In recent years, poplars have developed rapidly, and good varieties have grown up, but poplar diseases have also emerged quietly. A recent survey of 107, 46 poplar forests found that poplar canker disease is widespread and the incidence of severe land masses has reached more than 30%. The ulcer disease seriously weakens the tree vigor, inhibits growth, and if not prevented, it will inflict greater economic losses on growers. Disease symptoms The ulcer disease is mainly harmful to the trunk. It is a chronic disease. In the early stage, it forms vesicle-like ulcer spots at the edge of the lenticels. It is round and extremely small. Then the vesicles grew and bulged. They had different sizes, and the bubbles were filled with brown liquid. After the rupture, the liquid flowed out and turned into rust. Then the lesions shrink and sink, with a longitudinal crack in the middle. The lesions of the diseased trees are united and covered in the entire tree trunk. It looks like a layer of yellow mud. The bark becomes very rough. The incidence of annual seedlings less incidence, more than two years old seedlings and plants susceptible to disease, pathogenic bacteria in the trunk of the winter. The disease began in the province in early April and peaked at the end of May to June and September to October. If the winter temperature is high, the onset is early, and vice versa. The incidence of drought ridges, small stand density, four-sided trees, transplanted seedlings, and weak tree vigor is heavy. Plus Yang, Shalan Yang disease resistance, 46 Yang was more severe than 107 Yang. In the same diseased plant, there were many more lesions on the Yang surface than in the shade. One of the prevention and control measures is to strengthen the inspection of nursery stocks in the garden, burn the diseased seedlings, and prohibit the use of afforestation. The second is to promptly plant, transport, and plant the seedlings after transplanting to reduce water loss before planting, ensure watering immediately after planting, and shorten the seedling-reducing period. Third, dry and dry areas should be cut down to afforestation. The fourth is the initial incidence of forest land, in the April-May and early August before the onset of the peak, the general spray prevention of trunk. The agent can be used 2:2:100 times Bordeaux mixture, 30% Formamide arsenic 40 times, 40% carbendazim 50 times, 70% thiophanate methyl 100 times. The fifth is to scratch the epidermis of the diseased lesions, remove the lesions, and apply 10% alkaline water (sodium carbonate) to the trunk for prevention and treatment.
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