Common diseases of delphinium and their control methods

Common diseases of delphinium: powdery mildew

Symptoms

The disease affects the leaves and stems of the plant. In the early stage of the disease, white powdery mildew spots appear on the diseased parts of susceptible plants. When the disease is severe, young leaves and shoots curl and growth is inhibited. In the later stage of the disease, small black particles are formed in the mold spots, which are the closed capsules of the pathogen.

Disease pattern

The pathogen overwinters in ascocarps and produces conidia and ascospores in the spring of the following year. The spores are spread by wind and rain, infecting and harming the host. The disease is more serious in damp and cold seasons.

Prevention and treatment methods

Reduce the source of infection: After flowering, burn the diseased plants and diseased remains in a concentrated manner.

Strengthen cultivation management: Pay attention to drainage of the planting site to prevent moisture. The plants should not be too dense and should maintain good ventilation and light conditions.

Chemical control: When the disease occurs, spray 1000 times diluted 50% benomyl wettable powder, or 800-1000 times diluted 15% fenadine wettable powder. Delphinium root collar rot is a devastating disease of delphinium. The pathogen invades the plant through the roots and root collar, cutting off the water supply and causing the plant to suddenly wilt and die.

Common diseases of delphinium: black spot

Symptoms

The disease harms the leaves, petioles, stems and flowers of the plant, mainly the leaves. The lower leaves of the plant are often the first to become infected. Shiny black spots appear on the front of the infected leaves, and the spots are irregular in shape. The spots on the back of the leaves are light brown.

Disease pattern

Pathogenic bacteria overwinter on the soil surface or on diseased leaves. When conditions are suitable in the spring of the following year, the pathogens spread through rainwater, invade through the host's stomata, and cause infection. Seeds can also carry bacteria and diseases. The disease is more serious when there is a lot of rain and the soil is moist.

Prevention and treatment methods

Manual removal: If diseased leaves are found, remove them immediately and burn them, and cut off old stems in autumn.

Chemical control: When the disease occurs, spray 1000 times diluted streptomycin.