What to do if black spots appear on the leaves of Allium orchid

Symptoms of Zephyranthes leaf spot

Black spots appear on the leaves of Allium orchid, which is what we often call leaf blight, also known as anthracnose, is a common disease of Allium orchid.

In the early stage of the disease, reddish-brown spots or segments will appear on the plant, and finally it will turn black and curl up and die. When the lesions are severe, large areas of the leaves will appear with lesions, which look like they are burned from a distance.

Onion leaf spot disease

Allium leaf blight is mainly a bacterial disease. The bacteria will overwinter in the diseased leaves and begin to cause disease in the spring of the following year. The pathogen is mainly spread by wind and rain, and the disease may occur as long as there are wounds on the leaves. Leaf blight can occur multiple times during the growing season, with the most severe occurrences in May and June and some relief during the high temperatures of summer.

Prevention and control methods of Allium leaf blight

Increase maintenance and plan everything before planting. Choose fertile, well-drained soil. The distance between plants should be moderate to ensure sufficient light transmittance and ventilation. When applying fertilizer, be careful to apply thin fertilizers frequently and avoid dirtying the leaves. Appropriate amounts of phosphorus and potassium fertilizers should be applied to enhance the plant's disease resistance.

In autumn, pruning should be combined to clean the forest in time with dead stems and leaves, and fungicides should be sprayed to take preventive measures.

Spray the pesticide in time when the disease occurs to achieve effective prevention and control. Commonly used pesticides include thiophanate-methyl and thiram, which are sprayed once every 10 to 15 days. Spraying continuously for about 3 times can effectively control the occurrence of the disease.