The Irresistible Lure of Pheromone Traps

by

By Thomas Schmid

When Lasioderma serricorne (tobacco beetle) or Ephestia elutella (tobacco moth) afflict stored tobacco, processing machinery, or even finished product, the results can be devastating – not to say extremely costly. It is therefore only common sense that any tobacco company should continuously monitor for these two insect species so pest control measures can be initiated before harm is done. The pests can occur at virtually any stage in the supply chain.

Sometimes they are introduced with a newly arrived container shipment, their eggs hiding away in tobacco bales, only to happily hatch in the warehouse a short while later. When infested tobacco finds its way into machinery, an entire production floor can soon be affected. And in case eggs or larvae find their way into a finished product, entire production batches may have to be destroyed.

United Kingdom-based Barrettine Group almost two decades ago introduced its MoBe trap as a joint innovation with pheromone specialists, Agrisense Limited. The successor model, the MoBe Combo Mk. 2 trap, was launched as recently as 2010, effectively phasing out the original version. As the name implies (“MoBe” equals “Moth/Beetle”, get it?), the trap was designed to specifically monitor for Lasioderma serricorneandEphestia elutella; or to be more precise, for the adult stages of the two species.

A surprisingly simple working principle

The trap works on a surprisingly simple principal – the instinct of all living things to procreate. Steven Bailey, managing director of Barrettine Group subsidiary Barrettine Environmental Health, is not beating around the bush: “In the MoBe Mk. 2 we use the sexual hormones – a.k.a. pheromones – of the two species to lure adult moths and beetles into the trap.” A special slow-release polymer pad impregnated with the pheromones remains active for four to six weeks once the pad has been removed from its sealed pouch and placed in the trap. But, there is more to it. The trap also is designed in a way that promotes optimal air cross flow so the pheromone plume emanating from the pad is distributed evenly.

“Additionally, a laminate barrier layer has been added to the inner surface of the trap to reduce the volatile migration of the pheromone and to decrease possible interactions between the glue and the trap’s outer shell,” elaborates Bailey. The two individual pheromones have been proven not to conflict with each other and regardless as to whether only one or both pests are actually present. Furthermore, the trap has been independently tested, showing that it is highly effective in attracting both species, out-performing a number of single pheromone traps.

It’s the glue that binds them

Each trap is fitted with a sticky glue pad, into the center of which the lure is placed.Without that sticky surface, the entire contraption would be useless as beetles or moths would simply scatter once they realize that the irresistible scent wasn’t omitted by a potential mating partner. But, thanks to the glue, there is no escape. “We have in fact improved the glue recipe to make it even tackier while it remains stable under variable atmospheric conditions. Furthermore, the surface is designed so that it does not detract [the insects] from actually entering the trap,” Bailey explains. The use of non-repellent printing inks likewise is an important feature, because otherwise the insects just might avoid entering the traps altogether.

Deployable for all situations

“Extremely versatile, the MoBe Combo Mk. 2trap can be deployed in all tobacco supply chain situations,” asserts Bailey, such as tobacco warehouses, shipping containers, manufacturing facilities, and tobacco product storage. It is very easy to set up, as each pack comes with the necessary instructions.

“In essence, the pheromone lure is removed from the foil pack, the protective paper is removed from the glue surface and the lure is placed in the center of the glue pad. The trap is then closed and placed in situ,” explains Bailey, adding that “depending on the ambient temperature and general environment, the exposed trap should last between four and six weeks.”

Some attention to detail must be given as to how to set up multiple traps to ensure optimal monitoring. “Our recommendation is that one trap should be placed every ten square meters in a grid pattern and approximately 1-1.2 meters off the ground,” says Bailey. But when is the number of caught insects an indicator that an infestation has occurred that requires immediate action? That, insists Bailey, is entirely up to the respective company, each of which has audit requirements that include thresholds which would trigger pest control treatments in accordance with their established operating procedures.

Effective even at elevated air temperature

It is worthy to note that the MoBe trap is one of the few pest monitoring traps that has been scientifically tested at an elevated air temperature of 37 degrees Celsius. Where some other traps may lose their efficacy due to rapid evaporation of their luring agent, the MoBe trap remains active at these temperatures and for the recommended duration.

“This aspect ensures end user suitability within processing and supply chain areas located in tropical and equatorial environments,” claims Bailey, adding that “MoBe Combo Mk. 2is approved by all major tobacco manufacturers, producers and processors.” But, while Barrettine is represented with its product in virtually every corner of the world, the company still would like to develop more sales and create better brand awareness in North and South America, Africa, and Asia. “The trap often gets confused [in these regions] as a pesticide and is inaccurately categorized as such,” Bailey reasons.

The Borgwaldt twins from Germany

The British company is of course not the only one that successfully markets pheromone traps to the tobacco industry. Borgwaldt Flavor GmbH, a subsidiary of Germany’s well-known Hauni Group, is supplying two comparable products to leading tobacco distributors, processors, and manufacturers worldwide. The company banks on two distinctive shape designs for its traps, named Contrap and Lasiotrap, respectively. The reason for that is sound.

“The difference between the two designs provides advantages for specific placement spots. Our Contrap, for example, brandishes a rather flat, oval shape and thus perfectly fits into fully loaded [shipping] containers where space is constricted. Whereas our Lasiotrap -- with its triangle shape -- is designed for placement in warehouses and processing areas where available space is usually not a problem,” explains Niels Danielsen, Borgwaldt’s sales management group manager. But, of course that doesn’t mean that Contrap couldn’t be deployed in production areas, or Lasiotrap couldn’t be placed in containers. “The two designs simply give users a choice in cases where there are space restrictions,” says Danielsen. Additionally, it is also an option to use Contrap in specific processing areas where a lot of tobacco dust can occur. Its flat design helps protects the sticky surface from being covered with too much dust.

Two lures for insect-specific targeting

The working principles of both traps are similar to Barrettine’s product, again deploying a pheromone lure affixed in the center of a sticky glue patch. However, the marked difference is that Borgwaldt deploys not one combo lure but two special capsules, one containing tobacco beetle pheromone, the other tobacco moth pheromone. Keeping the two hormones in separate capsules affords the option to specifically monitor for either insect. Alternatively, both capsules can be placed in the trap together to lure both species simultaneously. The capsules themselves are perforated with micro holes, allowing the pheromones to slowly release in minute quantities over time.

That controlled release ensures that each trap remains active for up to six weeks after placement. In containers (where Contrap is recommended), the contraption should be positioned close to the door when insect count recording is desired while product is being loaded, according to Danielsen. During transport, one trap per container is usually sufficient for monitoring. As per storage or production floor monitoring, as many Lasiotraps as needed should be positioned 15 to 20 meters apart from one another. “Ideally, traps are placed on a wall, on top of a tobacco bale, or affixed to the rear of a machine at a height of approximately 1.20 meters off the ground,” Danielsen elaborates.

Taking Into account climatic conditions

But Danielsen also cautions that prevailing climatic environment must be taken into account. In warm, humid climates the insects may proliferate at a faster rate than intemperate regions. In the latter, larger numbers could already be indicative of an infestation, whereas in the tropics an increased insect count might still be considered normal.

Yet wherever a company might be located, it is crucially important to painstakingly record the numbers of caught insects regularly, “at least once a week, or even daily if an infestation is suspected,” as Danielsen recommends. “If the insect count increases faster than proportionally, pest control measures should be initiated.” After disinfestation, the traps could subsequently again be deployed to confirm whether the procedure has been successful or needs to be repeated. “By taking advantage of Lasiotrap or Contrap, the use of harmful insecticides -- and thus pest control costs --can be significantly reduced,” Danielsen concludes.

Testing MoBe Combo Mk. 2

To demonstrate the efficacy of the MoBe® Combo Mk. 2 Trap, it was independently tested and compared to a well-known leading beetle trap brand from Japan. The trial protocol involved the evaluation of the traps within large commercial facilities selected with a range of representative infestations.

• Four replicates per trap were maintained, with at least four sub-replicates in each test (4 x 4 traps of each type).

• Traps were randomly assigned and rotated weekly and traps were suspended on the walls, approximately 1.8 meters above ground, and replaced at weekly intervals.

• The distance between traps within the same replicate was >5 meters, distance between replicates >10 meters.

• The two evaluation periods lasted 12 weeks in 2011 (spring-summer) and 8 weeks in 2012 (spring- summer).

Test results: The performance of the MoBe Combo Mk. 2 Trap was comparable with the brand leading trap, especially at lower beetle population levels, where sensitivity of monitoring the beetle is paramount to the decisions made to control the pest.