What are the latest control methods for peach bacterial shot hole disease?

Peach bacterial shot hole disease is a common and widespread disease affecting peaches. It not only harms peaches but also harms fruit trees such as cherries, plums and apricots. Some varieties are severely affected, such as Zhonghua Shoutao and Haishuimi. The pathogen mainly harms peach leaves, and also harms the fruit. Warm and rainy weather is the breeding ground for the disease. Such diseases must be prevented as early as possible and treated promptly. Now let us understand the harmful characteristics of the pathogen, the symptoms after infection, and the control methods.

1. Pathogen and transmission

The disease is caused only by infection with short rod-shaped yellow bacteria. The pathogen overwinters in diseased branches. Wind, rain and insects can all spread it, and it infects through natural openings and wounds. It is a rainy-season disease, starting in spring, stopping in drought, and recurring in the heavy rain season in summer. Red spider mites and densely closed orchards aggravate the disease. The pathogen has a latent period with no visible symptoms. It is generally affected by temperature and tree vigor, with a latent period of about one week to one month. The lower the temperature, the longer the latent period; the better the tree vigor, the longer the latent period.

2. Symptoms and signs

Infection starts first on the leaves, beginning at the leaf veins. At first there are small water-soaked spots, which gradually expand and become round or irregular in shape. Yellow halos appear, and the diseased spots dry up and fall off on sunny days, forming holes. When the spots merge and spread, defoliation occurs. When the fruit is harmed, small brown spots appear first, then turn black, expand and merge, and then the fruit skin cracks.

3. Prevention

It is best to first spray protective agents such as lime sulfur mixture or Bordeaux mixture before the disease occurs, spraying once every one or two months. Do not spray too many times, as this will affect growth when there is no disease. When establishing an orchard, do not build it in low-lying land or paddy fields. Always pay attention to cleaning the orchard, and regularly prune dead branches and old leaves. Prune the interior to adjust the growth structure and space, and always maintain the best natural tree shape.

4. Treatment

When the disease is mild, use naphthalene acetic acid to regulate and inhibit the pathogen. Or use microbial agents to eliminate the pathogen. Generally these agents should be mixed with water into a 400 solution for spraying. When the disease is severe, reduce the amount of water for spraying. Generally spray about 4 times, about once a week. After spraying, promptly prune diseased branches, diseased leaves and diseased fruit, and any place where the pathogen gathers. Collect them and burn them, and also spray the ground with the agent. Dig ditches and set up drainage channels properly so that drainage is smooth. Apply fertilizer to strengthen tree vigor and enhance resistance.

When peaches develop bacterial shot hole disease, it affects tree vigor and harms the fruit. It can be considered a generally damaging disease that directly affects quality. Affected fruit cannot be sold, and the income of fruit growers is also affected. Therefore attention should be paid to it, preventing the disease and ensuring tree vigor, yield and quality.