Tea tree black shank

Symptoms The disease is a disease of old tea tree branches. There are tea scenes in Anhui, Zhejiang, Hunan and Yunnan provinces. At the beginning of the disease, small gray spots appear on the branches, the edges of the lesions are slightly brown, and then gradually expand, the shapes are different, and the diseased and healthy parts are indistinct. There are scattered round spots of black lacquer on the lesions, namely pathogenic bacteria. The child seat. Sometimes the lesions surround the branches, causing the tree to weaken.

The pathogen, Coccochorina hottai Hara, is called Ascochyta fungi. Pathogens are born in the tea tree tissue, covered with epidermis, spherical to oblate spheroid, wall thickness, black, carbonaceous, 350-500 μm in size, the tissue is transformed from the host's cell tissue, endophytic capsule fruit 1 The top of the fruit of the capsule has a round opening with a size of 30 to 40 μm. The ascariat is cylindrical to stick-shaped, with a small handle at the base and containing 8 ascospores. Ascospores are arranged in ascending rows, arranged in a single row, with single rows at the top and bottom, and two rows at the middle. The ascospores are spindle-shaped to oblong, and the primary cells are colorless, with 4 oil globules, yellow-brown afterwards, and 3 septa. Between the ascus, there are many side wires that are much longer than the ascus.

Transmission routes and conditions of the disease The disease is only incipient infection, no re-infection. Poor tea plantations, poor drainage or moisture retention, and declining old tea trees are susceptible to disease. Old tea trees have a heavy incidence.

Prevention methods (1) Pay attention to the ventilation of the tea plantation, drain water immediately after the rain, and prevent the moisture from staying. Clean up the miscellaneous trees or shrubs in or around the tea garden. (2) Taiwan tease or heavy pruning of senile tea trees, adjustment of tree vigor, and burning of branches cut. (3) Severe onset, spraying 0.6% to 0.7% of lime half Bordeaux fluid or 30% of green detergent suspension 400 to 500 times during spring and summer tea gaps.