Scientific control of cucumber downy mildew

Cucumber downy mildew, commonly known as "horse race", is a devastating disease that occurs more commonly in cucumber production and is more seriously damaged. It can generally reduce production by 30-40%, and heavy ones can reach 60~70% or even reject or Destroy the seed.

Cucumber downy mildew is a fungal disease, which is extremely epidemic, mainly affecting the leaves of plants, and can occur in seedling stage and adult stage. At the beginning of the disease, there are small spots of faint green irregular water-immersed on the back of the leaves, which gradually become yellow-brown, which is limited by the veins and is polygonal. When the air humidity is high, the gray-black mold layer grows on the back of the blade, and the diseased spots are contiguous in the later stage, causing the diseased leaves to die, and the field is yellow when it is serious. Because it is similar in symptoms to cucumber target spot and bacterial keratosis, it is not difficult to diagnose and control.

The pathogenic bacteria of the disease are transmitted by airflow, and it takes only 3 hours to germinate and infect under dew condensation conditions, so humidity is an important factor affecting the occurrence of the disease. Secondly, the disease is the fastest-growing disease among various types of bacteria, so it is often called "horse race". Due to the close connection and mutual alternation of greenhouses and open cucumbers over the years, there have been bacterial sources almost all year round. Therefore, the prevention and control of cucumber downy mildew cannot be relaxed.

In the prevention and treatment process, it is possible to use 68.75% fluorobacteria, downy mildew suspension 600 times solution or 10% cyanosin suspension agent 600 times liquid spray control, or 60% azole ether·Dyson water dispersion granules 750 times Liquid +80% dimethomorph water dispersible granule 2500 times liquid or 72% cream urea · manganese zinc wettable powder 600 times liquid + 72.2% creamy chloric acid saline 750 times, 68% fine nail cream · manganese zinc water Dispersing granules 600 times liquid + 80% pyraclostrobin-mycin wettable powder 750~1000 times liquid mixed spray control, achieving the effect of treating both cucumber target spot and bacterial angular spot disease.