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The IR-4 Project: Supplying Pest Management Tools for Specialty Crops for Over 40 Years

David Thompson
Plant Pathology Coordinator
Michael Braverman Biopesticide Manager
Sherrilynn Novack PR/Communications
Cristi Palmer Ornamental Horticulture Program Manager

IR-4 Headquarters
Rutgers University
681 US Highway 1 South
North Brunswick, NJ 08902

(Corresponding author:
Thompson, D., Braverman, M., Novack, S., and Palmer, C. 2006. The IR-4 Project: Supplying Pest Management Tools for Specialty Crops for Over 40 Years. Online. APSnet Features. doi: 10.1094/APSnetFeature-2006-0606

For over forty years, the Interregional Research Project #4 (IR-4 Project) has been the major resource for supplying pest management tools for specialty crops by developing research data to support registration clearances.

Traditionally, agrichemical companies conduct only limited research on specialty crops. This results in few pest management options being labeled for specialty crop growers. In 1963, the Land Grant Universities recognized this need and established the IR-4 Project to provide a means for U.S. growers to have specialty crops included on pesticide labels. The success of the IR-4 Project, with additional USDA funding, is proven and can be measured in its development of data to support nearly 20,000 food use and ornamental horticulture label clearances.

Specialty Crops

Specialty crops include plants grown for human consumption and for use in ornamental horticulture.

Food Use Ornamental Horticulture
Fruits Nursery
Vegetables Greenhouse
Herbs Christmas trees
Nuts Landscape
Spices Sod Farms

Even though these crops are classified low acreage, their value is substantial. They make up about 46% of U.S. agricultural crop production and $43 billion in sales. Specialty crops are grown throughout the U.S., and twenty-six states derive more than 50% of their agricultural crop sales from specialty crops (Fig. 1).


Fig. 1. Value of specialty crops across the United States. Source: 2002 Census of Agriculture United States Summary Table 56.


Priorities and New Technologies

IR-4 uses an extensive stakeholder driven process to prioritize research to ensure that it is focusing on the most critical pest management needs of specialty crop producers. The IR-4 website ( is a good source of information about past and present projects. IR-4 receives requests for projects through a Project Clearance Request (PCR). Except for the chemical companies, just about anyone can submit a PCR. Requests are usually submitted by Cooperative Extension specialists, commodity groups and growers. Once we receive a request it is sent to the appropriate chemical company to determine if they would register the use if IR-4 developed the necessary data. If approved, the project goes into a list of potential projects. In September of each year projects are selected for the upcoming year at the Food Use Workshop and Ornamentals Workshop. See Figures 2 and 3 for additional detail on the Food Use and Ornamental Horticulture registration cycles, respectively. The priority setting process engages representatives from state and federal agricultural scientific communities, state extension systems, commodity and grower groups, the crop protection industry, food processors, and state and federal regulators.


Fig. 2. The IR-4 regulatory clearance process for food crops.



Fig. 3. The IR-4 regulatory clearance process for ornamental horticulture crops.


Since 2000, over 80% of IR-4's research effort has involved new pest management technologies with biopesticides and lower risk chemistries. This new technology effort is accomplished through a three pronged approach consisting of: 1) partnering with the agricultural chemical companies, 2) educating specialty crop stakeholders, and 3) partnering with the Environmental Protection Agency (EPA) to facilitate specialty crop registrations.

The other aspect of IR-4's emphasis on new technology is the educational facet of providing the latest information. It became clear that with mergers and acquisitions, chemical companies were working with reduced staffs. Thus federal and state research and extension scientists were not always given the ability to test the newest products. IR-4 instituted a mechanism through the publication of the "New Products Transitional Solution List" ( to inform the public about the availability of new technologies. The goal of this publication is to help growers learn about new technologies to assist in the transition away from crop protection tools that are deemed vulnerable, due to the Food Quality Protection Act (FQPA), and implement the new Reduced Risk products.

IR-4 Partners, Supporters and Cooperators

Crop protection companies. IR-4 recognizes that without access to new crop protection technologies, it can not assist specialty crop growers. IR-4 scientists approach crop protection companies and encourage them to work with IR-4 on new product development strategies. This results in the companies including more specialty crops in their development plans. Often IR-4 and companies work collaboratively on new products. Companies develop supporting data on major crops, and IR-4 develops data on specialty crops. Then the entire data package is submitted to the EPA. For the first time, specialty crop growers have access to new product technology at the same time as major crop growers.

EPA. IR-4 and the Environmental Protection Agency (EPA) formed the IR-4/EPA Technical Working Group (TWG), which began in 1999 for the purpose of enhanced coordination. This cooperation benefits specialty crop growers and both organizations by allowing enhanced efficiency in data development and review. The IR-4/EPA TWG meets quarterly to explore initiatives that facilitate specialty crop registrations. The TWG provides a means for the EPA to review the annual IR-4 residue program and discuss data evaluations and summaries that are prepared for final reports. The TWG has also taken a leadership role with the EPA on electronic petition submission, and IR-4 plans to submit all of its petitions to the EPA electronically in 2006. Using electronic submissions could reduce the EPA's resources for reviewing IR-4 data by 35%.

Stakeholders. The Commodity Liaison Committee (CLC) serves as a bridge between IR-4 and the growers of specialty crops to make sure that the program continues to focus on significant pest management problems. They provide guidance and advice and encourage their members, other commodity organizations and specialty crop growers to submit Project Clearance Requests (PCRs) to define pest control problems needing IR-4 support. Another important CLC role is to support federal IR-4 funding and budget initiatives and to help secure other sources of extramural funding.

Land Grant Universities. The U.S. Land Grant System supports IR-4 with grants of approximately $0.5 million and in-kind funding valued at over $10 million annually. They provide: four GLP Laboratories, 25 research farms, offices, infrastructure and administrative support and expertise. IR-4 could not operate effectively without this support.

Other Financial Support. Major funding for IR-4 is provided by: USDA-CSREES, USDA-ARS, Regional Research (Hatch Act) funds to National Research Support Program #4 (NRSP-4), as administered by State Agricultural Experiment Station directors. Additional support is provided by commodity and industry Partners (gifts).

NAFTA Cooperation. IR-4 and Agriculture and Agri-Food Canada (AAFC) are cooperating jointly in generating data on specialty crops and are recognized as members of the North American Free Trade Agreement (NAFTA) Technical Working Group (TWG) on Pesticides.

In the past six years, IR-4 supported over 4,450 new uses that were registered in the U.S. but only a few of these uses were made available to Canadian growers. The recognition of cooperative projects allow the EPA and Canada's Pest Management Regulatory Agency to simultaneously review and accept submissions.

The partnership between the IR-4 Project and the Canadians began in 1996, and over the past nine years has contributed to 91 cooperating projects involving 207 joint residue trials conducted in Canada. Members of the AAFC Pest Management Centre have been active participants in annual IR-4 Food Use and Ornamental Horticulture Workshops and National Research Planning Meetings.

The IR-4 Organization

IR-4 operates as a unique partnership between the Land Grant University system and the USDA (ARS and CSREES) to accomplish its goals. The Headquarters staff is located at New Jersey’s Agricultural Experiment Station at Rutgers University, and the USDA/ARS management is located at Beltsville, Maryland. The four regional staffs are located at the University of California, Davis; University of Florida, Gainesville; Michigan State University, East Lansing; and Cornell University, Geneva, New York. All of these units operate independently under the umbrella of the Project Management Committee (PMC).

The PMC meets three times a year to review the status of ongoing programs, develop policy and procedures, set operational budgets, develop strategic plans, and ensure that the program's overall goals are being met. Its members include the IR-4 Executive Director, the four Regional Directors, the ARS National IR-4 Director, the Administrative Advisers (one for each of the four regions and the USDA/ARS Advisor), the USDA/CSREES IR-4 National Program Leader and the Chair of the Commodity Liaison Committee (CLC).

IR-4 Headquarters is located at Rutgers University in North Brunswick, New Jersey. Headquarters provides the overall program coordination with the various internal and external partners. This is where we archive all of the raw data from studies. Study Directors reside at Headquarters and they originate the study protocol, oversee studies, write reports and make submissions to the U.S. EPA.

Regional Directors are responsible for the staff and programs in their regions, which are managed by Regional Field Coordinators (RFC), Regional Laboratory Coordinators (RLC) and Regional Quality Assurance Coordinators (RQAC). Regional Field Coordinators assess regional pest control needs and manage field trials at the IR-4 Field Centers, with individual researchers or with private contractors. The Regional Laboratory Coordinators are in charge of their regional laboratory and oversee the assignment of analyses to satellite and contract laboratories in their region. The Regional Quality Assurance Coordinators oversee all quality assurance audits for field trials and laboratory analyses within their region. With an average of 100 residue projects, nearly 700 field trials, over 1,200 (in 2005) ornamental efficacy and crop tolerance trials and over 50 Biopesticide Program projects, the collaborative coordination of these projects and trials is remarkable. Yet, IR-4 does it, and its success is evidenced by the results.

IR-4 Food Use Program

The IR-4 Project had an outstanding year in 2005 by obtaining 991 clearances for specialty crops. The EPA continues to review and grant decisions on a large number of IR-4 data submissions, which accounted for more than 50% of the EPA new uses for existing products approved between 2001 and 2005. Since 1963, IR-4 food use data have contributed to the approval of over 9,300 registrations.

In 2005, IR-4 implemented new procedures resulting from the Pesticide Registration Improvement Act (PRIA) of 2004 (Fee for Service), the EPA hired a new Minor Use Team Leader, and progress for new clearances continued at a high pace. As required by PRIA, the EPA issued their multi-year work-plan ( The plan projects that IR-4 has 154 reports scheduled for review in 2006. Overall the EPA should be maintaining 50% of its overall work-plan related to the number of IR-4 new uses.

Additionally, the 2005 annual IR-4 stakeholder priority setting Food Use Workshop drew a record attendance of over 200 stakeholders who worked together to define high priority needs for the 2006 specialty crop research program.

Post-harvest disease control in stone fruit is one example of how the IR-4 has helped growers control diseases. Post-harvest fungicides were being lost during re-registration that was mandated by Congress with amendments to the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) in 1988, as registrants found it financially prohibitive to re-register them. The Food Quality Protection Act (FQPA) unanimously passed by Congress in 1996 further eroded the available disease control tools by placing additional constraints on re-registration. Researchers in California ( saw this loss and evaluated potential replacement fungicides including many Reduced Risk fungicides for their ability to control brown rot of stone fruit crops caused by Monilinia fructicola and M. laxa as well as Botrytis gray mold caused by Botrytis cinerea and Rhizopus rot caused by Rhizopus stolonifer (Fig. 4). 







Fig. 4. Nectarines showing three primary post-harvest diseases: (A) Rhizopus stolonifer, (B) Monilinia fructicola, (C) Botrytis cinerea following no post-harvest treatment (left) or 0.5 lbs fludioxonil per 200,000 lbs fruit as a post-harvest treatment (right). Photos by J. Adaskaveg.

Over the next several years, IR-4 utilized the disease control information provided by the California researchers to conduct residue programs and obtain registrations on two reduced risk fungicides, fludioxonil and fenhexamid. IR-4 is presently completing the registrations of three additional products that include two additional Reduced Risk fungicides, pyrimethanil and boscalid, as well as tebuconazole and pyraclostrobin. These registrations are providing safe disease control tools for the grower and allowing practices, such as mixtures and rotations, to be used to prevent resistance from developing and ensure the lasting efficacy of these fungicides.

IR-4 Ornamental Horticulture Program

In 2005, IR-4 conducted over 1,200 ornamental horticulture research trials to support registrations in the greenhouse, nursery, landscape, Christmas tree, and forestry industries. Of these, 186 were efficacy trials focusing on tools to manage insects and mites; 224 were efficacy trials with fungicides; 8 were plant response trials for plant growth regulators; and the remaining trials were conducted to determine the level of phytotoxicity to crops with herbicides used to manage common weeds in and around nurseries. The Ornamental Horticulture projects take a slightly different pathway from the food crops in that they do not require the establishment of a tolerance or maximum residue limit before registering the use. The chemical companies make the decision as to what should go on a label and also require crop safety and efficacy data; however, requests for projects come from grassroots sources and many aspects of the ornamental horticulture registration cycle are similar to the food crop registration cycle (see Figs. 2 and 3).

One example of how IR-4 is having an impact on growers is the data the Ornamental Horticulture Program has generated on Gentry (quinoclamine), an herbicide recently submitted to EPA for use in containerized ornamental plants grown in nurseries and greenhouses. At the 2004 Annual Ornamental Horticulture Workshop, participants in the weed science session selected developing crop safety data for Gentry (known as Mogeton at the time) as a high priority project because of the need for a safe and effective liverwort control product.

Liverwort spreads on the surface of pots, preventing water and fertilizer from reaching the ornamental plants’ root zone, leading to crop loss. Growers with liverwort problems in their crops face financial hardships because only a few products are registered for use, and these do not provide effective, long-term residual control. Hand weeding is very time consuming and expensive. Once liverwort weed control was selected as a high priority project, weed scientists throughout the U.S. conducted 140 trials on 84 different plant species for a total of 215 studies on 107 plants, including the data generated in the program prior to 2005. These data contributed to the Gentry label written by Chemtura and submitted in February 2006. The final EPA registration is anticipated in early 2008.

IR-4 Biopesticide Program

The primary objective of the IR-4 Biopesticide Research Program is to further the development and registration of biopesticides for use in pest management systems for specialty crops or for minor uses on major crops. IR-4 data supported 39 new biopesticide food uses for eight products. These included: Reynoutria sachalinensis on all food commodities for 28 new food uses; AgriPhage on tomato and pepper; Polyoxin-D (Endorse) on ginseng; Bacillus subtilis (Serenade) on horseradish; Psuedomonas syringae (Bio Save ESC11) on sweet potato; Muscodor albus (Arabesque) on orange, cherry, and grape; Paecilomyces lilacinus strain 251 (MeloCon) on tomato and pepper; and Alternaria destruens strain 059 (Smolder) for control of dodder (Cuscuta spp.) in cranberry. The biopesticide program also funded 56 efficacy projects, several of which were co-funded by the EPA. Many of these products are important to the organic market.

Pilot Efficacy Program

In 2005, IR-4 funded a pilot efficacy program to identify potential products that effectively manage the target pests: 1) thrips in onion, 2) Phytophthora capsici in squash and pepper, and 3) weeds in leafy vegetables and herbs.

Thrips in onion. The control of thrips infesting onion was identified as a serious issue with growers facing thrips populations that are becoming more difficult to control every season. Standard control products and practices were becoming less and less effective. It is not that talented entomologists have not been researching this problem; they have. Unfortunately, identification of broadly effective solutions had proven to be an elusive goal. It was hoped that IR-4 could help identify a solution. In only one year, treatments were identified and cooperators enlisted for efficacy evaluations in many onion production regions. One product, formetanate hydrochloride, was identified as extremely efficacious by all cooperators and became a high priority residue study in 2006. Another outstanding material was Dow AgroScience’s XDE-175, a new, yet to be registered product closely related to spinosad, which is itself a rather good thrips control material that has recently been registered through the IR-4 Project.

Phytophthora capsici in squash and pepper. To assist in learning more about Phytophthora capsici, IR-4 sponsored a Workshop that brought together scientists who identified strategies to fight this disease. The group discussed the basic biology of the pathogen and methods of control. As a result of this discussion, it was proposed that the disease is a race between the crop and the pathogen. Sometimes the pathogen is adequately slowed by fungicides, but when conditions are highly favorable for the pathogen, the race ends in a pool of dead plant tissue (Fig. 5). The group developed many ideas and put forth a list of potential fungicides for testing, including cyazofamid, dimethomorph, fluopicolide, mandipropamid, mefenoxam, phosphorous acid generators like ProPhyt, and an older fungicide, captan. Six trials were funded in 2005 and their results discussed at a second workshop. In 2006, we are again evaluating the best performing fungicides of the 2005 trials, as well as two new fungicides. Twelve trials are being conducted in 2006 with the hope of identifying those fungicides that have the greatest ability to control each phase of the disease: root and crown rot, foliar blight, and fruit rot.


Photo by C. A. Wyenandt.


Photo by M. Hausbeck.


Fig. 5. Destruction of field-grown vegetable crops by Phytophthora capsici.


Weeds in leafy vegetables and herbs. The weed science pilot project objective was to identify potential new and old herbicides for weed control in many leafy vegetable crops and herbs. IR-4 coordinated the efforts of weed scientists, IR-4 Field Regional Coordinators, and chemical company representatives from Dow AgroScience, Arvesta, Gowan, FMC, Bayer CropScience, Nichino America, Kumiai, BASF, and Valent. Thirteen weed scientists from all four IR-4 Project regions and USDA/ARS Centers participated in the program. Field research was conducted in lettuce, spinach, garden beets, leafy brassica greens (collard, kale, mustard greens, turnip greens), dill and cilantro. Herbicides evaluated (pre and post emergence) were clomazone, ethofumesate, flufenacet, pendimethalin, thiocarbamat, prometryn, oxyfluorfen, sulfentrazone, pronamide, triallate, s-metolachlor, triflusulfuron-methyl, flucarbazone-sodium, V-10142, and KIH-485.

Crop Grouping Program

The current EPA Crop Grouping Regulations include 500 specialty crops. As a result of the IR-4 Crop Grouping project, the EPA will increase that number to at least 1000, increasing the number of specialty crops that will be considered in each IR-4 petition submission.

Through the effort of the International Crop Grouping Consulting Committee (ICGCC), which consists of over 170 members representing over 30 countries, a number of crop group petitions were submitted to the EPA in 2005. Among those, bulb vegetables has been approved, and the EPA is reviewing several others.

To bring the new crop groups to final federal approval and publication, IR-4 worked with the EPA to develop a rule making process; a Regulation Workgroup will be formed within the EPA/OPP in early 2006.

In September 2005, IR-4 facilitated the first ICGCC meeting to discuss world harmonization of crop classification. Nine countries were represented. As a follow up to this meeting, representatives from the IR-4/EPA Crop Grouping Working Group and the Codex Revision Workgroup met in the Netherlands to discuss technical issues about the cooperation between the U.S. and the Codex crop classification revision projects. Members developed a five-year harmonization work plan, which was presented at the CCPR (Codex Committee on Pesticide Residues) annual meeting in April 2006.

Methyl Bromide Alternatives

IR-4 has begun to reduce its role in the Methyl Bromide Alternatives Programs since methyl bromide has officially been phased out and is being used only with approved critical use exemptions (CUE's) in commodities where acceptable methyl bromide alternatives are not in place. In 2005, IR-4 facilitated support for products that have been accepted for registration by the EPA. They included Basamid (dazomet) for strawberries and tomatoes, and Propoxide 892 (8% propylene oxide and 92% carbon dioxide), which is a new product registration for post harvest protection of stored spices, nutmeats, in-shell nuts, cocoa and cocoa beans.

IR-4 Strategic Plan 2006-2008

In February 2005, over 150 researchers, commodity representatives, and industry personnel participated in a Strategic Planning Conference to discuss their needs and share inputs in helping IR-4 consider its strategic direction. Recommendations from this Conference played a major role in helping the IR-4 PMC formulated a Strategic Plan for 2006-2008, which includes new initiatives for Seed Technology, Aquatic Herbicides and a Global Specialty Crop Program.

Aquatic Herbicide Program. The aquatic herbicide program has been approved as a new program initiative with additional acquired funding. Aquatic weeds, particularly non-native invasive species, are serious threats to the natural and production-based ecosystems in the U.S. They have become a major national problem, as key waterways (rivers, reservoirs, canals, etc.) are interconnected, traversing political boundaries throughout the country, and allowing for convenient avenues for movement of aquatic weeds. The proliferation and continued spread of these weeds restricts water movement in flood control and irrigation canals, increases sedimentation rates in reservoirs, reduces biodiversity, threatens endangered species (plants and animals), degrades water quality, increases mosquito breeding habitat, and causes major economic losses to agriculture, recreation, fisheries, electric power generation, and property values. Faced with the threat of a growing national aquatic weed problem and with few practical solutions on the horizon, the Aquatic Herbicide Working Group is collaborating with IR-4 to discuss the serious need for new products. This new program initiative will expand the IR-4 Project mission to include weed control in irrigated canals and other aquatic sites.

Seed Technology Program. In 2005, and with industry funding, IR-4 began seed technology research in Brassica vegetables and cucurbits in Washington and California (Phoma spp. control in crucifers), and cucumber beetle control on cucurbits in North Carolina, New York and Ohio. Studies will continue in 2006 with multiple pest control products in Texas-grown onions, carrots, radish and cabbage, as well as control of insects in spinach, collards and other Brassica vegetables in Arkansas, Tennessee and Virginia. Additionally, a number of tests that target plant parasitic nematodes in tomato, pepper and cucurbits will be run in Florida, Alabama, and possibly other locations. Efforts will also focus on the support of special labeling to address immediate pest control needs in the Pacific Northwest (Section 24 C label for thiabendazole to control black leg) and Section 18 emergency use for clothianidin to control onion maggot.

Global Specialty Crop Program. As IR-4 registrations increase, new minor use problems begin to emerge. Although U.S. growers have access to newer, lower risk pest management products, many growers are reluctant to use these products due to international trade barriers that are created from the lack of Maximum Residue Limits (MRL's) being established for these new products in countries where the growers export their crops. Unfortunately, in many cases, U.S. growers are still using the older, less environmentally friendly pest management products on commodities that will be shipped abroad. Therefore, it is critically important that global MRL's and registrations be established, rather than segmented country by country. Global registrations are needed to level the playing field for U.S. specialty crop growers who wish to export their crops. This will also promote the use of the new, safer products being integrated more rapidly into production systems, providing even greater protection for applicators, consumers and the environment.

Recognizing this need and considering the work IR-4 has already contributed to international concerns, IR-4 is uniquely positioned, with its expertise in both specialty crops and partnerships, to manage a Global Specialty Crop Initiative. This initiative could also play a major role in assisting with international reviews for JMPR (Food and Agriculture/ World Health Organization Joint Meeting on Pesticide Residues) or by participating more actively on CODEX and OEDC (Organization of Economic Cooperation and Development) committees. This Global initiative would enhance global registrations and reduce trade barriers, while at the same time further promote the use of new, safer pest control products.