(1) Long-term rainy days have high humidity, which induces root diseases and leads to the decline of root function. (2) Under the condition of high humidity for a long time, the leaf transpiration is small. When the sunny environment changes suddenly, the humidity drops and the temperature rises, the leaf transpiration increases, and the crops can't adapt for a while, resulting in wilting and even seedling death.

Preventive measures are as follows: (1) After sunny days, increase the ventilation volume in the morning and evening, narrow the tuyere at about 10 in the morning, control the temperature at about 23 degrees, and properly put down the grass curtain to shade the sun to prevent strong light injury. (2) Spraying 600 times of "Tianda Miaozhuangling"+6,000 times of 96% hymexazol +600 times of fluoperacid liquid medicine to improve plant resistance and root activity and prevent fungal and bacterial diseases. Cucumber leaves are big and it is not easy to bear melons. What happened? It is the excessive use of nitrogen fertilizer and the excessive growth of nutrients.

Remedial measures: pay attention to using less available nitrogen fertilizer; Spray 750 times growth promoter (65,438+065,438+06 kg of water to 25ml of growth promoter to 265,438+06,20ml a day) for 600 times a day, once every 7 days and continuously for 2-3 times. Yellow and white spots appeared on the leaves of cucumber seedlings. What happened? It may be a bacterial disease caused by cucumber bacterial blight. At first, small round chlorosis spots will appear on the leaves, and then gradually expand to form round or polygonal chloasma. Note: This pathogen is mainly transmitted through seeds, so you'd better treat the seeds with chemicals before sowing. Once the disease occurs, spray 600 times of 2.5% norfloxacin +600 times of "Tianda-2116"+2000 times of silicone solution. Spray once every 5-7 days for 2-3 times.