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 24, 2014
Recent rains are elevating risk but most fields are out of danger
Rain events of the past few days have increased the risk of Sclerotinia development. However, most fields are by now past the full bloom stage and therefore are out of immediate danger. Dry spells like the one experienced during the past two weeks usually reset the carpogenic germination clock and consequently apothecia will not be produced in time to cause problems in fields that have not yet reached the full bloom stage.
If rainy weather continues, however, apothecia may develop at a later time and could create some problems in areas where heavy lodging occurs. Unfortunately, fungicide applications in such fields will likely not produce a positive return because the fungicide will not be able to penetrate the canopy to protect the areas closer to the ground.
July 18, 2014
Windy days with warm temperatures and no rain are reducing risk of Sclerotinia development
Windy days combined with warm temperatures and absence of precipitation has brought down the risk of Sclerotinia development for most areas where canola is grown. Warmer temperatures forecasted for the next several days will help keep the risk low in most areas while speeding up flowering.
July 3, 2014
Apothecia found in canola fields in Cavalier County
A recent visit to ten canola fields in Cavalier County revealed the presence of apothecia in three of them an indication that fungicide applications may be needed to reduce damage by Sclerotinia. Growers in this county should keep in mind, however, that the risk applies only to fields that are at the flowering stage. Fields that have not entered flowering should not be sprayed at this time.
Growers in all other areas of the state 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 26, 2014
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.