Alternatives to Methyl Bromide; IPM in three typical danish flour mills

Abstract

Methyl bromide prohibited

In the past the Danish flour mills have relied on a pest control strategy, which includes fumigation with methyl bromide, typically once a year, in order to prevent problems with various insect pest species. In Denmark the use of methyl bromide as a pesticide was banned on the 1st January 1998.

New system - IPM

The fact that methyl bromide was prohibited in Denmark has forced the Danish mills to improve their pest management systems. The IPM concept is considered to be a way to manage pest problems in flour mills without fumigation, previous works have pointed out that practical experience was limited. The public does not want to find insects in the flour, at the same time there is also a strong public wish for the production of food without a reliance on insecticides. IPM could be a way of fulfilling both of these expectations, although the removal of methyl bromide could lead to an increasing use of residual insecticides.

This project has dealt with the control of insect pests in three Danish flour mills. The purpose was to increase our knowledge of technically and environmentally acceptable prevention and control methods on these insect pests, at an acceptable price level.

Increased sanitation

The present investigation shows that the flour mills in Denmark have replaced fumigation’s using methyl bromide with increased efforts in sanitation. By implementing more comprehensive cleaning practises combined with surface treatments using residual insecticides, during regular shutdowns in production, they have been able to manage to a degree pest problems. For the time being they are learning and gathering experience regarding how to operate without methyl bromide.

Missing documentation

Creating useful documentation on the efficacy of the insect pest control was found to be difficult, this could be an important objection against the present IPM systems. A possible way to improve the IPM systems, could be the establishment of a team of relevant experts, in order that a co-ordinated strategy be applied to pest control.

Main pest species

The two main pest species in the mills are the Mediterranean flour moth Ephestia kuehniella Z. and the confused flour beetle Tribolium confusum Duval. Other pest species cause only local or minor problems, although these problems will sometimes be of economic importance. This report forms the framework for further improvement of the IPM systems, without the reliance on fumigation with methyl bromide.