The Species Distribution,Biological Characteristics And Pathogenicity Of Cytospora On Populus And Salix In Xinjiang

Populus and Salix have become important ecological forest and commercial forest species in Xinjiang Uygur Autonomous Regions(XJUA)due to their strong ecological adaptability.However,with the widespread occurrence of forest canker in Xinjiang,the ecological and economic benefits of protective forests with Populus and Salix as the main species are restricted.The existing studies on canker in Xinjiang mainly focus on characteristic fruit trees,while the studies on canker in the ecological protection forest with Populus and Salix as the main tree species are less.There is a lack of systematic research on the biological characteristics and pathogenic differentiation of this kind of fungi in Populus and Salix in Xinjiang.In this study,the distribution of Populus and Salix Cytospora in various regions of Xinjiang was counted,and the culture characteristics,biological characteristics and pathogenicity were studied.The main results were as follows:(1)The distribution of 19 species of Cytospora from Populus and Salix in Xinjiang was different in different regions.C.chrysosperma and C.nivea were two species with wide distribution.The distribution of Cytospora in Tacheng was the most,with 11 species,followed by that in Yili(8 species),and relatively few in Altay prefecture(3 species),kashgar(2 species)and Hotan(1 species).According to the colony color,edge shape and sporulation of the strains on PDA medium,19 species of Cytospora were divided into 7morphological groups.The colony color of strains 1173-1(C.davidiana),2045-3(C.atrocirrhata)and 1579-1(C.chrysosperma)was brown and the edge shape of the colony was radial.During the observation period,fruiting bodies were produced and belonged to the brown edge radial sporulation group.The colony characteristics of strains 1918-1(C.sp.1)and 1851-4(C.salicicola)The colony color was gray,and the edge shape of the colony was feathery.During the observation period,fruiting bodies were produced,which belonged to the radial sporulation group with gray edge.(2)19 species of Cytospora fungi from Populus and Salix can grow at 15-32°C and p H 4-9.The optimum temperature is 25°C and the optimum p H is 6～7.The best carbon source is glucose and the best nitrogen source is yeast extract.Temperature,light and p H have different effects on the sporulation of Cytospora,and temperature has the greatest effect.(3)19 species of Cytospora from Populus and Salix can cause disease on Populus and Salix,and there are significant differences in pathogenicity.Strains 2067-3(C.nivea)and 1579-1(C.chrysosperma)had the strongest pathogenicity on Populus and Salix,with the highest lesion areas of 6021.30 mm~2 and 5661.87mm~2,respectively.The lesion area of Populus and Salix inoculated by 5 species of Cytospora was significantly larger than that of Salix inoculated.The 5 species of Cytospora from Populus and 9 species if Cytospora from Salix were pathogenic after cross-infection,and the pathogenicity was different.The pathogenicity of strains 1918-1 and 1886-1 from Populus was higher on Salix than that Populus.Strains2191-2(C.leucostoma),1010-1(C.salicacearum)and 2095-4 from Salix have higher pathogenicity on Populus.