Cover crops for flea beetle management

Project Summary

Background

Flea beetles are the most important insect pest of canola on the Canadian Prairies. Currently, flea beetles are primarily managed using insecticides, both as seed treatments and in-crop foliar applications. Since insects regularly adapt to insecticides and there can be deleterious effects of insecticides in the environment and in non-target species, it is crucial to develop alternative techniques.

Cover crops are a promising management strategy that provide multiple benefits to cropping systems, including improving soil health by increasing erosion control, water quality, soil moisture retention, accumulation of soil organic matter and microbial biomass, and increasing pest control and crop yield. It is an important time to evaluate if cover crops can contribute to integrated pest management strategies for flea beetle management in canola.

During the 2021 growing season, a few farmers and agronomists in Western Canada shared on social media their observation that flea beetle damage was lower when canola was direct seeded into rye cover crops. Building on these observations, a preliminary experiment in 2020, and knowledge for the published literature on the contributions of intercropping and crop residue to reduce flea beetle damage in canola, this project will evaluate the impact of fall rye and oat cover crops on flea beetles and their natural enemies in canola.

Objectives

The specific objectives of this project are:

1. Evaluate the impact of overwintering and spring planted cover crops on flea beetle damage to canola seedlings.
2. Quantify the impact of overwintering and spring planted cover crops on canola yield and quality.
3. Evaluate the impact of overwintering and spring planted cover crops on the abundance of ground predators known to provide biological control of flea beetles.
4. Compare cover crop management strategies (cover crop species, termination date, seeding rate) to maximize flea beetle control while minimizing negative canola crop impacts.
5. Evaluate the effectiveness of the most promising cover crop strategies for flea beetle control in on-farm experiments.

Potential impact

Using new management tools to control flea beetles in canola will be crucial to ensure sustainable production of this crop in the future. Pairing small plot research experiments with on-farm testing will help evaluate how the most promising cover crop treatments for this new practice could scale up for deployment on commercial farms.