Pest Control Question:

What is the name of the fly that just flies in circles, like in the garage or patio? I put out Maxforce fly bait, but nothing works. I make sure to pick up all the dog and cat droppings, so where do they come from?

Answer: 

There is one species of very annoying little fly, appropriately called the Little House Fly (Fannia canicularis), that spends its time flitting endlessly around in shaded locations. This often is covered patios, open garages, breezeways between buildings, or under shade trees. Sometimes dozens of them may be present, and the annoyance is increased when you walk through the area. Their appearance is similar to the regular Housefly, but the little house fly is much smaller and males have patches of light yellow on the sides of their abdomen, which is very slender.

 

Like so many other “filth” flies these breed in decaying materials, such as garbage cans and dumpsters, rotting vegetation, animal waste, etc. In the landscape the source often will be dog droppings that have laid around for too long, allowing the flies to lay their eggs on the droppings and for the maggots to move through their stages and to the pupa. To resolve this the homeowner needs to be coached on frequent removal of the pet droppings, with no more than one week between cleanup periods. Vegetation that has piled up and remains wet is a perfect breeding medium, and lawn clippings are often the culprit. As a pile of lawn clippings begins to rot it generates heat, and now the warmth and moisture within that pile can produce huge numbers of flies for a long period.

 

Control can be a little difficult when it comes to dealing with the adult flies. Since they are able to fly and are drawn to a shaded place, it may not even be on your customer’s property that they are breeding. We preach source control when it comes to dealing with flies, rather than focusing on the adult flies, and this is extremely appropriate for filth flies. But, if they are breeding in some other yard but just coming to your customer’s property because there is some great place to fly around, that makes it tough. The little house fly seems to be far less attracted to the highly effective fly baits than the House Fly, but I would still try these, such as the Maxforce Granular, Maxforce Spot On, or the QuikStrike. The adult flies normally feed on nectar and other sugary resources (honeydew from aphids), so they do like sweet liquids.

 

Since the problem is very often outdoors it really limits the use of UV light traps, which would have too much competition from sunlight to be very effective. If possible you might be able to install fans or in some other way create air movement, which discourages the flies from using a particular area. Treating surfaces near the flight area with a residual contact insecticide may be helpful, as at some point in time even these tireless fliers do have to land, and if they land on that material it may be sufficient to kill them. A microencapsulated or wettable powder formulation may be best, such as Demand CS, Tempo, or some other pyrethroid. The use of pyrethrum sprays will also be pretty limited in effect, as they would dissipate rapidly outdoors.

 

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