Walnut Stalk Canker Disease Occurrence Law And Chemistry Preventing Measures Research

Walnut (Juglans nigra l.) is one of the famous four nuts in the world, is a deciduous tree, its seeds have high nutritional value and health care function, can be making cooking oil and produce all kinds of food. Walnut Canker Disease has been less studied, and there were less reports in China. Walnut Canker disease caused by Cytospora juglandina Sacc. Conidium is buried in epidermis, more room, irregular shape, dark brown, Have a long neck,35 to 49 um long; Conidium terrier 13.6-19×11.6-18.4μm. Conidium unit cell, colorless, sausage 3.9-6.9×0.9-1.8μm.3, Walnut Canker pathogen for weak parasitic fungus, and has the characteristics of latent infection. In general, bacteria from the wound into the cortical tissue of death, secretes toxic substances, kill living cells, caused disease. The disease hyphae and conidium apparatus in sick in the winter, the spring produced conidium, spread by wind, rain, insects, etc.Therefore, this study in order to make the anniversary of walnut Canker occurrence regularity and its relationship with environmental factors clear, which provides the theoretical basis to take correct method of prevention and cure. The main results were as follows:1, Walnut Canker disease have a close relationship with planting density, tree age, amount of intercropping mode, the management level, and the production. The orchard which the Planting density is 3 m x 8 m had a higher degree. The disease index is 37.5. The walnut in full productive age has more severe disease, incidence of the disease as high as 66.4%. Different interplanting mode different incidence, walnut and wheat intercropping incidence was as high as 55.8%.2, By control test, from the method, the scraping knife of walnut Canker control effect is best, control effect reach to 90%. From the point of the effect of reagent, the Zhi fuling has better control effect, disease recurrence least, control effect was 86.7%.