U.S. farmers have been estimated to have spent over $20 billion annually on average in recent years on pesticides according to data reported by USDA’s Economic Research Service, helping them to fight a variety of pests or diseases that could otherwise wreak severe damage on their crops. Analysts at that same agency estimate that per acre application rates of various types of pesticides have fallen significantly in recent decades, from about 1.7 pounds per acre in 1990 to 0.7 pounds per acre in 2021. This decline is due to improved formulation of the agricultural chemicals with new, more effective modes of action, as well as increased use of integrated pest management (IPM) practices, which helps enable improved targeting of pesticides to where they are needed, thus reducing the amount that is applied.
The concept of Integrated Pest Management (or IPM) was developed in part as a response to the public furor caused by the publication of the environmental book Silent Spring in 1962, written by Rachel Carson, a marine biologist who had once worked for the agency that became the U.S. Fish and Wildlife Service. In her book, Carson pointed out that the pesticide DDT, which had been marketed as an effective product that did not harm humans and other mammals, in fact had long-term adverse effects on many kinds of animals by accumulating over time in the fatty tissues that characterize most mammals, leading to higher incidence of cancer and genetic damage to subsequent generations.
The use of DDT was banned in the United States in 1972 CE except for public health emergencies, and many other countries followed suit, either with total bans or similar stringent restrictions. While Carson’s book dealt primarily with the cumulative impacts of DDT, research conducted in the 1950’s had shown that overuse of pesticides on a broad basis was actually leading to many insect species developing resistance to the chemicals, causing a resurgence in pest problems for farmers. In response to this phenomenon, “integrated control” was developed emphasizing use of selective insecticides so that natural enemies to those pests were conserved in the system.
Credit for this breakthrough has been primarily given to Dr. Perry Adkisson (Texas A&M) and Dr. Ray Smith (U.C.-Berkeley), who were among the first to deduce that most plant diseases, weeds, insects, and other pests could be controlled by employing good crop management practices and maximizing the many controls already existing in nature. The two men jointly received the World Food Prize in 1997 for their work.
As formulated over the last several decades, the core principles of IPM include the following action steps:
• Monitor the emergence of insects in crop fields and identify which ones are potentially harmful to that specific crop (scouting)
• Set action thresholds by specifying the level of infestation at which chemical pesticides would be applied
• Use physical or mechanical tools or blocks to keep pests under control, such as setting traps or laying down mulch
• Protect and use natural enemies to suppress damaging insects (known as biological control), and
• Use chemical sprays only as a last resort
A large number of American farmers have adopted some or all of the suite of practices associated with IPM, even if they don’t specifically use that terminology to describe their operations. High adoption levels are particularly associated with farmers raising specialty crops such as fruits and vegetables. In a 2025 survey administered by USDA’s National Agricultural Statistics Service (NASS) to American fruit producers, more than 90 percent of those surveyed reported use of scouting practices in their fields and orchards to detect infestations, 66 percent utilized biological pesticides, and more than 60 percent used other suppression tactics such as laying down mulch or other forms of ground cover.
Most organic crop farmers use this same set of practices, except they use natural pesticides, such as Bacillus Thuringiensis (BT), pyrethrins, or insecticidal soaps, rather than synthetic pesticides. Use of synthetic pesticides in their operations would prevent them from qualifying for Certified Organic status under USDA rules. As of the 2022 Census of Agriculture, there were just over 17,000 certified organic farming operations in the United States, accounting for about one percent of U.S. crop acreage.
Farmers have been using biological control techniques for many centuries. History records that Chinese citrus growers placed colonies of a specific species of ants (Oncophylla smaradina) in their orchards to feed on insects which would otherwise eat the leaves of their trees, as far back as the 3rd Century. Scientific discussion of the merits of biological control began to appear early in the 19th Century, one notable piece by the naturalist Erasmus Darwin in 1800 (the paternal grandfather of Charles Darwin), who wrote about preserving certain species of wasps and flies which fed on aphid species.
My personal awareness of biological control practices came about in January 1996, when I participated in a visit to China as part of a USDA delegation to learn more about what was being done to combat an outbreak of mealy bugs, an invasive species that was hitting China’s pine forests and plantations really hard. Since it had been determined that the pest had likely entered China on packing pallets from the United States that had not been properly fumigated, USDA was trying to help their Chinese counterparts deal with that outbreak. The main tool being used was to introduce several species of parasitic wasps that fed on the mealy bugs.
Another effective biological control practice being used by farmers across the country is to erect a nest box near the farmstead to attract barn owls to inhabit in order to help control rodents in barns and grain silos without the use of synthetic rodenticides. Numerous studies have shown that high occupancy and success rates in agricultural and open landscapes can be achieved with this practice, with a single family of owls consuming thousands of rodents per year. This success requires that the boxes be correctly placed, maintained, and kept free of rodenticides.
