There are long rows of them hanging from the ceiling, yellow plastic buckets bought for 19 SEK a piece. With a decimetre-wide strip of adhesive-coated paper, of the old fly-paper type, just inside the rim, a few litres of water at the bottom and a little detergent to reduce the surface tension. Sooner or later they come here to drink, the now very few almond moths (an insect pest with the Latin name Ephestia cautella) that make the mistake of seeking out CloettaFazer´s chocolate factory in Ljungsbro near Linköping. Most of them drown straightaway, but the slightly more cautious characters, the ones that land on the inside of the bucket to sip the water, come to a sticky end on the fly-paper.Generally, there is every chance of these little moths feeling at home in a confectionery factory, with its supply of food - finely powdered sweet chocolate - served up at just the right temperature. ‘It would be unpleasant, to say the least, to find eggs and larvae in a piece of chocolate,´ says Mats Ekeberg, hygiene manager at the factories in Ljungsbro and Norrköping. ‘It would be devastating for the entire industry, and simply can´t be allowed to happen.´
Attract to kill
Ekeberg has a certificate of competence to use Class 1 SO pesticides, but they are very rarely employed these days. ‘Getting out the spray-gun doesn´t have a lasting effect.´
Instead he relies on a method known as ‘attract to kill´. The insects are lured to their death using either water, food scents, or the species-specific chemical messengers - pheromones - by which they communicate. Another strategy is to disrupt mating, reducing the number of offspring produced. The scent of female moths is intense. It comes from 33 little white bags of pheromones, placed in a grid pattern in certain areas of the factory. Of course, we humans cannot smell it, but the male moths can. And it confuses them.
Cooperation produced results
Mats Ekeberg collaborates closely with scientists on the Mistra programme Pheromones and Kairomones to Control Pest Insects. He himself contacted LundUniversity when he joined CloettaFazer a few years ago from the pest control firm Anticimex. To find someone to discuss his work with, and to keep abreast of innovations in his field.
He has not regretted it. He produces graphs and statistics - the results are truly impressive. Working with the researchers has been mutually beneficial. ‘We´ve had a relaxed, generous approach on both sides. I get a lot out of my cooperation with them, and I offer them something in return. ‘It´s important to keep the puck moving,´ says this former ice hockey player. ‘It doesn´t work if one person decides to keep information to himself.´
That is his approach within the company, too, getting the staff to pull together as a team. They can now boast a virtually perfect record in terms of personal hygiene, cleaning and reporting - all of which are crucial in this context.
Silkworm moth first
It has been known for over a century that insects communicate by scents. In the late 1950s, the first sex pheromone was identified, the scent of the female silkworm moth. Since then, research has made great strides. Pheromones for several hundred insect species are now available.
‘The idea of course is to reduce the need to spray insecticides,´ says Olle Anderbrant, a professor at LundUniversity and communications officer for the programme, which is known as Biosignal for short. ‘This is particularly vital in countries with a warmer climate than ours, where harmful insects are a bigger problem.´
Thanks to their cold winters, the Nordic countries have something of an advantage over more southerly nations, but they are by no means immune to insect pests.
From research to business
Pressure to achieve quick profits is a major problem when it comes to translating research results into practical applications.
‘Moving from research to large-scale commercial use is a big step. It would have been useful to have had established business partners involved in the programme from the outset,´ comments Anderbrant. ‘But when we started there weren´t many companies in this field in Sweden.
‘We did get in touch with a few we thought would be interested, but got no response. Now, though, we are collaborating with both producers and pest control firms.´
Getting growers and other end-users on board has been easier. Virtually every apple grower south of Stenshuvud in Skåne, for example, has accepted an invitation to work with the researchers.
Sweden´s tastiest apples
Per Olof Persson runs the Dagstrop orchards between Lund and Landskrona. He has a small, fairly recently planted, organic apple orchard. Its five hectares, he says, produce ‘Sweden´s tastiest apples´.
He has used pheromones before, and for a year now has been taking part in trials aimed at getting rid of the codling moth. In this case, the pheromones are contained in decimetre-long plastic ‘ropes´, which are twist-tied to the branches.
‘They have to be quite close together, on roughly one tree in three. But attaching them doesn´t take long,´ he points out. ‘They have no unpleasant smell, and aren´t at all difficult to handle.´
The codling moth is just one of many insect pests that feel at home among the apples. ‘An organic orchard attracts much more life than a conventional one,´ says Per Olof Persson. ‘But we can´t try to exterminate every undesirable insect. The consequences would be far too drastic and depressing. If we succeeded, we´d also eradicate the insects that feed on the pests - and deprive small birds of their food supply.´
Now, apple growers are not all that fond of small birds either, since they also help themselves to the crop. But fortunately there are also kestrels in the area. ‘Yes, I´m grateful there are birds of prey, too,´ says Persson. ‘They keep the smaller birds away.
