How to stop these maggots from killing all the worms in your worm farm!!!

by Stephan
(Cape Town and Radevormwald)

Large Black Soldier fly maggots can cause massive problems in a worm farm

Large Black Soldier fly maggots can cause massive problems in a worm farm

The maggots in the picture are the offspring of the Black soldier fly "Hermetia illucens that belongs to the family of "Stratiomyidae."

Now the good news is that Black soldier fly (short BSF's) maggots don't kill compost worms themselves but nevertheless their presence in a worm bin leads in most cases to the loss of all the worms that have been living happily in their bin for month or even years. So it is vital to remove those maggots from a worm bin as soon as possible once you have found them in it.

Luckily Soldier flies which are attracted by decomposing vegetable and fruit waste are usually not around in large numbers and don't get that often into well run worm farms to lay their eggs. But if they do and the maggots hatch they will feed ferociously on the decomposing vegetable matter and the worms which don't like to share their home with those maggots will either migrate out of their bin or to the lower parts of their bin where they will perish.

An interesting fact about BSF maggots is that they similar to compost worms like to recycle organic waste and there are many people around the world that use those larva to convert vegetable matter into compost. The problem for every worm farmer is that worms and BSF maggots can't live in the same bin as I mentioned earlier.

There are a few steps that can be taken to prevent the loss of your entire worm herd.

1. Keep your worm food and your worm farm always well covered to prevent the soldier flies which look similar to black wasps from laying their eggs into your scraps. We usually collect our kitchen scraps in a bucket with a lid in the kitchen or on the stoep which works quite well.
When we add kitchen waste to a worm farm we do this swiftly. It takes usually less than a minute to service one of our worm bins. The following URL from our facebook page shows you in a short video clip how easy it is to feed a worm herd.

If your worm farm hasn't got a tight fitting lid it is a good idea to always cover the worm food with a plastic bag and on top of it a 5cm / 2 inch layer of shredded newspaper. The bag and the paper will act as additional barriers against unwanted invaders like BSF's

2. Whenever you feed your worms have a quick glance at the surface of bedding or remaining food if there is some left. BSF maggots are usually active on or close to the surface of the worm bedding and this way they can be easily spotted if they are present in a worm farm. If you find those maggots in your bin remove them asap. They normally huddle all together in a feeding frenzy and can be easily picked up and taken out of the bin. They will most likely be no worms near them so there is no danger of accidentally removing worms as well.

Once you have removed the maggots either feed them to your pets (Fish and chickens like them for sure) or place them in a different bin without worms and let them recycle vegetable matter for you. Another alternative is to put them in a shallow tray without soil and let them die in the sun. Once they are dead they can be used as worm food.

Should the surface your worm bin start to look soggy and produce bad odors there is a good chance that it has been invaded by BSF maggots which have been active in the bin for probably several days and it might be to late to save your worm herd. However as described before quickly remove all the maggots from the bin to hopefully save some of your worm herd. Any worms that might still be alive in the bin will most likely be in the lower parts of the bedding.

I have been farming with worms for nearly 20 years now and only had a few incidences of really bad BSF maggot infestations in our bins.

So far we never lost a complete worm herd to them but having been a commercial worm farmer and author on vermiculture for many years now I found that BSF maggot infestations have been one of the main causes of the complete loss of entire worm herds in previously well established worm farms.

Having said that if you take the precautions I mentioned above your worms should be fairly safe.

Have a look at the following link for more information about Black soldier flies

If you have additional questions about this subject please fee free to share them with us and we will get back to you asap.

Kind regards

Stephan Kloppert
Author of "How to start a profitable worm business on a shoestring budget"

Editor of

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Aug 26, 2022
Worm tower
by: Kevon

I'm not sure if you're familiar with this at home tiny vermiculture farm but there are tons of holes in it and we keep it's outside. I probably v have to pick off 5-6 egg layings from BSFs every day... It is horrible. Is there a way to deter them? They already almost destroyed the whole colony and I'm currently building them back.

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