Get The Most

Out of Your Fly Light Program (ILT’s)

Fly vectors can pose human exposure to food-borne pathogens.  Due to their ability to fly great distances and their attraction to animal waste and decaying organic material as well as food prep areas, they can spread these pathogens.

Therefore, it is important to put great thought into the correct fly light program.  The program should help monitor and verify all the right things you are already doing in your facility.

For the purpose of this conversation we will be speaking of Insect light traps, glue board style, not zappers.  Beyond the basics of shatter proof bulbs and frequency of bulb change, a fly light program can leave food processors confused.  Throughout the last 20 years of building pest programs in food processing, medical devices, surgical centers, hospitals and pharmaceutical manufacture facilities, I have come across complicated situations and many great questions.  Many times, I have had clients call me, “we have a fly issue and need more fly lights”.  More fly lights are not always the appropriate response.  Sure, we would always like to bill more, we are a business.  However, billing for the sake of billing and not rectifying a client’s real concern does not build a long-lasting relationship. It is important to step back and look at your building with a new set of eyes. 

Look at lighting; could we make adjustments to the building? make it less attractive to flies? 

New technology with LED’s that emit lower UV spectrum lighting and lower heat should be considered.  Lights pointed at buildings instead of lights hanging on buildings can help greatly.  Positive pressure buildings help greatly. Audit your doors and windows, repairing where needed. Fix or install screening, repair holes.  There are also inspections to sanitation and sanitation procedures that will help with indoor breeding.  This will become more apparent as we describe how to build a proper fly light pest program.

Building the right program for you and your process

When building an ILT program I like to start at packaging and processing/OR’s.  This is when products or humans are most vulnerable to flies.  These areas will be your secondary lights or your verification lights.  This light should verify that all other procedures are working, sanitation and exclusion measures like screens and closed doors.  This light or lights should always have lower counts than your primary lights.  Primary lights should be located at doors used most frequently, employee entrances, overhead doors and at shipping and receiving.  In some cases, there may be a need to have a light between overhead and packaging or processing areas.  Again, counts should be lower than primary lights.  If secondary lights have more fly counts then primary lights, this is an indication of a faulty program.  Depending on species this could mean a sanitation failure or poor exclusion measures.  Either way there should be an inspection and corrective measure. 

How lights should be hung

Insect light traps should not be seen from the outside of the building.  This will attract flies to your building and defeat the purpose of the program.  When in processing or packaging areas, lights should draw fliers away from the product, not towards or above product.  Ideally you would not want product near these lights.  Although they are not zappers, flies will dry out and flake, you do not want to add that to your ingredients list.  Also remember that lights are line of sight, hanging them so you get the most view from an area or room gives you the best coverage.  The conversation of how high to hang a fly light always raises an eyebrow or two.  The target vectors we are after are typically low fliers.  Knee height is ideal however, this is not functional in the real world of processing.  We aim for 4-6 feet high.

Article Written By:

Andrew W. Sievers, ACE

Associate Certified Entomologist
profishant, inc.

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