By John Ippolito, Regional Crop Specialist, Kindersley
Many pulse crops have been a disappointment so far this year. There have been varying degrees of acres lost or damaged due to root rots and associated problems.
There is no simple and easily identified cause for these problems. There are a number of factors that may be coming into play all at the same time. Initial low soil fertility may be a factor. Cropping history and residue management may play a role. Saturated soils are often associated with these symptoms and may cause the initial stress that makes the pulse crops more susceptible to the root rot pathogens. In addition there is more than one pathogen involved in causing these symptoms. There are a number of Fusarium species that could be involved as well as Pythium and Rhizoctonia. The complex of these three is difficult to manage as they are pathogens of a broad range of crops including canola.
Aphanonyces has been identified as a pathogen of peas and lentils in the province in the past two years and is being found this year as well. The spores of this pathogen are long lived in the soil and there are currently no seed treatments that will control it. As a result it is very difficult to control. Current recommendation is to have a minimum of six years between susceptible hosts for Aphanomyces.
In terms of planning for next year producers of pulse crops may wish to look closely at the agronomic practices being used. A four year rotation may be beneficial and keep in mind that canola and other crops are also hosts to the complex of pathogens that may cause root rots and seedling blights. Seed treatments are important as well but will only provide early season protection. Ensuring that the plants have adequate fertility to handle stress and nodulate effectively is important.
Identifying root rots in pulses and management strategies for future crops is described in more detail in the July 24 edition of Crop Production News on the ministry website at http://www.agriculture.gov.sk.ca/Crop-Production-News