Black Soldier Fly Larvae In House – What To Do

Do you have an infestation of black soldier larvae in your house? We will share with you some ways in which you can get rid of them easily.

Just like houseflies and blowflies, you might have noticed black soldier flies buzzing around over a pile of trash.

Though originally only found in the Neotropics, black soldier flies are now cosmopolitan insects that are found in a wide range of habitats.

While seeing a bunch of their larvae in a compost pit isn’t fun (and we will discuss how to get rid of them), they’re actually harmless.

In fact, these insects can be quite beneficial! Let’s take a look at how.

What Are Black Soldier Fly Larvae?

Hermetia illucens, or the black soldier fly, is a medium-sized, black-bodied fly found across almost all continents of the world.

The adult female lays over 500 eggs at a time, which hatch into dull, white larvae.

The black soldier fly larvae are the first stage in the soldier fly’s life cycle.

The larvae are between 0.4 and 1 inch long and go through multiple instar stages before emerging as adults.

They have chewing mouthparts and are voracious feeders. They feed on any organic matter or food waste.

Today, these larvae are being raised to help recycle waste food.

They are also reared on agricultural farms as bird feed since their bodies contain more than 40% protein.

They remain in the larval stage for 14 days before becoming a pupa. Adults do not eat and rely on their existing fat stores for nutrition.

Are They Dangerous To Humans?

Black soldier flies, both as adults and as larvae, do not possess a stinger. Hence, they cannot sting humans.

Neither are any of the two poisonous. As such, they do not pose a threat to humans, pets, or livestock.

Consuming a black soldier fly, on the other hand, may place you at risk.

While they’re a good source of protein and widely considered edible insects, human consumption can be harmful depending on what the soldier flies feed on as larvae.

For flies that have not been blanched, scientists found various microbes as well as traces of arsenic, heavy metals, and other pesticides within their bodies.

There is also little knowledge of what reactions allergens from soldier flies may produce in humans.

However, traces of the allergens tropomyosin and myosin have been found in them (also found in crustaceans).

To ensure that your livestock remains safe, you should only feed them blanched larvae.

Do They Bite or Sting?

Black soldier flies do not bite or sting as larvae or as adults. However, adults produce a constant buzzing sound, which can be quite annoying.

In fact, adults don’t even have eating mouthparts, as they do not consume food and rely on stored fat.

They are also less active (in terms of flying) than regular houseflies due to their limited fat stores.

Are They Poisonous or Venomous?

Black soldier flies are not poisonous or venomous.

However, consuming a BSFL that earlier fed on heavy metals, arsenic, or similar toxic substances can, in turn, transfer these materials onto the host’s body.

Are Black Soldier Fly Larvae Useful?

Black soldier fly larvae are highly beneficial for the recycling and agricultural industries.

They help break down organic matter into compost, which can then be converted into fish feed, fertilizer, or poultry food.

Nutrition-wise, the larvae are rich in protein and have good amounts of amino acids, lipid content, and calcium. They’re a great addition to livestock food or poultry mixes.

How To Get Rid of Black Soldier Fly Larvae

If the flies are causing a menace in your garden, then there’s no option but to get rid of them. Here’s what you can do:

Get Rid of their Food Source

For long-term control, you need to eliminate two things:

• Their breeding source
• Their food source

If you have a compost pit or any place with collected organic matter, it could be a great breeding and feeding ground for these insects.

For larvae, you can simply handpick them out and boil them.

For adult flies, use a fly swatter. Alternatively, you can clear out the food source and wait a few days for the flies to die out or move away.

In general, try to keep your compost pile closed with a lid, and try to empty it bi-weekly.

Since the eggs take around four days to hatch, clearing the ground within them can break the life cycle chain.

Chemical Control

As these insects form a part of animal feed, using chemicals is not advised since it introduces toxic substances into the food chain.

However, if absolutely necessary, you can use an insect spray that contains pyrethrins to kill both the larvae and the adults.

A less harmful alternative is spraying them with a strong vinegar mix. This is sure to kill the larvae, though it may not have the same effect on adults.

Wrap Up

Black soldier flies aren’t harmful insects but they can be a menace if you find too many of them near your compost pit or chicken manure.

They lay several eggs, and finding their larvae all over the house is another problem that you might face.

Their population increases during the summer months, as that is when the flies mate.

You can follow our steps for getting rid of them, and remember to resort to natural means as far as possible.

Thank you for reading the article.

Frequently Asked Questions

Reader Emails

Over the years, many of our readers have shared stories of how they found an entire infestation of black soldier fly larvae in their house.

We have always labored to tell them that these insects are harmless, but removing them is easy with the tips provided above.

Thank you for reading!

Reader Emails

4041

Letter 1 – Black Soldier Fly

 

Slow and dumb Location: South Central VA August 27, 2011 5:23 pm We LOTS of these fly’s, bee’s or whatever they are. They don’t have stingers and fly really slow and are really easy to swat once they have landed…. I call them the B-52’s of flies (fly slow and low)…What are they? We have a small goat herd with a couple of cows and pigs and these are in the barn. Once they get inside they gravitate to the windows, or up into the lights. Signature: Fed up with swatting bugs

Dear Fed up with swatting bugs, If you are truly “Fed up with swatting bugs”, then just stop.  This is a harmless Black Soldier Fly.  They are often associated with compost piles and similar habitats because that is where the larvae live.  Black Soldier Fly Larvae are a positive contribution to a healthy compost pile.  As your letter indicates, they do not sting, nor to they bite.  We would urge you to learn to tolerate these harmless creatures.

Letter 2 – Horse Fly Larva, or possibly Soldier Fly Larva

 

Subject: Larvae with ”tooth?” Location: South of Dallas, TX October 24, 2012 5:08 pm Hello Bugman – My son found a very strange larvae/caterpillar that I have been unable to identify. The creature was found on October 20, in leaf litter at a campsite south of Dallas, Texas. It has a large ”tooth” that it retracts when threatened, and otherwise uses to aid in moving along the ground. I have scoured BugGuide, Google Images and of course WTB, and cannot find anything similar. As always, thank you for your time and resources!! Signature: -Brandon

Hi Brandon, This is some type of Fly Larva.  We believe this is a Horse Fly Larva.  Here is an image from our archive for comparison and there is this image from BugGuide that also looks similar.  Most Horse Flies have aquatic larvae, but some Horse Fly larvae develop in damp earth.  We also have these photos of Soldier Fly larvae that we originally misidentified as Horse Fly larvae that look quite similar.

Daniel – Thank you!  I would not have suspected the larva of a fly, as this creature is relatively large (nearly 1.5″ long).  After reading more, I too lean toward Horse Fly as the most likely suspect. Thank you again for helping me with this.  My son and I are both fascinated with the small, typically unseen, life that we share our planet with.  Your site, coupled with our continuous field searching, has provided a steady stream of education and entertainment. Best regards, -Brandon Hi again Brandon, Your response has caused us to ponder something that we have long known but have never quite put into words.  As educators in the public schools, we are well aware of the responsibilities that teachers have, but when assessing student learning, there are many outside factors that do not ever seem to be addressed.  Parents also have a major responsibility in their children’s education.  Instilling a love and appreciation of nature at an early age like you are doing is critical if we want future generations to find value in the world around us.  That early appreciation will also make the learning that students do at all levels, elementary school, high school and college, more relevant if it is a reinforcement of values they learned at a young age at home.  It is the responsibility of the parents to help prepare their students for the future, but sadly, teachers and educators cannot control what happens in the home.  Quality time cannot be underestimated and learning is best when there is dialog involved.  Alas, as our classrooms get more and more crowded and there is less time for instructors to interact individually with students, we can only expect that learning outcomes in public schools will plummet.  Daniel – I agree with your pondering, and find that it’s a sad result of our busy corporate society.  Parents can easily become too focused on, and too busy with, careers and always seeking to attain more.  They rely on school/teachers to do all of the work of educating.  Our children pay the price for this more so than what is immediately apparent. Beyond that, I encounter fewer and fewer adults or kids who are deeply interested in science and nature.  We live in a large metropolitan area, and nature is not as readily available here as it was where I grew up in a more rural area.  However, it IS most certainly available if you go looking for it.  The problem I see is that people just don’t think about nature; they are too busy with “more important” things.  My son is always eager to share with his friends about what we’ve found and the pets we keep (reptiles and inverts).  His friends become excited and interested when they are exposed to things they don’t commonly see.  We frequently receive comments like “You found THAT in your BACK YARD?”  While my son and I seem to share this excitement almost inherently, it is something that others must first be exposed to before they can even think about developing an interest in it.  This exposure falls outside the realm of the public school system, because it requires venturing out of the classroom or beyond the standard curriculum.  If parents (or other leaders) do not offer this exposure, many children will likely never receive it. I am quite passionate about my hobbies, and my cube at work is full of my photos of both pets and things we’ve found in the wild.  Not only does it make for interesting conversation with coworkers, it also raises awareness. We do what we do for our own hobbies and interests, not necessarily for a larger purpose.  But, I can only hope that we positively influence others along the way, and cause them to stop and look down the next time they are walking around outside. Thank you for doing what you do.  I read comment after comment on your site reflecting the appreciation of your audience.  You are clearly filling a void and serving a great purpose. Regards, -Brandon Hi again Brandon, Thanks for being a fan, but even more, thanks for being a great dad.

Letter 3 – Probably Black Soldier Fly Larvae

 

Subject: Grubs found in rotting wood of coral tree Location: Los Angeles August 19, 2016 9:30 am Good morning, Bugman. We discovered today a large area of rot on the base of our coral tree. Excavating the rot, I found several communities of this grub pictured. The animals seemed at first not to move at all, but after some time, it became evident that they do move, very slowly. I am inclined to believe that they are taking advantage of the rotted wood, and are not the cause of it. They were surely not expecting this sudden exposure! Can you identify them? Signature: Swami M

Dear Swami, We are nearly certain these are Black Soldier Fly larvae, Hermetia illucens, which you may find pictured on BugGuide.  Black Soldier Fly larvae are frequently found in compost piles, where they are beneficial as they aid in decomposition.  According to BugGuide:  “Commercially distributed for composting” and “Larvae live in compost, dung, rotting vegetation.”

Om Dear Daniel, Thanks so much for getting back to me. Yes, I agree the larvae match the images of Black Soldier Fly larvae on your website. I am hoping we can save our tree; it seems to be infected with some kind of rot that turns the wood right under the bark to mush. Apparently these larvae love it, as there are quite a few. Best wishes, Mahayogananda ps I’m at the Vedanta Society in Hollywood

Letter 4 – Black Soldier Fly

 

Subject:  What bug is this? Geographic location of the bug:  Mid Atlantic. Southern Delaware by the ocean Date: 01/23/2018 Time: 11:20 AM EDT Your letter to the bugman:  I brought my red worm composting operation in doors because of the super cold temperatures.  I am sure these bugs hatched in the worm bin.  I have seen at least a dozen of them in the house.  I looked in the worm bin and there were several in the bin. If the picture is not adequate I probably can get a better one. Thanks for all your efforts! How you want your letter signed:  David Elder

Dear David, This Black Soldier Fly, Hermettia illucens, also called a Window Fly because of the transparent areas on the abdomen, is perfectly harmless.  Its larvae have no doubt been living in your compost pile and the warm conditions indoors probably hastened the maturing process. Thanks so much DAN da Man! David

Letter 5 – Black Soldier Fly

 

Subject:  Large black flies (Mydas??) showing up in my house. Geographic location of the bug:  Charlottesville, VA Date: 03/25/2019 Time: 07:05 PM EDT Your letter to the bugman:  I’ve noticed several of these bugs around the windows in my house. I will find many of them dead on the ground or sometimes crawling around on the window sill. They are black and quite large (3/4″ long). I’m thinking that they are mydas flies but am not 100%. Any information you could provide would be greatly appreciated. If these are Mydas flies where are they coming from and what can I do to get rid of them? Thank you! How you want your letter signed:  Zushi

Dear Zushi, This is not a Mydas Fly.  Rather, it is a Black Soldier Fly or Window Fly, Hermetia illucens.  The name Window Fly refers to clear patches in the abdomen, and not because they are found in windows.  Do you have a nearby compost pile?  Larvae of Black Soldier Flies are frequently found in compost piles.  We do not provide extermination advice. 

Daniel, Thank you for the reply/information. I will have a look at their abdomen and look for the transparency. I do have a personal compost bin in my backyard garden. I’ve used the compost in soils around my garden and most likely i’ve dug up some of that soil to use in pots that I have some plants in inside my house. This is probably my source. I understand not giving extermination advice. Once the weather changes for the better I plan on moving most of my plants outside. I will probably go through the process of replacing a lot of the potted soil as well and moving the current soil back into my compost. Anything else you could provide would be greatly appreciate. Best regards, John Boyd  

Letter 6 – Black Soldier Flies in Basement

 

Subject:  Small black wasp? Geographic location of the bug:  Charlottesville, VA Date: 07/23/2021 Time: 12:02 PM EDT Your letter to the bugman:  Hi, I’ve been finding lots of these insects in our basement — often dead. I’m not sure where they came from or how to keep them outside, but I figure a good first step will be identifying them! Thanks in advance for your help. How you want your letter signed:  Kyle

Dear Kyle, Though it resembles a Wasp, this is actually a harmless (doesn’t sting nor bite) Black Soldier Fly, Hermetia illucens, also called a Window Fly because of the transparent features of its abdomen clearly visible in your image.  Have you a compost pile in or near your basement?  Black Soldier Fly larvae are frequently found in compost piles where they are considered beneficial. Hi Daniel, Thank you so much! As it happens, we have a compost pile right outside, so that’s definitely where they come from. Hopefully most end up staying outside. Seriously, thank you so much for the quick reply. I know how many of these you get, and appreciate you taking the time. Kyle

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Soldier Fly Larva

 

What the heck is this thing???
Hello –
These larvae are in our swimming pool. I noticed them this morning submerged with their breathing "tube" attached to the water surface, similar to what you see with mosquito larvae. These are about 1 inch long. The top [left] picture is the dorsal view, and the bottom [right] is supine. If you are able to ID then my next question is if these are harmful to humans. Thanks!
Sam Rua
Tucson



Hi Sam,
This is some type of Aquatic Maggot, or Fly larva. We will bet on it being a Horse Fly Larva. We can find similar images online, including a drawing, but no exact match. BugGuide has an interesting entry from a person who was bitten by a Horse Fly Larva. As far as the adult flies go, only the females bite. Horse Flies are also known as Gad Flies. Eric Eaton then wrote in with the following comments: ” Daniel: I suspect these are actually the larvae of soldier flies (family Stratiomyiidae), but I’m not positive. Typically, horse fly larvae have a leathery appearance, and are much larger (mature specimens at least). Eric”