Control of latent mosaic disease of peach planted with peach trees

Peach latent mosaic disease is also known as peach mosaic disease, peach yellow mosaic disease, peach miscellaneous disease and so on. It has occurred in the United States, Japan and many other countries, and there are similar disease strains in China. The host of this disease is only peach.

The main results are as follows: (1) symptomatic peach latent mosaic disease is a latent disease, and the leaves generally do not show mosaic symptoms. The main feature of the disease is slow growth and late flowering and ripening of peach. In the first year, the plant growth was slightly affected, and the fruit was slightly flat, which was not as clean and bright as the normal fruit. The diseased fruit is streaked, deformed, dark in color, often faded and lack of aroma. The nucleus is also slightly flat, dehiscent, suture cork, cracking is the external characteristics of the disease.

In the fifth year, the diseased plants began to age and mature prematurely, many buds were necrotic, the plants were bald, with many branches and weak growth. The yield of the diseased fruit is reduced, and the quality is not as good as the normal fruit. Fertilization could not restore the diseased plants to normal, and the decline of diseased plants was irreversible. Due to the gradual weakening of the tree, the diseased plant is very sensitive to parasitic bacteria and adverse climatic environment, and the resistance is reduced.

A few leaves have flowers and leaves without deformation, but only show bright yellow disease or milky white variegated, or chlorotic spots and diffused flowers and leaves. Only a few seriously susceptible plants showed ulcers in yellow leaves, rolled leaves and branches of the whole tree. High temperature is suitable for the obvious appearance of this diseased plant. Rose mottling occurs in the white petals of Rosaceae.

Sometimes the xylem of the new shoot has large and deep stripes, but there is no damage to the bark, no cracking and necrosis. The earliest leaves were spotted and penetrated abaxially.

(2) Disease cycle and epidemic it is reported in the United States that 20% of peaches, tight walnuts and nectarines are infected with the disease. 60% of the varieties exported from Japan to France are susceptible, often showing flowers and leaves, and some leaves occur in spring. Latent mosaic is quite common within a radius of 20 meters around the infected strain. According to experiments, peach sprouts can spread the disease. It takes 3-4 years for a tree to be generally infected.

(3) the disease can be detected by using peach seedling GF305 as indicator plant in greenhouse. The instructions for inoculation should be repeated 10 times. Two months after the first inoculation, the highly virulent strain was used for budding. Because of the effect of the attenuated strain on the virulent strain, if the plant has been infected by the peach latent strain beforehand, the virulent strain does not show any symptoms on the indicator plant, which indicates the existence of the latent strain. This technology has been tested abroad for 15 years and has been proved to be reliable.

The purification of viroid has recently been successful in the laboratory.

(4) virus-free breeding materials are used in prevention and control methods, and tools should be disinfected when pruning to avoid infection.