Establishing and Evaluating Selected Cover Crops on Small Farms to Increase the Impact of Beneficial Arthropods on Crop Pests

Final Report for OS13-079

Project Type: On-Farm Research
Funds awarded in 2013: $14,984.00
Projected End Date: 12/31/2016
Region: Southern
State: Florida
Principal Investigator:
Robert Hochmuth
University of Florida
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Project Information

Abstract:

This on-farm research project demonstrated how to deploy cover crops as strip or trap crops on operating farms about 10 miles from the Suwannee Valley Agricultural Extension center to increase the species and populations of beneficial arthropods. Strip plantings of selected annual cover crops, such as buckwheat, sunflower, rye, triticale, and sunn hemp were established on two farms, but there was an emphasis on buckwheat. On the Hoover farm, strips of buckwheat were planted within tomato fields. On the Rooney farm, Strip crops were planted in drive rows and around the perimeter of the 5-acre blueberry field at the Rooney farm. Collections were made in both strip and cash crops to determine the composition and abundance of pest and beneficial insects. A total of 41 families of insects were collected at both farms; however, an additional 20 families occurred at the Hoover organic vegetable farm. The major pests of tomato were the stink bugs, Nezara viridula, Euschistus quadrator, Thyanta custator custator, and Oebalus pugnax pugnax. All four species were parasitized by unidentified tachinids. Piezodorus guildinii was relatively abundant in the buckwheat. The types and abundance of beneficial arthropods that parasitize or prey on arthropod pests were identified. Cooperators at both farms received training at SVAEC in whole farm pest management practices. It is intended that these “first-adopters” will influence other small-holder specialty crop farmers to plant cover crops to reduce the use of chemical insecticides, protect the environment and increase profits.

Introduction

Sustainable agriculture in the South is increasingly practiced on small farms with limited resources by farmers who live on the farms and therefore are committed to enhancing environmental quality and conserving natural resources. This situation requires that farms be economically viable, preserve the natural resource base, and enhance the quality of life for the farmers and their families. Moreover, both large and small farms play an important role in supporting the competitiveness and sustainability of U.S. rural economies.

Southern farmers continue to face many challenges, including marginal profitability and uncertain economic security. One key production challenge for farmers in the South is the cost of effectively managing the myriad of pests that infest their crops. Southern farmers must combat many insect pests, diseases, and weeds almost year-round. In particular, Florida is at risk of agricultural loss by invasive pests due to its expansive tourism industry (84 million visitors a year) and multiple ports of entry. Hurricanes also have been blamed for introducing a number of economically important invasive pests into the Gulf States (Florida, Alabama, Louisiana, Mississippi, and Texas), and the region’s warm and humid climate is favorable for pest establishment.

To support southern farmers’ efforts to manage pests sustainably, a unique, hands-on, whole farm “Living Extension IPM Field Laboratory” has been created at the University of Florida, Institute of Food and Agricultural Sciences (UF/IFAS), Suwannee Valley Agricultural Extension Center (SVAEC) with support from the USDA, NIFA EIPM-CS and the UF/IFAS Extension programs. This specialized IPM learning environment is used continuously to demonstrate how to enhance agro-ecological systems for specialty crop farmers and other clientele groups by adopting a diversity of beneficial cultural and ecological practices to minimize the use of chemical pesticides. Small farm specialty crop producers in the region have participated in training workshops at the SVAEC and wanted to implement some of the sustainable IPM practices on their farms but required assistance in selecting appropriate cover crops and monitoring their impact on pest abundance and crop yields. The practice of particular interest to the farmers was the use of cover crops to provide habitat for native beneficial arthropods but these practices had not been tested or demonstrated on small private farms in the region. This project was designed specifically to help them manage pests in fruit and vegetable crops by demonstrating and communicating the use of cover crops to create habitats for beneficial arthropods.

Project Objectives:

This on-farm research project was designed to demonstrate how to deploy cover crops on operating farms so that the species and populations of beneficial arthropods will be increased. We taught farmers how to increase their skill in identifying beneficial arthropods that are attracted to cover crops and how to maintain and enhance these populations on the farm year-round. Strip plantings of cover crops, e.g., selected annual cover crops, such as buckwheat, sunflower, rye, triticale, sesame, sunn hemp and others, were located on both farms, but there was an emphasis on buckwheat cover crop strips. Specific objectives for this on-farm research were as follows: 1. Plant low maintenance annual strip and trap crops at strategic locations in association with cash crops on two small farms to provide a variety of cost-effective, sustainable ecological services from native parasitoids and predators. 2. Periodically collect, identify and count all of the beneficial arthropods in the strip and cash crops, and curate a representative sample as a resource for training farmers, technicians, and students. 3. Conduct training events for small holder farmers, such as field days and UF/IFAS Small Farms Academy (SFA) workshops to present research results and provide additional information on the benefits of using cover and strip crops.

Cooperators

Click linked name(s) to expand
  • Bradley Hoover, Jr.
  • Dr. Norm Leppla
  • Scott and Billie Rooney
  • Elena Toro
  • Dr. Danielle Treadwell

Research

Materials and methods:

The research on strip and trap crops was conducted on two very different family farms near the SVAEC, the Hoover and Rooney farms. For the buckwheat strip crops, seeds were planted using a seeder from the farms or a small no-till drill from SVAEC. The buckwheat was established using best management practices for fertilizer, irrigation and weed management on the two farms. Trials previously conducted at SVAEC showed the importance of providing adequate water and fertilizer (300 lbs/A of 13-4-13) for buckwheat plots in the dry, deep, sandy soils typical of the Suwannee Valley. The strip crop plots were planted beginning in summer 2014 following a schedule that provided habitat year-round. This strategy was essential to maintain beneficial arthropod populations at high levels because they need pollen and nectar sources as well as physical habitat. The strip crop plantings on these farms provided habitat for several beneficial arthropod species that parasitize or prey on the target pests.

The Hoover Farm is a small, diversified certified organic vegetable farm. Vegetables grown on this farm, e.g., squash, cucumber, pepper, tomato, eggplant and leafy greens, are primarily sold to wholesale markets in the area. Primary insect pests identified by the Hoovers at the start of the project included: stink bugs, thrips, aphids, corn earworm, armyworm species, and silverleaf whitefly (fall only). Three sets of buckwheat strips were established between rows of tomato plants in a 7-acre field, so that a 10-ft strip of buckwheat alternated with 10 feet with no strip. Insects were collected weekly beginning in the spring from the strip crop, adjacent cash crop, and cash crop without the buckwheat strip. Ten sweep net samples were made in the center of each buckwheat plot and the adjacent cash crop, and in the crop without an adjacent buckwheat strip. The arthropods from each sample were placed in a plastic bag, transported to the UF/IFAS Entomology and Nematology Department for identification to species, if possible. Otherwise the taxonomic family was noted or type of arthropod, e.g., spider. A representative sample of the arthropods was preserved and retained at SVAEC. Data on the relative abundance of pest and beneficial arthropods in the plots was recorded.

The Rooney Farm is a blueberry farm with the primary insect pest prior to this project being a stink bug complex, including leaf-footed bugs. It is primarily a U-Pick berry farm and signage was used to educate the berry pickers about the wide variety of IPM strategies being used or tested on the farm. The Rooney’s simultaneously evaluated buckwheat strip plantings to increase beneficial invertebrate populations, and stink bug trap cropping systems. There is no idle land because blueberry and blackberry are permanent plantings, so strip crops were planted in drive rows and around the perimeter of the 5-acre field. Ten sweep net samples were made weekly in the center of each strip to determine the presence and abundance of pests, parasitoids and predators. Based on three prior years of observations and monitoring beneficial arthropods in such plantings, the populations increase very quickly, within one year from establishing the habitat areas. Both the Hoover and Rooney farms served as demonstration sites for farmers, allied industry representatives, and agency staff in the region. The two cooperating farmers fully participated in the project and served as first adopter leaders to encourage other farmers to adopt strip crops.

Research results and discussion:

Beneficial arthropods commonly found on both farms included lady beetles, a diversity of parasitic wasps, big eyed bugs, spiders, assassin bugs, minute pirate bugs, lacewing larvae, syrphid fly larvae, and many species of native pollinators. Families of insects at both the Rooney and Hoover farms included Orthoptera: Tettigoniidae, Acrididae, and Gryllidae; Hymenoptera: Formicidae, Scoliidae, Vespidae, Tiphiidae, Apidae, Crabronidae, Thynnidae, Pompilidae, Mutillidae, Halictidae, Platygastridae, and Megachilidae; Lepidoptera: Noctuidae; Diptera: Phoridae, Syrphidae, Bibionidae, and Dolichopodidae; Coleoptera: Chrysomelidae, Corylophidae, Carabidae, Mordellidae, Scarabidae, Curculionidae, and Cantharidae; Hemiptera: Pentatomidae (Asopinae), Cicadellidae, Miridae, Lygaeidae Dictyopharidae, Membracidae, Geocoridae, Cicadellidae, Cydnidae, Anthocoridae, Alydidae, and Coreidae; and Odonata: Corduliidae and Libellulidae. There also was an abundance of spiders. Additionally, the Hoover farm had families of vegetable pests and associated natural enemies, such as Diptera: Calliphoridae and Tachinidae; Hemiptera: Berytidae, Flatidae, Blissidae, Fulgoridae, Reduviidae, Pentatomidae, Nabidae, and Cercopidae; Thysanoptera: Thripidae; Hymenoptera: Braconidae and Chrysidae; Neuroptera: Ascalaphidae; Odonata: Coenagrionidae; Coleoptera: Anthicidae, Staphylinidae, and Cerambycidae; Blattodea: Blattelidae; and Lepidoptera: Geometridae. Stink bugs the primary pests of tomato at Hoover farm were collected as both nymphs and adults: Nezara viridula, Euschistus quadrator, Thyanta custator custator, and Oebalus pugnax pugnax. All four species were parasitized by unidentified tachinids. It was confirmed on this farm that an orange tachinid fly that is reported to attack stink bugs was attracted to the blooming stage of buckwheat. The eggs of this fly were found on stink bugs collected from the research plots. The stink bug, Piezodorus guildinii was relatively abundant in the buckwheat. Stink bugs were identified as the primary blueberry pest at the Rooney farm, so special emphasis was given to stink bug trap cropping using triticale. Approximately four insecticide applications were made only to the triticale in the early spring of 2015, thus eliminating any need for insecticide applications to the blueberry crop.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

Using Cover Crops for Pest Management on Small Farms for Final Report Cover Crop Workshop Flyer_Revised 05_15_15SARE Press Release, Title: Using Cover Crops for Pest Management on Small Farms Author: Candace Pollock (cpollock@uga.edu), Date Released: 06/27/2014 http://www.southernsare.org/News-and-Media/Press-Releases/Using-Cover-Crops-for-Pest-Management-on-Small-Farms

Project Outcomes

Project outcomes:

This on-farm research project supported several Southern SARE priorities, primarily “Beneficial Insect Habitat,” “Organic Agriculture” and “Increasing Sustainability of Existing Farming Practices.” It will help to make agriculture in the South more sustainable by quantifying and delivering sustainable strip crop capabilities for enhancing beneficial arthropods primarily on small diversified farms in Florida and other southern states. Sustainability of southern farms can be increased by enhancing native populations of beneficial arthropods and increasing the ecological services provided by implementing whole farm IPM strategies. The benefits of using sustainable strip and trap crops on small farms in the Suwannee Valley has been proven at SVAEC and local farms, and is ready for adoption by cooperating farmers. The ongoing use of strip crops at University of Florida, SVAEC has transformed unsustainable pest management practices from weekly pesticide applications to infrequent spot treatments based on scouting and pest thresholds. This remarkable conversion resulted in more than a 50% reduction in insecticide applications on the 300-acre farm. Not only was there a reduction in insecticide applications, but selection of low-risk pesticides protected the beneficial arthropods. The IPM training through the UF/IFAS Small Farms Academy was offered in June, 2015, and will continue. Cooperators from the Hoover and Rooney farms shared their experiences as a part of the trainings and hosted tours for the participants as well. An evaluation of the cover crop workshop held in June, 2015 was conducted with 35 respondents. A pre and post test questionnaire was used and showed an increase in knowledge about cover crops of 30 %, from an average score of 38 to 68%. As a result of attending this workshop, 91% indicated they plan to adopt the use of cover crops on their farm, and 86% indicated they were somewhat or very confident they had learned how to manage the cover crops properly. Attendees indicated the top three benefits of them adopting cover crops on their farms included: improved pest management, improved weed control, and improved soil health.

Economic Analysis

This project had no formal economic analysis.

Farmer Adoption

Hoover Farm During the two years of this study, stink bugs and leaf-footed bugs were by far the most damaging insect pests on this farm. Buckwheat strip cropping was difficult to implement and several planting strategies and locations within the tomato crops were tested. In the final test, the farmer decided to plant one extra mulched buckwheat bed with drip irrigation as the center bed in a six-bed block of tomatoes. Although this was a more expensive strategy, it was adopted because all other buckwheat planting systems performed poorly due to weed pressure. Because the Hoovers needed to spray the test areas for stink bugs, it was difficult to document the impact of the buckwheat strips on the immediately adjacent vegetable crop. However, the Hoovers observed consistently high beneficial insect populations in the buckwheat and have proposed a new strategy for increasing the use of buckwheat strip cropping on their farm. The Hoovers’ believe that having larger plots of buckwheat, as close to year-round as possible; will maintain a much higher resident population of beneficial arthropods. Therefore, larger blocks of solid planted buckwheat have been adopted within the overall farm cover cropping strategy. The current cover crops being implemented at Hoover Farms includes: rye as a winter cover crop, sunn hemp as a summer cover crop for soil building, and buckwheat to support predators and parasitoids. All of these cropping systems have been adopted as a result of this project and associated University of Florida Extension activities. Rooney Farm Buckwheat strip crops complimented the pre-existing wildflowers planted on the Rooney farm to increase beneficial insects, including native pollinators. The Rooneys confirmed that buckwheat plantings caused these increases, as high populations of beneficial insects were commonly noted in the bloom stage of the buckwheat. However, these increases could not be correlated with a reduction in blueberry pest populations. This was partly due to the overall low pest pressure in the blueberry crop, other than the stink bug complex. The Rooneys have adopted planting buckwheat strips on their farm to increase beneficial arthropods and triticale as the primary trap crop to eliminate stink bugs that arrive early in the season. This system worked so well for the Rooney’s, they have fully adopted using a triticale trap cropping system on their farm.

Recommendations:

Areas needing additional study

Additional studies are needed on the relative size of buckwheat strip crops required for a specific area of cash crop. A more intensively managed system of trap crops will be necessary due to the high stink bug populations and limited number of effective organic insecticides available. The Hoovers observed the potential of both sunflower and triticale as effective trap crops for their farm, but work is still needed on the most effective trap cropping strategy.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.