Apple powdery mildew is one of the common diseases of apple trees and one of the more difficult diseases to control in apple. In addition to harming apples, the disease also harms pear trees. The average disease-infected strain rate in general years is 60%, and in severe years, the incidence rate is 90% or more. The growth of damaged shoots is greatly affected, not only affecting the current year's yield, but also adversely affecting the differentiation of leaf buds and flower buds, thereby reducing the yield in the second year. In a few severely damaged fruit trees, the leaves die prematurely and fall off causing the death of new shoots, severely affecting tree vigor and shortening the number of years of results.
Symptoms: The disease is mainly responsible for the emergence of tender seedlings, large tree buds, tender shoots, young leaves, but also damage flowers and young fruit. The main feature of the disease is that the surface of the disease is covered with white powder. The seedlings were killed, and gray and white patches appeared on the leaves and tender stems. When the disease became severe, the leaves were atrophic, curled, browned and withered. The late disease ministers had dense black spots. The trees were killed, the buds were dry and thin, the spring sprouted late, the internodes were short, the diseased leaves were narrow and long, the quality was hard and brittle, the leaf margin was rolled up, the erection did not stretch, and the new shoot was covered with white powder. During the growing period, the healthy leaves were damaged, the chlorophyll was uneven, and the diseased leaves were crumpled and twisted and even died. Flower buds are damaged, flowers are narrow and long and atrophy. Young fruit was killed, white spots appeared on the top of the fruit, and rust spots formed afterwards.
The law of onset: apple powdery mildew is the wintering of hyphae between winter bud scales or within scales. In the second year when the diseased sprouts germinate, the wintering hyphae produce conidia, which are transmitted by the airflow and directly invade the new shoots. Diseases invade buds, young leaves and young fruit, mainly within one month after flowering, so in May it is the height of the onset of disease. Usually the most serious disease is the emergence of new shoots. During the growing season, pathogens spread one after another in the leaves and shoots, and the diseased shoots produce sexual generations. Ascospores are released by ascospores. The spores on the autumnal shoots invade the shoot shoots in the fall, forming secondary peaks. It is rarely infested after October. The warm spring drought is conducive to the pre-epidemic disease.
Prevention and control techniques: 1. Powdery mildew is overwintering in the bud scales, which is mainly apical buds and bacteria, and autumn shoots are higher than spring shoots. Therefore, after the onset of winter, spring, and early spring, disease buds, disease shoots, and diseased leaf groves are cut off and burned or deep concentrated. Buried, this is the key to reducing bacteria source control disease. 2. If the planting density in the orchard is too high, partial application of nitrogen fertilizer and unreasonable irrigation and drainage will make the small environment conducive to disease. Therefore, we must attach great importance to rational cultivation practices such as fertilization and pruning, so that the park is airy, light, strong and strong, and improve disease resistance. The resistance of different apple plants and apple varieties to powdery mildew has obvious differences. In the disease-prone areas, it is necessary to suppress the cultivation of susceptible species such as: Fuji, Suijin, Hongyu, Guoguang and others. 4. Chemical control: Because the powdery mildew has the characteristics of multiple infections, long duration of infestation, latent wintering in buds and many influencing factors, chemical control is the key. Spray on the buds and trees before the flowers. Apple flower buds exposed before the red spray 5 degrees lime sulfur. When the disease is heavy, the second 25% triadimefon can be sprayed 1500 times after flowering. It is very important to do a good job of spray protection during the growing season. The medicine can be used with 25% triadimefon 1000-1500 times, 70% thiophanate-methyl 800-1000 times, and sprayed before, 70%, and 15 days after flowering. .
Symptoms: The disease is mainly responsible for the emergence of tender seedlings, large tree buds, tender shoots, young leaves, but also damage flowers and young fruit. The main feature of the disease is that the surface of the disease is covered with white powder. The seedlings were killed, and gray and white patches appeared on the leaves and tender stems. When the disease became severe, the leaves were atrophic, curled, browned and withered. The late disease ministers had dense black spots. The trees were killed, the buds were dry and thin, the spring sprouted late, the internodes were short, the diseased leaves were narrow and long, the quality was hard and brittle, the leaf margin was rolled up, the erection did not stretch, and the new shoot was covered with white powder. During the growing period, the healthy leaves were damaged, the chlorophyll was uneven, and the diseased leaves were crumpled and twisted and even died. Flower buds are damaged, flowers are narrow and long and atrophy. Young fruit was killed, white spots appeared on the top of the fruit, and rust spots formed afterwards.
The law of onset: apple powdery mildew is the wintering of hyphae between winter bud scales or within scales. In the second year when the diseased sprouts germinate, the wintering hyphae produce conidia, which are transmitted by the airflow and directly invade the new shoots. Diseases invade buds, young leaves and young fruit, mainly within one month after flowering, so in May it is the height of the onset of disease. Usually the most serious disease is the emergence of new shoots. During the growing season, pathogens spread one after another in the leaves and shoots, and the diseased shoots produce sexual generations. Ascospores are released by ascospores. The spores on the autumnal shoots invade the shoot shoots in the fall, forming secondary peaks. It is rarely infested after October. The warm spring drought is conducive to the pre-epidemic disease.
Prevention and control techniques: 1. Powdery mildew is overwintering in the bud scales, which is mainly apical buds and bacteria, and autumn shoots are higher than spring shoots. Therefore, after the onset of winter, spring, and early spring, disease buds, disease shoots, and diseased leaf groves are cut off and burned or deep concentrated. Buried, this is the key to reducing bacteria source control disease. 2. If the planting density in the orchard is too high, partial application of nitrogen fertilizer and unreasonable irrigation and drainage will make the small environment conducive to disease. Therefore, we must attach great importance to rational cultivation practices such as fertilization and pruning, so that the park is airy, light, strong and strong, and improve disease resistance. The resistance of different apple plants and apple varieties to powdery mildew has obvious differences. In the disease-prone areas, it is necessary to suppress the cultivation of susceptible species such as: Fuji, Suijin, Hongyu, Guoguang and others. 4. Chemical control: Because the powdery mildew has the characteristics of multiple infections, long duration of infestation, latent wintering in buds and many influencing factors, chemical control is the key. Spray on the buds and trees before the flowers. Apple flower buds exposed before the red spray 5 degrees lime sulfur. When the disease is heavy, the second 25% triadimefon can be sprayed 1500 times after flowering. It is very important to do a good job of spray protection during the growing season. The medicine can be used with 25% triadimefon 1000-1500 times, 70% thiophanate-methyl 800-1000 times, and sprayed before, 70%, and 15 days after flowering. .
Shiatsu Massager,Shiatsu Neck Massager,Shiatsu Back Massager,Electric Muscle Massager
Ningbo Prestigeplus Commodity Co.,Ltd , https://www.prestigemedics.com