First present in Canada in southern Alberta within the Nineties, the pea leaf weevil is constant to increase its territory to the east.
The invasive pest whose larvae feed on the rhizobia in nitrogen-fixing root nodules has since unfold throughout many of the pea-growing areas of Alberta and Saskatchewan. It was first detected in Manitoba, within the Swan River Valley, in 2019.
“Final fall we did a giant survey push going into these pea crops post-harvest, we collected some weevils, and we confirmed that they’re fairly widespread in western Manitoba,” says Laura Schmidt, manufacturing specialist with Manitoba Pulse and Soybean Growers, on this Pulse College episode.
If it wasn’t already, agronomists and producers in southwest and central Manitoba ought to have pea leaf weevil and the telltale hole-punch leaf notching that it causes on their radar.
“Primarily based on some local weather modelling throughout the Prairies, Manitoba falls within the beneficial to very beneficial class. So whereas inhabitants numbers have been declining in Alberta and Saskatchewan from the dry climate, we’ve obtained plenty of moisture to work with right here in Manitoba. We’re more likely to see this inhabitants enhance slightly bit. So we need to hold an eye fixed out.
As of this summer season, pea leaf weevil’s presence was confirmed “just about wherever west of Freeway 34 in Manitoba,” says Schmidt. “If we’re within the central area, and we’re seeing leaf notching, that’s the place we need to give myself or (Manitoba Agriculture entomologist) John Gavloski a name so we are able to get some extra data. Have we seen an expanded vary? Or is that this one of many different weevil species that we’re not so involved about?”
There are foliar pesticides registered for pea leaf weevil, however Schmidt says they are often ineffective for a number of causes: adults which might be managed by spraying have already laid eggs, and there will be a number of migrations right into a discipline.
An insecticide seed remedy is usually a more practical management possibility, she says, as it could possibly delay larval growth, however on the similar time, Schmidt says there might not be an financial return on utilizing a seed remedy.
A lure crop, akin to faba bean, which stays inexperienced a later into the season than peas, can also be an intriguing idea, she says. “As soon as that pea crop comes off and is harvested, all of these newly emerged, grownup weevils would transfer into that strip of faba beans…After which you may management them once they’re all concentrated in that faba bean strip earlier than they moved to overwintering websites.”
Try the Pulse College video above — filmed on the 2022 Manitoba Crop Diagnostic College — for extra on pea leaf weevil’s transfer east, tips on how to scout for the pest, and potential choices for managing it.