Common Diseases of Tree Peonies - Powdery Mildew

Common Diseases of Tree Peonies - Powdery Mildew

  The symptoms of tree peony powdery mildew mainly manifest in leaves, petioles, stems, and other parts. In the early stages, white powdery substances often appear on the leaves, which gradually expand and connect into patches, even covering the entire leaves and stems of the plant. In the later stage, many black small particles will scatter in the powder layer, which are the closed shells of pathogenic bacteria. When the disease is severe, it can cause premature aging or death of plants.

  Disease incidence pattern

  Wintering and infection: 

  Pathogens overwinter on diseased buds as mycelium. When the diseased buds sprout in the following spring, the pathogens infect the leaves and new shoots. In addition, conidia are also important sources of initial infection, capable of both initial and reinfection.

  Transmission mode: 

  Spores are mainly transmitted through wind, directly invading or invading the plant through stomata.

  Disease occurrence conditions: 

  The occurrence of diseases is closely related to climate, variety, and cultivation conditions. Spores can germinate under low humidity conditions, but the germination rate will significantly increase under high humidity conditions. When it is dry after rain, with little rain but high humidity between plants, the spread of the disease will accelerate. When high temperature and drought alternate with high humidity, and there are a large number of powdery mildew and susceptible hosts, this disease will spread.

    Peak incidence period: 

    Tree peonies cultivated in the open field have a higher incidence of disease in May, June, September, and October;tree peonies cultivated in greenhouses can suffer from diseases all year round.