This visual guide to field pea insect and disease pest identification in Manitoba was created to supplement the scouting calendar. Refer to this ID resource guide for identification of common field pea pests, while scouting during the growing season.
Mycosphaerella Blight
Mycosphaerella blight lesions on pea leaves at R6 near Roblin on July 31.
Mycosphaerella blight in peas.
Mycosphaerella blight in the lower canopy of a pea crop, not likely severe enough to warrant a second fungicide application.
Early symptoms of Mycosphaerella blight in peas appear as small dark freckles on lower leaves.
Mycosphaerella blight early symptoms showing up on lower leaves on June 28, 2020.
Close-up of symptoms in field peas.
Bacterial Blight
Bacterial blight in peas shows up as angular, water-soaked lesions.
Bacterial Blight infecting peas in the mid-canopy.
Bacterial blight infection in peas – the lesions follow leaf veins and have a ‘window pane’ appearance letting light shine through the leaf.
Severe bacterial blight on peas.
Bacterial blight lesions on pea stipules at R4 on July 28 near Arborg.
Close-up of symptoms in field peas.
Bacterial blight in peas showing up in the lower canopy due to leaf tearing earlier in the season from high winds and heavy rains.
Bacterial blight on pea pods, showing a water-soaked appearance around lesions (July 21).
Bacterial blight lesions on a dry bean pod, July 31.
Downy Mildew
Downy mildew infection in peas – the upperside of the leaf is pale and discoloured, the underside of the leaf has fuzzy grey growth.
Downy mildew infection in peas – the underside of the leaf has fuzzy grey growth.
Downy mildew infection in peas. On the upperside of the leaf, the lesion is pale green to yellow, and on the underside of the leaf there is grey fuzzy growth.
Downy mildew lesions on the upper surface of a pea stipule on June 24.
Downy mildew lesions on the underside of a pea stipule, opposite to the yellow lesions (June 24).
Downy mildew on the undersides of pea leaves on June 30, 2020.
Pea Leaf Weevil
Microscope close-up of an adult pea leaf weevil.
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Pea leaf weevil caught using a sweep net in faba beans on August 24, 2021.
A hollowed out root nodule from pea leaf weevil larvae feeding. The larvae is feeding on the nodule above the hollowed out nodule in the center of the photo.
Pea leaf weevil larvae on faba bean roots in northwestern Manitoba.
Pea leaf weevil and pea clam leaf in a small container for size reference.
Distribution of pea leaf weevil (PLW) in Manitoba as of August 24, 2021.
Pea leaf weevil (center) and alfalfa curculios from a pheromone-baited trap near Plumas.
Notching of peas by the pea leaf weevil following pea harvest in August. Checking regrown or sprouted harvest loss areas of the field are an easy way to look for signs of the PLW.
Pea leaf weevil feeding on lower pea leaves showing up as distinct notches around leaf edges near Roblin.
Suspected pea leaf weevil samples taken near Dauphin for identification on September 10. Leaf notching is indicative of pea leaf weevil feeding.
Field pea at V3 near Hamiota with notched leaf edges from adult pea leaf weevil feeding.
Pea Aphids
Field pea aphids with pink morphs near Portage la Prairie on July 27, 2022.
Check the closed uppermost stipule leaves for pea aphids.
Pea aphids clustered on a faba bean leaf on July 28.
Pea aphids tend to feed on the youngest leaf tissue. Unfold the clam leaf (newest stipule) to check for aphids.
