Daffodil brown spot occurs in all parts of the world. It mainly damages the stem and leaf tissue of daffodil. In severe cases, the whole plant withered in 4-8 weeks in advance and affected the normal growth of the bulb, causing significant economic losses to the producer. For this reason, after many years of practice, the author summarized the technical measures for preventing and controlling brown spot of daffodils and made an introduction. In the early stages of the onset of symptoms, lesions mostly appear at the tip of the leaf, appearing brown, causing the tips of the leaves to die in stages, and then gradually extending to the upper part of the stalks. Careful observation of lesions showed that the spindles formed an ellipse, while
Others were semi-circular or irregularly shaped. When several lesions are combined together, they will show obvious large-sized streaks of reddish-brown color, which will cause the blades to be distorted, and later, the disease will be broken and cause disease. If the air is wet, there will be dark brown spots in the diseased part, that is, the bacteria Sub-entity. 2 Reasons Temperature and rain Temperature and rain are closely related to the occurrence of brown spot disease on daffodils. As the pathogenic bacteria used hyphae to overwinter in the diseased leaves of the previous year and passed through the bulbs and scales during the summer, in the early February of the following year, when the bacteria first invaded, the temperature was higher if there was more rainwater. Years, the occurrence of disease is also more serious, from April to May is the peak of onset; otherwise, the incidence is light. Nutrition and Fertility Nutritional conditions are also directly related to the occurrence of diseases. When planting daffodils, in the densely planted fields, the amount of fertilizer is too large and the plants grow crisply. At this time, if there is too much water in the field and the water is not drained in time, brown spot disease will easily occur. 3 Prevention 3.1 Scientific management to remove pathogens After harvesting bulbs or flower bulbs every year, we must intensify the removal of all weeds in the field and in the field, especially the daffodil bulbs, in order to completely eliminate the source of disease and eliminate the host. In particular, strict removal of diseased seeds, so that one does not stay. All kinds of narcissus balls left as seeds are stored in good quality. The storage method is very particular. Choose a cool, dry house as a storage room. At the same time, it is necessary to regularly ventilate and turn more to avoid seed rot. It is extremely important to adhere to the rotation and persist in the rotation. After cultivating narcissus in the field, it will be very easy for the fields to accumulate disease year by year, which will increase the disease. Therefore, the continuous cropping system should be strictly controlled to reduce the sources of disease infestation. Rational fertilization and timely drainage strictly control water and fertilizer, pay attention to reasonable fertilization, especially to avoid partial nitrogen fertilizer. To prevent excessive soil moisture, in the rainy season, field management should be strengthened, drainage work should be done in time, and water should be suitable. 3.2 Drug prevention and treatment before planting Before planting, pre-sterile ball sterilization. Using 300-times times that of zeson zinc or 600-800 times of water solution of thiophene, soaking the special ball for 15-30 minutes can reduce the incidence of bulbs. The foliar spray was started during the growing season of narcissus, that is, from the middle of March, spraying 1% Bordeaux or 700 times 75% chlorothalonil on the foliage, spraying once every 10 days, and continuously spraying 5-7. Times is appropriate and good control effect can be obtained.
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