Myscosphaerella blight — more commonly known as ascochyta — can cause significant devastation in pea, lentil, chickpeas and even faba bean crops.
Robyne Bowness Davidson, research scientist with Alberta Agriculture and Forestry, says in this Pulse School episode that farmers should be out scouting for ascochyta just before the crop starts flowering.
“You can certainly go in earlier, but we usually suggest the early part of July as the best time to go,” she says. Another reason you might want to start thinking about it is if there’s been a lot of wet weather in your area over the last little while, you might be suspicious that disease might be starting to move in.
She adds that it’s important to keep an eye on whether your crop canopy is open or closed, and if there has been any stress caused to the plants.
“Unfortunately this year hail has been something that has gone through and is affecting your pea crops. So if you’ve had a hail event go through, it brought a lot of rain, or your peas look beat up, that might be another indication that you want to get out and scout your crops,” Bowness Davidson says.
Ascochyta is an airborne disease, so if you see it in a nearby field, there’s a good chance it will reach adjacent fields as well.
“We have the spores available in the air,” she says. “They are everywhere, they are floating around, and whether or not ascochyta is in your area, the answer is yes. Whether or not ascochyta is going to be a problem is strictly climate.” (Story continues below player)
Spraying decisions can be difficult, as it always comes back to the same question — does it make economical sense to spray for this disease?
“A good way to know whether your crop canopy is susceptible a little bit more than other crop canopies is if you go out to your field at noon, on a beautiful day, and you stick your hand in the crop and it comes out wet, that’s an indication that your canopy is a very dense canopy where ascochyta might do really well,” she says.
Timing is also imperative for spraying, but as Bowness Davidson notes, a single application won’t cover you for the whole season.
“If you’re going into your field, and seeing a little bit of disease, and it’s very very minor, then you may want to consider waiting a little bit, because a little bit of disease does not economically warrant a fungicide application,” she says, adding that most fungicides only offer protection for about 10 days post-application.