1 Institute of Plant Protection，Shandong Academy of Agricultural Sciences，Key Laboratory of Plant Virology of Shandong
Province，Jinan 250100，Shandong，China；2 Plant Protection College，Shandong Agricultural University，Tai’an
271001，Shandong，China；3 Jinan Apollo Chitosan Fertilizer Industry Co. LTD，Jinan 250101，Shandong，China
This paper carried out identification on pathogen of rhizome rot disease in ginger by morphological
observation，pathogenicity test and sequence analysis；and studied the antifungal activity of chitosan against
ginger rhizome rot disease by mycelium growth rate method，in vivo biospy and field experiment. The results
showed that the pathogen of ginger rot disease was identified as Pythium myriotylum，Pythium spinosum and Pythium sylvaticum，the mycelial growth of those pathogens were restrained by chitosan and the EC50 values were
422.711 2，401.699 5，446.910 7 μg·mL-1，respectively. Micrography observation showed，while inoculated
in the substrate with chitosan，the mycelia would abnormally grow，like：bulging，contorting，having more
branches，and vacuolation appearing inside of mycelia. These results showed that chitosan could obviously inhibit
the occurrence of rhizome rot disease in ginger. The results of field control experiment showed that chitosan could
significantly prevent the occurrence of rhizome rot disease in ginger，and consequently improve the ginger yield.
