By John Cooksey

To view this article as it appeared in PCT magazine, please click here.

Now that it is June, fly season is in full swing all around the United States. Large and small flies can be the most irritating pests to your customers and sometimes the most difficult to manage. When fly populations get out of control, the problem can snowball and become difficult to stop. But, it doesn’t have to be that way. With good customer cooperation and some of the newer products on the market, flies can be kept in check and managing them correctly can generate additional revenue to your existing accounts. Let’s talk a bit about fly control that really works.

Fly Types. In the pest control industry, flies are generally thought of as falling into two categories: large flies and small flies. Large flies include flesh flies, blow/bottle flies and house flies. These species typically breed outside of structures and come in through any opening available to them.

Small flies usually breed inside structures and include species such as phorid flies and drain flies. A good fly program utilizes techniques to deal with both types of flies. Some of these techniques will work well against both types, but often each type of fly has specific biological characteristics requiring different measures to effectively control.

A standard fly program consists of five main elements: ILTs, drain treatments, baits, sanitation/exclusion and chemical treatments.

Insect Light Traps. Insect light traps have, for a long time, been the backbone of fly control programs. They offer a great way of monitoring fly populations. They can be used to identify the species of flies you are dealing with and can be a great indicator of population threshold limits. In smaller accounts like restaurants and cafes, they can be a good system of control as well. ILTs should be placed in areas where the general public doesn’t notice them but the flies do. Sometimes this can be a difficult task. Generally, they should be 3 to 6 feet off the ground and in areas they can be checked with minimal difficulty. The more difficult they are to check, the less likely they will be checked consistently. Care should be taken to avoid placing them where they may contaminate food, such as over or near food preparation areas. They also need to be close to electrical outlets and on a wall service that can support them with screws.

Maintenance of ILTs is critical. Generally, each type of ILT has its own specific glueboard that should be changed on a monthly basis. The light source in an ILT comes from a fluorescent bulb. These bulbs are designed to emit a frequency of light that is attractive to flies and draws them in. Over time these bulbs can change their output in both wavelength and intensity. Studies are underway to see exactly what these changes are and how they affect fly attractance. Manufacturers often recommend that these bulbs be changed on an annual basis, which can be quite expensive. Don’t forget to charge for this service!

Drain Treatments. Drains are a big source of small fly issues. When they don’t function properly, they can build up deposits that make an ideal small fly breeding ground. Drains can be tricky — they are more complicated than just a hole in the floor that water goes down. They normally have a two-piece body with a reversible flashing collar to permit seepage into the drain body. They need to be taken apart and inspected on a monthly basis and cleaned and/or treated if necessary.

Luckily, we now have several options to help us with drain problems. Microbial drain treatments can work well when they are used consistently and appropriately. Most contain enzymes that help break down deposits either on the floor or in the drain system, eliminating the breeding sources of many small flies. They can be foamed, poured, injected, sprayed or even added to your customer’s mop water. There are automatic, timed devices that can be installed at your customer’s facility that inject the products for you. All you have to do is make sure these devices have product in them. By the way, you should charge for this service as well!

There are endless options for cleaning drains. Many PCOs use the same steam machine they use for bed bugs to effectively clean drain systems. In some cases, it can be more complicated than this. Pipe breakages under buildings can cause small fly issues that are seemingly impossible to stop. The only way to solve the problem is to fix the pipe. Don’t limit your options when dealing with drains – be creative using multiple treatment methods to maximize fly control effectiveness.

 Fly baits have been around for a long time. Thankfully, some recent advances in fly bait product development have made fly control much easier. I am sure we all have had an experience where we have been trying to control flies inside a facility and were left scratching our heads because there was no legal product to use or no legal application site on which to apply it. Now there is a new liquid fly bait product on the market that has better label language and has brought some relief to this situation. These newer bait products are good at attracting flies and have great efficacy.

Additionally, there are some new bait devices that allow for liquid and granular applications, making it easy to create baiting opportunities in areas where locations for product placement are limited. Fly baits used on the exterior of facilities are a great way to knock fly populations down to a manageable level. What better way to impress a customer than to show them thousands of dead flies after a bait treatment; it makes you feel like you accomplished something too. You should charge for this as well!

Sanitation/Exclusion. This part is a no brainer for most of us. Garbage on the outside of structures breeds flies, and openings to the inside bring them in. It’s important to work continually at minimizing both. This is a great opportunity for customer communication. You should constantly document issues and give recommendations for improvements. Just a basic comment of “clean up outside” is never enough. Be specific, i.e., “Dumpster needs new cover” or “trash pick-up should be increased to twice a week during summer months.” Always provide a solution in addition to identifying the problem; your customers will appreciate it. Remember, the enzyme treatment you used on the drains works great on Dumpsters and the back areas of facilities as well. Use it, and more importantly, charge for it!

Chemical Treatments. The use of chemicals is still a good option for some situations, both inside and out. If you’re taking over a problem account with a large population of small flies on the inside, sometimes the customer can’t or won’t wait for slower measures to work. Fogging will certainly knock down fly levels until other methods can achieve long-term results. The use of chemical applications on exterior fly landing areas can be useful as well, but the effectiveness is typically not very long. With label restrictions on the rise, these applications are going to become more limited in the future.

The important thing to remember is that there are many options for fly control and the integrated use of these different approaches will bring the best results. In many cases, fly control is considered its own separate entity apart from the overall facility’s pest control. It has its own materials and methods and can be one of the more difficult aspects of any program. As such, it deserves to be charged at a fair rate to best protect your customer’s property and brand.


John Cooksey is chief operating officer of McCall Service, Jacksonville, Fla., and a member of the Copesan Technical Committee. He can be reached