Ответ на вопрос: 3. Ответьте на вопросы по тексту: 1. What do the plant pathologists concentrate their efforts on? 2. What is the most effective means of reducing disease in cultivated plants? 3. What is the best way in destroying the sources of infection? 4. What plays an important part in the control of some diseases caused by rust fungi? 5. What are spray mixtures used for? 6. What is used to control some of the rots, blights and mildew diseases?