Identification of ratoon stunting disease（RSD）of differentsugarcane varieties and isolation of RSD pathogen

In order to understand the inf ective rate of ratoon stunting disease（RSD）of dif f erentsugarcane varieties，13 sugarcane varieties were identified by PCR. The results showed that the infectiverates of different sugarcane varieties were different，and two CP sugarcane varieties had the lowest infectiverates. And a kind of coryneform bacterium with slow growth and milky white colony was isolated from RSDinfected sugarcane juice by MSC culture. By colonial morphology，microscopic examination，specific primersand identification of 16S rDNA，the coryneform bacterium was identified as Lei f sonia xyli subsp. xyli，thepathogen of sugarcane RSD.