Biological and Cultural Methods of Insect Management in Vegetables: Survey and Case Studies of Organic Farms and Evaluation of the Scientific Literature

Biological and Cultural Methods of Insect Management in Vegetables: Survey and Case Studies of Organic Farms and Evaluation of the Scientific Literature

Summary

Summary
This project brought together farmers, scientists, and farm advisors in a conference to discuss alternatives to insecticides for managing vegetable insects. The first day we discussed broad topics: the effects of plant and soil health on plant susceptibility to pests, the principles of biological control, using crop diversification to encourage biological control, and strategies and tactics used by organic farmers. The second day we discussed application of these principles to specific vegetable crops and pests. The proceedings of this conference have been published as a book and as a website on the Internet.

Objectives:
To bring together a small group of farmers and scientists in an exchange of research results, ideas, and questions about biological and cultural methods of insect management in vegetables.
To make the information exchanged available to farmers, farm advisors, researchers, and others as a book and an Internet website.

Methods
The principal investigator (PI) identified farmers with information to share about alternative insect management from lists of SARE farmer research projects, participants in the previous farmer/scientist conferences in Massachusetts, and contacts in organic farming organizations. In the invitation to the conference, farmers were asked what information they could share and what insect problems they wanted more information about. The PI designed the conference around their answers and invited scientists either with expertise that would supplement farmers’ information on a particular topic, or scientists with experience with an insect problem the farmers wanted to solve.

The conference was intended to be small—with fewer than 40 people—in order to encourage participation from everyone present. Everyone—whether a farmer, a scientist, or an extension agent—either made a presentation or moderated a session. Sessions were recorded on audiotape and volunteers also took written notes.

Results
The farmer/scientist conference on Alternatives to Insecticides for Managing Vegetable Insects met on December 5 and 6, 1998, in New Haven, Connecticut. Attendees addressed general principles on the first day, including the effects of soil and plant health on susceptibility to pests, the role of crop diversification in insect management and encouraging biological control, and the history and current practice of biological control.

On the second day, small-group sessions addressed insect management in related groups of vegetable crops, specifically corn, the cabbage family, the Cucurbitaceae (squash, pumpkins, cucumbers, and melons), the Solanaceae (potatoes, tomatoes, peppers, eggplant), and beans. At the same time, small groups also addressed two key insect pests that move among crop species, the potato leafhopper and the tarnished plant bug.

The book, Alternatives to Insecticides for Managing Vegetable Insects: Proceedings of a Farmer/Scientist Conference (NRAES-138) was published in early December of 1999. By September 30, 2000, it had sold 410 copies. The web site went online on November 22, 2000. The address is www.state.ct.us/caes/AlternativestoInsecticides/alterna-tives.htm

Impacts
Because this conference addressed insect pests in many different vegetable crops, and because the information offered at the conference was at various points along the way between basic research and farmer adoption, it is difficult to quantify the potential contributions.We can say the following:

Number of contacts: There were 23 farmer/participants at the conference and 14 who made presentations. There were also many people who spread information in a variety of other ways: three Cooperative Extension educators, three researchers who also have extension appointments, two private agricultural consultants, two technical advisors to organic farming organizations, and six farmers who also write books and articles about agriculture. Letters from two farmers who were participants were attached to the 1998 annual report, and excerpts from those letters and four others are attached here, along with a letter from the president of the Connecticut chapter of NOFA that praises the conference and book.

Influence on other research and extension efforts: The Organic Farming Research Foundation has expressed interest in using this conference as a model in their program of farmer/scientist exchange (Scientific Congress on Organic Agricultural Research).

At the conference session on corn, Ruth Hazzard presented a biointensive program for management of caterpillars in fresh market sweet corn that provided commercially acceptable levels of control using only Bacillus thuringiensis (B.t.) and direct application of vegetable oil to the corn silks. Steve Mong, a farmer collaborator on the project, also presented his experience with Ruth’s project. Dr. Michael Hoffmann presented his work with inoculative releases of Trichogramma ostriniae. Since the conference, these projects have expanded to include cooperators in other states in the Northeast (see the letter from farmer Kathy Caruso, attached), and a combination of these two biological approaches is developing.
Similarly, multi-state collaborative projects involving on-farm research have developed to work on biological control of Mexican bean beetle (Maryland and Connecticut) and on the biology and management of crucifer flea beetles (New York, Connecticut, and Massachusetts).

Areas Needing Additional Study
Perhaps the major benefit of this project will be in identifying areas needing additional study. Here are some of the questions identified by participants in the conference:

What are indicators of soil health and plant health (other than absence of insect pests and disease)? Would we measure the balance of fungi and bacteria in the soil? The amount and form of nitrogen in the plant tissues?

How can the principles of no-till or minimum tillage, which clearly have benefits in building soil organic matter, be adapted to the needs of organic farmers and other farmers who want to reduce the use of herbicides?

What specific elements (plants or practices) are most effective in providing supplemental food of nectar and pollen and habitat for useful natural enemies of insect pests?

How can products of research be made available to farmers more rapidly? Two examples are the “zea-later” device for applying oil to the corn ear for control of corn earworm and the “TIC” lure (made from a mixture of three naturally-occurring chemicals) that doubles the trap catch of striped cucumber beetles. Other examples could be drawn from the realm of biological control, where the possibilities of using natural enemies in augmentative or inoculative releases have been demonstrated, but the natural enemy is not commercially available.

What are the possibilities of using weeds or other plants commonly found in the Northeast—or plants farmers could grow—as sources of insect repellents or as herbal treatments to produce healthy crop plants and domestic animals?

How can weather and seasonal phenology be put together in a form more useful to farmers? What kinds of records of weather and seasonal phenomena are farmers already keeping? How are they using that information to time their actions in the field? We need monitoring methods for natural enemies in relation to pest populations, so that we can predict when the pest population can be left alone because biological control is working well.

For potato leafhoppers: Could an early warning system be established to alert northern growers to unusually high numbers or favorable weather for migration of leafhoppers as they move into the Northeast each year?

For crucifer flea beetles: Are they a significant pest in Eurasia, where they originated? What natural enemies are present in other parts of the world that could be brought here as biological control agents?

For tarnished plant bug: Does the level of parasitism in alfalfa result in declining populations across the Northeast? Does it result in lower abundance of these insects and their damage in vegetable, berry, and fruit crops? What can be done to increase the effect of these parasites? Is there some way to provide host reservoirs and overwintering sites for the parasites without increasing the population of tarnished plant bug?

For Mexican bean beetles: An artificial diet for raising Mexican bean beetle would decrease the cost of production of the parasite Pediobius foveolatus. We also need information on the timing of release of these parasites and release rates necessary to get control of Mexican bean beetle earlier in the season in snap beans.

Outreach and Dissemination
The book itself is an important form of outreach, and 410 copies were sold in the first 9 months after publication. Material from the book has also appeared in other publications. The first article based on the conference actually appeared before the book, a story about flea beetles in the New York Times by conference participant Cass Peterson . The newsletter of the Mountain State Organic Growers and Buyers Association (an organic farming group in West Virginia) was given permission by NRAES to reprint a series of sessions from the conference in their newsletter. Growing for Market printed an excerpt from Eero Ruutilla’s presentation on using straw mulch to manage Colorado potato beetles along with their review of the book. The Natural Farmer also published, along with their review, two tables from the book, one a summary of organic methods used for insect management, and one cross-listing insect natural enemies found in corn and their hosts or prey. Other publications such as Hortideas and SARE 2000 Highlights printed notices about the book. The website just went online recently, so it is too soon to measure its popularity or impact.

Reported November 2000

Collaborators: