Interregional Research Project No. 4 (IR-4) is a program begun in 1963 to conduct the research necessary to obtain tolerances and registrations of pesticides needed to grow "minor" crops. Minor crops refer to nearly all crops except cotton, corn, soybeans, wheat, oats, and rice (and in some cases even work on these crops). Traditionally minor crops are vegetables, fruits, nuts, herbs, but other specialized crops are also included in the program. The definition of minor crops also encompasses ornamentals, landscape plants, commercially grown flowers, shade trees, and turf grasses.
The IR-4 program was designed to make products available which otherwise might not be available due to high research costs and minimal returns to the product manufacturer. The commitment of Indiana researchers permits research to be conducted more economically and more quickly than if conducted by commercial companies. The program is committed to a 30-month completion goal from the initiation a given crop project. IR-4 works with farmers, agricultural scientists, extension personnel, and private companies to conduct research necessary to obtain tolerances for specific pesticides to support the regulatory clearance by the Environmental Protection Agency (EPA). A pesticide tolerance is the amount of pesticide that can be legally present on a crop at harvest (or after processing). Frequently, IR-4 projects involve research to achieve changes in amounts, timing, and types of application of registered pesticide uses as well as the addition of new crops or pests to existing labels.
Indiana entomologists, horticulturists, nematologists, weed scientists, and plant pathologists work in close cooperation with the IR-4 Regional Office at Michigan State University and the National IR-4 headquarters to design and conduct field and/or greenhouse research to obtain necessary pesticide data. The generated data when complete are submitted to EPA for appropriate regulatory approval. All data, including laboratory log books, raw data packages, and report drafts are checked and cross-referenced by IR-4 regional staff and an independent Quality Assurance auditor before being sent to IR-4 headquarters and the EPA.