Abstract: The morphology,biological characteristics,rDNA internal transcribed spacer and screening of fungicides of leaf disease on Yingshan daylily（Hemerocallis citrina） were studied. The results showed that the pathogen was Nigrospora sphaerica.The optimun pH of mycelium growth was 5. The optimal C-source was maltose and the optimal N-source was yeast extract;The lethal temperature of mycelium growth was 55 ℃. According to screening results,prochloraz had the best inhibition on the mycelium growth of the pathogen among the nine tested fungicides. According to the symptom,the disease was named as leaf streak.

Key words: daylily（Hemerocallis citrina）, leaf streak, pathogen identification, screening fungicides