Insects in Compost

Asked August 28, 2020, 1:04 AM EDT

The insects in the attached photo have invaded our compost bin.
Please tell me what they are, if they are beneficial, etc.

Marion County Oregon

1 Response

What are those insects in your compost bin? Those are the larvae and pupa of a fly, and are most likely the larvae and pupae of the Black Soldier Fly. These insects are beneficial, in that they help to transform the raw materials that you put into your compost pile into the rich organic matter that you can use as a garden ammendment. However, they can also become nuisance, as they grow into numerous adult flies that may fly around while you're working in the garden.

To keep your compost pile from becoming a source of nuisance flies, you can:

  • turn the pile, more often
  • temporarily limit the amount of high nitrogen material you add to the pile, such as grass clippings or vegetable scraps
  • temporarily add more high nitrogen materials to the pile, such as sawdust or shreeded leaves or shredded wood waste from the garden
You can learn more about black soldier flies by visiting this link:
https://extension.oregonstate.edu/news/big-maggots-your-compost-theyre-soldier-fly-larvae