Pesticides are used far beyond farms. While agriculture accounts for the largest share, pesticides are also applied in homes and gardens, along railway lines and pipelines, inside schools and commercial buildings, and across public spaces to control disease-carrying insects. Here’s a closer look at each setting and what’s actually being applied.
Agriculture: The Biggest Share by Far
Farming dominates pesticide use. In the United States, five crops alone account for roughly 80% of all pesticides applied across 21 major crops studied by the USDA: corn, soybeans, cotton, wheat, and potatoes. Corn has been the top pesticide-using crop since 1972, receiving about 39.5% of all pesticides applied to those crops, mostly herbicides to suppress weeds. Soybeans come in second at nearly 22%, again almost entirely herbicides.
Potatoes rank third at about 10%, a share that climbed significantly during the 1990s as growers ramped up treatments against fungal diseases and insects like the Colorado potato beetle. Cotton, once responsible for 40% of U.S. pesticide use in the early 1960s, dropped to just over 7% by 2008, largely because newer insecticides work at much lower application rates. Wheat sits at under 5%. Fruit and vegetable crops like oranges, tomatoes, grapes, and apples each account for 1 to 2.5% individually, but they tend to receive more intensive treatment per acre because the produce is sold directly to consumers and cosmetic damage lowers its market value.
Even certified organic farms use pesticides, though only substances approved under the USDA’s National Organic Program. The approved list includes naturally derived compounds and certain synthetic materials deemed compatible with organic principles. Organic does not mean pesticide-free; it means a different set of allowed tools.
Homes, Lawns, and Gardens
Residential use is a surprisingly large category. According to the EPA, Americans applied about 66 million pounds of conventional pesticide active ingredients in and around their homes in 2007, representing 8% of all pesticide use nationwide. Home and garden applications made up 8% of total herbicide use, 15% of all insecticide use, and 10% of fungicide use. That insecticide figure stands out: one in every six or seven pounds of insecticide applied in the country went onto residential property.
The most common household applications include weed killers on lawns, ant and roach sprays indoors, grub treatments in turf, and fungicides on ornamental plants and garden beds. Many homeowners also apply granular insecticides to their yards for tick and mosquito control, especially in regions where Lyme disease or other vector-borne illnesses are prevalent. Because residential users often lack the training that commercial applicators receive, over-application is common, and runoff from treated lawns contributes measurably to pesticide levels in local waterways.
Public Health and Disease Prevention
Governments and health agencies use pesticides to fight diseases spread by mosquitoes, ticks, fleas, and freshwater snails. The World Health Organization identifies several core tools for this work: insecticide-treated bed nets, indoor residual spraying (coating interior walls with long-lasting insecticide), outdoor fogging operations that release insecticide as a fine mist, and larvicides applied directly to standing water where mosquitoes breed. In tropical regions, molluscicides are also applied to waterways to kill snails that carry parasitic infections like schistosomiasis.
In the United States, municipal mosquito control programs spray insecticides from trucks or aircraft during peak mosquito season, particularly after flooding events or in areas where West Nile virus or Eastern equine encephalitis has been detected. These programs balance disease prevention against environmental costs, since broad-spectrum spraying also kills beneficial insects.
Railways, Pipelines, and Utility Corridors
Infrastructure maintenance is a major but often overlooked category of pesticide use. Railroads apply herbicides across five distinct zones: rail yards, bridges, main lines, road crossings, and brush corridors alongside tracks. In rail yards, vegetation control keeps workplaces safe, prevents fires near storage areas, and stops plant growth that causes wheel slippage. Along main lines, which represent the largest number of treated acres in railroad operations, herbicides protect the roadbed by maintaining proper drainage and keeping signals, switches, and signs visible to train crews.
Wooden bridges receive special attention because vegetation growing near them raises fire risk and blocks structural inspections. At highway grade crossings, weed control is often a legal requirement, ensuring that both drivers and engineers have clear sightlines.
Pipeline companies face similar concerns. Rights-of-way must stay clear so inspection crews can spot signs of leaks from the air or ground. Open corridors also allow emergency repair teams quick access. Around pumping stations and storage tanks, total vegetation control is especially critical to reduce fire hazards. Electric utilities follow a parallel approach, keeping corridors clear to prevent trees and brush from contacting power lines.
Schools and Commercial Buildings
Pesticides are routinely applied inside and around commercial structures to control cockroaches, ants, wasps, and rodents. In schools, this use is tightly regulated. Ohio’s rules, which mirror frameworks in many states, define three application scenarios based on timing and product type. During school hours, most pesticide treatments require a restricted-entry period of at least four hours after application, with no children or unnecessary staff allowed in the treated area.
Certain lower-risk products can be applied while school is in session without restricted entry. These include manufactured paste or gel baits, rodenticides placed in tamper-resistant bait stations, termite-baiting stations, rodent poisons sealed inside wall voids inaccessible to people, and dust formulations applied in unoccupied building areas. Disinfectants and antimicrobial agents are also exempt. Applications made on weekends or during breaks follow only the requirements printed on the product label.
Hotels, restaurants, office buildings, and hospitals all rely on regular pest management as well. Most contract with licensed pest control companies that visit on a set schedule, typically monthly or quarterly, applying targeted treatments in kitchens, storage rooms, utility spaces, and around building perimeters to prevent pest entry.
Environmental Traces in Water
Wherever pesticides are applied, some fraction moves off-site. Rain washes residues from fields and lawns into streams, and certain compounds leach downward into groundwater. EPA reviews have found that herbicides in the triazine family, particularly atrazine and simazine, are among the most frequently detected pesticides in groundwater across the United States. Soil fumigants have also shown up repeatedly in well-water testing.
This contamination isn’t limited to agricultural regions. Urban and suburban runoff carries lawn herbicides and insecticides into storm drains that empty into rivers and lakes, meaning residential pesticide use contributes to water contamination alongside farm applications. Municipal water treatment systems can remove most pesticide residues, but private wells in agricultural areas are especially vulnerable because they typically lack advanced filtration.