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

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 107 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 105 spores mL-1 prepared artificial and a natural inoculum source. Inoculum source and anopy 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 107 spores mL-1 inoculum transmitted the most disease followed by natural incidence and 105 spores mL-1 inoculum in wet conditions. In dry conditions 107 spores mL-1 inoculum transmitted the most disease followed by 105 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.