Alternatives to Methyl Bromide; IPM in three typical danish flour mills 1. IntroductionDefinition of IPM IPM (Integrated Pest Management) in the area of stored products can be defined as a system which comprises of hygiene, technical, technological and bio-technical methods, physical control, biological control, and chemical control. These methods should be combined in such a way that highest priority is given to the protection of the human health as well as the environment. Moreover, commercial policy is a possible further element of IPM (Reichmuth, 1996). IPM is a dynamic system that should be harmonised with local conditions in order to use the most promising elements with regard to the environment and economy. IPM in stored products The use of IPM in the area of stored product protection is at a stage which can be characterised as a ‘learning to understand and assimilate the technology’ (Schöller et al., 1997). The most detailed scientific experience has been gained in grain stores (Hagstrum & Flinn, 1996), where it is possible to sample the insect population, and thereby follow the pest population level in detail. Knowledge of the IPM concept is limited at consumer level (Platt et al., 1998). In the past the majority of Danish flour mills have relied on a pest control strategy, which included fumigation with methyl bromide, typically once a year, in order to prevent problems with insect pest species. This situation changed on the 1st of January 1998, when the use of methyl bromide was banned in Denmark. History The phase out of methyl bromide in Danish flour mills was supported by the Danish government through financial support to two projects dealing with IPM in mills. A preliminary project (Skadedyrcentralen Danmark A/S, 1997), which condensed and improved the present experience with IPM into a general guideline including theoretical options of using alternative methods of pest control in mills, concluded that there are alternatives, which - when combined in a joint strategy (IPM) - can replace fumigation’s. This first report (Skadedyrcentralen Danmark A/S, 1997) also concluded that practical experience is limited in the milling industry. It was therefore found relevant that further practical experience under Danish conditions should be obtained in order to support the development of effective IPM programmes against insect pests. During 1998 the second project (reported here) was initiated and this project has dealt with the insect pest control situation in three Danish flour mills. The purpose was to increase the knowledge of technically and environmentally acceptable prevention and control methods on insect pests in flour mills, at an acceptable price level. Several reports (Hallas et al., 1993; UNEP, 1994; Hansen & Mourier, 1995) have concluded that it is technically possible to manage pest control without fumigation with methyl bromide, also that the theoretical contents of IPM in mills exist (Mills & Pedersen, 1992; Skadedyrcentralen Danmark A/S, 1997; MBIGWG, 1998). The work in the second project originated from the recommendations given in the earlier works, and it was also connected with the project "Investigation on the possibilities of using the IPM concept for pest control in Scandinavian flour mills", affiliated to the Nordic Council of Ministers, in which the present use and limitations of IPM in one of the Danish mills are compared with a mill in Norway. The project was supported by "Council for recycling and cleaner technology",
which is affiliated to The Danish Environmental Protection Agency, and who paid 47% of the
costs. The project was carried out by Per Sejerø Nielsen, Danish Pest Infestation
Laboratory together with the staff at the flour mills and the PCO’s.
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