Survival and transmission of Colletotrichum lindemuthianum from naturally infected common bean seeds to the seedlings

Abstract

Surveys were made of major seed-borne fungi associated with seeds of common bean (Phaseolus vulgaris L) in different bean-growing areas of Ethiopia. Field and laboratory experiments were also carried out during the 2003 and 2004 crop seasons to study the survival and transmission of bean anthracnose pathogen Colletotrichum lindemuthianum to the seedlings. The major seed-borne fungi associated with common bean seeds were Colletotrichum lindemuthianum, Phaeoisariopsis griseola and Ascochyta phaseolorum. Bean anthracnose survived in infected seeds but not in the soil, and the primary source of bean anthracnose infection in the field was from infected seeds. Seed infection of common beans by bean anthracnose resulted in both pre-emergence and post-emergence mortality of bean seedlings. A significant positive relationship was found between the levels of primary seed infection and seedling infection in the field. Further development of bean anthracnose in the field was influenced by weather variables (rainfall, number of rainy days, humidity and temperature). Copyright © 2007 John Wiley & Sons, Ltd