Causes and Control Measures of Peach Gummosis

Causes and control measures of gum disease in peach trees

1 symptoms of disease

Gum disease mainly occurs in the root neck, trunk, main branches and other parts, and the trunk is the most prominent, the trunk is heavier than branches, branchlets and fruits can also be killed. At the initial stage of the disease, the disease swelled and continued to flow out translucent yellow gum, especially after rain. After the outflow of gum comes into contact with air, it gradually turns brown and becomes a crystal soft jelly block, and when dried, it becomes a brown hard glue block (figure 1).

Fig. 1 after flowing glue, it becomes brown hard rubber block

3. 4 glue beads are connected together to form irregular round glue spots with a diameter of 3 to 10 millimeters, which are jelly-like and turn reddish brown after drying. The bark is swollen and rough, cracked, the wound is not easy to heal, the cortex and xylem gradually turn brown and rotten, and are easy to be infected by saprophytic bacteria. With the development of the disease, the glue spots continue to increase and increase, and in severe cases, the trunk is covered with glue. When the disease spot surrounds the main branch, the tree weakens, the leaves turn yellow, the treetops wither, and even the branches or the whole plant die.

With the incidence of the diseased fruit, the yellow glue is secreted from the fruit core, which overflows the fruit surface, the diseased part hardens, and the serious one appears the phenomenon of cracking, the diseased fruit can not grow and develop, and has no edible value.

2 conditions for onset of disease

The occurrence of gum disease in peach trees lasted for a long time, and it could occur from April to October, and the damage was the most serious from May to September. The occurrence of peach gum disease is closely related to tree age, tree potential, cultivation and management level, temperature and humidity and so on. The disease of the old tree is serious, while that of the young tree is light. The activity of latent bacteria in branches is related to temperature. When the sap flow is exuberant in early spring, that is, when the temperature is about 15 ℃, the diseased part can overflow glue. With the increase of air temperature, when the temperature is about 25 ℃ and Rain Water is more, the gum flow point of the tree increases, and the disease becomes more and more serious (figure 2).

Fig. 2 the first peak of incidence

There were two peaks in one year, from late May to late June and from early August to mid-September (figure 3). The glue flow stopped after winter. Clay loam, lean soil and orchards with excessive acid and alkali are prone to gum disease, and peach orchards with low level of comprehensive management or serious diseases and insect pests are prone to serious disease.

Fig. 3 the second peak of incidence

3Pathogeny

Gummy disease can be divided into two types: non-infectious gummy disease and infectious gummy disease, but they are mainly caused by fungal invasion. after the pathogen invaded the trunk and branches (figure 4), after spending the winter smoothly, a large number of spores were produced in the early flowering stage of peach blossom in the second year, and the spores were transmitted by wind to invade the trunk wounds of other peach trees and infect the next peach tree.

Fig. 4 the wound of gelatinosis was invaded.

4. Scientific prevention and cure

4.1 selection of excellent rootstocks and varieties

The resistance of mountain peach as rootstock is stronger than that of hairy peach. Avoid continuous cropping in Taoyuan.

4.2 strengthen the management of peach orchards and enhance the tree potential

Increase the application of organic fertilizer, improve soil aggregate structure, improve soil aeration performance, 3-5 tons of chicken manure per mu; pay attention to drainage in low-lying waterlogged land, acid-alkali soil should be properly applied lime or calcium superphosphate. In order to improve the soil, attention should be paid to the discharge of salt in saline-alkali soil.

4.3 do a good job in clearing the garden

Clean the orchard before winter or after the beginning of spring, burn the damaged branches and fallen leaves, scrape off glue lumps and rotten tissue, and eliminate the source of bacteria. Use Kuifuling 60x 100 times liquid whole garden spray. Boron application in soil or spraying boron outside the root during the growing season has a good effect on the prevention and control of gum disease.

4.4 adjust pruning time

Pruning reasonably to reduce the wound of branches and stems. Peach trees are cut short and pruned during the growing season, resulting in man-made wounds, which are prone to glue flow in medium temperature and high humidity environment. By adjusting the pruning period, light pruning should be taken during the growing period to remove some overdense branches in time. The main branch thinning, truncation, retraction pruning, adjusted to winter after defoliation.

4.5 Trunk whitening

Two times of trunk whitening are carried out in winter and summer, the first time after the peach trees are defoliated, and the trunk is sterilized with 5 Bo Meidu stone sulfur mixture + fresh cow dung + fresh lime or brushed with 20% 25% lime milk to prevent frost injury and sun burning. eliminate tree trunk overwintering diseases and insects, reduce disease infection and radiation heat harm, can effectively reduce the occurrence of glue disease.

4.6 covering the whole garden with grass in summer

If there is no green manure in the orchard, the whole orchard is covered with weeds or straw 10 cm thick in high temperature and dry season in summer and autumn, which can not only increase the soil water content of the orchard, benefit the root growth of fruit trees, and strengthen the tree body. and it is very effective to prevent sunburn caused by ground radiation heat, so as to prevent the occurrence of gum disease.

4.7 Application of protective agent

Spray the whole garden with Kuifuling 60-fold 100-fold liquid, and spray it with 500-fold liquid before flowering (red period of blossom). For trees that have occurred gum disease, the twigs can be trimmed and removed, the glue on the branches should be scraped clean, and the wound should be smeared with Liangguoan 10-50 times (note that the smear area should be more than 1-2 times of the affected area). The effect is more significant if it is applied again every 7 to 10 days. The most suitable period for smearing is when the sap begins to flow, that is, at the end of March, which is the initial period of gum flow, with a small number of plants and a small range of glue flow, which is easy to control and reduce the nutrient consumption of trees. In the future, it will be prevented and treated with smear when it is found.

4.8 timely pest control

From April to May, we should timely control longicorn beetles, gibberries and other pests, avoid infecting the root neck, trunk and branches, control peach borer larvae, leaf roll moth larvae, pear heart borer, blind Toona sinensis, etc., and avoid causing gum disease due to fruit damage (figure 5).

Fig. 5 timely control of pests harmful to fruits

4.9 Chemical control

If it is caused by bacterial pathogen, spray and brush the trunk with agricultural streptomycin or Ye Qingshuang. If it is caused by fungal pathogens, the trunk can be sprayed or brushed with antimicrobial agents 401, carbendazim, methyl thiophanate and isobarbazide, and the concentration of brushing the trunk can be relatively higher than that of spraying the crown. Before the trunk is brushed, scrape the glue off the glue part with bamboo, then brush the medicine solution, or cut the waste clean cotton cloth into strips and soak the medicine solution, then wrap it in the affected area, and then wrap it with a 10 cm wide film, which has a better prevention and treatment effect. 50% carbendazim ultra-fine wettable powder 1000 times liquid or 50% carbendazim wettable powder 1500 times solution can be used for chemical control, and the control effect is better. The period from late March to mid-April is the period of ejecting conidia of infectious gummosis, which can be prevented by spraying 600 times of Guoan 800 times of liquid to prevent other diseases. The two peak periods of infectious rheumatosis were from early May to early June and from early August to early September. On the eve of each peak, Guoan was sprayed 600 times 800 times, once every 7-10 days, 2 times every 3 times, depending on the disease.