Supporting Natural Enemies of the Cabbage Aphid with Hedgerow Plantings

View the project final report

Commodities

• Vegetables: greens (leafy), kale

Practices

• Education and Training: demonstration
• Natural Resources/Environment: hedgerows
• Pest Management: biological control

Our project seeks to expand the adoption of Conservation Biological Control practices for aphid
management on vegetable farms in northern Utah and the Intermountain West. Most farmers in
the region are faced with significant hurdles in learning and upfront costs required to implement
such practices. Aphid control is a fruitful “introduction” to Conservation Biological Control as
aphids have many natural enemies, and are a persistent problem for vegetable growers. Cabbage
aphid problems in particular have increased in recent years, as more farmers in the region grow
kale and other brassica crops year-round to meet customer demand.
Our project will establish aphid-control hedgerows at six farms, four of which will be used as
demonstration sites. Hedgerows at three sites will be evaluated for their potential to attract
natural enemies of cabbage aphid and to reduce aphid damage to cole crops, using associated
control plots (without hedgerows) for comparison.
Education and outreach components of the project focus on building knowledge and visibility of
Conservation Biological Control practices at the grassroots level, and on making connections
between Master Gardeners, urban farmers, and established vegetable growers on larger acreages
to share their experience with Conservation Biological Control in our region. We will extend
Conservation Biological Control education and the results of this study to growers throughout
the Intermountain region with USU Extension publications.
Our project attempts to lower the barriers to adoption of Conservation Biological Control
practices by emphasizing 1) economic-yielding hedgerow plants that increase profitability (via
sales of culinary or medicinal herbs, seeds, or bouquets), 2) flexibility of hedgerow
implementation using a 4-component design for demonstration hedges, each component a standalone
border, and 3) the multiple resource conservation possibilities to meet other challenges on
the farm (e.g., reducing soil erosion, filtering runoff, preventing weed encroachment).

Objective 1. Evaluate whether hedgerows attract natural enemies of cabbage aphid

Objective 2. Evaluate whether fewer cole crops reach economic loss thresholds with
hedgerows

Objective 3. Use established hedgerows and outcomes of this study (Objectives 1 and 2) to
support broader education goals with Conservation Biological Control through
Master Gardener program and Urban/Small Farms Conference.

Objective 4. Encourage grower-to-grower information exchange regarding Conservation
Biological Control with grower field days.