The most common measure, or metric of “pesticide use” is the pounds ofapplied in a given year on an acre of a specific crop, and/or across all acres of a crop. The geographic scope of “pesticide pounds applied” on a given crop, or all crops, could be a farm, all cropland in a county, state, nation, or the world.
Pesticide use in the U.S. is most reported byat the state level and nationally, e.g. on all acres of corn in the nation, or all corn acres in Iowa.
Pesticide use data are available down to the county level from two sources in the U.S.: California-specific data from the California Department of Food and Agriculture, and nationwide data from the U.S. Geological Survey for 1992-2012, and preliminary estimates for 2013-14.
Around the world, use data are reported in pounds or kilograms of pesticide active ingredient applied, rather than pounds or kilograms ofproducts. Virtually no pesticide active ingredient is applied in a 100% pure form.
Typically, adjuvants and surfactants and other so-called, are combined with the active ingredient in formulated, end-use products. Inert ingredients are added to:
- Help sustain the active ingredient in the proper state (solid, liquid, gas),
- Facilitate mixing with other pesticides or liquid fertilizers,
- Assure the active ingredient sticks to plant leaves even if it rains,
- Accelerate the penetration of the active ingredient into plant tissues, and
- Protect the active ingredient from normal degradation processes driven by sunlight, rain, and air.
Inert ingredients account for one-third to three-quarters of the weight of a formulated pesticide. Rates of application per acre or hectare are usually based on pounds or kilograms of the active ingredient, rather than on the basis of active ingredients plus inerts. The pounds of pesticide active ingredient applied in common application scenarios are a small fraction of the volume of spray material applied per acre.
Publications by the industry such as product labels, catalogs, and user guides are also very useful sources of information about herbicide use. We have collected several such resources and incorporated them into the Project Bibliography, click on the Herbicide Industry Labels and User Guides category to pull up a full list of publications by the herbicide industry. While specific application rates will vary by crop and region, these industry recommendations provide a valuable snapshot of how products are being used by farmers.
Industry publications are listed below by company:
Du Pont Pioneer
- “From Seed to Harvest 2015,” catalog of Du Pont Pioneer Canada products and services.
- “Roundup Ready Plus 2015 Weed Management Recommendations and Incentives” for the Southwest; Plains, Midwest, Northeast; and Midsouth, Southeast
Extent of Use Metrics
Pesticide impacts on the environment and human health are clearly a function of how widely and often a pesticide is applied, in addition to the rate at which it is applied.
It is also important to take into account how widely and frequently a pesticide is used on a given farm, on a crop, and/or across all crops in a region.
Seven metrics are needed to track the frequency and extent of use of a given pesticide:
- “Percent Acres Treated” is the percent of the acres of a given crop in a region that is treated with a given pesticide.
- “Number of Acres Treated” is the number of acres of the crop treated one or more times with a given pesticide, calculated as the (percent acres treated) multiplied by (total crop acreage).
- “Acre-Treatments” takes into account both the percent of acres treated and the average number of applications with each active ingredient applied, and is calculated as (acres treated) multiplied by (number of applications) made with a given pesticide.
- Average “One-time Rate of Application” of active ingredient on an acre/hectare of a given crop.
- Average “Number of Applications” made with a specific active ingredient on a crop in a production cycle (usually a calendar year).
- “Rate per Crop Year” is the average rate of application per production cycle, and is calculated as (average one-time rate of application) multiplied by (average number of applications).
- “Pounds Applied” is the total pounds of active ingredient applied per production cycle on a given crop, or across all crops or sets of related crops (i.e., fruits or small grains).
Measures of Reliance on Low-Dose and High-Dose Chemistry
Additional metrics are needed to gain deeper insight into how changes in one-time rates of application impact trends in overall pesticide use. This is because, since the early 1980s, the pesticide industry has focused on identifying new modes of action that are highly specific to target pests and usually effective at low-dose rates.
Such active ingredients typically target specific metabolic, biochemical, physiological, developmental, or reproductive processes in target pests. Several are applied at very low rates, which bring down measures of overall pounds of pesticides applied per acre, in a region, or on a given crop. But shifting acres treated from one or a few high-dose pesticides to multiple low-dose active ingredients can make intensification of pesticide use appear to be a reduction in use.
Five additional metrics are useful in coaxing out the impact of changes in rates of application over time:
- “Number Low-Dose Chemistry” is the number of a.i.’s applied at a rate <= 0.1 pound/acre.
- “Reliance on Low-Dose Chemistry” is the percent of acres treated with an a.i. applied at a rate <= 0.1 pound/acre.
- “Number High-Dose Chemistry” is the number of a.i.’s applied at a rate =>1.0 pound/acre.
- “Reliance High-Dose Chemistry” is the percent of acres treated with an a.i. applied at a rate =>1.0 pound/acre.
- “Weighted Average Rate of Application” is the average rate of application per acre treatment across all pesticides applied within a category of pesticides (i.e. herbicides/ /fungicides), weighted by each pesticide’s share of total acre treatments.
Metric 11 is the best way to track the overall impact of changes in average rates of application. This key indicator, coupled with trends in the average number of acre-treatments on any given acre, provide the most reliable empirical assessment of changes in the intensity of pesticide use on a given crop.
It is worth highlighting that most of the widely used, high-dose pesticides applied by farmers in the 1980s have been replaced in the intervening years by moderate, low, or very low-dose active ingredients. As a result, pounds applied have declined, whether measured per acre, by crop, or across all crops. But unfortunately, this reduction does not mean that farmers have become less reliant on pesticides.
Measures of the Extent of Use By Type of Pesticide
The above 12 metrics represent a “” (MDS) for assessing use of a specific pesticide on a given crop in a given year. This MDS can be applied to a pesticide applied on a field, on all acres of a specific crop on a farm, and/or all acres producing a crop across all farms in a county, state, province, region, nation, continent, or worldwide.
But the impacts of pesticide use on farm production costs, the environment, the emergence and spread of resistant pests, and public health are driven by the total number and weight of pesticides applied. Accordingly, additional pesticide use metrics are needed to take into account how many different pesticides are needed to bring a crop to harvest in a given production cycle.
Typically, pesticide use data and trends are studied by major type of pesticide, and the categories of pests targeted by pesticides. The three major categories, and their corresponding type of pesticide, are: weeds (herbicides), insects (insecticides), and plant diseases (fungicides). These three major types of pesticides are referred to herein as H/I/F/O, with the “O” referring to all “Other” types of pesticides (e.g., desiccants, rodenticides, fumigants).
For each type of pesticide, there are three essential metrics needed to account for aggregate pesticide use within a given type of pesticide. These can be quantified per acre, on a field, across all fields on a farm, and/or in a county, state, region, nationally or globally:
- “Number of H/I/F/O AI’s Applied” is the number of different pesticide active ingredients applied on the crop/region/year combination.
- “Number H/I/F/O AI’s per Acre” is the average number of H/I/F/O active ingredients applied per acre.
- “Number of H/I/F/O Acre-treatments” is the total number of acres treated with a distinct H/I/F/O active ingredient (e.g., one application of a tank-mix containing three active ingredients counts as three acre-treatments).
- “H/I/F/O Acre-Treatments per Acre” is the total number of acre-treatments divided by the number of acres planted.
- “Pounds of H/I/F/O Applied” is the sum of pounds a.i. applied across all pesticides within a type of pesticide in a given crop year/region combination.
- “Pounds H/I/F/O per Acre” is total pounds applied divided by total acres planted.
Over the last several decades in most years and regions, farmers have managed weeds, insects, and plant diseases with one or two active ingredients on most fields, and often none.
Until very recently, soybeans grown in the U.S. were almost never treated with fungicides or insecticides, and corn was rarely treated with fungicides. But nearly 100% of the conventionally managed acreage of both crops has been sprayed with herbicides annually. For decades, most conventionally managed fruit and vegetable crops, on the other hand, have been sprayed with 1-3 herbicides, 2-5 insecticides, and 2-4 fungicides.
Given that many pesticide use variables are constantly changing, it can be tricky to answer seemingly simple questions:
- “Has pesticide use gone up or down?”
- “Are pesticide impacts on pollinators going up or down?”
- “Has corn increased or decreased pesticide use?”
- “Did the emergence of resistant weeds in an area lead to a change in herbicide use?”
To help answer these sorts of questions, a series of tables have been designed within the Pesticide Use Data System (PUDS). Some tables focus on extent-of-use metrics, while others strive to highlight trends over time.
Exploring Pesticide Use Indicators Within PUDS
Collectively, six basic tables within PUDS provide a comprehensive overview of contemporary pesticide use, as well as changes over time. Three trend tables come in multiple configurations, each one reporting changes over time in the values of a specific indicator.
Table 1 is the basic use table by crop-year-region combination. For each given crop, it reports seven pesticide use metrics for all fungicides applied, herbicides applied, insecticides, and other pesticides. Versions of this table can be generated for any crop-year-region combination. The table(s) can be limited to one type of pesticide, or cover H/I/F/O.
This table reports the values for metrics #1 through #7 by H/I/F/O. PUDS produces a unique version for each crop-year-region combination. For an example, see the table reporting herbicide use on soybeans in Iowa in 2015.
Table 2 reports the values for the five indicators designed to reflect reliance on low-dose-rate pesticides, in contrast to high-dose rate active ingredients within a type of pesticide (H/I/F/O). Values for Metrics #8 through #12 appear in the columns of Table 2, and there is a row for each type of pesticide. A unique version of this table is created for each crop-region-year combination.
The relative number and reliance on low versus high-dose pesticides in corn production in Ohio in 2015 is evident in the example below.
Table 3 shifts the focus to overall use across all pesticides applied on a crop in a given year-region combination, within each type of pesticide (H/I/F/O). It encompasses metrics #13 through #18, and a unique version of this table is produced for each crop-region-year combination.
Overall H/I/F/O use on soybeans in Wisconsin in 2015 is presented in the below table.
The three basic tables shown above cover the use of a specific pesticide, or all H/I/F/O pesticides applied on a given crop, in either a state or nationally, in a given year. It provides snapshots of pesticide use at a point in time. Three additional, core PUDS tables are designed to highlight trends, and focus on changes in specific metric values from year to year.
Table 4 reports trends in the values of five metrics by crop-region combination over time –
Table 4a. Percent Acres Treated (metric #1)
Table 4b. Rate of Application (metric #2)
Table 4c. Number of Applications (metric #3)
Table 4d. Rate per Crop year (#4)
Table 4e. Acre-Treatments (#5)
Table 4f. Acre-Treatments per Acre (#6)
Table 4g. Pounds Applied (#7).
The rows in each of the above tables are pesticide active ingredients, and the columns report annual values for each specific metric over time. A partial data set of the average acre-treatments per acre for H/I/F/O pesticides applied on soybeans in Indiana is shown below as an example of Table 4f. Click this link for the full table, which is too large for on-screen display.
Table 5 provides the same annual trend data for H/I/F/O pesticides by crop-region combination for the five low-dose metrics –
Table 5a. Number Low-Dose Chemistry
Table 5b. Reliance on Low-Dose Chemistry
Table 5c. Number High-Dose Chemistry
Table 5d. Reliance High-Dose Chemistry
Table 5e. Weighted Average Rate of Application.
The weighted-average rate of application by type of pesticide in the production of soybeans in Iowa is presented below as an example of Table 5e.
Table 6 covers changes over time in four key metrics reflecting overall reliance on H/I/F/O pesticides in production of a given crop in a given region –
Table 6a. Pounds Applied
Table 6b. Average Pounds Applied per Acre
Table 6c. Number of AI’s per Acre
Table 6d. Acre-Treatments per Acre.
The average number of active ingredients applied per acre in the production of corn in Ohio has steadily risen over time, as shown in the example of Table 6c below.