How to prevent and treat Geranium blackleg disease? Introduction to practical methods
Symptoms This disease occurs on both cuttings and mature plants, with cuttings being more severely affected. Decay begins at the base of the stem and develops upward, causing death. After mature plants are affected, they turn black, and the blackening spreads upward, the leaves drop, and the entire plant withers and dies.
Pathogen Pythium splendens Braun, belonging to the Mastigomycotina. The hyphae are well developed, branched, and non-septate, appearing as white cottony fluff when growing vigorously. Sporangia are filamentous, round, or nearly round, and produce zoospores that cause infection.
Prevention and treatment methods
1. When taking cuttings, branches must be cut from healthy plants, and they must be inserted into a seedbed free of pathogenic bacteria.
2. When transplanting, a new plot must be used or the potting soil replaced to prevent the spread of the disease. If necessary, a 1000-1500 times dilution of 70% Dexon wettable powder can be poured onto the soil surface.