Some growers say that their jujube trees should be sprayed with fungicides several times a year. Why does it shrink? What I want to say here is that the occurrence of fruit shrink disease is related to many factors, and sterilization is only one aspect.
First of all, growers need to know what disease bacteria cause fruit shrinkage. At present, the pathogen of fruit shrinkage disease is generally considered to be bacteria. Therefore, the bacterial fungicides such as kasugamycin and clothianidin copper should be selected to prevent and control jujube fruit shrinkage. However, some growers often choose pyraclostrobin, tebuconazole, difenoconazole and other drugs during the whole growth period, but these drugs have poor control effect on bacterial diseases, which leads to the disease can not be controlled after medication.
Second, jujube fruit shrink disease is not only caused by bacteria. There are two kinds of fruit shrinkage diseases. The first one is caused by the bacteria we just mentioned. The early symptoms of this fruit shrinkage are obvious, and there will be lesions that can be observed by the naked eye. The second external environment is not suitable, which will also lead to physiological fruit shrinkage of jujube trees, such as low temperature freezing injury of jujube trees planted in greenhouse, a large number of jujube trees bearing fruit, fertilization of jujube trees during fruit bearing period and so on. And this physiological fruit contracts. It can't be solved by spraying bactericide.
Thirdly, the occurrence of jujube fruit shrinkage disease has a great relationship with field pests. At present, it is generally believed that if there are a large number of pests in the orchard, such as green leafhopper, green blind stinkbug, jujube rust tick, wax cicada, etc., the phenomenon of fruit shrinkage in the orchard will be more serious. Because these pests suck juice on the surface of jujube trees through piercing-sucking mouthparts, and then leave wounds, these wounds are more likely to let pathogenic bacteria invade jujube trees and cause diseases. Therefore, if the number of pests in the orchard cannot be effectively controlled, even if pesticides are sprayed, it is very easy to happen in the later stage. In addition, if the planting density of orchard is relatively high and the fruit quantity of jujube trees is large, then the friction between fruits and leaves will also form wounds on the surface after the wind and rain, which will increase the incidence.