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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…
Diseases
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Check patches of prematurely ripening canola for signs up disease. Dig up roots to check for clubroot galls. Early infection at the seedling stage can result in wilting, stunting, yellowing and even death of canola plants in the late rosette to early podding stage… -
Hot and dry or hot and humid? Hot, dry weather should reduce the risk of heavy sclerotinia infection, even if moist weather earlier promoted a lot of apothecia emergence and spore release. Hot, humid weather that leads to morning dew and a humid canopy can promote the disease. Keep in mind that even thought the sclerotinia fungus does not like… -
These can be hard to tell apart sometimes. Pinched or otherwise damaged-looking stems can occur with all three. The photo shows blackleg infection. Here’s how to tell them apart… -
If conditions were dry, then turned wet, the sclerotinia risk depends on when this transition occurred. Early dry weather doesn’t matter as much as long as you have moisture within the canopy leading up to and during the flowering period… -
As a rough estimate, the 20% flower or "bloom" stage is when the main stem has around 15 “flowers”. Canola can reach 20% bloom in 4-5 days after first flower… -
Prevalence of sclerotinia stem rot has a direct correlation to above-average moisture. If a field has regular rains or high humidity or both from two weeks before flowering and through flowering, then infection will likely occur. If growers decide to spray, the window for most products is 20-50% flower. Earlier is usually better as early infection on the main stem… -
For fungicide to provide an economic level of blackleg suppression, the crop has to be susceptible to the disease, blackleg incidence and severity must be high (usually due to short canola rotations) and the fungicide has to go on early – cotyledon to 4-leaf stage – before visible symptoms appear… -
Those same moist fields that have delayed spring harvest as well as seeding in central Alberta (and some other regions) also mean more mud clinging to equipment. More mud means more clubroot spores riding along on tires and equipment frames. Though the time crunch is on, knocking off as much mud as possible will reduce clubroot spread. In these conditions,…
