Abstract: The importance of mite pests is increasing in Finnish apple production due to lack of efficient pesticides and the effect of climate change. Integrated pest management has been successful to enhance natural control of mites by indigenous OP-resistant phytoseiid mites but rejection of OP-insecticides will cause increasing problems. Plant derived substances have been successful to restrain pest populations in greenhouses. Tests with a growth enhancer ‘Carbon Kick Booster®’ containing rape seed oil, emulsifiers and triacontanol were conducted in the laboratory and field conditions to evaluate its effect on apple rust mite (Aculus schlechtendali) and fruit tree red spider mite (Panonychus ulmi). In the laboratory 1-2% solution killed a majority of the pest mites in 1-4 days. In field tests the results were inconsistent but comparable to sulphur treatments. Mites of the families Tarsonemidae and Tydeidae were not affected and in field tests phytoseiid mites survived the enhancer sprayings better than the sulphur sprayings. Predatory cecidomyiid larvae were present in the trees and limited both red spider mite and apple rust mite population increases in all treatments.