Study On The Pathogenies Of The Main Jujube Fruit Disease In The Part Of North China And Screening Of Fungicides

Chinese jujube is a kind of important economic tree in the north of China. In recent years, the jujube fruit disease widely occurred in Henan, Hebei, Shandong, Shanxi, Beijing, Shanxi, Anhui and so on.On one hand,the disease resulted in a mass of fruit falling ahead of schedule and output reduction.greatly. On the other hand ,it influenced the quality of the jujube fruit and brought on extensive losses to peasants.Diseased jujube fruits from Henan ,Shanxi and Beijing were divided into two symptom types according to their symptoms ,which were isolated, 13 taxa of fungi were identified and two others were not identified yet..Inoculation Coniothyrium olivaceum Bon., Alternaria tenuissima (Fr.) Wiltshire and A. alternata into Chinese jujube cultivar Bianhesuan and Lizao in the lab proved that they were pathogens of jujube brown iron disease.The author also isolated fungal organisams from fruit, branches and flowers of Lizao and Bianhesuan from Henan Puyang at regular intervals and made certain that A. tenuissima and A. alternata invaded the fruit from the tresses sprouted, and C. olivaceum invaded when the fruit were developing.lt was found that jujube brown iron and shrink fruit disease were two different symptoms of a sort of fruit disease on Chinese jujube.Toxin produced by A. tenuissima was separated and purified and its pathogenicity was determined with bioassay methods.Its lowest pathogenic concentration to leaves of Dong zao was about 0.6mg/ml,which provided reference for further research on pathogenesis of jujube leave spot,jujube fruit disease and how to select resistant jujube species with toxin. .The test against jujube fruit disease with biological fungicides was conducted in the lab and in the field. The results showed that in the lab, at certain concentrations,3% zhongshengmycin WP,yibao,4% agri-antibiotic 120 WC and YIB(yield—increasing bacteria) had distinct effect on C. olivaceum .Copper hydroxid,zhongshengmycin WP,Yibao,4% agri-antibiotic 120 W C and YIB(yield—increasing bacteria) had good effect on A.tenuissima and A. alternaat.ln the field ,3 % zhongshengmycin WP 800 times ,4 % agri-antibiotic 120 WC 400 times,4% BI-antic W C 400 times were obtained .which had the best control effect.Three physiological indexs were measure by the following methods : anthrone colorimelry, acid—base titration method and reagent kit method respectively.The result showed that those biological fungicides had no effect on total sugar, total acid and Vitamin C content of Bianhesuan,which means that those biological fungicides could be used in th field .