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Pest Control/Drain Flies in french drain


We had a french drain installed in our basement two years ago. Since then we have had drain flies in the rocks in the drain.  I can't seem to get rid of them.  They get worse when the weather is damp and humid. I can see the flies in rocks.  The drain goes around the perimeter of my basement. I use a dehumidifier in the basment and have tried some bio foam products but not having much success.  Any suggestions.  Please help.

Hi Cathy sorry for the delay. DF 5000 Gel is a highly selective active bacteria complex (not an insecticide) available in a convenient, ready-to-use 32 ounce container to rapidly attack and destroy the organic matter that supports drain fly development. When applied, the gel clings to pipes and traps. Pour the product around the drain edge to coat the sides. Treat five days in a row and then monthly. It does not harm plastic, metal or glass plumbing, and will keep drain lines flowing freely. Bleach should not be used in conjunction with this product as it will kill much of the beneficial bacteria and reduce its effectiveness. This product is not sold for the customer market. It is sold to pest control operators, hospital, restaurant and food service personnel. For additional information, contact: J.I. Holcomb Manufacturing Company. As always follow lable instructions on product as the label is the law.  

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Steve Oswalt


My Pest Control and Nuisance Wildlife Removal experience is in Residential, Commercial, Public Housing, Multiple Story Hi Rises, Agricultural facilities. My company is located in Lewisburg, Ohio and our Web sites are


20 years in Pest Control and Nuisance Wildlife Removal business were we provide exclusion services for pest control and nuisance wildlife along with latrine and gauno cleanup.

National Wildlife Control Operators Association's, Bed Bug Professional Group, Pest Management Professional Network, Wildlife Professionals Network, Rodent Management Network

Licensed and Certified in Ohio with the Department of Agriculture and Ohio Division of Wildlife as a Nuisance Wildlife Operator.

Past/Present Clients
Commercial Kitchens, Pre-Schools, librarys, Banks, Post offices, Urgent care, Fire houses, Kennels, Veterinarian offices, grocerys, nursing homes.

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