Study targets effective pea leaf weevil strategies
Hector Carcamo Ongoing Research | Faba Beans and Peas | 2016, 2017, 2018, and 2019 | Yield
A large expansion of pea leaf weevil in 2015 made clear that pea and faba bean growers need better ways to deal with this insect.
It was the third week of April when Hector Carcamo saw his first pea leaf weevil of 2017, in his own garden.
For Carcamo, Lethbridge-based Research Scientist, Insect Pest Management, with Agriculture and Agri-Food Canada, the backyard appearance by this pest heralded the start of a busy research year.
With funding support from Alberta Pulse Growers, he’s now entering the second year of a three-year project to study the biology and management of pea leaf weevil in faba beans and field peas.
“In 2015, we saw a very large increase in the intensity and geographic expansion of pea leaf weevil,” Carcamo said. “There previously had been a mild winter, so they were able to overwinter. We counted pea leaf weevil in faba beans at both the pod and flowering stage.”
As Carcamo explains, this study’s first aim is to determine the impact of pea leaf weevil on nodulation and yield of faba bean. The project will also consider whether a foliar insecticide, insecticide seed treatment or both could be effective management strategies. Research plots in Lethbridge and Lacombe are the locations for this work.
“In order to develop a chemical management strategy, we have to look at the biology of the weevil,” Carcamo said, “and gather more information on its feeding and other practices.”
Peas or faba beans: which do weevils prefer?
Carcamo cites previous greenhouse research done elsewhere that showed pea leaf weevil appears to prefer faba beans to peas. If this could be confirmed, it could open up a viable management strategy. Growers could plant a strip of faba beans around a pea field; the insects might stay in the faba beans and steer clear of the peas. Based on his field observations from 2016, however, Carcamo’s now inclined to believe that weevils don’t favour one crop over the other. Work in 2017 and 2018 could change this view, however.
One year of field work has found it’s likely that seeding dates are highly relevant in weevil management. This could form the basis for agronomic recommendations for growers.
“We believe that seeding date can be a huge factor,” Carcamo said. “It’s very clear that peas or faba beans that are seeded earlier have more damage, so there may be an advantage to seeding them later.”
Whether the management strategies proposed by Carcamo involve cultural practices, insecticide application or other tactics, he maintains that growers need to deal with pea leaf weevil in an integrated manner. In the same spirit, this project involves scientists from multiple disciplines.
“Our number one objective in this project is to develop management strategies for pea leaf weevil in faba beans,” Carcamo said. “One should do this research in an integrated manner, making sure that what we do for one pest does not harm another component. We need to use the right tactic for the right pest.”
Project at a glance
Project title: Biology and management of pea leaf weevil in support of faba bean and field pea production
Project lead: Hector Carcamo, Agriculture and Agri-Food Canada
Total value of project: $105,562
Start date: March 1, 2016
Completion date: February 28, 2019