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Hello friends of today's headlines! Today I want to talk about cherries, sweet cherries are planted in many parts of China, such as Sichuan, Shandong, Liaoning, Henan and other regions. In the main cherry-producing areas in China, compared with other diseases, cherry gum disease is not only wide-ranging and harmful, which seriously affects cherry yield and quality, and even destroys trees with dead branches, reduces production and harvest. Therefore, the prevention and treatment of fluid gum disease is a tough battle, and it cannot be taken lightly!
Expert exchanges flow gum disease
In the past, it was believed that cherry gum disease was a physiological disease caused by cutting saws, insect mouths, waterlogging, frost damage, drought and other factors.
Later, Cornell University and the New York State Agricultural Experiment Station found that the main pathogenic bacteria causing cherry stream gum were Pseudomonas licorice and bacterial canker bacteria, and cherry stream gum was a bacterial disease! Cornell University's authoritative letter is self-evident, so the country began to use fungicides to prevent and control, some areas can be cured, some areas can not be cured. This is a strange thing, but any strange thing has its scientific logic, and it must be that we have not yet discovered its laws.
Pseudomonas lilac Image from: http://www.theverge.com/
In order to find out the causes of cherry flow gum disease in Yantai area, the national public welfare industry cherry research special project team collected 33 large cherry flow gum disease samples, and found that there were 7 kinds of fungi in the area that caused cherry flow gum disease, of which Berenger Staphylococcus and Streptomyces spirene were the main pathogenic bacteria, and the frequency of occurrence was 33.33% and 28.57% respectively (data source: Zhang Fuxing, Dong Xiangli, Pan Fengrong, Sun Qingtian. A review of research on sweet cherry stream gum disease[J]. Yantai Fruit Tree, 2015(03):1-5. ), it was determined that the causative agent causing large cherry stream gum in Yantai and its surrounding areas was fungi.
Staphylococcus
The above two study cases show that cherry flow gum disease may be caused by bacteria or bacteria, and there may be differences in different regions. The mainstream view of cherry stream gum disease in a large number of literatures, artificially caused by cherry flow gum disease are Staphylococcus and Pseudomonas lilac (Reference: (1) Elizabeth A. Botryosphaeria canker and dieback of trees and shrubs in the landscape [J]． Virginia Cooperative Extension：450-726．
②Vries D P. Field resistance to bacterial canker in some cherry seedling populations[J]．Euphutica，1965，14：78-82．）。
Therefore, according to the cause of the disease, cherry stream gum disease can be divided into two types of non-invasive and infectious, non-invasive refers to physiological flow gum disease, the site of incidence is mainly the main trunk and main branch, sometimes the twigs will also occur, manifested as swelling of the diseased part, the disease part flows out of the translucent yellow gum. Fruit onset secretes yellow gum. Infective fluid gum disease is mainly caused by Staphylococcus and Pseudomonas syringum, and the cortex of the diseased branch is warty and raised, or a depression appears in the center of the skin hole, and the glue oozes from the skin hole, and there may be small black dot-like protrusions on the new shoots that emerge near the dead branches. So find out what cherry gum disease is, we can prescribe the right medicine!
Cherry gum disease
Just like people are sick, such as a toothache to see a doctor, the doctor prescribed medicine to say that you should brush your teeth morning and evening, do not eat too cold things to stimulate your teeth. We know that your toothache may be caused by a lack of attention to oral hygiene. What about cherry gum disease? What kind of environment creates a breeding ground for bacteria and fungi? There are four main points, namely humidity and temperature, soil conditions, varieties and rootstocks, and tree wounds.
Humidity and temperature
Cherry stream gum disease can occur throughout the growth period and is closely related to temperature and humidity. Spring temperature rises, rain is heavy, there may be glue disease, continuous rainy weather will aggravate the condition of cherry trees, because rain can easily spread pathogenic bacteria to the skin holes and wound areas, thus spreading. Wounds and skin holes are the main routes of pathogenic invasion, of which wounds are more conducive to the invasion of pathogenic bacteria. As temperatures drop and precipitation decreases, gum disease slows down.
Soil conditions
The orchard soil is fluffy, has a high organic matter content, good drainage conditions and sufficient nutrients, and is not prone to gum disease. Acidity, poor air permeability and cherry-grown soil gel disease are prone to occur. Plots with partial nitrogen fertilizer, excessive load, low-lying terrain and poor drainage during the rainy season are seriously affected.
Varieties with rootstocks
Different varieties and rootstocks have different ability to resist glue disease. According to Pan Fengrong and other surveys, it was found that Hongyan's ability to resist flow glue was the strongest, followed by Mei morning, red light, juhong, Rennie, 8-102, and red honey had the worst ability to resist flow glue disease (below).
Resistance of different varieties to gum disease
In addition, Mahali and Benxi mountain cherry are the rootstocks whose red light resistance to gum disease is strong, followed by the large-leaf grass cherry as the rootstock, and the Laiyang dwarf cherry is the worst rootstock (below).
Different rootstocks have the ability to resist flow gum disease
Tree wounds
Diseases such as giddings, red-necked celestial bulls, and mulberry white beetles can cause wounds in the trunk of cherry trees, causing gum disease in cherry trees. Pathogenic bacteria have gained the invasion route due to frost, frostbite, sunburn and mechanical damage, thereby increasing the incidence of fluid gum disease.
In fact, the research on cherry flow gum disease is still in the exploratory stage, the effect of flow gum disease control is not good, there is no fundamental way to find an effective control method, the emergence of plant disease attractants, for the control of plant diseases provides a feasible way. Here is an introduction to provide reference for everyone. Shi Zhongqiang and others treated the diseased cherry tree with 5 kinds of antagonists and found that the control effect of salicylic acid was relatively good. The relative control effect of salicylic acid was 53.7% (data source: Shi Zhongqiang, Luo Jun, Miao Fujun, Wang Keren, Ding Yadi, Wang Hongqiu. Screening test of the most suitable anti-gluing agent for cherry stream gum disease[J]. Western Forestry Science,2015,44(02):157-160.] ）。 Foliar sprays were performed every 5 days with a concentration of 0.12 ml/L salicylic acid for 30 consecutive days.
For the prevention and treatment of cherry gum disease, it is still necessary to focus on prevention. First of all, we must strengthen the management of soil fertilizer and water, and cherry ridge planting can reduce the occurrence of gum disease. Secondly, scientific pruning, protecting the wound, for the branches that have occurred with glue, it is necessary to scrape the gel scar in time, and apply the wound 1. 6% thiamethione aqueous agent 2 times liquid, 40% flusilazole 200 times, 21% peracetic acid 5 times liquid or gray copper preparation.
It should be noted that although the flow of gum disease broke out in the spring, the focus of prevention work should be placed on the autumn and winter, killing the germs in the cradle! Because gum disease bacteria generally begin to infect in late autumn and winter, ulcerated tissue is formed in early spring. Between December and January, the garden is cleared, the glue blocks and necrotic tissue are removed, the dead branches are pruned, the fallen leaves are cleaned, and the ground is sprayed with stone sulfur compound. Agricultural streptomycin and copper preparations were sprayed 3 to 4 times during the dormant period in early spring and the deciduous stage in autumn to prevent and reduce primary infestation.
The following are references for specific medication regimens: Spray stone sulfur compound or 40% fluosilazole 500 times, 21% enemies of bacteria (peracetic acid) 100 times, 5% caprylamine (bacterioxin clear) 50 times liquid before budding; after fruit harvesting, combined with the prevention and control of leaf diseases, spray 2 to 3 times 40% fluorosilazole 4000 times, 10% phenoxymethozole 2000 times, 25% pyrazole ester 2500 times. When spraying, the main trunk and main branch are sprayed wet and sprayed evenly; before the autumn leaves fall, spray copper preparations such as Bordeaux liquid or quinoline copper 200 times, a total of 2 to 3 times.
Compared with other diseases, cherry stream gum disease not only has a wide range of diseases but also has great harm, which seriously affects the yield and quality of cherries, and even destroys trees with dead branches, reduces production and harvests. According to the cause of the disease, cherry stream gum disease can be divided into physiological flow gum disease and invasive flow gum disease, the latter mainly caused by Staphylococcus bacteria and Pseudomonas syringum. It is necessary to strengthen the management of soil, fertilizer and water, scientific pruning, and protection of wounds, and the focus of prevention work should be placed on autumn and winter.