Survival of the bean anthracnose fungus (Colletotrichum lindemuthianum) on crop debris in Canada

摘要

Anthracnose caused by the fungus Colletotrichum lindemuthianum (Sacc. Magnus) Lams.-Scrib. has been a major constraint to dry bean (Phaseolus vulgaris L.) production in Manitoba and Ontario, as well as elsewhere in the world. There is a lack of consensus on the length of time the anthracnose fungus can survive on infected crop debris as well as the effectiveness of crop rotation to control the disease under temperate climatic conditions. A multi-year study was established at field sites near Morden, MB and Exeter, ON to examine the survival of C. lindemuthianum on seed, pod and stem tissue samples of infected beans on the soil surface and buried in the soil over different 2-year periods. The survival of the anthracnose fungus was influenced by location, type of infected tissue and burial in the soil. On average, C. lindemuthianum could persist for 18months at Morden and about 9 months at Exeter, which was long enough to serve as a source of primary infection to subsequent crops of dry beans. At both field sites, the anthracnose fungus overwintered longer on infected stems and pods than it did on infected bean seed. The burial of infected bean tissue reduced the viability of C. lindemuthianum in all tissue types compared with samples that remained on the soil surface. A 3-year crop rotation study at Morden in which either a wheat, fallow or bean treatment were grown in the second year, confirmed that the anthracnose fungus could survive long enough under zero-tillage conditions to infect a bean crop in the third year of the study and cause considerable downgrading of the seed. This study demonstrated the importance of tillage and crop rotation in the integrated control of bean anthracnose.