Common diseases and control of pear
long-term plant Pear Farmers reflect that it is not very difficult to plant pears, but management should not be slack, especially if the disease is neglected, the yield and quality will be affected. Zhu Chuanfang, Shen Jinbing and Zhang Chuncheng, workers of Diaodong farm in Hanchuan City, Hubei Province, have been planting pear trees for more than ten years, and the pears produced each year are very popular in the market. They attach great importance to the prevention and control of diseases and insect pests. They believe that the most common florists in Pear management are pest control, and there are more than ten kinds of diseases. For example, rust and scab are common pathogens invading pear trees, and yellow leaf disease, small leaf disease and red leaf disease are physiological diseases. In view of years of experience and lessons, they said that as long as early identification, timely prevention and control is very effective.
When the young leaves, new shoots and young fruits of pear trees have rust like round spots, some of them show yellow hair whiskers in the bulge of disease spots, and then the disease spots gradually turn black. When the disease spots are dense, the leaves are easy to fall early. This symptom is called Pear Rust. Some young buds, new leaves, petioles and young fruits appear black or dark green block disease, the front of the leaf is yellow plaque, serious susceptible leaves have begun to fall off, this symptom is scab. When there is more rain in spring, it is easy to induce these two kinds of diseases.
In order to prevent and control Pear Rust and scab in time, the prevention method is to remove the diseased leaves and fruits, cut off the diseased branches and take them out of the pear orchard and burn them. The other is chemical control. For rust, one can spray 1:2: (160-200) times Bordeaux solution, once every 10-15 days, a total of 2-3 times. 2. Spray 1000-1500 times of 25% Triadimefon. For scab, one can spray 1000 times solution of 40% Xinxing water, two can spray 1000 ~ 1200 times of 80% mancozeb wettable powder, and three can spray 2000 ~ 3000 times liquid of 12.5% diniconazole wettable powder. 4. Spray the stone sulfur mixture in early spring.
The physiological diseases of pear include yellow leaf disease, lobular disease and red leaf disease.
At the beginning of the disease, the leaves of FZJ were more serious than those of the dead leaves. The main reason for yellow leaves is the lack of iron in soil. During the vigorous growth period of new shoots in spring and autumn, if the iron supply is insufficient, the yellow leaf disease is most likely to occur. The prevention measures include: 1) improving the water system facilities of pear garden to achieve energy drainage irrigation; 2) increasing the application of organic fertilizer or between rows of pear trees plant 3. Spraying 0.5% ferrous sulfate solution after pear sprouting.
Red leaf disease often occurs in pear orchards where pear trees grow faster in spring and summer. Some pear trees have red leaves and even branches, which is an obvious feature of lacking phosphorus in pear trees. Because of the insufficient supply of phosphorus, the carbohydrate produced by photosynthesis can not be transported in time, and accumulated in the leaves to become anthocyanins, which makes the leaf color red. For the prevention of red leaf disease, the first is to apply ammonium sulfate to acidify the soil with alkaline or calcium content to improve the phosphorus content in the soil; the second is to spray 0.2% - 0.3% potassium dihydrogen phosphate solution after the new leaves of pear trees are developed; the third is to spray 1% superphosphate solution.
The symptoms of the disease are that the new leaves are smaller than the normal pear leaves, the leaves spread late, the leaf color is light green, the internodes of new branches are shorter, and some small leaves are clustered. Due to more leaflets, the flower buds of the whole plant are reduced, the flowers are small and light, and the fruit setting rate is very low, which not only affects the yield but also reduces the quality. The disease is mainly caused by the deficiency of zinc fertilizer in soil. When pear trees are lack of zinc, the raw materials for synthesizing IAA will be reduced, the activities of various enzymes will be reduced, and photosynthesis will be affected. The prevention measures are as follows: first, reduce the amount of nitrogen fertilizer and increase the application of phosphorus and potassium fertilizer; second, increase the application of enzyme fungus bio organic fertilizer or bio organic compound fertilizer to the pear trees that have already bear fruit; third, spray the mixture solution of 0.3% zinc sulfate and 0.5% urea twice before the pear blossom.
432100 Yu Hongzhang, senior agronomist, Xiaogan Agricultural Bureau, Hubei Province