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Gummosis, also known as verrucosa and resinous disease, endangers stone fruits such as peach, apricot, plum, cherry, plum, and some trees for landscaping. It is a common and serious disease. In particular, the incidence of disease is more than 95% in the extensive orchard and trees with weak tree vigor, which weakens the tree vigor, affects the orchard yield and ornamental effect, and even causes the dead trees to destroy the orchard.
1. Cause of disease:
There are two types of gummosis: non infectious and infectious.
Non infectious Gummosis
It is a common physiological disease that occurs in all areas. The pathogen often invades from wound, disease and insect wound, freezing injury and so on, causing glue flow in wound part, or extensive management, excessive pruning, more nitrogen fertilizer application, clay and so on. The physiological imbalance of tree body occurs in the glue flow in fruit and lenticel part (Fig. 1).
Fig. 1 overflow of yellowish translucent adhesive gum
Infectious Gummosis
It is caused by infection of coeloma Vitis and Botrytis. The pathogenic bacteria invade from the dermis or wound with mycelium and conidia, and can infect repeatedly later.
The causes of gummosis in stone fruit trees such as peach and cherry
(1) The harm of parasitic fungi and bacteria.
(2) The wounds caused by insect damage and mechanical damage, as well as frost damage, frost damage, hail, sunburn, etc.
(3) Bad scion and use of incompatible rootstock.
(4) The orchard is dry or waterlogged.
(5) The soil is too sticky and acid-base.
(6) Improper fertilization, excessive pruning and regrouping during the growth period, and too deep planting.
2. Disease symptoms and Law:
Non infectious Gummosis
It mainly occurs in the trunk and main branches. In serious cases, the twigs can also damage the fruits. At the initial stage, the diseased part was slightly swollen, and then secreted translucent and soft gum. After rain, the glue flowed heavily, and then it became brown in contact with the air, becoming crystal soft glue block. After drying, it became reddish brown or tawny hard glue block (Fig. 2). As time went on, the amount of glue flowed increased, and the cortex of diseased part became rough protuberant plaque (the rain part was serious, and the back was light). Then the xylem gradually It gradually turns brown yellow and decayed (but no pathogenic substance is produced). As a result, the trees become weaker and weaker, and the prevention and control is not effective gradually. Old trees are seriously ill, young trees are lightly ill.
Fig. 2 the gelatinous lesion becomes a hard brown rubber block after drying
Infectious Gummosis
It is mainly harmful to the branches and fruits. The pathogen invades the new shoots of the year, and takes the pores of the new shoots as the center, forming a lump like protuberance, but does not flow glue. In May of the next year, the tumor skin cracked and overflowed the glue liquid, which was colorless and translucent sticky substance, and then turned into a hard brown lump. The lesions are concave into round or irregular patches with scattered small black spots. The disease of perennial branches causes water spore like protuberance, and brown glue exudates from the diseased parts, leading to the decay and even death of the branches. When the fruit is infected with the disease, it begins to flow gum in dots, then turns brown and rots, on which there are dense small grains, and white lumps can flow out when it is wet (Fig. 3). The hyphae and conidia were overwintering in the diseased branches, and the conidia were transmitted with wind and rain from March to mid April of the next year, mainly invading through wounds, lenticels and lateral buds. Especially in rainy days, a large number of bacteria overflowed from the diseased part, flowed down the branches or splashed on the new shoots to invade. The activity of latent bacteria is related to the temperature. When the temperature is about 15 ℃, under the conditions of less sunshine, continuous rain and high humidity, the diseased part will flow out glue liquid. With the increase of temperature, the gum flow of trees will increase and the disease will worsen. The bacteria were most suitable to grow on PDA medium and at 25-30 ℃. The disease has two peaks in a year. The first is from the first ten days of May to the first ten days of June, and the second is from the first ten days of August to the first ten days of September. After that, the disease will not infect any more. The growth season of new shoots before the two peak periods is the key period of control.
Fig. 3 white colloid spilled from the particle mouth when the humidity is high
3. Prevention measures:
In the whole process of production and management, the combination of agricultural control and artificial control should be the main method, supplemented by chemical pesticide control. The key period of chemical control is to control spore dispersal and spore invasion in the two peak periods of infection. The specific measures are as follows:
(1) Choose the high-lying and fertile sandy soil to build the garden. Strengthen the management of soil, fertilizer and water, strengthen the tree vigor and improve the disease resistance ability.
(2) Timely control of diseases and insect pests. Strengthen the prevention and control of various dry rot diseases and rot diseases; timely prevent and control borers such as longicorn and gilding insects; at the end of autumn, the overwintering bacteria and insect pests can be eliminated by painting white on the trunk and big branches, and the garden can be disinfected in winter, and the rubber block and its lower rotten skin and wood can be scraped and burned. Before germination, spray 5 Baume degrees of stone sulfur mixture on the whole tree to eliminate overwintering bacteria.
(3) For the flow glue, use a knife to clean it; for the flow glue part with black and rotten cortex and xylem, first clean the flow glue, then clean the blackened and rotten tissue; and use a knife to cut several times, then use liangguoan 30-50 times liquid + penetrant (silicone, etc.) (note that the application area should be 1-2 times larger than the area of the disease); also use 4-5 Baume's sulfur mixture for disinfection and application. In serious cases, the interval is 7-10 days, and another application is required.
(4) Quicklime control method. The application time, in the sap flow period, Jincheng area in the middle and late March, at this time, it is the initial period of gum disease, but also the key period of control. The application method is to spread quicklime on the glue flow part of the diseased tree, or put quicklime powder into the bag and apply it on the glue flow part; in case of severe tree, it is better to scrape the diseased spot, dry glue and old warped skin first, and then apply it; according to the weather change, quicklime powder is more effective when it is easy to be touched on in rainy days, when the humidity is high and the viscosity of the glue liquid from the bark is high. 5-7 days after application, the glue flow stopped, the symptoms disappeared, and there was no recurrence. This method is simple and effective.
(5) Spray in time during the growing season. The period from March to mid April is the period of sporulation, from May to early June and from early August to early September are the two peak periods of infectious gummosis.
In the early stage of the disease, 72% streptomycin sulfate for agriculture was sprayed with 4000-5000 times solution, once every 7 days, twice to three times continuously, or 1000-1500 times solution of thiophanate methyl, once every 10 days, three to four times continuously. In the peak growth period of peach trees (May June), 500 times of 70% mancozeb WP, or 600 times of 50% ultramicro carbendazim WP were used, once every 7-10 days, 3-4 times in a row, the above pesticides were best used alternately, the combination of chemical control and agricultural control had good control effect on gummosis. In addition, if the above control is not ideal, it may be caused by Japanese cysticercosis.
Wang Youxin, the author of this article, is from friends of farmers magazine. It is for reference only. The copyright belongs to the original author!
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