Sclerotinia Risk in Canola
This forecasting program has been developed by the North Dakota State University Canola Pathology program with support from the
Sclerotinia Initiative, the Northern Canola Growers Association, and the Minnesota Canola Council. While the information presented
by this program is based on data generated through extensive research, it is only intended to serve as a guide for growers.
This forecasting program has two components, a general risk map and a risk calculator. The general risk map uses weather information
to estimate risk of disease development throughout the canola growing areas of the state. This map is updated twice every week
starting in mid June and continuing during the canola flowering period. The risk calculator combines information on cultural
practices and the field past history of Sclerotinia with weather information retrieved from the nearest NDAWN weather station to
estimate the risk of disease development for a specific field. To access the risk calculator visitors are asked to set an account
and to provide information pertinent to the field of their interest.
News and Tips for You
July 31, 2015
Last map of the season
The map of July 31, 2015 applies only to fields that were planted in the second week of June. These fields are at the flowering stage now. Canola fields planted earlier have finished flowering and are at various stages of ripening. The window for Sclerotinia infection for these fields has closed and with it the risk of widespread infection. If warm and dry weather prevail in coming weeks the crops will be safe; however, if heavy rains return to the region Sclerotinia damage may occur in localized areas of fields where heavily lodged canola plants are present. Fungicide applications at this time, however, would neither be recommended nor warranted as the product would not be able to reach the plant parts affected.
July 4, 2015
Warm and dry weather are keeping risk of sclerotinia development low
The warm and dry weather conditions are giving us all a reprieve on the risk of sclerotinia. However, please remember this applies only to fields that are in bloom right now. The risk of infection may change in the near future if wet weather conditions return. In the meantime, however, enjoy the break. Happy 4th of July!
June 19, 2015
Reading Sclerotinia Risk Maps
Maps depicting the estimated risk of development of Sclerotinia stem rot on canola will be produced approximately every three days for the duration of the flowering period. When reading the maps growers should be aware that the estimated risk applies only to canola crops that are entering the flowering period or are already flowering. This risk is calculated considering the effect of environmental factors. A risk calculator that combines the effect of weather variables, cultural practices, and history of Sclerotinia is also available. While this information is intended to advise growers when conditions may be favorable for disease development, the final decision on whether to spray a fungicide or not should include economic considerations such as the potential yield of the field and the potential market price for the commodity.
Growers are encouraged to look for apothecia in their fields before making spraying decisions, especially if their fields are located in areas with intermediate or high risk.
June 19, 2015
Weather conditions are favorable for blackleg development
Rainy and cool conditions experienced in past several days in the northern half of the state are favorable for blackleg development. Growers are encouraged to scout fields for signs of infection that may include wilting of seedlings and girdling of stems. These symptoms are more likely to appear in fields that had blackleg problems the previous growing season. Fungicide use in such fields may be recommended if plants have not reached the 4th leaf stage. Once plants get older, fungicides will be less effective. A list of fungicides registered for use in canola against blackleg can be found in NDSU extension publication PP-622.