Study On Pathogen Of Walnut Stalk Rot Disease

It has a symptom of flowing black water on walnut in Xinjiang.To our knowledge, this is the first report to this kind of disease. It was onsidered as a new Walnut disease and has been named Walnut Stalk Rot Disease. On this paper, first and systematically studied on the symptoms of the disease identification biological characteristicsthe disease occurrence and control test of fungicides.The main results are as follows.Samples were collected from stands of diseased walnut in Xinjiang. The isolates were inoculated on both wound and health. Re-isolation from the lesion formed by the inoculation was the same as the inocula,demonstrating that the isolate was a pathogenic strain of Pythium oligandrum based on its morphological.The result of Molecular Identification is closest matching Pythium oligandrum up to 99%similarity.The biological characteristics of the pathogen of black water on walnut-Pythium oligandrum was researched. The optimal medium for the growth of parthogn was CMA, the best carbon source was sucrose, the best nitrogen source were yeast solid. For pathogen growth the optimum temperature was 20～33℃, the optimum pH value was 5.2-7.2, The light didn't effect on the growth of the mycelium. The P. oligandrum Liked middle highest temperature. It was a middle type.This disease is relate with density age intercrop and irrigation. The incidence of density 6 m×4m is 2.7%, it is higher than other orchard. The incidence of age 11-20a is 14.2%. The different intercrop has different incidence, when intercrop was wheat incidence was 7.80% higher than other intercrop mode. The more times of irrigation, the higher incidence. Before irrigation the incidence was 9.60%, after 3 times was 15.94%.Choosing 30mu yard. By methods fulankexing+lunfulhao has higher effect than other fungicides. It is 100%,Garlic+10%salt has better result, it is 16.3%.