Bacterial leaf rot

Distribution: Asia and the United States.

Pathogen: Erwinia chrysan-themi.

Strange owners: Dendrobium (Dendrobium), Vanda and so on.

Symptoms: the leaves of Dendrobium showed yellow and water stains after infection, while Wandailan showed translucent patches on the leaves. Finally, the plaque turns black and sinks.

Prevention and treatment: this disease is mainly caused by wound infection, such as folding, insect bites, etc., so we should try to avoid it. It is found that the diseased leaves should be removed as soon as possible and the wound should be smeared with Bordeaux mixture. The whole plant can be soaked in 0.1% potassium permanganate solution for 5 minutes, washed and exposed to the sun for 15 minutes before planting. Spraying with 0.5% Bordeaux solution or 200mg/L agricultural streptomycin also has a certain effect. Do not pour water when the disease is serious or spreads rapidly. Excessive humidity is also easy to induce the disease. (Chen Xinqi, Ji Zhanhe)