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Blowfly Larvae, Roaches, Compost Starter


September 7, 2018

My compost is infested with blowfly larvae. They are effectively making compost but I sure don’t want the thousands of flies they will become. I have a small apple orchard so there are many many rotting apples in the compost as well as kitchen scraps. Please help.


Answer by JZ: I will offer my opinions.  Other colleagues may also reply to you.

* You did not mention how your composting operation is set up.  Bin? pile? tumbler? straw bale? other 

* You did not mention where you live - zip code ?

* Are you doing cold process or hot process composting?

* Is your set up covered with a tarp?, rug? cardboard?

* It is difficult to answer your question without more information…

Some thoughts / ideas:

* Practice a hot process set up, where the internal temperature of pile would reach 150F.  This temp. would destroy larvae.

Follow the guidelines for hot process in this brochure.

* Cover the top of your pile so that flies cannot get to the organic material.  I use a piece of plastic, cut to fit.

* Bury, churn in the visible larvae deep into the pile.

* If you have a cold process set up, then in mid October, the drop in temp. or frost should slow down the flies & larvae.

* Scoop out some of the larvae and bury them deeply 18 - 24”, in the soil.

Let me know if this is helpful.  All the best.

Response from Questioner: Thank you for your suggestions. Some more information: 


We have a pile. Zip code: 87107 (North Valley). We are attempting to hot compost but having trouble getting it warm enough. It is currently covered in plastic.


Ps there are also many roaches in the pile.


It is a relatively new set up would compost starter help?

Answer by JZ: Thanks for the info.

The guidelines for the hot process are here.

If your pile is not heating up, assuming that you have air flow, 50% moisture and a cubic yard of organics, then the missing variable may be nitrogen - greens, which are required for microbial cell wall formation, growth and proliferation. A ball park guide would be to combine equal amounts of browns and greens, then chop before you drop and bulk as you build.

If you wish to inoculate your setup you may sprinkle in some finished compost which contains millions of decomposing microorganisms as you build the pile.  Purchasing a “starter” would be your choice.

Roaches are detritovores - they are beneficial to the decomposition process.  All the best.    Let us know if you have questions. Attend any of our free classes.

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