July 5, 2018
The three points of the disease triangle are host, pathogen and environment. When it comes to sclerotinia stem rot in canola in Western Canada, the disease triangle hinges on one component: Environment…
July 5, 2018
The sclerotinia stem rot infection cycle begins when sclerotia in the soil (left from the last time an infected crop was produced on that field) take up enough moisture to germinate and form little mushrooms known as apothecia. Spores are then released into the air from the mushrooms. Under ideal warm and moist conditions, it takes about two to three…
July 5, 2018
If conditions are dry at early flower and then it rains at 40% to 50% flower, spraying at the end of the window may be effective – as long as there was enough moisture before flowering to get apothecia germinating. In this situation, later sprays could be especially effective if moisture also promoted a longer flowering window due to later…
July 5, 2018
Small amounts of spores can lead to yield-robbing levels of sclerotinia in continued moist conditions. A petal test to confirm the presence of sclerotinia DNA on petals could be used to provide an indication of pathogen pressure at the time of petal collection…
June 27, 2018
The decision to spray or not spray fungicide to limit sclerotinia stem rot is rarely easy. Consider the following three scenarios as you assess the risk situation this year…
June 27, 2018
The timeline from when sclerotia in the soil first take on moisture, to apothecia germination, spore release, petal infestation, petal drop and finally canola plant infection takes up to three weeks. This graphic shows the final 24 hours as the fungus on decaying petals enters the plant and creates a lesion…
June 27, 2018
Michael Harding with Alberta Agriculture & Forestry recently compared 10 disinfectant solutions to see which is best to kill clubroot spores on machinery, tires and boots, etc. Four of those 10 products achieved 95% inactivation of clubroot resting spore viability, qualifying them as effective. Of the four, bleach achieved the 95% threshold at very low concentration (2%) and bleach is…
June 20, 2018
As earliest canola crops start to flower, the annual sclerotinia stem rot management conversations begin. This article describes factors that increase risk and reduce risk…
June 20, 2018
How many plants recovered? Are they at early stages and at risk of heavy blackleg infection? What is the crop nutrition situation?…
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