by Alain VanRyckeghem, BCE
After a pheromone has been synthesized in a chemistry lab, it is placed into a delivery device, or lure. These devices come in various forms: rubber septa, hollow fibers, flakes,
tape, laminated plastics, membranes over reservoirs, and polyethylene vials with acetate beads (shown above). The lure design should deliver the pheromone into the environment
in a manner that mimics natural release rates and concentrations of the target insects. Lures vary in duration of effectiveness and distance of attraction due to differences in
pheromone load and release rates. Many insects can be overpowered and repelled by too much pheromone (e.g. flour beetles, granary weevils). A controlled-release lure will allow
the pheromone to be released in small enough concentration to lure the pest into the trap, but strong enough to reach out and attract them in from a useful distance. In addition,
the lure needs to remain effective over a several-month period.
The quality of pheromone is important for some species such as the cigarette beetle, Lasioderma serricorne, flour beetles, Tribolium spp. and warehouse beetles,
Trogoderma variable. Some impurities in the synthesis are repellent in concentrations less than 5%. Good quality pheromones have high purity of the desired chemical
structure. Some pheromones are a blend of chemicals and require a
specific ratio. These lures are more attractive than lures that use only
one common compound that attracts several related species. Use of
species specific blends in lures may reduce the catch of closely related
species. For example Indianmeal moth, Plodia interpunctella, (IMM)
and almond moths, Ephestia cautella, are attracted to a common
pheromone and is widely sold as such. If you use a blended
pheromone for IMM that has additional pheromones, one of these
compounds will repel the almond moth and reduce its catch.
It is important that the users of pheromones determine the
shelf life, duration of pheromone release, recommended spacing
of lures, production dates and general composition (e.g. blended
pheromones) of the pheromone lures from the manufacturer in order to
get consistent, long-term release and attraction to the lures by the insects.
Cheaply made lures have very little pheromone, no control over release
rates, are poorly packaged and are often found on retail store shelves
for many months. These poorly made products have comparatively very
poor results and can even be past shelf life (expired) by the time they
are purchased. For this reason, all pheromones and pheromone lures
produced by Insects Limited are placed in a freezer prior to shipping.