IR–4 Addresses MeBr Alternatives for Growers of Minor Crops

Growers of certain minor crops will face additional challenges to economic survival once methyl bromide is banned in the United States in 2005. Products available to these growers to protect their crops are already limited because more attention is being given to products that will protect major crops. This is because pesticide manufacturers sell more products for major crops than for minor crops. Minor crops are those for which the volume of pesticide needed is not enough to justify a manufacturer's cost to meet the regulatory requirements for registration by the Environmental Protection Agency (EPA).

But growers of these crops—which include vegetables, fruits, nuts, herbs, ornamentals, and nursery plants—have an advocate: IR–4. IR–4, the Interregional Research Project No. 4, is a joint program of the U.S. Department of Agriculture and the state agricultural experiment stations set up in 1963 to address the needs of minor-crop producers in the United States.

"One of our current primary goals is to help develop new products that can serve as methyl bromide alternatives for strawberries and tomatoes. These crops account for about 80 percent of the preplant use of this chemical in the United States," says Jack Norton, IR–4 special projects manager. "We've always helped growers of minor crops produce a plentiful supply of the high-quality fruits and vegetables that U.S. consumers have come to expect and at reasonable prices. And we've just formed a new technology team to ensure that concerns of minor-crop growers are considered during the priority-setting process used by companies in developing these products."

Representatives from USDA's Agricultural Research Service (ARS), land grant universities, private research organizations, agrichemicals industry, EPA, and crop producers participate in the IR–4 program. IR–4 is headquartered at the New Jersey Agricultural Experiment Station in New Brunswick. Because of this collaboration, IR–4 is composed of a unique, highly trained group of professionals who have the interests of minor-crop growers at heart.

"We're looking at new products that will control soilborne diseases, nematodes, and weeds, which minor-crop growers now control with methyl bromide. Through field trials, we expect to determine optimum use rates, use patterns, methods of application, and crop safety of new products that have shown potential as methyl bromide alternatives. Also, we plan to demonstrate the efficacy of some products already registered for use as alternatives to methyl bromide and to use them as standards for new products," Norton reports.

"Weed control—both for annuals and for perennials like yellow and purple nutsedge—is a critical part of the IR–4 methyl bromide alternatives research program," he continues. "One concern is that most of the products available as methyl bromide alternatives on strawberries and tomatoes don't adequately control weeds."

The new team is bolstering the development of halosulfuron for weed control in tomatoes and expects to run crop safety tests this year. Norton says that IR–4 is also working with EPA to register metolachlor and pendimethalin for controlling weeds in tomatoes. Although these herbicides can be used on other crops, they're not yet approved for use on tomatoes. "We're also working with a couple of companies to register glyphosate to control weeds in ‘Roundup Ready' strawberries," he reports. "If plant material is available, we'll probably begin field tests in the fall of 2000."

The companies, Monsanto of St. Louis, Missouri, and DNA Plant Technologies, Oakland, California, are also collaborating with IR–4 on developing transgenic strawberry plants that will tolerate glyphosate. Plans call for this approach to be combined with standard programs such as metam sodium and Telone.

New products planned for evaluation by IR–4 include Plantpro 45, a complex form of iodine from Ajay, North America; Dazitol, a natural product from Champon Natural Products, and Enzone (sodium tetrathiocarbonate) from Entek Corporation. "Our research will be funded by participating companies," Norton notes. "And the research will be done and field tests run in the U.S. production areas where most of the strawberries and tomatoes are grown: California and Florida. We're seeking input from ARS and land grant universities."

The programs are expected to be ongoing until 2005, with program redirections being made as new products, technologies, and concepts become available.

Through contacts with agricultural chemical companies, IR–4's new technology team becomes aware much earlier of products and combinations of products that may substitute for methyl bromide. Fluodioxonil is a good example of this, Norton says.

"Fluodioxonil controls root rot/vine decline of cucurbits like cucumbers, squash, cantaloupes, and watermelons in Texas, Arizona, and California. Novartis produces this product, and IR–4 can give high priority to developing it as a potential methyl bromide substitute," he points out.

Norton says that in addition to chemicals, IR–4 will incorporate cultural practices into its methyl bromide alternatives program. "We've been talking with Speedling, Inc., a company with nurseries in Florida, Maine, and California, about using plug versus bare-root strawberry plants. Plug plants usually establish more efficiently than bare-rooted plants. This would be a clear advantage if alternative fumigants are only marginally effective against certain soilborne diseases or nematode species."

Interregional Research Project No. 4 (IR–4)

IR–4 is made up of representatives from state agricultural experiment stations; U.S. Department of Agriculture's Agricultural Research Service and the Cooperative State Research, Education, & Extension Service; Environmental Protection Agency; and the agrichemicals industry. It is a grassroots organization, which allows pest management needs to be initiated by individual growers, grower groups, nurserymen, agricultural scientists, and extension personnel. IR–4 provides a network of state and federal liaison representatives throughout the United States, including the District of Columbia, Puerto Rico, Guam, and the Virgin Islands to help growers of minor crops. For more information, contact the headquarters office of IR–4 at the following address:

Jerry Baron, Assistant to the Director Center for Minor Crop Pest Management Technology Centre of New Jersey Rutgers, The State University of New Jersey, 681 U.S. Highway #1 South North Brunswick, NJ 08902–3390 Phone: (732) 932–9575, ext. 605; fax: (732) 932–8481.

Last Updated: April 9, 1999