Applying fungicides to pulses early is crucial, particularly with polycyclic diseases which can spread through the canopy quickly. Downy mildew is one of these polycyclic diseases, but it’s trickier than most to control due to a few factors, says Kan-Fa Chang, research scientist with Alberta Agriculture and Rural Development. Chang says limited fungicide options makes in-crop control of the disease very difficult. Furthermore, thanks to the complex nature of the disease, resistant cultivars don’t yet exist. (It’s an obligate parasite characterized into a multitude of pathotypes, if you want to get all plant science geeky).
Chang suggests rotating crops to lower disease incidence (with a preference of six years between pea crops, especially where disease is present), applying fungicide when possible, and using tolerant varieties, if available. Chang also explained that spraying an entire field may not be necessary, but to at least consider applying fungicide in areas with high disease incidence.
But this is all really only a concern if there is downy mildew in your pea crop. So is there? It can be confused with powdery mildew, after all.
In this episode of Pulse School, Chang explains where downy mildew gets its name and describes some common symptoms to look for when scouting pea fields. He warns that even though the disease may not result in yield losses right away, it’s important to manage, as the oospores can survive in the soil for up to 15 years, and become a much bigger problem later on.
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