Located in temperate, maritime climate with frequent rainfall, crop protection in Belgian orchards is dominated by fungicides. Though, the importance of arthropod pests should not be underestimated. Pcfruit, the former Research station of Gorsem, has been maintaining a warning system for fruit pests in Belgium since 1944. Therefore, various pests and beneficial's and their life cycle stages have been monitored in Gorsem and in different observation posts across Belgium, being part of a monitoring network. Although up to 3000 arthropod species are present in pome fruit orchards, about 25% can be considered as harmful and another 25% as beneficial. Out of those species, around 100 harmful and 50 beneficial organisms are omnipresent. The list of monitored species is extended yearly for upcoming or difficult to control organisms. Integrated pest management was introduced in the eighties, with the accent on using selective pesticides and saving beneficial organisms. A shift in pesticide use affected the importance of secondary pests, together with recent exceptional climatic conditions. Following many years of monitoring insects and mites and editing warning bulletins in our station, a ranking of the economical importance of different pest species is presented.