Analysis On Urediospore Germination And Spread Of Melampsora Larici-populina Kleb. In Guanzhong Region In Shaanxi Province

Melampsora larici-populina Kleb. is a rust fungi that belong to Uredinales, Teliomycotes,Badidiomycotina.It is a heteroecious rust that needs two different hosts to complete its lifecycle and infect poplar in Tacamahaca,Aigeros and their hybrids.It is difficult to control thepoplar rust because M.larici-populina Kleb. have complex genetic background,distinguishedpathogenic dividion found within species and have caused worldwide losses in poplar.In this study, we explore the inoculation, germination and spread of Melampsoralarici-populina Kleb. urediospore to provide information on poplar rust research and control.Reacton type of asexual isolates and germination on different poplar extracts were explored inthe labroratory, and spread of urediospores in Guanzhong region in Shaanxi Province wereanalyzed outside the labroratory, the result shows as follows:1.Disease reactions of populus clones which were inoculated with4detached isolates(Hj1, Hj2, Hj3, Hj4) from a mix isolate Hj of Melampsora larici-populina Kleb. wererecorded by using a leaf-disc method. The results indicated that4isolates belong to oneisolate.2.When the concentration of poplar leaf extracts which is exracted fromPopulus.tomentosa,P.deltiodes,P.purdomii,P.×euramericana cv.‘Robusta’,P.deltiodes×P.trichocarpa was higher than0.5g/100ml, the germination of isolate Th was lowerthan CK. The rusult indicate that poplar leaf extracts inhibit the germination when theconcertration was equal to0.5g/100ml and inhibitory effect increased while the concertrationbecame higher.3.Research on urediospores spread of7poplar samples in Guanzhong region in ShaanxiProvince revealed that the trend of urediospore appera frequency and numbers in the samesample are consistant, the period of max numbers which is also called concentrated outbreakin Taibai mountains is earlier, the urediospore numbers reached max from August14toSeptember16in Taibai mountain, the same situation occured from September16to October2in the plain, the urediospore numbers in the mountain are higher;In the max urediospoesperiod, the increasing speed of urediospores in the plain is higher.