Pathogenicity Test of Sclerotium rolfsii, a Causal Agent of Jerusalem Artichoke (Helianthus tuberosus L.) Stem Rot

摘要

Stem rot disease caused by Sclerotium rolfsii can cause severe yield losses of Jerusalem artichoke. Pathogenicity of S. rolfsii in Jerusalem artichoke has not been well-researched especially in the semi-arid tropics. The objective of this study was totest pathogenicity of different isolates of S. rolfsii in Jerusalem artichoke. Ten isolates of S. rolfsii and three varieties of Jerusalem artichoke (JA 89, HEL 65 and CN 52867) were assigned in factorial experimental design. Plants were inoculated by spreading 20 seeds (0.6 g) of sorghum-based inoculums around the stems at 6-8 leaf stage. A non inoculated treatment is also included as control. The interactions between isolate and variety were not significant for all characters. The isolates were significantly different for disease incidence, Area under Disease Progress Curve (AUDPC), days to permanent wilting, plant height and shoot dry weight. The reactions of most isolates were aggressive except for the isolates 2 and 7. HEL 65 exhibited low disease incidence and AUDPC.