Glyphosate ban could deepen Illinois farm losses
Study puts losses at $609 million, but yield math may understate the bill
An Illinois glyphosate ban would not make corn and soybean production impossible. It would make weed control more expensive, more complicated and less forgiving — converting what appears to be a modest percentage of gross crop revenue into a potentially much larger share of farm profit. A new University of Illinois Urbana-Champaign and Illinois Soybean Association study estimates annual producer losses of $300 million to $609 million, or 1.8% to 3.6% of statewide corn and soybean revenue, after accounting for substitute herbicides, higher prices for those alternatives and a modest yield reduction.
The policy risk is not entirely hypothetical. Illinois state Rep. Joyce Mason (D-Grayslake) introduced HB 3803 in February 2025 to prohibit the distribution, sale and use of glyphosate or any product containing it. The blanket-ban proposal was referred to the Illinois House Rules Committee on Feb. 18, 2025, and has not advanced further. But the legislation demonstrated that a prohibition can enter the debate even in one of the nation’s largest corn- and soybean-producing states.
The size of the industry makes even a relatively small percentage loss consequential. Illinois farmers planted a combined 21.6 million acres of corn and soybeans in 2024, producing crops valued by USDA at approximately $16.68 billion. The study’s published $300 million-to-$609 million range therefore averages roughly $14 to $28 per planted acre, although actual costs would vary significantly according to crop, weed pressure, herbicide trait system and existing management practices.
That is not a trivial amount under current farm economics. University of Illinois farmdoc budgets released this spring project 2026 corn returns after all costs at losses of $45 to $91 per acre, depending on the region. Projected soybean returns range from $30 to $67 per acre, while a representative 50-50 corn-soybean rotation on high-productivity central Illinois farmland generates only about $11 per acre — including an expected government payment that would not arrive until October 2027. A statewide glyphosate-ban cost averaging $14 to $28 per acre could therefore consume the entire projected rotation profit and deepen losses on corn.
The study’s central conclusion is that adaptation would prevent the worst yield losses, but farmers would pay heavily for that adaptation. Researchers estimate glyphosate is used on 88% of Illinois corn acres and 93% of soybean acres, with annual direct spending of approximately $97 million to $186 million. Because state-level transaction data are unavailable, those figures are inferred from USDA acreage, application assumptions, market prices and internal industry survey information rather than measured directly from Illinois farm purchases.
A typical glyphosate-plus-residual program was estimated to cost $40 to $77 per hectare, equivalent to roughly $16 to $31 per acre. Glufosinate-based systems were estimated at $82 to $153 per hectare, or approximately $33 to $62 per acre, because they can require an additional postemergence application. Programs built around 2,4-D choline or dicamba were estimated at $47 to $89 per hectare, while clethodim and other selective grass-control systems require companion broadleaf and residual herbicides rather than serving as simple one-product replacements.
Aggregated across Illinois acreage, the paper calculates that substituting other weed-control programs would increase annual production costs by $238.5 million to $448.5 million. A sudden statewide demand increase could then raise the cost of replacement programs by another $35.8 million to $67.3 million under a 15% price increase, or by $71.6 million to $134.6 million if alternative-program costs rose 30%. Adding the study’s assumed yield effect produces the published loss range of approximately $300 million to $609 million.
Most of that figure is therefore not lost crop production. It is additional spending that comes directly out of producer margins. Farmers would still harvest corn and soybeans, but they would need more products, more precisely timed applications and, in some cases, additional trips across the field. The alternatives also carry narrower application windows and greater drift-management requirements, increasing the financial consequences of weather delays, labor shortages or insufficient custom-application capacity.
The published estimate also excludes potentially significant indirect costs. Glyphosate is widely used for burndown in no-till and reduced-tillage systems. Its removal could cause some producers to return to more mechanical tillage, raising tractor hours, fuel consumption, labor requirements and machinery depreciation while increasing soil disturbance. The study acknowledges that it did not calculate those expenses or potential effects on erosion, soil health and greenhouse gas emissions. It also does not quantify possible health or environmental benefits from a ban, meaning the report is a farm-cost analysis rather than a complete societal cost-benefit assessment.
Herbicide resistance cuts in both directions. Glyphosate-resistant waterhemp has already pushed many Illinois growers toward residual herbicides and multiple modes of action, meaning some farms are already bearing part of the expense modeled as a future substitution cost. That could make the incremental cost of a formal ban lower for those operations. However, rapidly concentrating millions of acres onto glufosinate, Group 4 herbicides and Group 15 residual products would intensify selection pressure and could shorten the effective life of the replacements. The study describes its estimates as short-run projections and notes that some Illinois waterhemp populations are already showing reduced susceptibility to residual chemistries that would become more important without glyphosate.
There is, however, an important numerical question surrounding the headline estimate. Table 8 in the report says the assumed 2% corn and soybean yield loss would reduce statewide revenue by only $25.6 million. Yet USDA values Illinois’ 2024 corn and soybean production at $16.68 billion, and 2% of that amount is approximately $333.6 million. Even using the study’s own Table 5, which calculates that a 9% yield loss would reduce gross receipts by $1.2805 billion, a proportional 2% loss would equal about $284.6 million — not $25.6 million. The published table appears to have applied the 2% factor to the previously calculated 9% loss rather than to total crop revenue, effectively modeling a yield loss of about 0.18%.
Because the journal version is an accepted, prepublication manuscript that remains subject to production changes, the authors or publisher may clarify or correct that calculation. Until then, the $609 million figure should not necessarily be treated as the upper boundary. Replacing the published $25.6 million yield component with 2% of USDA’s 2024 crop value — while leaving every other study assumption unchanged — would produce losses of roughly $608 million to $849 million under the 15% replacement-price scenario and $644 million to $917 million under the 30% scenario. That would equal approximately 3.6% to 5.5% of Illinois corn and soybean production value, or about $28 to $42 per planted acre. This is an independent recalculation, not an official revision of the study.
Bottom Line
The exact statewide number will remain debatable because farmers would respond differently, some operations already use costly diversified programs, and crop prices, herbicide prices and weed pressure change annually. But the study’s broader message is difficult to dismiss: banning glyphosate would not amount to simply replacing one herbicide jug with another. It would alter seed-trait choices, application schedules, equipment use, labor demand, tillage decisions and resistance-management strategies. During a period when Illinois corn production is already projected to lose money, even the lower published estimate would be a substantial margin shock — and the actual bill could be considerably higher.