What is Ultraviolet, UV?
Many people are interested in what ultraviolet is, how ultraviolet rays
(or UV rays) work and how the UV light bulbs can be used for fly
insects, tanning beds and in sanitation programs. This article will go
into a little detail that explains the ranges of the ultraviolet spectrum used
in these different applications, especially pest management, light bulbs in fly
traps and how flies and other flying insects are effected by UV light bulbs.
Ultraviolet topics covered:
What is Ultraviolet Light?
Ultraviolet light is not visible to the human eye, but can be found slightly to the right of visible light on the light spectrum.
Measured in nanometers, UV light has a wavelength lying between 100 and 400 nanometers in length.
UV is divided into three spectrums, namely:
UV-C, also known as Germicidal Irradiation, lies in the spectrum between 100 and 280 nm and is used for purification of air, water and surfaces.
UVB is used for tanning purposes and has a wavelength of between 280 and 315 nm.
UVA, sometimes referred to as black light/blue, lies between 315 and 400 nm and is used within insect control equipment.
|What is a Nanometer?
A nanometer is a unit of spatial measurement that is 10-9 meter, or one billionth of a meter. It is commonly used in nanotechnology, the building of extremely small machines.
Back to Ultraviolet Light.
Why Are Insects Attracted to UV?
The eye of the fly is made up of hundreds of tiny hexagonal lenses, which form a curved lattice across the of the eye. Unlike humans,
flies can see ultraviolet
light, due to the complex makeup of their eyes. Insects such as the House
Fly, which are attracted to light, are said to be phototactic.
All light sources emit some level of UV and it is this UV that flying insects actively search out, mistaking it for the sun's rays. Flies are most attractive to UV light between 350 and 370 nm in wavelength, most
noticeably at 365 nm. This UV peak falls in the middle of the UVA spectrum.
Ultraviolet fly traps are safer to use than indoor
How Does An Ultraviolet Tube Work?
Ultraviolet light is created by a fluorescent tube, containing a mixture of inert gases, a phosphor coating and a tiny amount of mercury (only 3 to 3 mgs.)
When the tube is fed electricity, the current flows through the gas mixture, which acts both to conduct the electricity and to ignite the tube. The mercury atoms absorb the energy of the current. This causes the atoms to become unstable.
To regain their stability, the mercury atoms must lose their excess energy. They release this energy in the form of UV radiation.
Once created, the UV radiation attempts to escape the confines of the phosphor coated glass tube. Depending on the variant of the phosphor, the thin coating allows the desired wavelengths through and absorbs the rest. This enables the tube to be tailored to release a precise level of UV.
How does UV-C kill microorganisms?
Due to its short wavelength, (200 to 270 nm) UV-C penetrates the outer membrane of bacteria, yeasts, molds and viruses, attacking the DNA which makes up their structure.
By breaking the chains between the two helixes within the DNA, the microorganism is rendered unable to reproduce,
i.e. clinically dead.
Each microorganism has differing tolerances to heat, radiation, etc. The microorganism is given a "D-Value" or measure of resistance to being broken down. If this value is known, along with the power given out from the UV-C source, the time take to destroy any given microorganism can be estimated.
Capturing Flying Insects
Knowing how and why house flies, gnats, fruit flies and other flying
insect pests are attracted to ultraviolet light bulbs is the first step in
understanding how to use the UV rays emitted to trap unwanted pests in certain
areas. Homes, offices, schools, nursing homes, hospitals, restaurants and
other commercial food handling areas often use ultraviolet fly traps to reduce
populations of flies and other pests to manageable levels.
two basic types of fly traps that use ultraviolet rays, each type using a
different method to kill or capture the flies. The oldest type falls under
the category of bug zappers or fly zappers. As their names imply, flies
that are lured to the UV rays are "zapped" by an electronic
grid. Electrocuted insects fall down to a tray or pan that can emptied and
cleaned as needed. The major down side of these bug zappers is airborne
body parts from the zapped bugs. These particles are unacceptable and
illegal in any commercial establishment where foods are processed, bottled,
prepared or served. This obvious sanitation problem brought about the
development of the second type of ultraviolet fly trap: those that capture flies
with a sticky pad.
The newer ultraviolet fly traps not only use sticky pads to capture flying pests
but they are also impregnated with a sexual attractant or pheromone that helps
lure flies to the trap. These pheromones are a great addition to the UV
bulbs in the trap. UV rays do not bend around corners in such a fashion as
to lure flies from many different rooms, when using one fly trap. The
pheromones will attract the flies from areas that are not effected by the
ultraviolet light bulbs. There are also certain flies (such as the Vinegar
Fly) that is not always attracted to UV light but there are attracted to the
pheromone glue pads used in powerful ultraviolet fly traps such as the Fly
Trap Professional, Luralite, Satalite
and Cento fly trap. Each of these traps
are shipped with the special pheromone glue pad. Replacement pads are also
available so that monthly or bi-monthly maintenance is simple and
inexpensive. Maintenance should also include changing out the ultraviolet
light bulbs about every 12 months.
Many people will wait until the bulbs burn out before replacing them.
These is not a good idea. Old ultraviolet light bulbs may seem to be okay
because they still light up the specified area but, as they age, the correct
spectrum of light is not being emitted and therefore the bulbs no longer attract
flies in the most efficient manner available.
Other links of interest:
of Household Flies Products for
Fly Control Ultraviolet
Ultraviolet Fly Zappers
Fly Breeding Sites Pest
Restaurant Pest Management Fly