Common diseases of osmanthus

Brown spot symptoms

In the early stage of the disease, small yellow spots appear on the leaves and gradually expand into circles with a diameter ranging from two to ten millimeters. The lesions are yellow-brown to gray-brown, with a yellow halo outside the lesions. Generally, the peak season is from April to October each year.

Symptoms of rot spot

The leaf spot disease mostly invades from the leaf margins and leaf tips, and occurs on the edges and tips of leaves. In the early stage of the disease, there will be light brown spots on the osmanthus leaves, which gradually expand into round or irregular spots with dark brown edges. It usually occurs between July and November.

Symptoms of Carbonaceous Fungus

Osmanthus anthracnose This disease infects the leaves of osmanthus. In the early stage of the disease, small chlorotic spots appear on the leaves of Osmanthus fragrans, which gradually expand to form circular, semicircular or elliptical spots. The lesions are light brown to grayish white with reddish brown rings around the edges. Under humid conditions, pale pink myxospore disks appear on the lesions. Anthracnose occurs from April to June.

Osmanthus disease prevention and control methods:

1. To prevent and control the following diseases, we must first reduce the source of infection. For example, diseased fallen leaves should be thoroughly removed in autumn, and diseased leaves of potted osmanthus should be removed in time.

2. Strengthen the management of osmanthus trees. Choose fertile, well-drained soil or substrate for planting osmanthus; apply more organic fertilizer and potassium fertilizer; the planting density should be appropriate to allow ventilation and light, reduce leaf moisture and reduce the occurrence of diseases.

3. Spray 1:2:200 times Bordeaux mixture at the early stage of the disease, and later spray 1000 times diluted 50% carbendazim wettable powder or 1000 to 1500 times diluted 50% benomyl wettable powder.

4. In seriously diseased areas, seedlings should be soaked and disinfected in 1000 times potassium permanganate solution before being taken out of the nursery.