The cause and control method of plum blossom leaf roll disease?

The causes and control methods of plum blossom leaf roll disease, the so-called leaf roll disease, refers to the plum blossom in the state of lack of water, the leaves on both sides of the front to the middle of the roll, showing a listless wilting state, is a physiological disease. Leaf roll disease not only affects the beauty of plum plants, but also causes leaves to fall off when it is serious.

The causes of leaf curl disease are as follows: high temperature and little rain, dry soil, low air humidity and strong light in the Yangtze River basin in summer, but the plum tree itself has poor ability to transport water, with many leaves, thin leaves and relatively fast water evaporation. leaf curling is easy to occur in the case of water deficit. Leaf curling starts from May to June and lasts until August to September. The rolled leaves softened slightly after the rain, and the leaves spread out slightly.

Under the condition of timely irrigation and adequate water supply, a large number of fallen leaves will not occur and flower bud differentiation will not be affected. Prevention and treatment: plum blossom leaf roll disease is the result of the special anatomical structure and physiological characteristics of plum blossom itself, as well as adverse climatic factors. Therefore, in the vast plum blossom cultivation areas, it is impossible for plum blossoms to keep their leaves spreading normally throughout the growing season. By strengthening the management, the root system grows well, the nutritious fibrous root is developed, the tree is strong, and the ability of absorbing and transporting water is enhanced, so as to avoid or reduce the occurrence of leaf curling. In the season of high temperature and drought, watering and foliar spraying should be given in time to ensure that the rolled leaves will not fall off because of excessive severity.

How to prevent and cure leaf roll disease of plum blossom

Leaf roll disease is a physiological disease. When the plum blossom was planted in the ground or pot, both sides of the leaves rolled in in the middle under water stress, and the whole plum plant showed a listless, tired and wilting state, which caused a large number of leaves to fall off.

Cause of occurrence

On the one hand, it is due to high temperature and little rain in summer, dry soil, dry air and strong light, on the other hand, the plum tree itself is a fine whisker root, and its ability to absorb and transport water is poor, and the leaf quality of plum blossom is thinner. At this time, the plum plant evaporates water quickly, which leads to the curl of its leaves because of the overall water deficit, especially the "green calyx plum" variety. The phenomenon of leaf curling begins about June, and the leaves can spread slightly after the rain; when the weather is favorable and the water supply is sufficient, the leaf curls appear later, will not fall a large number of leaves, and will not affect the differentiation of flower buds.

Prevention and cure method

Curling leaves are caused by the special structure and physiological characteristics of plum blossom itself, as well as adverse climatic factors. For this reason, the management should be strengthened to make the root system develop well and the tree grow healthily, so as to improve its ability of absorbing and transporting water. After entering the high temperature and drought season, root watering, foliar spraying and environmental watering should be strengthened to create a relatively cool environment through humidification and cooling. Potted plum blossom, especially the shallow pot plum pile, especially for the "green calyx plum" variety, can be shaded in a shed and shaded between 30-40% to protect its rolled leaves from falling due to excessive dehydration.

Prevention and treatment of leaf shrinking disease of plum blossom

-, harmful symptoms

It mainly occurs in spring, and the first victims are new buds and new leaves, the tender tip internodes become thicker and shorter, the leaves are dense, the leaf surface is wrinkled and thickened, the surface is fleshy, the surface is rough, and curls to the back of the leaves. The diseased leaves were yellow, red or purplish red at first, and then gradually turned into grayish white with powdery substance. When it is serious, the diseased tip dies, the tree is weak, and the number of flowers decreases.

The law of the disease

The ascospores and spores overwintered on the diseased shoots inside and outside the host bud scale. The hyphae are perennial or perennial, and the spores can be divided into two types: thin-walled and thick-walled, the former can continue budding, the latter has the function of dormancy and resistance to adverse environment, and then germinate to form spores to infect the host after the adverse environment. The pathogen began to infect in early April of the following year, and the disease occurred more seriously in the first ten days of May and stopped in June. The bacteria were infected once a year, and occasionally re-infection occurred. However, due to the high temperature and uncomfortable conditions, the harm is not significant. The cool and humid climate is most suitable for spore germination and infection. The injection of nba at about 20 degrees Celsius is most suitable for the growth of bacteria. At 28 degrees Celsius, the growth of bacteria is inhibited and the disease can not occur. The continuous rainy or foggy weather in early spring is disadvantageous to the occurrence of diseases.

III. Prevention and control techniques

If you need pruning in winter, be sure to pick up the fallen plum leaves and branches and clean the plum orchard. Combined with winter shearing, in topdressing management, more mature high-quality organic fertilizer and phosphorus and potassium fertilizer should be applied, and little or no nitrogen fertilizer should be applied, so as to promote the robust growth of branches and leaves of plum trees and improve the resistance of plants to plum blossom leaf shrinkage disease.

2. If pruning is needed in spring, take the diseased branches and leaves out of the garden and burn them centrally, so as to reduce the source of germs in the next year. When cutting off diseased branches and leaves, the scissors can be soaked in Bordeaux solution of l ∶ l ∶ l00 for 3 to 5 minutes, and then cut again.