Pomegranate black spot, also known as angular spot disease, is widely distributed in southern China. Symptoms: At the moment, only see damage to the leaves. The initial lesion on the leaf surface was a pinhole-like black spot, which continued to expand and developed into a round to polyhedral irregular spot with a size of 0.4-0.5-3.5-3.5 mm. Late lesions are dark brown to dark brown, often with dark lines on the edges. When the climate is dry, the central area of ​​the disease is often gray-brown. Under normal circumstances, the leaves scattered a few consistent lesions, up to more than twenty serious, leading to premature leaf litter. Pathogen: Cercospora punicae P.Henn. Taxonomic status belongs to the sub-subphylum subphylum, plexiformis, dark stem spore family, Cercospora genus. A solid layer of diseased atoms was born on the leaf surface, forming fine black spots and scattered. According to the literature, the sexual generation is the Mycosphaerella punicae Petr. It is difficult to find the ascospora in leaves in Guizhou. Infestation cycle: Pathogens use conidial stems and conidia to overwinter on leaf culm tissue, and from mid-April to early May of the following year, wintering conidia or newborn spores are splashed on fresh shoots of pomegranate through wind and rain. Silk infestation followed by repeated infections. The disease is generally in the period from late July to mid-August, from September to October, due to the increase in the number of lesions on the leaves, the increase in the rate of diseased leaves, the phenomenon of early leaf fall, the flower bud differentiation is unfavorable, is the reason for the severe punishment of physiological fruit drop in the coming year one. Prevention and control methods 1, combined with winter pruning and fertilization, thorough cleaning of the ground sick leaves, into the pit as fertilizer, reduce the bacteria source stock. 2. From late May to mid-July, there are many days of precipitation and the spread of diseases is fast. Chemical prevention should be carried out on a sunny day. The agent with better effect is 20% carbendazim sulfur glue suspension 500 times spray, not easy to be washed by rain, and the protection effect is good. In the middle and late period, it was spray-protected with 25% Daisen Zinc against high fat film 300 times.
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