Introduction
Corn and soybean are the two most widely planted crops in the United States. The United States is the leading producer of corn and the second-largest producer of soybean (FAO 2022). In 2023, 38.3 and 33.8 million ha were planted with corn and soybean, respectively (USDA-NASS 2024b). A total corn production of 389.6 billion kg added US$73.9 billion to the U.S. economy in 2023 (USDA-NASS 2023a), while a total soybean production of 113.3 billion kg added US$52.8 billion (USDA-NASS 2023a). Together, corn and soybean grain production was worth US$126.7 billion in the United States in 2023.
Weeds compete for resources and are a major yield-limiting biotic factor for agronomic crops (Oerke Reference Oerke2006; Singh et al. Reference Singh, Kukal, Irmak and Jhala2022). The evolution and widespread occurrence of herbicide-resistant weeds is a challenge for corn and soybean producers (Kaur et al. Reference Kaur, Rogers, Lawrence, Shi, Chahal, Knezevic and Jhala2024), adding cost to crop production (Striegel et al. Reference Striegel, Eskridge, Lawrence, Knezevic, Kruger, Proctor, Hein and Jhala2020). Oerke (Reference Oerke2006) estimated that weeds could cause 34% of the potential yield loss of major field crops across the globe compared with 16% to 18% potential yield loss from animal pests and pathogens. Globally, weeds are estimated to cause 40% and 37% potential yield loss of corn and soybean, respectively (Oerke Reference Oerke2006). In the United States and Canada, weeds can cause 50% potential yield loss of corn, equating to 148 billion kg of corn worth more than US$26.7 billion annually (Soltani et al. Reference Soltani, Dille, Burke, Everman, VanGessel, Davis and Sikkema2016). In soybean fields, uncontrolled weeds can cause 52% potential yield loss, a value reduction of US$16.2 billion and US$1 billion in the United States and Canada, respectively (Soltani et al. Reference Soltani, Dille, Burke, Everman, VanGessel, Davis and Sikkema2017). The potential yield losses are higher than the actual losses because they were estimated from research field plots with no weed control (Soltani et al. Reference Soltani, Dille, Burke, Everman, VanGessel, Davis and Sikkema2016, Reference Soltani, Dille, Burke, Everman, VanGessel, Davis and Sikkema2017), which often have higher weed infestations and weed seed banks compared with weed infestations in a typical grower’s fields. Actual losses of grain yield due to weeds is about 10% for corn and 8% for soybean (Oerke Reference Oerke2006), highlighting the benefits of chemical, mechanical, and other control tactics employed by growers.
To avoid or minimize yield loss from weeds, growers usually apply herbicides to control weeds (Jhala et al. Reference Jhala, Kumar, Yadav, Jha, Jugulam, Williams, Hausman, Dayan, Burton, Dale and Norsworthy2023). Most corn and soybean fields in the United States are planted with herbicide-resistant traits; for example, in 2023, 82% of corn planted in the United States had stacked herbicide and insect-resistant traits and 9% had only herbicide-resistant traits (USDA-ERS 2024), while about 95% of soybean planted in the United States in 2023 had herbicide-resistant traits (USDA-ERS 2024). About 96% of corn and soybean planted in the United States in 2021 and 2023, respectively, received at least one herbicide application (USDA-NASS 2022b, 2024c). Herbicides are a significant cost in row crop production systems; for example, Gregory and Leach (Reference Greogry and Leach2022) estimated an average herbicide program cost of US$136 ha–1 compared with an average insecticide cost of US$14 ha–1 in corn production fields in Mississippi during the 2018–2022 period. For soybean, the researchers estimated an average herbicide program cost of US$200 ha–1 compared with an average insecticide cost of $45 ha–1 and an average fungicide cost of $37 ha–1 in Mississippi from 2018 to 2022 (Gregory and Leach Reference Greogry and Leach2022).
Although economic and agricultural experts estimate herbicide and/or pesticide costs as part of the annual crop production budget in many states through methods such as surveys, expert input, and others (CCA 2024; Ibendahl and O’Brien Reference Ibendahl and O’Brien2024; Klein Reference Klein2024; Paulson and Schnitkey Reference Paulson and Schnitkey2024; Plastina Reference Plastina2024; Schnitkey and Paulson Reference Schnitkey and Paulson2024), limited quantitative data exists on estimates of herbicide cost at the national level. State-level estimates are valuable for evaluating or projecting costs, net returns, and profitability at the regional level, helping growers make informed decisions and enabling stakeholders to stay informed about the latest agricultural research advancements and developments. However, national-level estimates are essential for providing a broader perspective, highlighting trends, facilitating informed policymaking and nationwide planning and decision-making.
In 2001, Gianessi and Sujatha (Reference Gianessi and Sujatha2003) estimated a US$4.7 billion expenditure on 185.8 million kg of herbicides applied to 40 crops in the United States. In their estimate, the expenditure of herbicides in corn production was US$1.8 billion, and US$1.2 billion for soybean. In the 2005 update, Gianessi and Reigner (Reference Gianessi and Reigner2006) estimated herbicide costs in corn and soybean were US$1.9 billion and US$1.2 billion, respectively. Since then, however, herbicide usage trends in corn and soybean production have changed. For example, herbicide use on soybean has increased from 1.48 kg ha–1 in 2005 (41.3 million kg applied over 27.9 million ha; Gianessi and Reigner [Reference Gianessi and Reigner2006]) to 2.74 kg ha–1 in 2023 (89.1 million kg applied over 32.5 million ha; USDA-NASS [2024b]), likely to combat herbicide resistance issues through more herbicide applications or the use of multiple active ingredients per application in premix herbicide products, particularly for the residual herbicides applied at soybean planting. This increased usage has likely contributed to higher herbicide costs. Therefore, information about the cost of herbicides in corn and soybean production is warranted. In addition, updated data or estimates on the cost of herbicides in corn and soybean production can serve as a guide to policymakers, legislators, industry, and regulators to assess the economic impacts of potential herbicide restrictions and inform decisions about investing in nonchemical weed control methods, among other factors. Therefore, the objective of this project was to estimate the cost of herbicide use in U.S. corn and soybean production, as reported by growers to the U.S. Department of Agriculture (USDA).
Materials and Methods
Herbicide usage data for corn and soybean were acquired from USDA-NASS (2022a) and USDA-NASS (2024a) surveys, respectively. The USDA-NASS (2022a) corn survey was conducted in 19 states and covered 92.1% (34.8 million ha out of 37.8 million ha) of total corn planted in the United States in 2021 (Figure 1). The USDA-NASS (2024a) soybean survey was conducted in 19 states and covered 96.3% (32.6 million ha out of 33.8 million ha) of total soybean planted in the United States in 2023 (Figure 2). These surveys reported herbicide use on an active ingredient (ai) or acid equivalent (ae) basis.
Total herbicide applied (in millions of kilograms) to corn production fields in 2021 in the 19 program states of the USDA-NASS (2022a) survey.
Total herbicides applied (in millions of kilograms) to soybean production fields in 2023 in the 19 program states of the USDA-NASS (2024a) survey.
Commonly used or known single ai/ae herbicide products were selected to represent each herbicide ai/ae reported in the USDA-NASS surveys. There were cases where active ingredients were sold only as premixtures (for example, diflufenzopyr-sodium is sold as Status, and bicyclopyrone is sold as Acuron-branded products). In such cases, the amount of secondary active ingredients or acid equivalents in the selected product were subtracted from their respective totals. The approximate retail prices for herbicide products were extracted from 2021 (for corn) and 2023 (for soybean) extension publications from the University of Nebraska-Lincoln (“Guide for Weed, Disease, and Insect Management in Nebraska”; Knezevic et al. Reference Knezevic, Klein, Ogg, Creech, Kruger, Lawrence, Jhala and Proctor2021, Reference Knezevic, Klein, Weisbrod, Creech, Proctor, Lawrence, Jhala and Puckett2023), North Dakota State University (“North Dakota Weed Control Guide”; Ikley et al. Reference Ikley, Christoffers, Dalley, Endres, Gramig, Howatt, Jenks, Keene, Ostlie, Peters, Robinson, Thostenson and Valenti2021, Reference Ikley, Christoffers, Dalley, Endres, Gramig, Howatt, Jenks, Law, Lim, Ostlie, Peters, Robinson, Thostenson and Valenti2023), and Kansas State University (“Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland”; Lancaster et al. Reference Lancaster, Fick, Currie and Kumar2021, Reference Lancaster, Fick, Currie and Kumar2023). These three publications were selected because they provide herbicide cost estimates with annual updates. The cost for each herbicide (ai/ae) reported in the USDA-NASS surveys was calculated as follows:
$${\rm{Herbicide\;cost}}\; = {{{{\rm{Herbicide\;amount\;}}}} \over {{{\rm{Product\;concentration}}}}}\;$$$$ \times {\rm{Average\;retail\;price\;of\;the\;product}}$$
where herbicide amount is the total in kilograms (ai or ae) reported in the USDA-NASS surveys, production concentration is the amount (ai or ae) per kilogram or liter of the product, and average retail price is based on approximate product prices reported in the aforementioned publications from the three states (Ikley et al. Reference Ikley, Christoffers, Dalley, Endres, Gramig, Howatt, Jenks, Keene, Ostlie, Peters, Robinson, Thostenson and Valenti2021, Reference Ikley, Christoffers, Dalley, Endres, Gramig, Howatt, Jenks, Law, Lim, Ostlie, Peters, Robinson, Thostenson and Valenti2023; Knezevic et al. Reference Knezevic, Klein, Ogg, Creech, Kruger, Lawrence, Jhala and Proctor2021, Reference Knezevic, Klein, Weisbrod, Creech, Proctor, Lawrence, Jhala and Puckett2023; Lancaster et al. Reference Lancaster, Fick, Currie and Kumar2021, Reference Lancaster, Fick, Currie and Kumar2023).
Results and Discussion
Corn herbicides were estimated to cost approximately US$3.1 billion in the United States in 2021 (Table 1) (All monetary figures are stated in U.S. dollars). Considering that corn is planted on 37.8 million ha, and that 96% of planted acreage received a herbicide in 2021 (USDA-NASS 2022b), herbicides cost around $88 ha–1. This is $10 ha–1 and $26 ha–1 lower than the estimated corn herbicide costs of $98 ha–1 and $114 ha–1 in the 2021 production budgets from Iowa State University (Plastina Reference Plastina2021) and Ohio State University (Ward et al. Reference Ward, Shoemaker, Thomison and Stachler2021), respectively. This underscores the variability in the estimates that can stem from the herbicides chosen, their required rates, the price of products, and their market availability, among other factors. Like this estimate, the Iowa’s estimate appears to cover herbicide costs alone (Plastina Reference Plastina2021), whereas the Ohio’s estimate includes both herbicide and adjuvant costs (Ward et al. Reference Ward, Shoemaker, Thomison and Stachler2021). However, the Iowa’s estimate is more comprehensive, drawing on data from sources such as Iowa Farm Business Association records and statewide surveys of agricultural cooperatives and input suppliers. In contrast, the Ohio State estimate seems to be primarily based on expert input.
a Abbreviations: ae, acid equivalent; ai, active ingredient; KSU, Kansas State University, NDSU, North Dakota State University; UNL, University of Nebraska-Lincoln.
b Herbicide usage data were sourced from the USDA-NASS (2022a) Agricultural Chemical Use Survey for corn. Approximate retail prices of herbicide products were sourced from the 2021 Guide for Weed, Disease, and Insect Management in Nebraska (University of Nebraska–Lincoln; Knezevic et al. Reference Knezevic, Klein, Ogg, Creech, Kruger, Lawrence, Jhala and Proctor2021), the 2021 North Dakota Weed Control Guide (North Dakota State University; Ikley et al. Reference Ikley, Christoffers, Dalley, Endres, Gramig, Howatt, Jenks, Keene, Ostlie, Peters, Robinson, Thostenson and Valenti2021), and the 2021 Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland (Kansas State University; Lancaster et al. Reference Lancaster, Fick, Currie and Kumar2021). Values may not sum exactly due to rounding differences.
c Acuron Flexi contains 38 g L–1 mesotrione and 343 g L–1 S-metolachlor, contributing 504,396 kg of mesotrione and 4,508,040 kg of S-metolachlor. These values were subtracted from the total mesotrione (2,423,542 kg) and S-metolachlor (12,247,891 kg) amounts, resulting in 1,919,146 kg of mesotrione and 7,739,851 kg of S-metolachlor remaining attributed to Callisto and Dual II Magnum, respectively.
d The retail price for Rifle Plus or Marksman (dicamba, potassium salt) was not available in Kansas State, North Dakota State, and Ohio State university extension publications; instead, XtendiMax, which is the diglycolamine salt of dicamba, was used.
e Yukon contains 0.125 kg of halosulfuron-methyl per kilogram of product. After deducting 185,973 kg of dicamba, sodium salt from Status, the remaining 16,329 kg was attributed to 29,689 kg of Yukon (0.55 kg dicamba-sodium per kilogram of product). This amount of Yukon also contributed 3,711 kg of halosulfuron-methyl—1,897 kg more than the 1,814 kg of total use. This surplus would have cost $1,536,806 (based on the price of Permit) for 1,897 kg of halosulfuron-methyl, which was subtracted from the total cost.
f Status contains 0.4 kg ae of dicamba, sodium salt. Therefore, Status also contributed 185,973 kg of dicamba, sodium salt. This value was subtracted from the total use of 202,302 kg, and the remaining 16,329 kg dicamba, sodium salt was attributed to Yukon.
g Dual Magnum contains S-metolachlor as the active ingredient instead of metolachlor.
h The total (106,804,133 kg) represents the sum of the amounts of herbicides reported in this table. It is less than the total reported in the survey (107,872,430 kg).
According to this estimate in Table 1, acetochlor (Harness), glyphosate (all salt formulations), and mesotrione (Callisto) had the highest cost, equivalent to $597.1 million, $350.6 million, and $319.3 million, respectively. According to the USDA-NASS (2022b) survey, glyphosate (all salt formulations), atrazine, and acetochlor were applied the most in quantity, equivalent to 33.8, 26.8, and 18.9 million kg, respectively. However, on an area basis, the herbicides applied most in corn production in 2021 included glyphosate (all salt formulations: 11% glyphosate, 2% dimethylamine salt, 41% isopropylamine salt, and 25% potassium salt), which was applied to 79% of corn, atrazine applied to 65% of corn, and mesotrione applied to 47% (USDA-NASS 2022b). Acetochlor was applied to about one-third or 34% corn acreage, with a total use of 18,903,447 kg (USDA-NASS 2022a, 2022b). Very-long-chain fatty acid (VLCFA)-inhibiting herbicides are applied for residual weed control (Jhala et al. Reference Jhala, Singh, Shergill, Singh, Jugulam, Riechers, Ganie, Selby, Werle and Norsworthy2024) and constituted about one-third (35,807,460 kg, including 18,903,447 kg acetochlor, 1,311,334 kg dimethenamid-P, 3,290,356 kg metolachlor, 54,431 kg pyroxasulfone, and 12,247,891 kg S-metolachlor) of total herbicide usage (107,872,430 kg; USDA-NASS 2022a). Many of the preemergence herbicides are likely applied as premixtures, which may be more economical than mixing products containing individual active ingredients.
Assuming the entire amount is attributed to a single ai/ae herbicide product, the highest expenditure was $1.1 billion on VLCFA inhibitor herbicides ($597.1 million on acetochlor, $74.2 million on dimethenamid-P, $78.5 million on metolachlor, $21.1 million on pyroxasulfone, and $352.7 million on S-metolachlor), followed by $934.7 million on hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitors (Jhala et al. Reference Jhala, Kumar, Yadav, Jha, Jugulam, Williams, Hausman, Dayan, Burton, Dale and Norsworthy2023) ($300.2 million on bicyclopyrone, $74.7 million on isoxaflutole, $403.2 million on mesotrione, $100.6 million on tembotrione, and $56.0 million on topramezone), $350.6 million on enolpyruvyl shikimate phosphate synthase (EPSPS) inhibitors, $346.4 million on auxin mimics ($7.1 million on 2,4-D, $210.0 million on clopyralid, $124.6 million on dicamba, and $4.8 million on fluroxypyr), $257.3 million on acetolactate synthase (ALS) inhibitors ($51.3 million on flumetsulam, $2.0 million on halosulfuron-methyl, $17.2 million on rimsulfuron, $174.8 million on thiencarbazone-methyl, and $12.0 million on thifensulfuron), and $227.4 million on photosystem II (PS II) inhibitors ($217.5 million on atrazine, $6.1 million on metribuzin, and $3.9 million on simazine).
Furthermore, under this single ai/ae assumption, mesotrione (Callisto) and S-metolachlor (Dual II Magnum) would have cost $403.2 million and $352.7 million, respectively—both higher than the estimated cost of glyphosate ($350.6 million; all salt formulations) (Table 1). Iowa, Illinois, and Nebraska were the top corn-producing states, collectively accounting for 36% of the total corn planted in 2021 (USDA-NASS 2022b). Corn was planted on about 5.2 million ha in Iowa (13.8%), 4.5 million ha in Illinois (11.8%), and 4.0 million ha in Nebraska (10.6%) in 2021. According to the USDA-NASS (2022a) survey, 13.3, 16.6, and 16.0 million kg of herbicides were applied in Iowa, Illinois, and Nebraska, respectively (Figure 1). Interestingly, herbicide use rates in these states increased progressively, with Iowa at 2.66 kg ha–1, Illinois at 3.83 kg ha–1, and Nebraska at 4.29 kg ha–1 (Table 2). Indiana had relatively high rate of herbicides at 4.54 kg ha–1. Herbicide use varied widely across states, ranging from 1.73 kg ha–1 in Texas to 5.43 kg ha–1 in Pennsylvania.
Statewide herbicide use of corn and soybean reported in USDA-NASS surveys.
a Data source: USDA-NASS (2022a, 2024a).
b Data source: USDA-NASS (2021b, 2023b).
The estimated cost of soybean herbicides was approximately $4.1 billion in 2023 in the United States (Table 3). Soybean was planted on 33.8 million ha, 96% was treated with a herbicide in 2023 (USDA-NASS 2024b), and herbicides cost around $125 ha–1. This was $55 ha–1 lower than the estimated herbicide cost of $180 ha–1 used on herbicide-resistant soybean following a corn planting in the 2023 Iowa State University soybean production budget (Plastina Reference Plastina2023). The 2023 soybean budget from Ohio State University estimated a herbicide cost of 137 ha–1 (Ward and Laura Reference Ward and Laura2023), which was closer to the $125 ha–1 estimated cost in this study. The difference in the range of estimates between the two universities could be due to methodology, among other factors. The Iowa State estimate gathers data from multiple sources to represent average costs for Iowa farms, whereas the Ohio State estimate is based on applications of specific herbicides plus adjuvants for a particular crop.
a Abbreviations: ae, acid equivalent, ai, active ingredient; KSU, Kansas State University, NDSU, North Dakota State University; UNL, University of Nebraska–Lincoln; USDA-NASS, U.S. Department of Agriculture–National Agricultural Statistics Service.
b Herbicide usage data were sourced from the USDA-NASS (2024a) Agricultural Chemical Use Survey for soybean. Approximate retail prices of herbicide products were sourced from the 2023 Guide for Weed, Disease, and Insect Management in Nebraska (Knezevic et al. Reference Knezevic, Klein, Weisbrod, Creech, Proctor, Lawrence, Jhala and Puckett2023), the 2023 North Dakota Weed Control Guide (Ikley et al. Reference Ikley, Christoffers, Dalley, Endres, Gramig, Howatt, Jenks, Law, Lim, Ostlie, Peters, Robinson, Thostenson and Valenti2023), and the 2023 Chemical Weed Control for Field Crops, Pastures, Rangeland, and Noncropland (Lancaster et al. Reference Lancaster, Fick, Currie and Kumar2023). Values may not sum exactly due to rounding differences.
c Banvel contains dimethylamine salt of dicamba, not the sodium salt. Status and Yukon were excluded because they are not labeled for soybean use. Also, Status contains diflufenzopyr-sodium, and Yukon contains halosulfuron.
d Flexstar is sodium salt of fomesafen.
e Dual Magnum has S-metolachlor as an active ingredient instead of metolachlor.
f The total (88,731,213 kg) represents the sum of the amounts of the herbicides reported in this table. It is less than the total amount reported in the survey (89,063,696 kg).
g Although not approved for soybean use, the USDA-NASS database reports the total quantity of herbicide active ingredients or acid equivalents for the crop year, covering the period from the previous crop’s harvest to the current crop’s harvest.
According to this estimate, the highest costs are attributed to glyphosate (all salt formulations) at $1.1 billion, pyroxasulfone (Zidua SC; BASF, Florham Park, NJ) at $358.8 million, and glufosinate (Liberty 280 SL; BASF) at $343.8 million. Glyphosate, in various salt formulations (10% glyphosate, 25% dimethylamine, 46% isopropylamine, and 22% potassium), was applied to 103% of soybean-planted acres, indicating overlap, whereas 2,4-D salts (15% 2-ethylhexyl ester, 37% choline salt, and 6% dimethylamine) were applied to 58% of planted soybean acres (USDA-NASS 2024c). Among 2,4-D salts, the amine and ester formulations can be applied only before soybean is planted, and planting intervals should be maintained, while the choline salt is permitted for use on Enlist soybean (Pioneer, Johnston, IA). On an individual salt basis, glyphosate isopropylamine and 2,4-D choline were the most used, applied to 46% and 37% of soybean-planted acres, respectively, in 2023 (USDA-NASS 2024c). The estimated cost of 9,709,590 kg of 2,4-D choline was $328.8 million, an amount that could rise due to restrictions on using dicamba-based products (Engenia, BASF; Tavium, Syngenta, Greensboro, NC and XtendiMax, Bayer CropScience, St. Louis, MO) in dicamba-resistant soybean starting from the 2025 growing season (Zaric et al. Reference Zaric, Lloyd, Knezevic and Jhala2024). Glyphosate dimethylamine salt, glufosinate-ammonium, and glyphosate potassium salt were used, respectively, on 25%, 23%, and 22% of soybean planted in 2023 (USDA-NASS 2024c). The estimated cost of glyphosate dimethylamine salt (Durango DMA, Albaugh, LLC, Ankeny, IA), glufosinate-ammonium (Liberty 280), and glyphosate potassium salt (RoundupPowerMax3, Bayer CropScience) were around $113.2, $343.8, and $277.0 million, respectively.
Interestingly, herbicides that inhibit protoporphyrinogen oxidase (PPO) (30,844 kg acifluorfen sodium, 2,722 kg carfentrazone-ethyl, 5,443 kg flumiclorac-pentyl, 311,618 kg flumioxazin, 4,990 kg fluthiacet-methyl, 66,224 kg fomesafen, 399,161 kg fomesafen sodium, 12,247 kg lactofen, 57,153 kg saflufenacil, and 1,419,743 kg sulfentrazone; 2,310,144 kg total) cost $358.6 million, similar to pyroxasulfone in this estimate. After EPSPS inhibitors ($1.1 billion), the highest costs were attributed to VLCFA inhibitors at $761.6 million ($89.3 million on acetochlor, $38.1 million on dimethenamid-P, $24.8 million on metolachlor, $358.8 million on pyroxasulfone, and $250.6 million on S-metolachlor), auxin mimics at $691.1 million ($434.5 million on 2,4-D, $8.3 million on clopyralid, $248.3 million on dicamba), ALS inhibitors at $390.7 million ($131.0 million on chlorimuron-ethyl, $79.0 million on chlronsulam-methyl, $8.1 million on flumetsulam, $76.1 million on imazethapyr, $8.4 million on rimsulfuron, $61.9 million on thiencarbazone-methyl, $23.9 million on thifensulfuron, and $2.3 million on tribenuron-methyl), PPO inhibitors at $358.6 million ($2.0 million on acifluorfen, $2.8 million on carfentrazone-ethyl, $3.8 million on flumiclorac-pentyl, $71.8 million on flumioxazin, $13.7 million on fluthiacet-methyl, $33.2 million on fomesafen, $2.7 million on lactofen, $41.1 million on saflufenacil, and $187.5 million on sulfentrazone), glutamine synthetase inhibitors at $343.8 million, and acetyl-CoA carboxylase (ACCase) inhibitors at $272.7 million ($258.5 million on clethodim and $14.2 million on fluazifop-p-butyl).
About 5,331,067 kg of dicamba (29,030 kg dicamba, 28,049 kg N,N-Bis-[3-aminopropyl] methylamine [bapma] salt, 2,529,229 kg diglycolamine salt, 1,730,453 kg dimethylamine salt, and 114,305 kg sodium salt) use was reported on soybean fields in 2023 (USDA-NASS 2024a; Table 3), which was about 1.7 times higher than the reported estimate of 3,088,962 kg (51,256 kg dicamba, 952,997 kg bapma salt, 1,691,445 kg diglycolamine salt, 376,935 kg dimethylamine salt, 7,257 kg isopropylamine salt, and 9,072 kg sodium salt) in 2017 (USDA-NASS 2018) and 68.3 times higher than the reported estimate of 78,018 kg (33,566 kg diglycolamine salt and 44,452 kg dimethylamine salt) in 2015 (USDA-NASS 2016). This surge in dicamba use on soybean occurred with the commercialization of dicamba-resistant soybean in 2016. For example, in 2018, 43% of soybean planted in the United States was resistant to dicamba, including 71% of soybean planted in Tennessee and 79% of soybean planted in Mississippi (Wechsler et al. Reference Wechsler, Smith, McFadden, Dodson and Williamson2019). Dicamba-resistant soybean allowed the postemergence application of new dicamba formulations, such as bapma salt (Engenia) and diglycolamine salt (Tavium and XtendiMax), thus increasing its use in soybean fields. Illinois, Iowa, and Minnesota accounted for one-third of the total soybean planted (33.8 million ha) in the United States in 2023 (USDA-NASS 2024c). Products that contain dicamba are also applied to corn for control of glyphosate-resistant broadleaf weeds (Singh et al. Reference Singh, Barnes, Dintelmann, Bradley, Hager and Jhala2024).
Soybean was planted on about 4.2 million ha in Illinois (12.4%), 4.0 million ha in Iowa (11.9%), and 3.0 million ha in Minnesota (8.8%) (USDA-NASS 2024c). Herbicide use in Illinois, Iowa, and Minnesota was 11.3, 11.0, and 6.2 million kg, respectively (Figure 2). Herbicide use rates in Iowa and Illinois were similar (2.87 to 2.90 kg ha–1), whereas a slightly lower rate of 2.15 kg ha–1 was used in Minnesota (Table 2). Herbicide use rates varied across states, ranging from 2.15 kg ha–1 in Minnesota to 4.15 kg ha–1 in Mississippi. Herbicide use rates between 3.00 and 3.50 kg ha–1 were reported in several states including Arkansas (3.06 kg ha–1), Indiana (3.55 kg ha–1), Kansas (3.39 kg ha–1), Kentucky (3.23 kg ha–1), Louisiana (3.34 kg ha–1), North Carolina (3.50 kg ha–1), Ohio (3.3 kg ha–1), and Tennessee (3.01 kg ha–1).
Based on this estimate, herbicide use in corn production in 2021 and soybean production in 2023 would have cost $3.6 billion and $4.2 billion, respectively, in inflation-adjusted dollars (adjusted to December 2024), totaling $7.8 billion for these two major field crops in the United States (Table 4). The actual total cost of herbicides would vary with the chosen products and their prices; for example, choosing Warrant (BayerCropScience, 0.36 kg L–1; $10 L–1; Ikley et al. Reference Ikley, Christoffers, Dalley, Endres, Gramig, Howatt, Jenks, Keene, Ostlie, Peters, Robinson, Thostenson and Valenti2021; Knezevic et al. Reference Knezevic, Klein, Ogg, Creech, Kruger, Lawrence, Jhala and Proctor2021; Lancaster et al. Reference Lancaster, Fick, Currie and Kumar2021) instead of Harness (BayerCropScience, 0.84 kg L–1; $27 L–1) for 18,903,447 kg of acetochlor on corn would have decreased the estimated cost from $597.1 to $524.2 million in Table 1. This estimate does not include the cost of adjuvants, oils, surfactants, tank additives, and application cost. This is an approximate estimate, as product choices vary depending on the field and the grower. Additionally, corn and soybean growers have been using premix herbicide products with multiple ai/ae combinations to control herbicide-resistant weeds, and the prices of these premixes differ from those containing a single ai/ae. Furthermore, product prices could vary depending on the state, the area within the state, the quantity purchased, discounts on bulk purchases, the dealer, the wholesaler, seasonal fluctuations, the price structure, and specific programs/offers from the manufacturing company, among other factors (Ikley et al. Reference Ikley, Christoffers, Dalley, Endres, Gramig, Howatt, Jenks, Keene, Ostlie, Peters, Robinson, Thostenson and Valenti2021; Lancaster et al. Reference Lancaster, Fick, Currie and Kumar2021). Therefore, this estimate may be further refined by extracting approximate retail prices of products at the state/county/farm level and multiplying by the herbicide use at the product level in each of the 19 states of the USDA-NASS surveys. This estimate may serve as a baseline for evaluating the economic impact of targeted-weed management; for example, assuming 15% savings in herbicide use with targeted spraying of postemergence herbicides could theoretically save approximately $1.2 billion (15% of $7.8 billion) worth of herbicide in corn and soybean production. However, additional application costs (e.g., subscriptions) associated with targeted or site-specific technologies could offset their economic benefits.
Acreage, production, herbicide use, and costs for corn and soybean in the United States in 2001, 2005, and 2021/2023.
a Data Source: Year 2001, Gianessi and Sujatha (Reference Gianessi and Sujatha2003); Year 2003, Gianessi and Reigner (Reference Gianessi and Reigner2006); Year 2021, USDA-NASS (2022a); Year 2023; USDA-NASS (2024a).
b In the Total Acreage column, the numbers in parentheses represent treated acreage: 98% of corn was treated with herbicides in 2001 and 2005, and 96% in 2021. Similarly, 96% of soybean fields were treated in 2001, 2005, and 2023. In the Total Production column, the numbers in parentheses indicate production from treated acres. These figures for treated acreage or production used in subsequent calculations, rather than the total acreage or total production values.
c Inflation-adjusted dollar values were calculated using the U.S. Bureau of Labor Statistics CPI Inflation Calculator (https://www.bls.gov/data/inflation_calculator.htm). Values from 2001, 2005, 2021, and 2023 were adjusted from December of each year to December 2024 for comparison. After this adjustment, one dollar in December 2001, 2005, 2021, and 2023 was equivalent to $1.79, $1.60, $1.13, and $1.03, respectively, in December 2024.
On a real dollar basis (adjusted for inflation to December 2024), this estimate ($7.8 billion) is approximately 1.6 times the $4.9 billion estimate from 2005 ($3.0 billion for corn and $1.9 billion for soybean; Gianessi and Reigner [Reference Gianessi and Reigner2006]). This increase is partly due to higher herbicide usage. Combined herbicide usage for corn in 2021 and soybean in 2023 totaled 196.9 million kg (107.8 million kg for corn in 2021; USDA-NASS [2022a] and 89.1 million kg for soybean in 2023; USDA-NASS [2024a]) compared with 113.2 million kg in 2005 (71.9 million kg for corn and 41.3 million kg for soybean; Gianessi and Reigner [Reference Gianessi and Reigner2006]). The increase primarily reflects greater herbicide use per unit area, particularly in soybean, rather than significant expansion in acreage.
Herbicide-treated acreage in corn increased by 12% (32.1 to 36.1 million ha) in 2021, while total herbicide use increased by 50% (71.9 to 107.8 million kg) compared to 2005 (Gianessi and Reigner [Reference Gianessi and Reigner2006]; USDA-NASS [2022b]). Similarly, herbicide-treated soybean acreage increased by 16% (27.9 to 32.5 million ha) in 2023, while total herbicide use more than doubled, rising by 116% (41.3 to 89.1 million kg) compared to 2005 (Gianessi and Reigner [Reference Gianessi and Reigner2006]; USDA-NASS [2024c]). Consequently, herbicide use per hectare for soybean increased significantly, reaching 2.74 kg ha–1 in 2023—an 85% increase compared to 2005 (1.48 kg ha–1) and a 126% rise compared to 2001 (1.21 kg ha–1). This resulted in a 91% increase in total herbicide costs for soybean in 2023 ($4.2 billion) compared to 2001 ($2.2 billion) and a 121% increase compared to 2005 ($1.9 billion). Herbicide use per hectare in corn remained relatively stable, at 2.99 kg ha–1 in 2021, slightly below 3.11 kg ha–1 in 2001. It dipped to 2.22 kg ha–1 in 2005 primarily due to a 22 million kg reduction in total herbicide use (93.5 million kg in 2001 vs. 71.9 million kg in 2005). This decline was largely driven by replacing older, high-dose herbicides (e.g., butylate, cyanazine, EPTC, and metolachlor) with newer, lower-dose options (e.g., flufenacet, mesotrione, rimsulfuron, and S-metolachlor) (Gianessi and Reigner [Reference Gianessi and Reigner2006]).
The largest cost increase in real dollars was observed in soybean production. Herbicide costs per hectare in 2023 ($128 ha–1) were 1.8 times higher than the 2001 and 2005 average ($73 ha–1). Additionally, costs per unit of soybean grain in 2023 ($38 per 1,000 kg) were 1.4 times higher than the 2001 and 2005 averages ($27 per 1,000 kg). In contrast, herbicide costs for corn remained relatively stable. Per-hectare costs in 2021 ($100 ha–1) were consistent with the averages in 2001 and 2005 ($100 ha–1), while costs per unit of corn grain in 2023 ($10 per 1,000 kg) were similar to the averages in 2001 and 2005 ($9 per 1,000 kg). Although not all herbicides are equally valuable, the inflation-adjusted cost per kilogram has generally decreased or remained stable over time. For corn, the cost in 2021 ($33 kg–1) was lower than the cost in 2005 ($42 kg–1) and similar to the cost in 2001 ($35 kg–1). For soybean, the cost in 2023 ($47 kg–1) was lower than the cost in 2001 ($63 kg–1) and comparable to the cost in 2005 ($46 kg–1).
More herbicides are labeled for use on corn than soybean, particularly herbicides applied postemergence. Limited postemergence herbicides labeled for soybean that can control herbicide-resistant weeds such as Palmer amaranth (Amaranthus palmeri S. Watson) and waterhemp [Amaranthus tuberculatus (Moq.) J. D. Sauer] make it necessary for growers to use preemergence herbicides that are a premix of two to three herbicide active ingredients at soybean planting, which are more expensive than postemergence herbicides. In addition, certain residual herbicides (e.g., Warrant, Zidua) labeled to soybean can be applied postemergence, which can provide overlapping residual control of Palmer amaranth and waterhemp. In most cases, a residual herbicide applied at corn planting and a postemergence herbicide can provide effective control of most weeds that affect corn production, so an overlapping residual herbicide is not required. Therefore, herbicide programs usually cost more for soybean than corn.
Practical Implications
Growers often use herbicides as a primary method for managing weeds. Among pesticides, herbicides are the most widely used chemicals in corn and soybean production in the United States (Jhala et al. Reference Jhala, Singh, Shergill, Singh, Jugulam, Riechers, Ganie, Selby, Werle and Norsworthy2024). The cost of herbicides is significant for growers. Based on USDA-NASS (2022a) and (2024a) surveys, approximately 107.8 and 89.1 million kg of herbicides were applied in corn and soybean production in 2021 and 2023, respectively. Using an average retail price of herbicide products from the publications of three land grant universities (Kansas State University, University of Nebraska−Lincoln, and North Dakota State University), herbicides would have cost approximately $3.2 and $4.1 billion in producing corn and soybean, respectively (Tables 1 and 3). This estimated herbicide cost for corn production in 2021 was around 3.4% of $90.3, and for soybean production in 2023 the cost was 7.8% of $52.8 billion (USDA-NASS 2021a, 2023). Herbicide costs for soybean have significantly increased (values in real dollars, adjusted for inflation to December 2024), with per-hectare costs in 2023 reaching $128 ha–1, or about 1.8 times the 2001 and 2005 average of $73 ha–1 (Table 4). As a result, total herbicide costs for soybean nearly doubled, rising from $2.2 billion in 2001 to $4.2 billion in 2023. This increase is likely due to an 85% increase in herbicide usage per hectare, from 1.48 kg ha–1 in 2005 to 2.74 kg ha–1 in 2023, probably due to the need for additional herbicides to manage herbicide-resistant weeds in soybean (Gianessi and Reigner Reference Gianessi and Reigner2006; USDA-NASS 2024a). In contrast, herbicide costs for corn have remained relatively steady, totaling $3.3 billion in 2001 and $3.6 billion in 2021. Per-hectare costs in 2021 ($100 ha–1) were similar to the 2001 and 2005 average of $100 ha–1. However, herbicide use per hectare of corn increased by 35% from 2.22 kg ha–1 in 2005 to 2.99 kg ha–1 in 2021, likely driven by herbicide-resistant weed management efforts (Gianessi and Reigner Reference Gianessi and Reigner2006; USDA-NASS 2022a). Some data in the USDA surveys are intentionally withheld to maintain confidentiality, which may slightly affect conclusions or interpretations. This project aims to educate and inform stakeholders in the agricultural sector about national-level herbicide cost estimates for corn and soybean production in the United States.
Supplementary material
To view supplementary material for this article, please visit https://doi.org/10.1017/wet.2025.19
Acknowledgments
We are grateful for the data available made available by USDA-NASS via its pesticide use surveys. We thank the efforts of experts at the University of Nebraska-Lincoln, North Dakota State University, and Kansas State University for publishing updated approximate retail prices of herbicide products each year. We also thank Ian Rogers for editing this manuscript.
Funding
Funding was provided by USDA-NIFA Crop Protection and Pest Management award 2024-70006-43500, the “Nebraska Extension Implementation Program.”
Competing Interests
The authors declare they have no competing interests.
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