Brown spot
Also known as spot disease. Northeast, North China, Northwest, East China and other places are distributed. In the more rainy years, the occurrence of serious, resulting in early defoliation, seriously affecting the yield and tree vigor.
1, the harm symptoms
Only the leaves are harmed. At the early stage of disease, firstly, polygons or small round spots are formed between the veins and gradually expand. The center of the lesion is dark brown, with a reddish-brown edge, and the back surface can be dark brown or black moldy. The lesions in the latter stage are connected together. In severe cases, the diseased leaves are so dry that the early leaves fall.
2. Control methods
(1) Removal of pathogenic bacteria in the winter combined with pruning to remove diseased leaves, and the diseased leaves were removed at any time in the growing season and burned.
(2) Strengthen management, pay attention to timely drainage, remove weeds; raise the shelf and strengthen summer trim to facilitate transparency.
(3) Chemical control From mid-May to October, spray 2-4 times more than half the amount of Peel multi-solution according to the incidence; spray 65% dexamethasone WP 500-600 times every 10-15 days Spray once, continuous 2-3 times, have a good control effect.
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