Diseases and prevention methods of Camellia sasanqua

Diseases of Camellia sasanqua: Anthracnose

symptom

Anthracnose mainly harms the leaves and fruits of Camellia sasanqua.

In the early stage of the disease, nearly circular to semicircular or irregular brown spots appear on the leaf edges or leaf tips. The spots gradually turn grayish white, with ring-like wrinkles on the edges, and the boundary between diseased and healthy leaves is obvious.

In the later stage, small black spots of irregular shape or arranged in a ring-like pattern appear on the lesions. They are slightly larger and sparse on the front side of the leaves, and dense on the back side of the leaves. These are the conidia disks of the pathogen. The infected fruit develops purple-brown sunken spots.

When the humidity is high, the diseased part will overflow with pink mucus, which is a mixture of pathogen conidia and colloid.

Prevention and treatment methods

The potting soil for cultivation should be slightly acidic loess that is fertile and loose, has a good aggregate structure, and good drainage, moisture removal and air permeability.

Mature plants should be repotted every two years, and in conjunction with repotting, well-rotted base fertilizer should be applied, with 50% of the potting soil mixed with about 10% of compost or organic fertilizer fermented with enzyme bacteria.

Pay attention to light and shade. Camellia sasanqua likes sunlight and needs full-day sunlight in winter, but not direct sunlight in summer and autumn.

You can regularly spray 600-800 times dilution of Guoguang Yintai (80% mancozeb wettable powder) and Guoguang Sitalin for disease prevention and nutritional supplementation to improve ornamental value.

In the early stage of the disease, spray 500-600 times diluted 25% myclobutanil emulsifiable concentrate or 400-600 times diluted 50% manganese zinc wettable powder. Use 2-3 times in a row, with an interval of 7-10 days.

Diseases of Camellia sasanqua: White star disease

symptom

White star disease of Camellia sasanqua mainly harms young leaves and buds, especially young leaves, and the disease peaks in June.

Initially, small brown spots the size of a needle tip appear, which gradually expand into grayish-white circular spots with a diameter of 1-2 mm, which are concave in the middle and have dark brown to purple-brown raised lines on the edges.

When the humidity is high, small black spots appear scattered on the diseased parts, and the number of spots on the diseased leaves can reach dozens to hundreds. Some of them merge into large irregular spots, and the leaves become deformed or curled.

Prevention and treatment methods

Benomyl and Mancozeb are protective fungicides suitable for prevention before the disease occurs. It is recommended to use Guoguang Benomyl or 80% Mancozeb 600-800 times diluted spray for prevention and control before the disease occurs.