Diseases

  • Start your pre-harvest disease scouting

    Diseases

    Diseases are usually easiest to see and diagnose in the couple of weeks before swath timing. Patches of dying or prematurely-ripening plants are obvious areas to scout (and show up really well with drone images), but even clean-looking fields can provide some early warning if you take time to look. Here’s how to identify the major diseases of canola as fields get close to swathing stage…

    READ MORE

  • Clubroot watch begins

    Diseases

    Take a look at the roots of plants that are showing unusual amounts of heat and moisture stress. These plants may be facing premature wilting and even death due to clubroot, and mounting stress from the environment can make these plants stand out even more.

    READ MORE

  • The disease triangle: Moisture means sclerotinia

    Diseases

    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.

    READ MORE

  • Sclerotinia stem rot timeline for infection

    Diseases

    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 weeks for sclerotia to germinate and release spores.

    READ MORE

  • Sclerotinia stem rot: Late and second sprays

    Diseases

    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 compensatory growth. With lower seeding rates resulting in more branching, canola fields can be at 50% flower for a week or more.

    READ MORE

  • Sclerotinia: Positive petal test may not mean “spray”

    Diseases

    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.

    READ MORE

  • The sclerotinia spray decision: Moisture scenarios

    Diseases

    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.

    READ MORE

  • Sclerotinia stem rot timeline for infection

    Diseases

    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.

    READ MORE

  • Clubroot disinfectants: Bleach is best

    Diseases

    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 the lowest cost and easiest to find.

    READ MORE

  • Sclerotinia risk assessment: Fungicide planning

    Diseases

    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.

    READ MORE

Canola Watch