Managing Agricultural Drainage Ditches for Conservation Biological Control on the Delmarva Peninsula

View the project final report

Commodities

• Agronomic: soybeans
• Vegetables: cabbages

Practices

• Crop Production: drainage systems
• Education and Training: on-farm/ranch research
• Pest Management: biological control, integrated pest management
• Production Systems: agroecosystems

1) Problem, Novel Approach and Justification.

Agricultural drainage ditches serve a necessary function for water management on all farms. Especially for the flat Delmarva Peninsula (coastal plain portions of Delaware, Maryland, and Virginia) and portions of New Jersey, ditches are necessary to drain the high water table during the year. In addition, ditch habitats may also provide valuable ecosystem services to producers by enhancing natural enemies of pests and increasing their biocontrol. More broadly, ditches serve as examples of how uncultivated land in and around fields can provide ecological benefits. The goal of this proposal is to determine how to manage ditches to enhance populations of natural enemies, and to work with farmers to test management methods on farms.

2) Hypothesis and Research Plan.

The hypotheses are that ditches can be managed to increase numbers of natural enemies and to increase their biocontrol of pests in adjacent fields. The objectives are designed to complement each other and will be conducted over three years. During Year 1, we will focus on testing specific management practices to help determine which practices applied to drainage ditches will enhance natural enemies. Experiments will be conducted primarily on University farm ditches. During Years 2 and 3, we will test management practices as a way to enhance natural enemy populations and performance in ditches and adjacent crops. Experiments will be conducted on University and private farms. At the whole farm scale, the final objective will be conducted using two ditches on each of five farms, over three years of sampling, to determine if ditch management does indeed enhance natural enemies and suppress pest populations by biocontrol.

3) Outreach Plan.

Results from Objectives 1 and 2 will be delivered to farmers participating with Objective 3 as ditch modification practices are discussed and selected. Additionally, pamphlets detailing beneficial arthropods, pests controlled by them, and the habitats that favor beneficial arthropods will be produced and disseminated to farmers, extension personnel, and conservation groups. Project performance will be highlighted at other in-season events, such as research field days. Websites will be used to disseminate video clips, project summaries, and photographs of ditch management methods and natural enemies. Results will be shared at winter meetings, and project briefs will be prepared for trade journals.

4) Project Objective.

Our specific objectives include 1) to conduct experiments designed to enhance populations of natural enemies (e.g., spiders, predatory mites and beetles, and parasitoid wasps) in ditches by providing resources for shelter, food, and reproduction, 2) to compare natural enemy performance in ditch habitats and adjacent crop fields across a range of habitat conditions, and 3) to use ditches on farms to demonstrate the value of this enhancement of natural enemies for pest management.

Our objectives are 1) to conduct experiments designed to enhance populations of natural enemies (e.g., spiders, predatory mites and beetles, and parasitoid wasps) in ditches by providing necessary resources for shelter, food, and reproduction, 2) to compare natural enemy performance in ditch habitats and adjacent crop fields across a range of habitat conditions, and 3) to use ditches on farms to demonstrate the value of this enhancement of natural enemies for pest management.