Innovative combination of IPM (integrated pest management) tools--the IPM sugar beet model.

In many parts of the world, Cercospora beticola is the most important leaf spot disease of sugar beets. The frequent risk of losses caused by this pathogen demands the application of fungicides in many regions of sugar beet growing. However, the damage potential is variable to a big extent, dependent on year, site and cropping measures. Therefore, we developed an IPM-System, which is reacting flexible, according to the present epidemic development (6, 8, 9). On the primary, the innovation of our model lies on the effective combination of IPMtools (Fig. 1). Conversely we found, that a single tool is not able to fulfil the demands of Integrated Pest Management of reducing the chemical input by fungicides to a minimum, but to optimise yield factors. Hence, the model involves the prediction of incidence (7, 8), spraying thresholds (4, 6, 8, 9), the determination of the economic damage threshold (5, 8), where the prediction of yield losses is based on (10). The diagnosis is outstanding due to it’s keyfunction, because definitely, there is no IPM to be conducted without exact identification of disease symptoms. Or in simple words, the tools are not working, if the symptoms are ignored or confused. In general, these principles of combining IPM-tools may be applied for many other host-parasite systems as well, in particular, where an initial infection is tolerable. This is the case, if quality and yield of the crop is not affected at the disease level of a spraying threshold, and, on the other hand, if fungicides are available, high effective in controlling disease at initial epidemic stages. The presentation, following now, is mainly focused to the reasons why IPM-tools have to be linked with each other. Therefore, detailed insights in modelling of the different parts may be allowed to be neglected and substituted through reference of citations, where more detailed information is provided.