Does floral farmscaping really improve insect biological control in vegetable systems of the Coastal Plain?

View the project final report

• 2009 annual report
• 2010 annual report

Commodities

• Agronomic: buckwheat

Practices

• Crop Production: biological inoculants
• Education and Training: on-farm/ranch research
• Pest Management: biological control

Farmscaping (annual or perennial plantings in conjunction with target crops) to foster natural enemies of pests has great potential for agriculture and is increasingly popular in sustainable vegetable production, especially in the southeastern United States, where pest pressure can be particularly intense. However, there is little empirical evidence that floral farmscaping yields pest management benefits, although these benefits are often the primary purpose of such floral plantings. Indeed, farmscaping may expose the crop to increased pest problems. Decisions to farmscape and what to use in the farmscape are based almost entirely on anecdote and published lists of natural enemies attracted to flowering plants. The purpose of this project is to begin to fill a significant gap in our knowledge regarding farmscaping for pest management and to assess proof of concept for the southeastern United States. Our objectives are twofold: (1) to quantify the impact of floral farmscaping on vegetable pest management, and (2) to develop a database of arthropod natural enemies attracted to selected flower candidates for farmscaping in the southeastern United States. Specifically, we will determine how floral plantings impact pest and natural enemy populations in broccoli and cucumber, and assess the overall impact of the floral plantings on the yield and quality of these two vegetable crops in two geographic locations representing the southeastern United States (Athens in north Georgia’s Piedmont, and Tifton in south Georgia’s Coastal Plain). For Objective 1, we will survey and assess natural enemy and pest populations on selected farmscape elements (none, buckwheat, Asteraceae, Apiaceae) placed in the center of vegetable plots and the surrounding vegetable crop. We will also evaluate biological control efficacy and pest activity at distances of 2, 5, and 8 meters from the farmscaping section to allow us to evaluate spatial effects of the farmscape. For Objective 2, we will use portable floral plantings of various flowers placed in Athens, Tifton, Douglas (south central Georgia), and Sylvania (eastern coastal Georgia) to develop a database of the pest and natural enemy species attracted to the flowering plant species. This information will help to develop future focused farmscaping programs, and also ultimately (though not within the timeframe of this project) to develop an illustrated online field guide to arthropods attracted to flowers in this region. The results will help us develop directed farmscaping programs for use by vegetable producers that will foster natural enemies and discourage pests. Nearly all of the work on the project in the Athens location will be carried out by volunteer undergraduate student participants (from the University of Georgia’s (UGA) Organic Agriculture Certificate program), which will greatly reduce the project’s labor costs while providing hands-on opportunities for at least 20 students each year. In addition, four secondary science teachers will assist in carrying out the project, and will use this experience to develop related and relevant curriculum, extending the study into developing careers and into science classrooms. Field days will be used to extend the project to producers.

OBJECTIVE 1: Quantify the impact of floral farmscaping on vegetable pest management, specifically on biological control of arthropod pests by the full suite of naturally occurring enemies in broccoli and cucumbers. We will test several hypotheses to address Objective 1, based on the generally accepted, but unproven, ideas regarding farmscaping:
(1) Beneficial arthropod abundance and diversity will be greater in plots with floral farmscaping than plots without floral farmscaping, and furthermore, buckwheat will enhance abundance and diversity more than the other farmscape treatments because of its abundant nectar;
(2) Abundance and diversity of natural enemies will decrease with increasing distance from the central floral resource, and
(3) Biological control of arthropod pests will be enhanced when flower farmscaping is present in plots, and efficacy will decrease with increasing distance from the center floral resource.

We will characterize the density, species diversity and richness of pest and beneficial species in the agronomic crop and the farmscape, the rates of predation and parasitism of pests in the agronomic crops, and correlate the yield and quality of the produce with the overall pest abundance and damage. These data will permit us to test the outlined hypotheses, and assess mechanisms underlying the outcomes.

OBJECTIVE 2: Develop a database of arthropod natural enemies attracted to selected flower candidates for farmscaping in the southeastern United States. We will evaluate a selected suite of flowering plants for the pests and natural enemies they attract for future screenings in farmscape systems. These surveys will form the basis for development of an online field guide to arthropod natural enemies and pests attracted to various flowering plants. The field guide will be initiated with this project, but will require several additional years to complete.