Control of Infective Gummosis of Peach Tree

It is a disease caused by a fungus of the subphylum ascomycetes. It mainly harms the branches. When the disease occurs on the 1-year-old twigs, small protuberances are formed at the center of the lenticular layer, and then a tumor-like process with a diameter of 1-4 mm is formed, which does not flow glue in the same year. In the first ten days of April of the following year, the tumor skin cracked and overflowed with resin. at first, it was a colorless, translucent, thin and sticky soft glue, and soon turned tea-brown, the texture hardened into crystalline, and swelled into a colloid after absorbing water. The surface of the branch became rough and black, and gradually sunk around the tumor as the center, forming a round spot with a diameter of 4mm and 10mm, in which scattered small black spots. After the perennial branch was damaged, it showed a blister-like bulge of 1-2 cm, and the bacteria were harmful in the epidermis of the branch, reaching up to the xylem.

The injured area became brown and necrotic. When there are many disease spots on the branches, a large amount of glue will flow, resulting in the death of the branches and the premature senescence of peach trees. The pathogen wintered in the damaged branches, and the conidia were spread by Rain Water and the wind. On rainy days, a large number of bacteria overflowed from the diseased part, flowed down the branches or splashed on the new shoots, invaded from the lenticels and wounds, and became the main source of bacteria for the first time of the new shoots. The activity of latent bacteria in branches is related to temperature. When the temperature was about 14 ℃, the gum could be spilled from the disease part. with the increase of temperature, the gum flow point of the tree increased and the disease became more and more serious. there were two peaks in one year, from late April to late June and from early August to mid-September, respectively, and stopped after winter. The pathogen can lurk in the cortex and xylem of the damaged branches, produce conidia and conidia in the dead cortex, and become the source of infection. The most favorable time for bacterial invasion is during the gradual Lignification of cortical cells of branches and after the formation of lenticels. The control should be carried out in the peak period of new shoot growth (when lenticels are formed), and the protective effect of spraying is the best.