Improving control of diseases, pests and weeds. In spite of low doses of pesticides applied in Polish orchards we try to rationalize plant protection against insects and diseases. Effectiveness of pesticide sprays can be improved by signalization and monitoring of their development and appearance. Thus, the research work is concentrated on biology of the most important orchard pests, with much attention paid to biological preparations and predatory mites (Phytoseiidae) as important tools in plant protection. During 40 years of our activity we elaborated very precise methods of monitoring of all the important insects and diseases in Polish orchards, what enabled to organize the system of signalization of the spraying time for the whole country. Due to this system a number of sprays against the most important apple diseases (apple scab) and apple pests (codling moth) have been significantly reduced. Our Laboratory of Pesticide Residue Analysis is able to detect the lowest pesticide residues in fruits.