Transmission of anthracnose ( Colletotrichum lindemuthianum ) in dry bean ( Phaseolus vulgaris L.) with artificial and natural inoculum in a wet and dry canopy

Abstract

LeClair, E., Conner, R., Robinson, D. and Gillard, C. L. 2015. Transmission of anthracnose (Colletotrichum lindemuthianum) in dry bean (Phaseolus vulgaris L.) with artificial and natural inoculum in a wet and dry canopy. Can. J. Plant Sci. 95: 913–921. Anthracnose [Colletotrichum lindemuthianum (Sacc. and Magn.) Lams. – Scrib.] is a serious pathogen of dry bean (Phaseolus vulgaris L.). Disease transmission on artificial materials and clothing has been observed in other crops, where equipment and workers transmit pathogens from infected to clean plants. Initial studies in 2008 and 2009 at Exeter, ON, determined that anthracnose transmission in dry bean as measured by resultant disease severity occurred with denim, leather, metal, and rubber using a 10 7 spores mL −1 prepared artificial spore inoculum in both wet and dry crop canopies. In 2012 and 2013 at Morden, MB, and Ridgetown, ON, the studies were expanded by adding a 10 5 spores mL −1 prepared artificial and a natural inoculum source. Inoculum source and canopy moisture had the greatest effect on disease severity, while no differences were observed between materials within an inoculum sources. Transmission in wet canopy conditions resulted in a higher infection rate. Canopy moisture impacted the natural inoculum the most. The 10 7 spores mL −1 inoculum transmitted the most disease followed by natural incidence and 10 5 spores mL −1 inoculum in wet conditions. In dry conditions 10 7 spores mL −1 inoculum transmitted the most disease followed by 10 5 spores mL −1 inoculum and natural incidence. Producers need to recognize that there is real risk for the anthracnose transmission by common materials in dry bean, and take appropriate precautions to prevent it.