Anthracnose has been found in dry beans in Oxford County and may be present in other areas. Conditions have been ideal for the development of the disease.
Resistant Varieties
Some dry bean varieties carry resistance to anthracnose but there are popular varieties within each market class that do not carry resistance. There are currently no black bean varieties with resistance to anthracnose, and Etna cranberry beans are not resistant. Check the dry bean performance trial report in the “Characteristics and Distributors” tables for each market class to see if the variety you are growing is resistant to anthracnose Race 73. If you find anthracnose symptoms in a variety that is reported to be resistant, please contact Meghan Moran, OMAFA Dry Bean Specialist (meghan.moran@ontario.ca 519-546-1725).
Disease Management
Fungicide applications at this time may be on the late side but may still have some activity and reduce pick in infected fields. The ideal fungicide timing is in the early bloom stages, and application during late bloom or pod fill will be less effective. Research by Chris Gillard at University of Guelph has shown that of the products tested, Headlines, Quadris and Acapela provided good disease control and strong yields in the presence of anthracnose (click here for study results). Take note of the pre-harvest interval for the fungicide before applying it; you can find this info on the fungicide label or by searching for the product in the Crop Protection Hub. There are multiple articles on anthracnose at drybeanagronomy.ca describing disease management and symptoms.
The disease is spread by water movement in fields. Movement of machinery or people through a field when plants are wet can spread the disease around a field, or to other fields that are visited afterwards.
Producing seed in arid regions, use of fungicide seed treatments, use of foliar fungicides and resistant varieties are all factors in management of anthracnose. Production of foundation seed in Idaho is a major part of the reason there have been very few reports of anthracnose in Ontario in the past decade. Bin-run seed is at higher risk of carrying anthracnose.
Symptoms
Plant symptoms include round, angular or oval lesions on the leaves, stems and pods. The pod lesions start as tan or rust coloured and become sunken or “crater-like”, and develop a distinct, raised black ring surrounded by a reddish-brown border. The centre of the lesion may have a gelatinous mass of tan or salmon-coloured conidia that dries to numerous small, black or brown granular spore masses.
The veins on the underside of leaves are often red-brown or purple-red. Yield loss is due to early leaf senescence and plant death, shrunken seed and an increase in “pick” (seed that has disease lesions on the seed coat).
