近年来,黄瓜霜霉病、白粉病日趋严重,造成毁灭性灾害,影响了菜农的收入和市民的生活。为什么近几年黄瓜霜霉病、白粉病日趋严重呢?一、土壤本身带有大量的病菌孢子。由于每年都有黄瓜霜霉病、白粉病发生,病株残体遗留在田间,孢子在土壤中越冬。特别是用黄瓜蔓子堆沤肥料,而又未经充分腐熟,或是 In recent years, cucumber downy mildew and powdery mildew have become increasingly serious, causing devastating disasters and affecting the incomes of vegetable farmers and people’s livelihood. Why in recent years cucumber downy mildew, powdery mildew increasingly serious? First, the soil itself with a large number of bacteria spores. As a result of cucumber downy mildew every year, powdery mildew occurs, diseased plant residues left in the field, spores in the soil overwintering. In particular, with cucumbers piles of fertilizer, but without full maturity, or