have had lots of grubs in it, but then they mysteriously
disappeared. We aren’t positive they were BSF, but we did find an
adult a few feet away. We live in Hawaii, but it wasn’t hot & the Pod
is in the shade. There are lots of little ants in it–will they eat
the grubs? Or would chameleons enter through the small air holes to
eat every last one? Or could it be that they were housefly grubs that
flew out the air holes when mature? They were large, cream-colored, &
looked exactly like BSF grubs. I would really appreciate your help to
solve this mystery–our chickens are waiting for grubs on the menu.
Thanks for the awesome website! Aloha, Wandalea

I expect that the grubs you have are BSF. If you’ve looked at photos of BSF grubs I think you’ll be able to tell them apart from the smaller housefly larvae. Also, if it were houseflies you would have a noticeable number of adult houseflies around your unit. If they are a BSF colony then they will have a repellent effect on houseflies and you won’t see many of them near the unit.

Do you ever notice them on the outside of your BSF bin?

When they disappeared was it all of them or just most of them?

Did your collection bucket catch a lot of grubs at the time your colony was reduced? Where those grubs dark or light colored?

Is the humidity consistently high in your part of Hawaii?

Are you in a cooler high elevation?

When the humidity is very high, such as when it’s rained, you will often have condensation on the walls of your BSF unit. In that case it’s likely that the grubs could crawl straight up the walls and exit through any holes in the unit. The way a BioPod is shaped makes this much less likely because it has a lip molded into it that only the smallest grubs could get past, and the small ones tend to stay with the colony more.

If your colony was reduced because of grubs escaping it’s not too bad in the long run. Some of the escaped grubs will survive and mate, and the resulting females will probably come right back to your BSF unit to lay their eggs. Of course many of the escaped grubs will be eaten, and unfortunately not by your chickens. Since my old unit was on the sawhorses I placed some containers on the ground beneath it to confirm that many grubs were exiting the unit and dropping to the ground. Have you considered moving your BSF unit to where you keep your chickens? The adult BSF could still fly in to lay their eggs and any grubs that escaped would be caught by your chickens.

It’s possible that the ants are at least part of the problem. The BSF grubs are very tiny when they hatch and even a small ant could carry one off. The ants might also be competing for the food scraps. I started with a homemade unit and I kept it on a pair of sawhorses, off of the ground. Occasionally I would spray the legs of the sawhorses with insecticide which kept the ants out of my unit. An alternative to chemicals would be to set the legs in containers of water. The BioPod manufacturer recommends treating the legs of the BioPod stand with Tac-Gel which I believe is some type of sticky insect repellent. At least with that type of product you would only need a small amount and you would have good control over it. Using insecticide on the ground near the unit would work against the ants but it would also hurt any BSF grubs in the same area.

The lizards could also be part of the problem, although I would expect them to have a constant effect instead of causing a large scale reduction in a day or two. I had tree frogs living in my homemade unit and they were obviously well fed. I took them out regularly, but they always returned. If your vent holes are large you might have some other type of predators entering the unit, eating your grubs, and then leaving. There is a long list of animals that eat BSF grubs. I haven’t seen any frogs inside of my BioPod but I do sometimes see one on the lid. I always move those frogs far away from the BioPod because they’re probably eating BSF females which have been attracted to lay eggs. If the frog eats several BSF adults that represents the loss of thousands of BSF eggs/grubs in the BioPod. I doubt that a few frogs would have a great impact on the colony in a BioPod, but I would move them anyway to maximize my colony.

Thanks for the kind words about my blog. Please keep me posted on your progress.

Aloha,
Jerry

4) How to maintain colony while harvesting BSF grubs

Hello-
I know that somwhere on your website you probably explain how to keep
the colony thriving even though it looks like all the larvae get
harvested. Can you clue me in? Also, is there anyone in Massachusetts
who has a successful colony?
Thanks for your help!

I don’t have first hand knowledge of a BSF colony in Massachusetts. BSF have been found in the wild in Canada so I think it’s possible they’re there.

BioPods aren’t fully contained systems in that the pupation and mating take place outside of the unit. Female BSF will seek out rotting food to lay their eggs near, even more so if there is an active colony of BSF grubs already in the pile. If you harvested every grub produced in the BioPod you could still have wild BSF coming to lay eggs in the unit. Of course letting some grubs go free will strengthen the wild population and increase egg laying in the BioPod.

Please let me know if you have more questions.

Jerry

5) Processing pet waste

My new Bio-Pod seems to be functioning, there are a zillion little grubs in there munching away on the food scraps. I was planning, however, to use it also for dog and cat poop, and was disappointed to see in the Bio-Pod Guide that the home unit was not suitable for this because of dangers of disease, etc. We have always composted our dog poop (but not the cat) with no problems. So I’m wondering how hard it would be to build some sort of container that I could use to digest the dog and cat poop (we use wheat litter for the cats) separately and just dump in some of the grubs from the Bio-Pod to get it going. Are there any plans anywhere for homemade units? I guess I would just use the mature grubs from that one to feed to wild birds, not our chickens. The point is mostly to get rid of the cat litter and doggie doo without sending it to the landfill. I could let it drain onto the ground, I guess under the trees away from our garden. Maybe I could make it so it just let the mature grubs crawl out onto the ground for the birds too. It’s a bummer not to be able to feed them to the chickens tho, that was my main reason for buying the Bio-pod.

The reason the BioPod manufacturer says not to process fecal matter of any kind is because of liability issues. Anytime you handle poop there is a risk of infection. Processing pet waste with BSF is probably similar to cleaning a toilet, you keep your fingers out of your mouth while doing it and you sanitize yourself afterward.

You certainly could add pet waste to the colony and they would process it easily. As with any type of waste you would want to make sure you didn’t overload the colony with a large amount at one time. Of course if you added any type of manure you would have to expect a certain amount of odor which isn’t usually an issue when you process kitchen scraps.

BSF that have been raised on animal waste have been tested as animal feed in several studies. Often in these studies the grubs were sanitized by cooking or drying before being fed to animals, but not always. I’ve read that if you raise BSF grubs with manure, that you should not feed those grubs back to the same genus of animals. For example, if you raise the grubs on mammal waste you could feed them to birds, reptiles, and fish. If you raise them on chicken manure you could feed them to mammals, reptiles, fish, and so on. My knowledge about this is limited, so you should do some research before taking any action.

Thanks for your business Harmon, I’m glad to hear that your BSF eggs hatched and are thriving. Let me know if you have any more questions.

6) Concerned about BSF grubs in compost and possible “infestation” from adult BSF

Hi, Thanks for the blog, lots of useful information and I’m now a bit more reassured about the hundreds of grubs wriggling away in my balcony compost.
However, despite all the good they are probably doing to my compost and the fact that we now have no flies buzzing around it, I’m a bit concerned about what will happen next. the compost is on my balcony so I’m worried that we are soon going to be infested my the adult flys or that my compost will always be full of the grubs – there isn’t actually any of my compost that doesn’t have grubs, so I can’t use it to fertilise or repot plants.
Any advice on how to remove them or reduce their proliferation would be helpful otherwise I fear I’m going to have to throw out all of my compost.

First let’s address your being infested with black soldier flies. I’ve raised and released tens of thousands of BSF grubs on my property over the past few years and I’ve never seen more than about a dozen of the adult BSF at any one time. In addition please consider that I’m always involved in trying to attract them. The reason they’re relatively rarely seen compared to other fly species is that their life cycle is different. Adult houseflies live for up to 30 days and during that time they need to eat of course. BSF adults only live for 5 – 8 days and they don’t eat during that period. They’re sole purpose as adults is to mate and lay eggs. When a BSF adult is attracted to any type of waste it’s almost certainly a female looking for a place to lay her eggs. For that reason the male half of the BSF population is almost never seen at all. Then, after laying her eggs the adult female BSF has no interest in the food source so she simply leaves and shortly dies. That’s the long version of “you won’t get an infestation of adult BSF”.

I’m glad that you’ve observed how BSF repel houseflies and other pest flies. That’s something I’ve addressed many times, but it’s nice to have confirmation of that from a third party.

You certainly can use the compose for repotting plants. If you separate a portion of the compost from the main pile the BSF will soon cycle out of it assuming you don’t add more food scraps to it. The BSF grubs are there for one reason, food. If the compost is in an open container the grubs will simply leave after any remaining food is consumed. If you want to have more control in removing the grubs from the compost you can use food scraps as bait and capture them using the method I describe here.

You also have the option of repotting any outdoor plants without removing the BSF. As I stated above they will simply leave when there is a shortage of food scraps. You might damage some of the grubs by handling them that way, but that’s the only downside I see.

The following post might be helpful if you haven’t already read it: http://blacksoldierflyblog.com/2008/09/15/mythbusting-black-soldier-flies/

Whatever you do please don’t throw out your compost, the BSF are harmless and the compost will have only been improved by their work.

Please let me know if you need further advice.

7) Difficulty establishing BSF in Michigan

I wonder if I should give up hope on this lot.  The larvae hatched last week into flies.  I’m hopeful that they left me some eggs.  But we’ve come into cold-for-July weather (again) and that might be the end.  The only action I see in the food pit area are fruit flies.  Not even regular house flies are around.  If the new BSF did lay eggs, how long will it take for them to hatch?  They had 2-3 days in the 90’s and now for the past 4 days it’s barely hit 70.

When you say the larvae hatched into flies are you referring to the mature larvae that were included in the kit? It’s good that you had adult BSF emerging, but what happened with the eggs from the kit? Did you ever observe the newly hatched larvae either in the ziplock bag or in your BioPod?

Can you describe the contents of your BioPod currently? (how much material, what type, species present)

Have you removed any food waste at all from the unit?

Given your cool temps it might be best for you to relocate the BioPod to a spot that gets some sunshine. The standard advice is to keep the unit in total shade, but the real goal is to have the internal temperature in the 80º-95º range. Actually your climate is great for operating a large BSF colony once you get it established. BSF generate quite a bit of heat when they metabolize food and in hotter climates it’s common that the colony will overheat. A good plan might be to keep the BioPod in at least partial sun for now and then to move it back to full shade when the colony starts growing.

8.) What to feed to a BSF colony

Hello Bonnie & Jerry

While I am waiting for the arrival of my BioPod, I am saving food waste and freezing it. My question to you is what food waste should be avoided if any? I could not find this info on your website. I have been processing food waste with the use of vermicomposting. This method as you may know restricts the use of meats, dairy and oils. If this info is on your website please direct me there, I may have
just overlooked it.

Thanks for your help!

It’s funny to think that we haven’t stressed what BSF (Hermetia illucens) can eat and it’s probably because the list is so long. BSF grubs can eat practically anything except high cellulose items like grasses, leaves, paper, etc. They can eat literally anything that people eat. In addition they do very well on manure from just about any animal. Fish bones and possibly chicken bones may be eaten eventually, but mammal bones will not. I’m pretty sure they can’t break down eggshells. This versatility of BSF is usually most appreciated by those who are used to the limitations of vermiculture and traditional composting. BSF happily eat meats, dairy, oils, onions, and citrus. They also seem to love old coffee grounds and teabags for some reason. I’ve also given them jellybeans and chocolate candy.

BSF can eat food that is quite spoiled, but it’s best to avoid anything that you think might contain toxins or high concentrations of pathogens, especially if you’re feeding the mature grubs to animals. The toxins/pathogens won’t hurt the grubs, but there is a risk of passing some to pets or livestock that eat the grubs. BSF have been proven to reduce bacteria like e. coli and salmonella, but it’s always best to err on the side of safety. If you have any doubts just limit yourself to “fresher” waste.

9) Limitations of feeding manure-raised BSF grubs to animals

I am confused about feeding animals waste to the BSF grubs . THe biopod site says NOT to use pet waste and then feed the grubs to other animals. But everysite I see , including the research done by NCSTATE uses them for just that purpose. Using BSF to process poulty waste and then feed the grubs back to the chickens. I raise rabbits and want to process the pellets( poop) with the BSFgrubs and then feed the prepupea to my chickens? Are they concerned about cats and dogs only? I hope some one can help my confucion.
THanks

The reason ProtaCulture says not to process pet waste is because of liability issues. Handling feces is more risky than handling kitchen scraps and in our society lawsuits are very common.

When feeding manure-raised BSF grubs to animals there is a basic rule that Robert from ProtaCulture (BioPod company) has given. BSF raised on manure from one type of animal (mammal, reptile, fowl, fish, etc) should not be feed back to that same type of animal. Accordingly you should be fine feeding BSF raised on rabbit manure to your chickens.

The information above is based on feeding live or unprocessed BSF to animals. I believe that if you process the BSF sufficiently, as was probably done in the studies you cited, it’s acceptable to feed them back to the same animals that produced the manure that fed the BSF. The issue is most likely about pathogens like parasites, bacteria and viruses, so by sterilizing the BSF the risk is eliminated and they may be feed to the same animals that helped produce them.

I’m not a biologist so please don’t take my comments as fact. (Yes, that was a disclaimer )

10) Trouble shifting BSF from compost pile to BioPod

I’d really like to order a multistage starter kit, but didnt see where I could from your webpage. Please contact me with the information you’d need if one’s available, or to let me know when one would be available. I’m having lots of trouble getting the BSF population to shift over from ovipositing in my compost and the local Blow Fly population is all that’s taking advantage of my Biopod.
Help!

We don’t have an automated way to buy kits because the availability isn’t consistent. Bonnie will send you a bill if you decide you want one, and then I’ll begin the collection process.

In my opinion you really don’t need a starter kit because you have BSF on your property already and redirecting them won’t be difficult. To seed your BioPod you can cut 1/2 to 1 inch strips of corrugated cardboard against the “grain” so that the voids are exposed on the long side. Add some new food scraps to your compost pile and place the cardboard close to the scraps. A few inches above the waste would be an ideal location for the cardboard. When you see clusters of pale colored eggs in the cardboard simply move the cardboard to your BioPod. If the strips of cardboard are 8 inches or longer you can weave them into the large vent holes on the BioPod lid. This is simple if you invert the lid to access it from the underside. BSF eggs take about 4 days to hatch and they will then drop onto the food scraps.

Actively feeding juvenile BSF grubs are a strong attractant to ovipositing BSF so it would also be good to move some to your BioPod manually. Below is a link that describes how I collect juvenile grubs from my BioPod. This isn’t usually as effective in a compost pile, but you should have some success.

http://blacksoldierflyblog.com/2008/07/25/collecting-immature-larvae/

Since the BSF in a compost pile are less concentrated than in a BioPod you will have better success if you use a container with a larger diameter. The bottom of a 5 gallon bucket comes to mind, or even larger. Coffee grounds and a paste made from cheap dry dog or cat food are good bait. Almost any table scraps will work so you can just experiment.

Not much of a salesman am I? I think the kit is a neat project and you might want one just for the fun of it. The eggs come in a small container that allows you to see the tiny grubs concentrated in one area, something that you probably won’t see otherwise. I don’t have too many kits waiting now so if you want one I should be able to ship it in a few days. That is if the BSF and weather cooperate.

Thanks for your interest,
Jerry

11) Protecting BSF grubs while establishing a colony

Spectacular crawl-off last night!  Almost 300 mature larvae! I painstakingly cleaned and counted them so my kids could re-enact your “fist full of maggots” video.  Half of them I sprinkled strategically in the yard, the other half went in the pupation bucket.

I recommend against placing any grubs in the yard or anywhere outside of a protected environment. There is a long list of critters that love to eat BSF in any form including raccoons, possums, rodents, birds, lizards, frogs and other insects like ants. For many of these predators it doesn’t matter that the grubs can bury themselves because they can be located by scent. Each pair of BSF that are eaten represents a lost potential of 500-900 eggs that might have been deposited in your BioPod. This isn’t an issue with an established breeding colony, but it’s a significant issue when you’re trying to establish one. Of course if your property is treated with any type of insecticide that’s another reason not to release the grubs.

It’s best to keep the mature grubs in a container such as a bucket with a lid to protect them. The container needs to have several holes with a diameter of at least 1/2 inch to allow the emerging adults a way to escape. The holes will also provide necessary air for the pupating BSF and also aid in keeping the temperature regulated. Like the BioPod, the prepupae container must be completely shaded and protected from rain. Adding an inch of bedding material such as sawdust (not pressure treated), peat, etc to the container will encourage the grubs to pupate, but it must stay dry and loose so the emerging adults can crawl to the surface.

12) What to do with harvested grubs if you don’t have animals to feed

Hi- I am very intrigued by the idea of composting with
black soldier flies, but am not sure what to do with the harvested
larvae? I am a home gardener, so the compost & tea would go right
into my garden, but I don’t have chickens, or fish, or anything I can
think of that would dispose of the larvae. Any ideas? thanks!!

When I first began culturing BSF I didn’t have fish or anything else to feed the grubs to either. I simply released them. It’s true that you’ll be reinforcing the population by protecting the larvae though their most vulnerable stage, but I don’t see that as a problem. I believe that the BSF population is self regulating based on the available food, so I highly doubt that releasing mature grubs (larvae) would lead to an overabundance of BSF. I’ve probably released as many as 100,000 mature BSF grubs on my property over the past few years and it’s still unusual to see an adult. A wide variety of animals prey on BSF larvae including ants, rodents and other small mammals, lizards, amphibians, and many birds. By releasing mature BSF around your property you’re essentially feeding the many types of wild creatures around you. Of course if you have any friends with chickens, fish, lizards, etc., you’ll become even more popular if you have free high quality feed to offer them.

13) Containing BSF that are migrating out of a worm bin

We have plenty of BSF’s in our worm bin. I don’t mind them,
of course, except… they wander. They find ways to get out and I
find them wandering all over my garage where we keep the bin. Any
ideas about how to contain them?

The easiest way is to set the bin in a larger container or tray to catch the BSF as they migrate out of it. The grubs can’t scale a vertical surface if it’s dry so even something with a two or three inch wall will probably do the trick. Adding a thin layer of sawdust will ensure the grubs that fall into the catch-tray will be too dry to climb out.

14) Starting in a non-native area, concerned about BSF pestering neighbors

Hi Jerry!
I saw your link and subsdequent posts on Backyardchickens.com.  I have a few questions regarding composting with BSF larva.  How often do I need to buy/replace the larva (they are not native to the area) or will the flies stick around long enough to breed?  Also, the flies…they worry me.  I live on a half acre in a subdivision.  Our properties are big enough to not be in each other’s hair, but will the flies be a nuisance?  My biggest worry is that a neighbor will complain and attribute it to my chickens.  How do I control the fly population and nuisance while being able to compost with the larva?  Thanks so much for your time!

Are you sure BSF are not native? I live in south Georgia where BSF are plentiful and most people here are completely unaware that they exist. Many people like farmers/gardeners are familiar with the larvae, but they don’t know what the adult even looks like. This is because the adult BSF is shy and only lives a few days. BSF are found in northern Viriginia, into central Illinois, throughout the south and up the west coast into Canada.