Maggots By The Millions........Well, Hundreds

Monday September 17, 2012


Mr Pest Control


I have an account that has maggots in the cracks of the concrete next to the building. The maggots are in the hundreds. The compactor is in the same area. I have treated the crack with a microencapsulated product which did not work. I have not dealt with this issue before and do not know where to go from here. Some guidance in the treatment would be greatly appreciated.

terry, VA

Mr Pest Control


I'll go with the fact that these are, indeed, maggots, and thus probably from blow flies. I have also seen some great images of a rare phenomenon where thousands of small fly larvae of fungus gnats are migrating en masse out from under a concrete slab, perhaps heading off to a better place to pupate. But, this is pretty unusual and these larvae are far smaller than your typical maggot. 

Blow fly larvae do this. They move out from their food and move to some protected place to pupate, sometimes moving pretty long distances. They often fall out of ceilings from dead animals in the attic. They climb up out of filthy garbage cans and dumpsters and crawl across the floor or the parking lot. In your case, since these are outside, it tells you there is some source out there producing the maggots, and this needs to be found and dealt with at that point. Since the garbage compactor is nearby that does sound like a reasonable place for garbage to accumulate and rot, but I wouldn't stop with that possibility. Investigate other things around there such as piles of lawn clippings, filthy dumpsters, maybe some dead animals in the bushes, etc. 

Treating the maggots in the crevices may kill some of them, but if you have an ongoing source its likely that many more maggots are growing and developing there and they will replace the ones you manage to kill. Fly control always relies on source control. So, find some way to dig into that compactor and get it serviced and cleaned. This is a sanitation issue that should not be left alone. It may require a technician trained in servicing this kind of equipment, but it really does need to be done. Otherwise, if it is dirty dumpsters or other sources they can be washed properly and maintained with lids closed and in good condition. 

Mr. Pest Control

Register now for PestWeb to get instant access to all of Mr. Pest Control's in-depth answers!

Register Now Ask a Question Add to My Favorite Questions

Please note, Mr. Pest Control is answering questions supplied by PMP customers across North America. His answers are generated from industry and manufacturer-provided information. The answer may not be specific to the laws and regulations for your State, Province, Territory or Country. In addition, products mentioned may not be registered and or available in all areas. Always check with your local Univar office for specific information to your area. Always read and follow label directions.