What Your Pest Control Technician Won't Tell You About Fly Killers

Or Six Fly Control Urban Myths

We recently published an article in Pest magazine discussing an approach for standardising fly unit testing and invited the industry to join the debate.

Interestingly, the results of our testing so far have revealed a number of urban myths about EFKs, which are important for customers to know about when making an informed decision about fly control.

Not true. The wattage of a fluorescent lamp is a measure of the power it draws from the supply, not the quantity of light it produces.

Did you know the same quantity of light (around 750 lumens) is produced by a 60W incandescent bulb, a 42W halogen bulb and a 15W compact fluorescent lamp?

Equally important is the light produced. It must be of the correct wavelength (350 or 365 nm) to influence the behaviour of house flies. Producing more light at other wavelengths can have no affect on the behaviour of flies.

It certainly helps, but maximising UV-A output can lead to other unintended outcomes.

We found that fitting reflectors behind the bulbs in a unit will increase the amount of UV-A emitted into the room, but unfortunately it also provides a nice landing site for flies to perch on without capture. Therefore the unit’s catch rate is reduced despite the reflectors assisting by attracting more flies.

Probably true, but not that relevant. There are scientific studies on the behaviour of flies in laboratories that show a fly’s behaviour is influenced by a number of different sensory cues including glueboard colour and contrast, pheromone lures and green light. Equally there are also scientific studies that show no significant attraction to any of these cues when they are used in the field.

The reasons for these different findings are probably due to the range of different sensory information the flies experience outside the uniform environment of the laboratory.

Different insects are attracted to different wavelengths of light though, and it is important to keep in mind what it is you are hoping to catch. In addition, the customer may prefer a black glueboard that disguises the appearance of captured flies.

Our tests found no significant difference in catch rates when glueboards of different colours and contrast were compared in the same units.

Not true. Coverage figures quoted by EFK manufacturers have very little application in the field.

If you think about it, a wall-mounted unit covers half the area that would be covered by a suspended unit with the same number of lamps.

The area covered by a wall-mounted unit is a 2:1 rectangle of 4d²/2 = 2d² = 12.5n m² where: d = distance in metres from unit to minimum effective level = √6.25n and n = no. of 15W lamps

It is assumed there is: no significant reflection of UV-A by the back-plate or chassis; that the area in front of the unit is completely unobstructed; and that the power (W) of the bulbs is generating the same amount of UV-A per 15W bulb.

In pratice, coverage depends almost entirely on what the surroundings are. In a store house with pallets stacked floor to ceiling, you are going to need more EFKs than in a perfectly empty room, and if there is a lot of ambient light you will need more units than in a pitch-black space.

Not true. If flies are not attracted to the unit, they will not be caught on its glueboards. The worst performing unit tested had one of the largest catch areas, and also one of the lowest UV-A output readings.

Not true. There are many factors that influence EFK catch rate including:

• Size, position and orientation of the glue board(s)
• Distance between glue board(s) and lamps
• Type of adhesive used on the glue board(s)
• Amount of sites within the unit where a fly can perch without capture
• Cover design
• Unit colour
• Degree of colour contrast between the unit and its surroundings.

Optimising EFK catch rate may also be a lower priority to a customer compared with other factors such as:

• Cost
• Aaesthetics
• Ease of servicing
• The environment the unit will be used in.

Ultimately, the catch rate of an EFK in the field is going to depend upon the environment it is in and the placement of the unit. A high-powered EFK is no substitute for the experience of a professionally trained field biologist or technician who can assess the environment and customer requirements.