How to prevent and control rose downy mildew? These methods you need to master

Downy mildew is a fungal infectious disease. Rose downy mildew develops quickly and is extremely harmful, making it a devastating disease. It mainly affects new shoots and leaves in the middle and lower parts of the plant. In the early stage, chlorotic spots appear on the underside of the lower leaves, and the spots are irregular and covered with a frost-like mold layer. Later they turn dark purple, resembling water-soaked areas, until they become brown. The spots are polygonal and gradually become scorch-like. When the damage is severe, all the leaves drop and the plant dies.

Control measures 1. Plant at a reasonable density, no more than 12 plants per square meter, and it is best that the leaves do not overlap one another. 2. Fertilize reasonably and balance nutrition, apply more organic fertilizer, and on the premise of sufficient nitrogen fertilizer, apply more phosphorus and potassium fertilizer during the reproductive growth stage to enhance the plant's resistance. 3. Timely clean up residual branches and fallen leaves and destroy them in a centralized way. Or spray amobam 2000 times dilution during the dormant period to prevent the pathogen from invading. 4. After the plant is infected, use metalaxyl, chlorothalonil, Kelu, etc. alternately. Generally spray once every 7 to 10 days, for three to four consecutive sprays.