Interregional Research Project No. 4 (IR-4) is a federally funded program established in 1963 to conduct the research necessary for obtaining registrations of pest control agents needed to grow minor crops.  IR-4 works with farmers, agricultural scientists, and extension personnel to conduct research and petition the Environmental Protection Agency (EPA) for tolerances for specific pesticides.  The IR-4 program has grown to include biological pest control agents and biochemicals, which are important in the implementation of Integrated Pest Management (IPM).

Minor crops refer to nearly all crops except cotton, corn, soybeans, and grain crops such as wheat, oats, and rice.  The definition of minor crops also encompasses ornamentals, landscape plants, commercially grown flowers, shade trees, and turf grasses.  Approximately 72% of all crops grown in Washington State are considered minor crops with a value of $2.3 billion.

Crop samples arriving at the IR-4 laboratory at YARL are stored, processed, and analyzed under carefully controlled and monitored conditions.  Samples are processed using one of several methods to insure a uniform matrix.  Chemical extraction methods must be EPA approved, and are often lengthily and complicated.  Analysis of extracts is accomplished with gas chromatography (GC) or high performance liquid chromatography (HPLC) coupled with a variety of extremely sensitive detectors.  The generated data is analyzed with sophisticated, specialized software and assembled for the final Analytical Summary Report.  All data, including laboratory logs, raw data packages, and report drafts are checked and cross-referenced by IR-4 laboratory staff and an independent Quality Assurance auditor before being sent to IR-4 headquarters and the EPA.