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

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

Summary

The overarching purpose of our SARE project is proof of the concept of farmscaping in the southeastern United State using simplified cropping systems, with the intent to establish appropriate farmscape plantings.

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. Broccoli and cucumber were selected as model systems because (1) they are attacked by a suite of arthropod pests that is typical of vegetable crops (e.g., caterpillars, aphids, beetles), (2) they are not susceptible to many diseases that could confound arthropod studies, and (3) they represent crops widely grown in the southeastern United States in the spring and summer (crucifers and cucurbits). Following the three years of the proposed project, we will broaden our study to include other vegetable crops, integrating pathogen, weed, and economic components. In the short term, our studies will clarify the validity of floral farmscaping for insect pest management in vegetables, elucidate mechanisms of the interactions between flowering plants and natural enemies, and lay the groundwork for adapting such a system to vegetable production in the southeastern United States. Ultimately, our goal is to develop appropriate farmscaping systems that can be utilized by smallholders, organic producers, and conventional producers who desire to move toward more sustainable production systems.

The active field components of the project have only recently been initiated, and our activities are reported below. We have no results to report at this time.

Objectives/Performance Targets

Our objectives and their respective hypotheses are:
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.

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.

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.

We have only recently initiated the field studies and have as yet no data or conclusions to report (see below).

• Planted and irrigated 2010.JPG

Accomplishments/Milestones

We met with project participants in November to review the project and prepare for the field work to begin in 2010.

Preparation of land at the locations in Athens (University of Georgia Horticulture Farm) and Tifton (University of Georgia Tifton Campus Horticulture Hill Farm) was initiated in August 2009. Approximately half of the land to be used in Athens had several trees that were removed in late fall. Austrian winter peas were planted as a cover crop at both locations, but plantings were late due to delays caused by weather and land preparation. Austrian winter peas were planted in Athens in half of the land on 26 November 2009. Plantings in Tifton were completed on half of the land 4 December 2009 (20 lbs of seed per acre). The other half was planted on 5 January 2010.

Broccoli transplants (var. ‘Windsor’) for the project were prepared by 19 students in the “Organic Agricultural Systems” (AESC3125) class at the University of Georgia, Athens. The students also assisted in preparing flower transplants and in land preparation. These activities were built into their class curriculum to give them hands-on experience with organic production.

Broccoli transplants were transported to Tifton and planted on 22-23 March 2010 and drip irrigation was installed. Yarrow, fennel, and dill were transplanted into the plots on 1 April. Buckwheat and sunflowers will be transplanted in approximately two weeks (ca. 15 April). The broccoli in Athens will be planted next week, and drip irrigation installed at that time. Flower transplants will follow approximately two weeks later. Pitfall traps are currently being prepared and will be placed in the field in Tifton in two weeks (ca. 15 April). They will be placed in Athens in approximately four weeks (end of April). A beet armyworm colony has been established in Tifton and is producing large numbers of eggs in preparation for placing sentinel egg masses in the plots when insect sampling starts. Additional floral plantings (phacelia, coreopsis, cilantro, pulchella) have been initiated in large portable planters (36” long by 24” wide by 8” deep) in Athens and will be moved to Tifton, Sylvania, and Douglas in about three weeks to monitor for insect activity on the flowers.

A graduate student (PhD) has been hired to coordinate the project and he is making good progress with his training to carry out all of the various aspects of the project (agronomic, photographic, taxonomic, statistical). We will soon begin reviewing applicants for the secondary ed science teachers to be selected to participate in the project as part of the Georgia Internships for Teachers (GIFT) program. One teacher will work in Athens and one in Tifton in 2010, and they will each develop science curriculum materials from the project to enhance their science instruction in the classroom. An intern student will soon be hired to work on the project in Athens for spring and summer of 2010. A student in the UGA Masters in Plant Protection and Pest Management Program will be a part-time intern in Tifton for the project in 2010.

The start of the project in the field was significantly delayed by prolonged inclement weather. We also were compelled to reduce the plot size for the vegetable plantings from 20×20 meters to 12×12 meters due to increased expenses of the project and some land challenges. Nevertheless, we are confident we will obtain valuable data.

Impacts and Contributions/Outcomes

Have integrated 19 undergraduate students and 1 graduate student into the project to date, giving them experience in organic vegetable production. No other impacts to report as yet.

Collaborators: