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OSUNPK Fertilizer Market Outlook: Local Nitrogen Prices Break Lower 8.24.26
The most important movement of the past two weeks is the decline in Oklahoma nitrogen references. From August 7 to August 21, UAN 28% fell $39.70 per ton, urea fell $38.73, and anhydrous ammonia fell $46.00. USDA attributes the weakness to reduced demand as persistent heat and limited rainfall constrain field activity across the state.
Price-source note: The accompanying graphic’s Oklahoma average, minimum, and maximum come from the USDA Agricultural Marketing Service Oklahoma Production Cost Report. USDA does not identify its contributing dealers. Named public dealer cash quotes, including Two Rivers Cooperative, are monitored separately and are not blended into the USDA statistics.
The local decline does not mean that global nitrogen risk has disappeared. StoneX reported August 19 that India secured about 1.7 million metric tons in its latest urea tender with ample offers, including an expected contribution from China. That supply response eased immediate pressure, but attention now shifts toward Brazil’s September-through-December import window. Brazil needs granular urea, while much of China’s available export supply is prilled, so timing, product form, and destination still matter.
Josh Linville’s August 12 market commentary likewise described a well-supplied Indian tender and a weaker NOLA urea market, while cautioning that UAN and ammonia manufacturers held strong forward sales books. That distinction matters in Oklahoma: a softer urea benchmark can move faster than UAN or ammonia when producers have already covered substantial forward demand. Local weather can amplify the difference by weakening spot demand even while manufacturer positions remain supported.
Phosphate prices were nearly unchanged in the Oklahoma report, but their cost structure remains exposed to ammonia and sulfur. CoBank noted August 13 that Middle East disruptions and Russian supply constraints have affected ammonia production and sulfur availability, while China’s phosphate exports remain sharply restricted. Linville also highlighted sulfur as a bottleneck because a large share of globally traded sulfur normally moves through the Strait of Hormuz. Those pressures can raise the cost of producing DAP and MAP even when local posted values are temporarily steady. They also deserve attention for AMS and ATS, although Oklahoma’s reported averages changed little this period.
Potash remains the quietest major nutrient. Its production base is less directly tied to Middle East natural gas and sulfur, although ocean freight and broader logistics can still affect delivered replacement costs.
Over the next several weeks, watch Oklahoma rainfall and fall field demand, Brazil’s urea buying pace, the mix of Chinese exports, further Indian tenders, phosphate operating rates, sulfur availability, and freight. These forces point in different directions, so the current local nitrogen decline should be read as a market development rather than a definitive forecast.
For Oklahoma producers and dealers, the practical step is to compare current cash quotes on the same pickup or FOB basis and separate material price from delivery and application. Soil-test needs and product fit should remain central; price movement alone does not determine the best nutrient plan.
Fertilizer markets, local prices, and availability can change quickly. Confirm current prices and terms with local dealers before making purchasing decisions.
Market Sources
- USDA Agricultural Marketing Service. “Oklahoma Production Cost Report,” August 21, 2026. https://www.ams.usda.gov/mnreports/ams_3621.pdf
- StoneX. “Brazil’s Urea Import Window Now Decides Where Global Tonnes Land Next,” August 19, 2026. https://www.stonex.com/en/insights/brazil-s-urea-import-window-now-decides-where-global-tonnes-land-next/
- Hoosier Ag Today. “Josh Linville: Fertilizer Markets,” August 12, 2026. https://www.hoosieragtoday.com/2026/08/12/josh-linville-fertilizer-markets/
- CoBank Knowledge Exchange. “Why Higher Fertilizer Prices Are Here to Stay,” August 13, 2026. https://www.cobank.com/knowledge-exchange/why-higher-fertilizer-prices-are-here-to-stay
This report is produced via Chat GPT Plus Work, with review by Brian Arnall.
Sulfur Fertilizer in Wheat: Is It a Have-To?
Brian Arnall, Precision Nutrient Management Extension Specialist.
Sulfur has become a much bigger part of the fertility conversation over the last several years, and for good reason. We are producing higher-yielding crops, removing more nutrients from our fields, and receiving less sulfur from atmospheric deposition than we did several decades ago. But that does not mean sulfur fertilizer has become a “have-to” application for every wheat field.
Ms. Kelby Linn’s research provides a good example of why soil testing still matters. Across the environments in this study, sulfur fertilizer did not increase wheat grain yield. The soil was able to supply enough sulfur to meet the yield demand of the crop. When fertilizer margins are tight, that is important. Applying a nutrient that is already present in sufficient amounts is an expense without a yield return. At the same time, these results should not be interpreted to mean that sulfur fertilizer is unnecessary. Sulfur management is ultimately a mass-balance issue. Every bushel we harvest removes nutrients from the field. As yields increase, nutrient removal increases. If we continually remove more sulfur than the soil and other sources can supply, at some point we have to replace it.
That is why I am more concerned about sulfur in intensive, high-yield production systems, particularly on sandier soils and soils with lower organic matter. These soils generally have less capacity to supply sulfur, while a high-yielding crop is removing more of it. That combination increases the likelihood of sulfur becoming limiting. This is where soil testing becomes a valuable management tool. Rather than treating sulfur as something wheat either “always needs” or “never needs,” we should identify the fields where soil supply is unlikely to meet crop demand and put our fertilizer dollars there.
It is also important not to carry the wheat results presented here across every cropping system. Our ongoing work in corn has shown more response to sulfur fertilizer than we have observed in wheat. That fits the larger nutrient-removal discussion, particularly as we push corn yields higher. We will share two years of data after this year’s corn harvest.
Kelby’s research also raises another interesting question. If the soil already contains enough sulfur to maximize wheat grain yield, does additional sulfur do anything? His work suggests that it can. The response may not be additional bushels, but changes in how nitrogen is used and, ultimately, the quality and functionality of the grain.
Understanding Sulfur’s Role Beyond Grain Yield
Kelby Linn and Brian Arnall
Why Nitrogen and Sulfur Must Work Together
Nitrogen (N) has long been recognized as the most important nutrient for winter wheat production. It is a primary driver of vegetative growth, grain yield, and grain protein concentration, making N management the focus of most wheat fertility programs across Oklahoma. Sulfur (S) plays a different but complementary role. Nitrogen supplies the building blocks needed to produce proteins, while S is needed to form sulfur-containing amino acids such as cysteine and methionine. These amino acids contribute to the bonds that strengthen gluten proteins and influence dough strength, elasticity, and overall baking performance. When S becomes limiting, wheat may continue to take up N but may be less efficient at incorporating that N into functional storage proteins. Therefore, the relationship between N and S may become increasingly important as N rates and yield potential increase. The literature suggest that relationship can be wrong in both directions were N is in excess and S is deficient can cause yield loss but also where S is in excess and N is deficient we can experience loss.
Understanding the System
To better understand how S behaves under different N environments, field trials were conducted across north-central Oklahoma and south-central Kansas during the 2023–2025 growing seasons. The objective was to determine whether S responses differed when N was limiting compared with a high-N production environment.
Two N fertilizer rates were evaluated using ammonium sulfate (AMS) and urea:
- 60 lb N/ac, representing a sub-optimal or N-limited environment
- 140 lb N/ac, representing a high-N environment where S could have greater potential to become limiting
Each N rate was combined with five S rates supplied as AMS: 0, 5, 10, 20, and 30 lb S/ac.
Sulfur was applied before jointing, between Feekes 4 and 6, with the top-dresss N application, when wheat nutrient uptake is increasing and the crop is transitioning toward reproductive development. This allowed us to evaluate the influence of S on grain production, N utilization, and grain quality under both N-limited and high-N conditions.
Soil testing was an important part of interpreting the results. Across the locations, sulfate-S was present in the soil profile before fertilizer application. Soil test S varied among sites and depths, reinforcing that the amount of S already available to the crop can differ considerably among fields.
Table 1. Average composite soil sample results of pH, organic matter (OM), nitrate, and SO4 for all locations of the S interaction study.
First, What Happened to Yield?
Nitrogen remained the dominant factor controlling grain yield. Across environments, average wheat yield increased from 46 bu/ac with the lower N rate to 56 bu/ac with the higher N rate. Sulfur, however, did not significantly increase grain yield. Soil tests indicated that the sites generally contained measurable sulfate-S, which correctly predicted the lack of a yield response. If grain yield had been our only measurement, the story could have ended there. But the addition of S affected several characteristics related to how the grain performed during milling and dough development, particularly under the high-N treatment.
Why Wheat Quality Matters
Most Oklahoma wheat producers market wheat based primarily on grain yield and protein concentration. Once wheat moves farther through the grain chain, however, millers and commercial bakeries evaluate additional characteristics that determine how the flour performs. Hard red winter wheat is valued for its ability to produce strong bread flour. That ability depends not only on the amount of protein in the grain but also on the structure and functionality of those proteins. Nitrogen applications generally increases grain protein concentration, while S can influence the composition of those proteins. Adequate S promotes the formation of S-containing proteins involved in strong gluten networks. As a result, two wheat samples with similar protein concentrations can potentially behave differently during milling and baking.
Looking Beyond Grain Protein
Several measurements were used to evaluate wheat and flour quality. Grain protein represents the total protein concentration of the kernel and remains an important factor in wheat marketing. Flour protein measures the protein concentration after the bran and other components have been removed during milling. Other measurements tell us more about milling and baking performance. Milling yield describes how much usable flour can be produced from the grain, while flour ash is an indicator of the amount of mineral material remaining in the flour and can help evaluate milling efficiency. Falling number provides information about alpha-amylase activity and potential preharvest sprouting. Gluten index is particularly useful for evaluating gluten strength. A higher gluten index generally indicates stronger gluten that can better maintain dough structure during mixing and fermentation.
What Happened When We Made Dough?
One of the unique aspects of this study was evaluating flour with DoughLAB analysis. Rather than measuring only grain or flour composition, DoughLAB measures how flour behaves during mixing. Development time measures how long the dough must be mixed to reach optimum consistency. Dough stability measures how long the dough maintains that consistency before beginning to break down. Mixing tolerance index, or MTI, measures how rapidly the dough weakens after optimum development. Water absorption measures the amount of water required to produce dough at a standard consistency.
Of these measurements, dough stability provided one of the more interesting S responses. Under the high-N treatment, average dough stability increased from approximately 6 minutes without S to nearly 15 minutes at the highest S rate. Greater dough stability indicates that the gluten network was able to withstand mixing for a longer period before breaking down. For commercial baking, this can be important because stronger, more stable dough generally provides greater tolerance during mixing and more consistent performance during processing.
What Did We Learn?
Across these environments, N remained the primary factor controlling grain yield. Increasing N increased average yield, while adding S did not provide a significant yield response. However, the absence of a yield response did not mean S had no effect on the wheat. Under high-N conditions, S improved several measurements associated with grain and dough functionality, including gluten strength, dough development, and dough stability.
These results help separate two questions that are sometimes treated as the same question: Does the crop need S to produce more grain, and does S influence what happens inside the grain?
At the locations included in this study, the answer to the first question was no. The soils supplied enough S that additional fertilizer did not increase yield. The second question was more complicated. Sulfur influenced characteristics associated with protein functionality and end-use quality, particularly when N supply was high. That does not mean S should be applied routinely to improve wheat quality. For producers, the first fertilizer decision should still be based on whether the crop is likely to become S deficient. Soil testing, soil texture, organic matter, yield potential, and production history all provide information that can help make that decision. The larger lesson from this work is that S has a role in wheat beyond simply producing more bushels. Understanding that role helps us make better fertilizer decisions while continuing to put fertilizer where it is most likely to provide a return.
Data drawn from The Influence of Sulfur Under Nitrogen Extremes in Winter Wheat.
Linn, Kelby DeeAnn. Oklahoma State University ProQuest Dissertations & Theses, 2026. 32668685.
Cheap Nitrogen is not always the best Nitrogen, Timing matters
Brian Arnall: Precision Nutrient Management Extension Specialist, Oklahoma State University
In 2020, we published a summary of four OSU trial series comparing pre-plant nitrogen (N) to in-season N in grain-only winter wheat. https://osunpk.com/2020/09/10/value-of-in-season-application-for-grain-only-wheat-production/ Since then, three of those trial series have made it through peer review, and additional analyses have added considerably more data to the story. From both historic data from Dr. Raun’s program and new work. All together, these studies now represent more than 90 Oklahoma site-years across a wide range of environments, N rates, and application timings. So, after several more years of research, has the conclusion changed?
Does waiting to apply nitrogen cost wheat yield?
Across these studies, moving N from pre-plant to a properly timed in-season application generally maintained or increased grain yield. How often in-season N increased yield varied among datasets. Souza et al. found that winter wheat could recover from early N stress without sacrificing yield over a surprisingly wide application window. In other studies, in-season N was statistically similar to pre-plant N. The important point is that delaying N did not automatically mean giving up yield.
The Regional N study started by Dr. Raun 2in 2009, adds an important environmental piece to the story. Split N out yielded pre-plant N in approximately 29% of the 52 site-years, specifically those classified as highly responsive to N. These years tend to be wetter environments with greater yield potential. In the remaining 71%, split and pre-plant N produced statistically similar yields. Across all 52 site-years, splitting N never resulted in a significant yield loss compared with pre-plant N.
When a yield advantage with in-season N occurred, it could be meaningful. One study found a single in-season application produced approximately 8% greater yield than a full-rate pre-plant application. Sharry’s Gallagher/Green Hammer study found a single Feekes 4 (spring green up) application averaging approximately 11% greater yield than a single pre-plant application across two varieties and four site-years. The Regional N analysis found an approximately 5.4 bu/ac, or 14%, advantage for split N over pre-plant N in highly N-responsive environments, while there was no difference in the remaining environments. The message isn’t that in-season N always produces more wheat. It doesn’t. Properly timed in-season N generally maintained yield, and about 58% of the time increased it.
Protein Tells an Even More Consistent Story
Protein responded more consistently to N timing than yield. Later N increased grain protein across nearly every dataset. In the Regional N study, split N increased protein by 0.8 percentage points above the pre-plant compared with a 1.1-point increase from all N applied in-season. That advantage occurred across every environmental response category. In the end yield response to delayed N depends heavily on environment. The protein response is considerably more consistent.
If In-Season N Works, Is There a Reason to Split It?
Once the decision is made to move N away from a full pre-plant application, another question follows: should some N still go out pre-plant and the remainder in-season, or can the entire rate wait until the growing season? Two datasets tested that question directly, and neither found a consistent yield advantage to splitting N over a single, well-timed in-season application.
Sharry’s study found that a single green up application out-yielded both two-way and three-way splits by approximately 4.4 to 9.4 bu/ac at the site-years where treatments differed. At no site-year did a split application out-yield the single in-season timing. Abiola (2025) reached essentially the same conclusion. A single in-season application matched or exceeded a 50/50 pre-plant/in-season split across the timings evaluated. There was, however, an important exception. As the single in-season application was pushed into late March and April, having some N already applied reduced the potential downside.
Splitting N appears to be more about risk management than yield management.
Putting some N out early provides insurance against weather, field conditions, equipment problems, or other factors that prevent the planned in-season application from being made on time. If a single in-season application can be made at the proper time, however, these data provide little evidence that splitting N improves yield. So, in the end you reduce the “risk” but double application cost.
Timing Still Matters
None of this should be interpreted as saying N can be applied whenever it is convenient. The window for applying N to grain-only winter wheat is wider than many growers assume, but it isn’t unlimited. As application moves later, the opportunity for unfavorable weather to interfere with N availability becomes increasingly important.
The Regional N study provides a good example. For post top-dress applied N rainfall alone explained 27% of the site-to-site variation in how much the crop responded to N. The environments where split N increased yield over pre-plant N were generally the wetter, higher-yielding environments.
Waiting on N is a management strategy. Waiting too long is not.
Moving N in-season allows the rate decision to be made when considerably more is known about stand, growing conditions, and yield potential. But that flexibility only has value if the application is made while the crop can still effectively use the N. The data shows that the most risk adverse timing falls in the January to mid-March time frame.
What About Fertilizer Price?
Agronomy is only part of the decision. Anhydrous ammonia can provide a substantial cost-per-pound-of-N advantage over fertilizer sources typically used for in-season applications. When that price gap becomes large, the in-season strategy needs to create enough additional value through yield, protein, improved N-rate decisions, or reduced N loss to pay for the more expensive source.
The break-even calculation is straightforward: Additional N cost per acre ÷ wheat price = additional bushels needed to break even. At a 100 lb N/ac rate, every $0.10/lb difference in N price represents $10/ac in fertilizer cost.
For example, if the in-season N source costs $0.30/lb N more, that is a $30/ac disadvantage before the crop is planted. At $4.00 wheat, in-season N needs to produce 7.5 additional bu/ac to cover that difference. At $5.00 wheat, it needs 6 bu/ac, and at $6.00 wheat, it needs 5 bu/ac.
The range becomes fairly large as the difference in N price changes. At a 100 lb N/ac rate and wheat prices between $4 and $6/bu, a $0.20/lb N-price difference requires roughly 3 to 5 additional bu/ac, while a $0.50/lb difference requires roughly 8 to 13 additional bu/ac.
That doesn’t make either strategy automatically more profitable. In environments where yield is the same, the cheaper N source has the economic advantage. Where in-season N increases yield or protein, the economics can move in the other direction. There is also another economic benefit to waiting that is harder to put into a simple table: by waiting, the producer can adjust the N rate to the yield potential that is there rather than the yield potential hoped for before planting.
So fertilizer price adds another question to the N-timing decision: How much is the flexibility of waiting worth this year?
After more than 90 Oklahoma site-years, there is little evidence that grain-only winter wheat inherently benefits from having the entire N requirement available before planting. A properly timed in-season application generally maintains yield and can increase yield under responsive conditions. The opportunity to increase grain protein is even more consistent. Waiting also allows the final N decision to be made when the producer knows considerably more about the crop, weather, and realistic yield potential.
Splitting N does not appear to provide an additional yield benefit over a single, properly timed in-season application. Its primary value is insurance against missing that application window. But fertilizer price matters. When anhydrous or another pre-plant source provides N substantially cheaper than the available in-season source, those savings have real value and should be weighed against the potential benefits of waiting. There isn’t one N-timing strategy that wins every year. The goal isn’t simply to maximize yield or minimize fertilizer cost. It is to choose the N source, rate, and timing combination that provides the best economic return for the conditions in front of you.
These conclusions apply to grain-only winter wheat. Dual-purpose wheat requires sufficient fall growth for forage production and has a different early-season N requirement.
If you have any questions or comments, please feel free to reach out.
Brian Arnall
b.arnall@okstate.edu
Sources
Souza, J.L.B., Antonangelo, J.A., Silva, A.O., Reed, V., and Arnall, B. 2022. Recovery of Grain Yield and Protein with Fertilizer Application Post Nitrogen Stress in Winter Wheat (Triticum aestivum L.). Agronomy 12:2024.
Abiola, S.O., Souza, J.L.B., Sharry, R., Derrick, J.R., Maatougui, M., and Arnall, D.B. 2025. Split nitrogen applications provide no benefit over a single well timed application in rainfed winter wheat. Frontiers in Plant Science 16:1698494.
Ballagh, B., Ballagh, A., Bushong, J., and Arnall, D.B. The Effect of Nitrogen Fertilizer Placement and Timing on Winter Wheat Grain Yield and Protein Concentration.
Sharry, R. 2025. Response to nitrogen timing of varying winter wheat genotypes Dissertation, https://hdl.handle.net/20.500.14446/344867
Regional N study. 52 Oklahoma site-years, 2009–2023, Okstate Soil Fertility data unpublished.
Oklahoma Nitrogen Prices Continue to Move Lower 8.10.26
Nitrogen prices continued to decline in Oklahoma during the past two weeks, led by anhydrous ammonia. The statewide NH₃ reference fell $72 per ton to $875, while urea and both UAN concentrations also declined. The four-week decrease now exceeds 10% for NH₃ and approaches 7% for UAN 28. Phosphate and potash prices, meanwhile, have changed very little.
The Oklahoma average, minimum and maximum prices shown in the accompanying graphic come from the USDA AMS Oklahoma Production Cost Report. USDA collects FOB asking prices from Oklahoma distributors but does not identify the contributing dealers or disclose the number of observations. Public cash quotes from named dealers, including Two Rivers Cooperative, are tracked separately and are not blended into the USDA regional statistics.
The immediate Oklahoma explanation for softer nitrogen prices is relatively straightforward: hot, dry conditions have slowed fertilizer movement. USDA reported reduced demand across the fertilizer market, with triple-digit temperatures accelerating corn dry-down and allowing harvest to begin in parts of the state. With limited field activity and the primary summer application season behind us, dealers have less nearby demand supporting nitrogen values.
International nitrogen conditions are also becoming less restrictive. Fertilizer-market analyst Josh Linville reported that urea values continue to face pressure from weaker demand and a second round of approved Chinese exports. Additional Chinese availability matters because it gives international buyers another major supply origin and reduces competition for other export tons.
Nutrien’s second-quarter results reinforce the mixed nature of the nitrogen market. Global nitrogen benchmarks remained elevated, but second-quarter nitrogen sales volumes were lower. The market will now be watching whether increased export availability is sufficient to offset upcoming fall demand and additional international purchasing.
Phosphate remains a different story. Oklahoma DAP was unchanged during the latest reporting period, while MAP declined only $1.25 per ton. Stable local prices should not be interpreted as evidence that upstream supply risks have disappeared. Linville reported that Moroccan TSP and MAP are moving toward North America, which could improve regional availability. However, phosphate production continues to face elevated sulfur and ammonia costs and limited export availability from some traditional suppliers. These factors may support replacement costs even while weak seasonal demand keeps Oklahoma prices from moving higher.
Potash remains the most stable major nutrient. Oklahoma’s reported average increased only 50 cents per ton. Nutrien reported higher global potash benchmarks and record first-half sales volumes, but it also reported record production. Strong supply performance helps explain why firm global demand has not produced a significant Oklahoma price movement.
For Oklahoma producers, the most important development is the continued separation between nitrogen and phosphate markets. Lower nitrogen quotes may create purchasing opportunities, but the wide reported ranges make direct comparisons essential. Phosphate prices are locally steady but remain exposed to sulfur, ammonia and import-supply risks. Confirm the cash price, nutrient analysis, pickup or delivery basis, quote expiration and application charges before comparing dealer offers.
Fertilizer markets, local prices and product availability can change quickly. Confirm all prices and terms with local dealers before making purchasing decisions.
**The Oklahoma average, minimum and maximum prices shown in the accompanying graphic come from the USDA AMS Oklahoma Production Cost Report. USDA collects FOB asking prices from Oklahoma distributors but does not identify the contributing dealers or disclose the number of observations. Public cash quotes from named dealers, including Two Rivers Cooperative, are tracked separately and are not blended into the USDA regional statistics.
Market Sources
- USDA Agricultural Marketing Service. Oklahoma Production Cost Report. August 7, 2026. https://www.ams.usda.gov/mnreports/ams_3621.pdf
- Linville, Josh. Fertilizer-market commentary. August 7, 2026. https://x.com/JLinvilleFert
- Nutrien. Nutrien Reports Second Quarter 2026 Results. August 5, 2026. https://www.nutrien.com/news/press-releases/nutrien-reports-second-quarter-2026-results-1753
- Reuters. Nutrien Misses Profit Estimates as Lower Volumes Blunt Higher Fertilizer Prices. August 6, 2026. https://www.reuters.com/world/americas/nutrien-misses-profit-estimates-lower-volumes-blunt-higher-fertilizer-prices-2026-08-06/
- Two Rivers Cooperative. Fertilizer Index. Accessed August 10, 2026. https://www.tworiversks.coop/pages/custom.php?id=19995
This report is produced via Chat GPT Plus Work, with review by Brian Arnall.
OSUNPK Fertilizer Market Outlook — July 27, 2026
Produced by Chat GPT Work, reviewed by Brian Arnall, OSU Precision Nutrient Management.
Oklahoma fertilizer markets moved in two different directions during the latest reporting period. Nitrogen prices generally declined, while phosphate and potash remained nearly steady. That local stability does not mean the broader market is free of risk. International production costs, sulfur availability, trade flows and large import programs continue to influence the prices Oklahoma producers may encounter later in the season.
The USDA’s July 24 Oklahoma report placed urea at an average of $672.29 per ton, down $14.42 from the previous report. UAN 28 declined $16 to $472.60, UAN 32 fell $5 to $548.86, and anhydrous ammonia declined $29 to $947. One reported urea quote fell by approximately $300 per ton, while an NH₃ quote moved below $900 and a UAN 28 quote dropped below $400. Those individual movements contributed to unusually wide ranges and should not be treated as representative statewide prices without verification.
The USDA attributed part of the softer market to reduced fertilizer demand during triple-digit heat. Seasonal demand also appears less urgent following major spring and early-summer applications. However, the spread between low and high quotes remains substantial: $365 per ton for urea, $232 for UAN 28 and $225 for NH₃. Those differences make product basis, location and service charges particularly important when comparing offers. (USDA Oklahoma Production Cost Report)
International nitrogen conditions remain uncertain. Fertilizer-market analyst Josh Linville recently identified the resumption of vessel traffic through the Strait of Hormuz and the possibility of renewed Chinese urea exports as potentially bearish influences. Either development could improve global availability. However, fertilizer remains expensive relative to grain prices, and freight, energy or geopolitical disruptions could quickly change the cost calculation. (Josh Linville market commentary)
Oklahoma phosphate prices showed little immediate movement. DAP averaged $952.78, an increase of $2.22, while MAP held at $942.88. The local numbers appear quiet, but upstream phosphate conditions deserve attention. Linville has noted renewed strength in international phosphate values as limited sulfur availability and high production costs constrain output.
Sulfur matters because it is used to produce sulfuric acid, a critical input in manufacturing phosphoric acid and finished phosphate fertilizers such as DAP and MAP. Ammonia is another important production input. Consequently, higher sulfur or ammonia costs can support phosphate prices even when Oklahoma retail quotations have not yet responded. This is an upstream warning signal rather than a prediction that local prices must rise. (Josh Linville on phosphate and sulfur, World Bank fertilizer-market analysis)
Potash remained the quietest major nutrient in Oklahoma. The reported average increased only 75 cents to $491.55, with a range of $460 to $550. Global potash supply is geographically broader than the supply chain for several nitrogen and phosphate inputs. Expanded or recovering shipments from major producing regions may help moderate market pressure, although trade restrictions, transportation constraints and regional demand can still affect delivered costs.
International buying also remains important. India reported importing more than 3.2 million metric tons of urea and DAP during its first fiscal quarter and is pursuing longer-term overseas supply agreements. Large import programs can affect competition for available urea and phosphate cargoes, especially when export availability is already uncertain. (Times of India fertilizer-import report)
For Oklahoma producers, the current report offers a somewhat more favorable nitrogen signal, but not a uniform one. Wide quote ranges mean that comparison shopping may be as important as the regional average. Phosphate prices are locally stable, while sulfur availability and production costs remain meaningful external risks. Potash is comparatively steady.
Before acting on any quotation, confirm the nutrient analysis, cash-price basis, pickup or delivery terms, quote expiration and whether application or blending charges have been separated. UAN quotations should always be identified as either 28% or 32% before comparison.
Market Sources
Scout, Identify, Control: Winning the Battle Against Sorghum Headworms
Ashleigh M. Faris, Cropping Systems Entomologist
This week the OSU Cropping Systems Entomology crew detected treatable numbers of sorghum headworms at several North Central Oklahoma sorghum fields at milk to soft dough stages (Figure 1). Sorghum headworms are a complex of different caterpillar pests that can inflict severe economic damage on grain sorghum during its reproductive stages. The two primary species comprising the headworm complex in our region are the fall armyworm, Spodoptera frugiperda, and the corn earworm, Helicoverpa zea. A third species in this complex is the sorghum webworm, Nola sorghiella. Because these pests feed hidden in the developing sorghum head, timely scouting is important for protecting yields.
Pest Identification
Fall armyworm, corn earworm, and sorghum webworm are all moths as adults. The immature forms, caterpillars which are also referred to as “worms”, are the economically damaging stages. These caterpillars will progress through multiple instars, increasing in size and appetite as they grow. Oklahoma has multiple, overlapping generations of these pests. See Table 1 for identifying characteristics of sorghum headworms.
Table 1. Sorghum headworm identification. Image credits: Fall armyworm, OSU Extension. Corn earworm, Ashleigh M. Faris, OSU Extension. Sorghum webworm, Cliff Beaton, Mississippi Entomological Museum.
| Pest | Image | Body Characteristics |
| Fall Armyworm |  | Dark head capsule with a distinct, broad, white inverted “Y” shape. Dorsal lines running lengthwise down the body. Range in color from light green, brown, or tan. |
| Corn Earworm |  | Light-colored head capsule. Alternating light and dark stripes along the body. Body covered with small bristles visible with a hand lens. Vary in color from green and yellow to brown or pink. |
| Sorghum Webworm |  | Four distinct reddish-brown stripes down the back Many spines and clear white hairs on their body, grouped in clusters. |
Sorghum Vulnerability and Damage
Sorghum is most vulnerable to headworm infestations from panicle emergence (bloom) through the hard dough stage. Fall armyworms and corn earworm can also be considered whorl worms, caterpillars that feed during the vegetative sorghum stages. Whorl-stage feeding causes “windowpaning” (Figure 1) and “shot holes” (Figure 2) on the leaves, but this damage rarely reduces yields enough to justify chemical control. Open-headed sorghum varieties are more susceptible to headworm infestations than tight-headed varieties. Tight-headed varieties make chemical control penetration much more challenging but using high gallon per acre (GPA) when spraying can help.
Figure 1. “Windowpaning” caused by early instar whorl worms feeding on a sorghum leaf. Image credit: Ashleigh M. Faris, OSU Extension.
Figure 2. “Shot holes” caused by later instar whorl worms on a sorghum leaf. Image credit: Ashleigh M. Faris, OSU Extension.
Headworms directly feed on flowering parts and the developing starches within the grain (Figures 3 and 4). They feed in an irregular pattern on the sorghum head, leaving the starchy portion of the kernel exposed (Figure 5). A single larva can consume approximately 0.01 pounds of grain (up to 12 kernels per day) during its lifespan. Infestations of 1 to 2 larvae per head can result in a 5% to 10% overall yield loss.
Figure 3. Early instar corn earworm feeding on developing sorghum kernels. Image credit: Ashleigh M. Faris, OSU Extension.
Figure 4. Late instar corn earworm feeding on developing sorghum kernels. Image credit: Ashleigh M. Faris, OSU Extension.
Figure 5. Sorghum webworm feeding damage. Note the empty glumes and irregular feeding pattern. Image credit: Ron Schnell, Texas A&M University.
Scouting Procedures
Active monitoring gives producers the best chance at making timely insecticide applications. Scouting should begin at full panicle emergence and continue every 3 to 5 days until the hard dough stage. OSU Extension Specialists have developed a sequential sampling Sorghum Headworm Quick Count Sampling Plan to aid growers in management decision making. This support tool can be found at the OSU EPP-7087 Fact Sheet Sampling for Sorghum Headworms in Oklahoma Using the Headworm Decision Support System.
Alternatively, one can also scout for headworms using the following steps:
- Walk at least 15 to 20 feet into the sorghum field before taking your first sample.
- Grasp the stalk just below the emerged head and bend it into a white 2.5 – 5-gallon bucket.
- Vigorously beat the head against the side of the bucket to dislodge the larvae.
- Ignore any caterpillars smaller than 1/4 inch, as they feed very little and experience extremely high natural mortality.
- Count and categorize the remaining worms as either medium (1/4 – 1/2 inch) or large (greater than 1/2 inch).
- Walk 30 paces down the row, sample another head, and repeat this process across multiple rows to ensure field-wide representation.
Economic Threshold for Sorghum Headworms
Management decisions should be driven by the size of the larvae and the growth stage of the crop. When sorghum is in the reproductive/panicle stage, use a treatment threshold of 1 to 2 larvae per head for corn earworms or fall armyworms, or 0.5 headworms per head using sequential sampling. The threshold for smaller, less damaging pests like the sorghum webworm is higher, at 3 to 4 larvae per head.
Insecticide Management Options
If economic thresholds are met, selecting the appropriate chemistry is vital for control and the preservation of natural enemies. Spraying broad-spectrum insecticides like pyrethroids or carbamates can kill beneficial insects that are predators of sorghum aphids and other pests (Table 2). Removing these natural enemies can cause sorghum aphid populations to flare and reach/exceed economic thresholds. Always read the label to ensure the product is registered for use on sorghum and the target pest, and to be aware of restricted entry intervals (REI) and pre-harvest intervals (PHI).
Table 2. List of select available products labelled for managing headworms in grain sorghum in Oklahoma as of the date of this publication. Note that inclusion of insecticide in the table below is not an endorsement or guarantee by OSU Extension. Refer to and follow insecticide labels.
| Insecticide Active Ingredient | Trade Name | Notes |
| Spinosad | Blackhawk | Soft on natural enemies. |
| Chlorantraniliprole | Vantacor (formerly Prevathon) | Excellent option for larger worms and populations resistant to pyrethroids; provides effective control with lower toxicity to natural enemies. |
| Zeta-cypermethrin, lambda-cyhalothrin | Mustang MAXX EC, Warrior II with Zeon | Broad-spectrum activity may impact beneficial/natural enemy insect populations, potentially flaring sorghum aphids. |
How Much Nitrogen Does Double Crop Corn Need in Oklahoma?
Kelby Linn, MS Precision Nutrient Management
Emily Staton, MS Precision Nutrient Management
Josh Lofton, Cropping Systems Management
Brian Arnall, Precision Nutrient Management
Double crop (DC) corn is gaining attention in Oklahoma as producers look for opportunities to increase productivity following wheat harvest. While DC soybeans and sorghum remain common options, corn can serve as an alternative when planting windows are missed or when producers want to diversify their rotation. In Oklahoma systems, it is suggested DC corn is followed by a full season soybean crop the next year. This allows producers to maintain an intensive cropping system while maximizing land use. However, managing fertility in DC corn can be challenging because the crop is grown under a different environment than full season corn. One of the questions producers ask is how much nitrogen (N) is needed to maximize returns. Nitrogen is typically the largest fertilizer expense in corn production, but applying more N does not always result in higher yields. Recent Oklahoma research suggests DC corn may require less N than many would expect.
Understanding the System
To evaluate N requirements under Oklahoma DC conditions, field trials were conducted across 11 site years during the 2024 and 2025 growing seasons (Table 1). Corn was planted directly into wheat residue following harvest, creating a true DC production system. Nitrogen was applied as urea (46-0-0) at 13 rates ranging from 0 to 180 lbs N/acre in 15 lb N increments. The following data was collected: biomass production, grain yield, and grain quality responses across environments. The goal was to identify how much N is needed to maximize yield and profitability in Oklahoma DC corn.
Table 1. Field study locations for the 2024 and 2025 double crop corn trials in Oklahoma. Each location is listed with respective planting dates, corn varieties, planting populations and harvest date.
| Location | Planting | Variety | Population | Harvest |
| Perkins | 6/28/2024 | DK119-30 | 20k | 11/9/2024 |
| 7/11/2025 | DKC117-27RIB | 20k | 11/14/2025 | |
| Stillwater | 6/30/2024 | DK119-30 | 20k | 11/11/2024 |
| 7/12/2025 | DKC117-27RIB | 20k | 11/13/2025 | |
| Perry | 6/28/2024 | DK119-30 | 20k | 11/16/2024 |
| 7/7/2025 | DKC117-27RIB | 20k | 11/12/2025 | |
| Perry (Irrigated) | 7/7/2025 | DKC117-27RIB | 28K | 11/12/2025 |
| Lahoma | 7/9/2025 | DKC117-27RIB | 20k | 11/18/2025 |
| Fort Cobb (Irrigated) | 7/2/2025 | DKC117-27RIB | 28K | 11/15/2025 |
Yield Response: Nitrogen Helped, But Only to a Point
Across all harvested site years, N applications significantly influenced grain yield when environment was not the limiting factor. Average yields ranged from 40 to 94 bu/ac, demonstrating how variable DC corn performance can be from year to year and field to field (Staton, 2026) (Figure 1). While some locations responded positively to N fertilizer, others showed little response even when rates reached 180 lbs N/ac. The consistent finding was yield responses often plateaued around 60 lbs N/ac. Once this point was reached, additional fertilizer rarely produced enough additional grain to justify the added cost. Across two Oklahoma studies representing 11 site-years, unfertilized double-crop corn averaged approximately 52 bu/ac. That finding highlights just how much nitrogen can be supplied by the soil through residual nitrate and mineralization before fertilizer is applied. These results suggesting existing soil N and nutrient mineralization contributed significantly to crop demand (Staton, 2026).
Figure 1. Increase in yield of the highest yielding treatment as compared to the non-fertilized check yields of each location. Adapted from Staton (2026)
The Real Story: Return on Investment
While producers naturally focus on maximizing yield, these fertilizer decisions should be based on profitability. Average economic return peaked near 60 lb N/ac. Beyond that rate, additional fertilizer consistently reduced profit (Figure 2). Although individual economic returns varied among environments, the agronomic data suggest producers should approach DC corn fertility programs with realistic yield expectations. Unlike high yielding full season corn, DC systems often encounter environmental limitations that reduce the return on additional fertilizer investment.
Figure 2. Average profit response to nitrogen rate in US dollars (USD)/ac. Adapted from Staton (2026).
What This Means for Oklahoma Producers
The results from this study closely align with previous Oklahoma research evaluating N response in DC corn. Wyma (2022) reported approximately one additional bushel of grain for every 1.8 lbs N applied above the unfertilized control, similar to Staton (2026) who observed one additional bushel for every 1.7 lbs N in responsive environments. Together these studies suggest Oklahoma DC corn requires approximately 1.75 lbs N for every additional bushel of expected yield above 50 bu ac-1.
The goal of nitrogen management is not to apply the most fertilizer, it is to apply the right amount. Two independent Oklahoma studies now indicate that double-crop corn often requires substantially less N than full-season corn. Matching N rates to realistic yield potential can improve profitability while reducing unnecessary fertilizer costs.
Take Home
- Double crop corn is a economically viable option in Oklahoma.
- Use lower total N rates than full-season corn.
- Across two independent studies’, the unfertilized corn averaged about 50 bushels per acre.
- 1.75 lb N per expected additional bushel above the unfertilized expectation.
- Base final N rates on realistic yield potential and expected moisture.
- Consider residual soil nitrate following wheat before increasing fertilizer rates.
- Avoid applying N beyond expected crop demand.
References
Alcoz, Mercedes M., Frank M. Hons, and Vincent A. Haby. 1993. “Nitrogen Fertilization Timing Effect on Wheat Production, Nitrogen Uptake Efficiency, and Residual Soil Nitrogen.” Agronomy Journal 85(6):1198–1203. doi:10.2134/agronj1993.00021962008500060020x.
Chang, Jen-Hu. 1981. “Corn Yield in Relation to Photoperiod, Night Temperature, and Solar Radiation.” Agricultural Meteorology 24:253–62. doi:10.1016/0002-1571(81)90049-2.
Kravchenko, Anatoliy G., and Kurt D. Thelen. 2007. “Effect of Winter Wheat Crop Residue on No-Till Corn Growth and Development.” Agronomy Journal 99(2):549–55. doi:10.2134/agronj2006.0192.
Liu, Zheng, Jia Gao, Fei Gao, Shuting Dong, Peng Liu, Bin Zhao, and Jiwang Zhang. 2018. “Integrated Agronomic Practices Management Improve Yield and Nitrogen Balance in Double Cropping of Winter Wheat-Summer Maize.” Field Crops Research 221:196–206. doi:10.1016/j.fcr.2018.03.001.
Staton, Emily. 2026. “Nitrogen Management in Double Crop Corn” M.S., Oklahoma State University, United States — Oklahoma.
Wyma, Rhiannon Nichole. 2022. “Corn Grain Yield Response to Nitrogen Rate and Plant Population in Full and Double-Crop Systems.” M.S., Oklahoma State University, United States — Oklahoma.
Bigger Isn’t Always Better: The Relationship Between Plant Size, Yield Potential, and Yield Stability in Summer Crops
Josh Lofton, Cropping Systems Specialist
In the last several years, warmer springs and higher/widespread rainfall have resulted in summer crops reaching with a high amount of vegetative growth. This season has been quite different for the most part, cooler temperatures and more sporadic rainfall has resulted in much smaller plants. So that begs the question, are larger or smaller plants better for yield in Oklahoma. While many that have spent time in Oklahoma will probably have a preference, there is no direct answer to this question.
Larger plants generally have more leaves, more stems, more branches, and more overall biomass. They often appear healthier and more productive throughout the growing season.
In higher rainfall and lower stress environments, this assumption is true. Greater vegetative growth can support higher yield potential because larger plants capture more sunlight, accumulate more photosynthates, and develop a greater capacity to support grain or seed production.
However, in Oklahoma and throughout the Southern Great Plains, yield potential and yield stability are not always the same thing.
The challenge facing producers across this region is that crops must balance the opportunity to maximize yield with the risk of running short on water during critical reproductive growth stages. As a result, the plant with the greatest theoretical yield potential is not always the plant that produces the most grain across a range of environmental conditions.
The Tradeoff Between Yield Potential and Yield Stability
Many may have heard of this difference. Even you if have not directly of these concepts, most in Oklahoma will be familiar with the trade-offs
Yield potential refers to the maximum yield a crop can achieve when environmental conditions are favorable, and resources are not limiting.
Yield stability refers to a crop’s ability to maintain performance across varying environmental conditions, including drought, heat stress, and erratic rainfall.
These two characteristics are often related, but they are not always aligned.
High vegetative growth frequently possesses greater yield potential because they can intercept more sunlight and support more reproductive structures. However, those same plants often require greater amounts of water throughout the season.
In contrast, plants with more moderate growth habits may have slightly lower maximum yield potential, but they often maintain more consistent performance when environmental stresses occur.
So the difference between excessive, adequate, and too low vegetative production is not consistent and is impacted by a part of the year not yet experienced.
For producers in the Southern Great Plains, where growing conditions can change dramatically from one season to the next, yield stability can be just as important as maximum yield potential.
Why More Growth Often Means More Yield Potential
The relationship between vegetative growth and yield begins with photosynthesis.
More leaves generally mean:
- Greater sunlight interception
- Greater photosynthetic capacity
- More carbohydrate production
- More potential reproductive sites
And when we are talking about farming, what we are often farming is the sunlight indirectly through the crops we are growing. Therefore, the higher amount of sunlight that can be captured, this higher potential yield can be.
In soybean, larger plants often produce more nodes and branches, creating additional locations for pod formation.
In grain sorghum, larger canopies can support greater grain production when moisture remains adequate through grain fill.
In corn, larger plants often contribute to greater kernel production and kernel weight under favorable conditions.
Because of these relationships, management practices that encourage vigorous growth are frequently associated with high yield environments.
The key phrase, however, is under favorable conditions.
The Hidden Cost of Large Plants
Every leaf that captures sunlight also loses water.
As plant size increases, so does transpiration demand. Larger plants require more water simply to maintain normal physiological activity.
This creates a challenge in many Oklahoma production environments.
Rainfall is often adequate during early vegetative development, allowing crops to establish large canopies and accumulate substantial biomass (often during the months of April and early May). However, the period from flowering through grain fill frequently coincides with:
- Higher temperatures
- Greater evaporative demand
- Less reliable rainfall
- Increasing soil moisture depletion
This can be a two-fold issue. One, higher vegetative production early could have utilized and drained total surface and subsurface moisture, which is now not available during reproductive growth. However, it also increased daily moisture demand. This can result in with similar soil moisture and rainfall, a smaller plant will have a lower moisture demand than a larger plant.
The consequence is often a reduction in grain or seed production precisely when yield is being determined.
Soybean: A Classic Example
Soybean perhaps provides the best illustration of this concept.
When moisture is abundant, larger soybean plants can be extremely productive. Additional nodes and branches create opportunities for greater pod production, and large canopies intercept significant amounts of sunlight.
However, soybean also possesses one of the longest reproductive periods among major summer crops.
A soybean crop must successfully retain flowers, maintain pods, and fill seeds over an extended period. Water stress at any point during this process can reduce yield.
Large soybean plants often consume considerable amounts of water during vegetative growth. If drought develops during pod set or seed fill, those plants may experience:
- Increased flower abortion
- Increased pod abortion
- Reduced seed size
- Premature canopy senescence
In contrast, a more moderate-sized soybean plant may use less water during early development and preserve soil moisture for reproductive growth.
While that plant may possess fewer nodes or branches and therefore slightly lower maximum yield potential, it may be better positioned to maintain yield under stressful conditions.
Seeing this in practice
As shown in Figure 1, plant growth regulation substantially reduced soybean height compared to untreated plants. Three weeks after treatment implementation, regulated plants ranged from 5–10 inches shorter than untreated plants. These reductions in height were accompanied by fewer mainstem nodes, but plants compensated by producing more branch nodes and increasing canopy coverage. The response was relatively consistent across both growing seasons, demonstrating that soybean plants can modify their growth habit when mainstem development is restricted.
Figure 1. Impact of plant growth regulation (physical removal) on soybean plant height compared to untreated plants. Data were collected across the 2022 and 2023 growing seasons.
While reduced plant size altered canopy architecture, the impact on yield differed substantially between years (Figure 2). In 2022, when environmental conditions were generally favorable and resources were less limiting, plant growth regulation did not improve yield. In fact, yields were slightly lower than the untreated control. This response likely reflects the reduced yield potential associated with smaller plants, as larger soybean canopies often intercept more light, accumulate greater biomass, and support higher seed production when adequate moisture is available throughout the season.
However, the response was markedly different during 2023, when moisture became increasingly limiting later in the growing season. Under these conditions, regulated plants significantly outyielded the untreated plants. The smaller canopy likely reduced seasonal water use and delayed soil moisture depletion, leaving more water available during critical reproductive growth stages. In contrast, larger untreated plants developed greater vegetative biomass and therefore higher water demand earlier in the season. Although these larger plants possessed greater theoretical yield potential, they were more susceptible to late-season drought stress when water availability became limited.
These results illustrate an important principle for summer crop production systems in water-limited environments. Larger plants often possess higher yield ceilings because of their greater vegetative growth and capacity to capture resources. However, that same vegetative growth can increase transpiration demand and accelerate soil water depletion, increasing the risk of yield loss if drought develops later in the season. Smaller plants may not achieve the same maximum yield potential in favorable years, but they often provide greater yield stability by reducing water demand and preserving resources for reproductive development. Consequently, the optimal plant size is often a balance between maximizing yield potential and minimizing drought risk, particularly in environments such as Oklahoma where late-season moisture stress is common.
Figure 2. Impact of plant height regulation on soybean yield during the 2022 and 2023 growing seasons. Yield responses differed between years, highlighting the tradeoff between maximum yield potential and yield stability under water-limited conditions.
Lessons from Grain Sorghum
Grain sorghum offers another excellent example.
One reason sorghum has traditionally been viewed as a drought-adapted crop is its ability to regulate water use throughout the season. Traits such as leaf rolling, reduced transpiration, and stay-green characteristics help preserve plant function during grain fill.
Many of these mechanisms do not necessarily maximize growth early in the season. Instead, they improve the likelihood that the crop can complete grain development under stressful conditions.
This strategy may occasionally sacrifice maximum yield potential in highly favorable years, but it often improves yield stability across multiple growing seasons.
Managing for Consistency Versus Chasing Maximum Yield
One of the most important questions growers must answer is whether they are managing for maximum yield potential or maximum yield consistency.
In highly productive environments with irrigation or reliable rainfall, encouraging aggressive vegetative growth may be appropriate because water limitations are less likely to restrict grain fill.
In contrast, dryland production systems throughout much of Oklahoma often reward a more balanced approach.
The goal is not necessarily to produce the largest crop canopy possible. Rather, it is to produce enough canopy to efficiently intercept sunlight while preserving sufficient water to support reproductive growth later in the season.
Bigger Isn’t Always Better—Especially in Dryland Systems
This does not mean smaller plants are inherently superior.
A very small plant may lack sufficient leaf area to fully utilize available sunlight and may never achieve high yield potential regardless of rainfall conditions.
The ideal crop is rarely the smallest or the largest plant in the field.
Instead, the most successful crops are often those that achieve a balance between vegetative growth and resource conservation.
They develop enough biomass to support high levels of photosynthesis while avoiding excessive water consumption before reproduction begins.
Final Thoughts
Across Oklahoma and the Southern Great Plains, crop production is often a matter of managing risk as much as maximizing yield.
Larger plants frequently possess greater yield potential because they capture more sunlight and produce more biomass. However, that potential comes with increased water demand. When rainfall becomes limiting during flowering, grain fill, pod set, or seed development, those larger plants can become more vulnerable to stress.
Smaller or more moderately sized plants may not always produce the highest yields in ideal environments. However, they often provide greater yield stability because they conserve resources and maintain reproductive growth when environmental conditions deteriorate.
For soybean in particular, this tradeoff is frequently observed. The largest plants in July are not always the highest-yielding plants in October. More often, the most successful plants are those that balance growth with resource conservation, preserving enough water to support reproduction when it matters most.
In the Southern Great Plains, where late-season drought remains one of the greatest limitations to crop production, understanding the difference between yield potential and yield stability may be just as important as understanding yield itself.
Corn Leafhopper Detected in Southwest Oklahoma – What Growers Need to Know to Reduce Risk of Corn Stunt Disease
Maíra R. Duffeck: OSU Field Crops Extension Pathologist, Department of Entomology and Plant Pathology
Ashleigh Faris, OSU Field Crops Extension Entomologist, Department of Entomology and Plant Pathology
On June 5, 2026, the first corn leafhoppers of the year were detected in a corn field near Fort Cobb in Caddo County, Oklahoma. The insects were collected from grain corn by Dr. Maira Duffeck’s Row Crop Pathology team, and its identification was subsequently confirmed by Dr. Ashleigh Faris, OSU State Extension Entomologist for Cropping Systems.
The two corn leafhoppers specimens were collected from within the whorls of V6-stage corn plants during routine field scouting. Specimens were collected using a cordless vacuum for identification and documentation. In addition, one corn leafhopper was captured on a yellow sticky trap installed at the edge of the field. The trap has been monitored and replaced weekly since planting as part of ongoing surveillance efforts.
This 2026 detection occurred 18 days earlier than the first corn leafhopper detection reported in Oklahoma during 2025. Due to delayed planting associated with drought conditions, much of the corn across the state is currently at vegetative growth stages compared to this same time last year. This situation raises concerns about the potential transmission of corn stunt pathogens by corn leafhoppers.
Research outside of the U.S. has shown that corn plants are most susceptible to infection by corn stunt pathogens during the vegetative growth stages, from emergence (VE) through tasseling (VT). However, infection can also occur during the early reproductive stages. Early infection can result in significant yield losses because affected plants have a longer period to develop symptoms and experience reductions in growth and grain production.
It is not yet known if the corn leafhoppers detected in Oklahoma are carrying corn stunt pathogens, therefore growers should assume that any corn leafhopper has the potential to be infectious. Consequently, management efforts should focus on early detection and suppression of corn leafhopper populations, particularly in fields with corn at vulnerable vegetative growth stages. Regular scouting and timely management decisions will be critical for reducing the risk of corn stunt development during the 2026 growing season.
The Insect Identification
The corn leafhopper is a small insect, approximately 1/8 inch long (about the size of a grain of rice), with a yellow to tan body color. Adults are characterized by two small black spots surrounded by lighter-colored halos located between the eyes (Figure 1), as well as a clean face meaning there are no additional markings on the head or body. It is important to note that many leafhopper species also possess two spots between their eyes, however, these other leafhoppers will also have other dark marks on their head and/or face.
To distinguish corn leafhoppers from other leafhopper species, look for the combination of the two black spots with halos and the absence of additional markings. Corn leafhoppers do not have spots, stripes, or other markings on their wings, back, abdomen, face, or the top of the head (Figure 2). For mor information on how to distinguish the corn leafhopper from other commonly occurring leafhoppers see OSU e-Pest Alert EPP-25-24.
The immature or nymphal stage is wingless and resembles a smaller version of the adult. Nymphs may also lack the characteristic black spots and halos found on adults (Figure 3), making identification more challenging.
For additional information on corn leafhopper identification, biology, life cycle, and its role in transmitting corn stunt pathogens, see OSU E-Pest Alert EPP-23-17 and OSU e-Pest Alert EPP-25-29.
Scouting Tips and Guidance
Corn leafhoppers can be difficult to detect due to their small size, preference for hiding deep within the whorls of developing corn plants, and their rapid darting movement when disturbed. Because of these behaviors, effective scouting requires a combination of methods, including vacuum sampling, sweep net sampling, and direct visual inspection. Check the borders and edges of corn fields first as this is where most early migrators will be found.
During vegetative growth stages, plants should be carefully examined by inspecting the whorls, where corn leafhoppers often remain concealed (Figure 4 and 5). Individuals may be dislodged from the whorl using a cordless vacuum (Figure 6) or cordless leaf blower equipped with thigh high stockings to capture collected leafhoppers. Vacuum several whorls, randomly at the field borders, moving into the interior of the field.
Sweep net sampling is another useful scouting tool. When walking through corn rows, the net should be swept side-to-side in a figure-eight motion over the canopy and across plants on both sides of the row. After several sweeps, the net should be carefully closed, and contents slowly examined for the presence of corn leafhoppers. As the crop transitions into reproductive stages, sweep netting should be adjusted to target the lower portion up to through the upper and mid-canopy by sweeping up and down along the sides of the corn plants.
Visual inspection remains an important component of scouting throughout both vegetative and reproductive stages. In vegetative corn, focus on whorl inspection. As the canopy closes and plants reach reproductive stages, examine the underside of leaves where leafhoppers may congregate. Check the underside of lower leaves for nymphs. When entering a field, pause periodically to allow leafhoppers to settle, then slowly observe surrounding plants before moving forward.
In addition to the insects themselves, other indicators of corn leafhopper presence include honeydew deposits, which appear shiny and feel sticky, the development of black sooty mold growing on honeydew (Figure 7), and the presence of white or translucent cast skins (exuviae) resulting from molting (Figure 8).
Current Integrated Pest Management (IPM) Guidance for Corn Leafhoppers
Pre-planting and Planting Decisions
There are currently no known corn stunt resistant hybrids available on the U.S. market. In areas where volunteer corn is present, growers should remove it as this vegetation serves as a reproductive resource for the insect and a potential reservoir for corn stunt pathogens. When possible, growers are encouraged to plant corn early, as this will help reduce the likelihood of corn being planted when corn leafhoppers are present. In areas where corn leafhoppers will be present at planting, growers should use a high insecticide seed treatment containing Cruiser® Corn 1250 or Poncho® 1250 to allow for protection of early vegetative stages. Trials conducted by Texas A&M AgriLife Research and Extension indicate that 500 and 1250 rates of the insecticide seed treatments suppress corn leafhopper adults through V5 and suppress nymphs (or egg laying) at least until V10. The higher 1250 rates of insecticide seed treatment outperformed the lower 500 rates.
Scout for the Corn Leafhopper
Follow the scouting guidance outlined above to monitor for the insect. Due to the efficiency of corn leafhoppers in transmitting pathogens associated with corn stunt disease, no economic threshold has been established at this time. As a result, growers are encouraged to manage corn leafhopper populations when they are detected in the field.
At present, the exact corn growth stage at which scouting should cease is not known. Previous guidance suggested continuing scouting through the V8 growth stage; however, based on past observations by state Extension personnel, recommendations have been extended to encourage growers to continue managing corn leafhopper populations through the R1 or R2 growth stages. More research is needed to determine the cutoff point for insect management under U.S. crop production conditions.
Chemical Control Options
Results from foliar insecticide efficacy trials conducted in 2025 by Dr. Ashleigh Faris at Oklahoma State University, and by personnel at Texas A&M AgriLife Research and Extension, provide insight into current foliar management options for corn leafhopper.
In these studies, pyrethroid insecticides and dimethoate were largely ineffective against corn leafhoppers. Foliar applications of indoxacarb at 8 – 10 fl. oz./A rate and flupyradifurone at 7 fl. oz./A rate provided up to 14 days of suppression for corn leafhopper nymphs. Thiamethoxam and lambda-cyhalothrin at 10 fl. oz./A rate provided similar nymph suppression for 14 days. If applying a foliar insecticide prior to tassel, applicators should not use a non-ionic surfactant (NIS) as an adjuvant. An NIS applied pre-tassel, particularly mid to late vegetative stages (V6-VT) can result in arrested ear development which causes “baby” or stunted ears/cobs with reduced or absent kernels, underdeveloped husks, poor or absent silk emergence and reddish/purple leaves These symptoms can appear like corn stunt disease symptoms; however, confirmation of corn stunt disease pathogens can only be done through molecular testing.
When selecting an insecticide, growers should prioritize products that are not broad-spectrum and that are less disruptive to beneficial arthropods, to preserve natural biological control in the agroecosystem. Insecticide applications should only be made when corn leafhoppers are confirmed to be present in the field being treated. As with all pest management decisions, the insecticide label must be followed; the label is the law.
Integrated pest management (IPM) recommendations for corn leafhopper will continue to evolve as additional research becomes available under Oklahoma growing conditions. Growers are encouraged to stay updated through future OSU Pest e-Alerts and to follow Cropping Systems Extension Entomologist Dr. Ashleigh Faris (@OSU_crop_insects) and OSU Field Crops Pathologist Dr. Maira Duffeck (@osu.plantpath) on Instagram for ongoing updates on corn leafhopper and corn stunt disease distribution in the state and results from 2026 insecticide efficacy trials.
Banding P for Acidic Soils: Its not the time to be paying for poor practice.
I am bringing this topic back to the surface now with the current outlook on phosphorus fertilizer. If you have heard its not only becoming more expensive but the supply is short and will likely stay short through summer into the fall, which wont help prices. So this year’s wheat crop, we need to be prepared to be smart with Phosphorus, and applying an extra 30lbs to band aid for soil acidity should not be in the cards. Look at it this way, if the phosphorus was at $0.66 a lb that $20 that could be spent on a ton of lime. That lime will last 3-5 years, while that P needs to be added every year. Not only that, but the lime will help root growth (better when we dry up), produce significantly more biomass, and make the phosphorus you’ve applied in the past available again for plant uptake. So make the plans now to soil sample as soon as this crop is off, you can get a soil test recommendation and plan for the lime trucks. This is also not the year to just apply phosphorus for the sake of applying. Soil tests are inexpensive relative to buying excess fertilizer.
Current quotes on 4.24.26 are at $0.54 + per lbs P2O5 with DAP at $830 a ton.
Quick Fertilizer Price Calculation:
Urea at $860 a ton means N is $0.93 a lbs.
DAP at $830 has $334 worth of $0.93 nitrogen and $495 of phosphorus at $0.54 a lb.
Banding P as a band-aid for soil acidity, not so cheap now.
Original Blog Posted in 2021
Whoi Cho, PhD student Ag Economics advised by Dr. Wade Brorsen
Raedan Sharry, PhD Student Soil Science advised by Dr. Brian Arnall
Brian Arnall, Precision Nutrient Management Extension.
In 2014 I wrote the blog Banding P as a Band-Aid for low-pH soils. Banding phosphate to alleviate soil acidity has been a long practiced approach in the southern Great Plains. The blog that follows is a summary of a recent publication that re-evaluated this practices economic viability.
Many Oklahoma wheat fields are impacted by soil acidity and the associated aluminum (Al) toxicity that comes with the low soil pH. The increased availability of the toxic AL3+ leads to reduced grain and forage yields by impacting the ability of the plant to reach important nutrients and moisture by inhibiting root growth. Aluminum can also tie up phosphorus in the soil, further intensifying the negative effects of soil acidity. More on the causes and implication of soil acidity can be found in factsheet PSS-2239 or here (https://extension.okstate.edu/fact-sheets/cause-and-effects-of-soil-acidity.html). The acidification of many of Oklahoma’s fields has left producers with important choices on how to best manage their fields to maximize profit.
Two specific management strategies are widely utilized in Oklahoma to counter the negative impacts of soil acidification: Lime application and banding phosphorus (P) fertilizer with seed. While banding P with seed ties up Al allowing the crop to grow, this effect is only temporary, and application will be required every year. The effects of liming are longer lasting and corrects soil acidity instead of just relieving Al toxicity. Historically banding P has been a popular alternative to liming largely due to the much lower initial cost of application. However, as P fertilizers continue to increase in cost the choice between banding P and liming needed to be reconsidered.
A recent study by Cho et al.,2020 compared the profitability of liming versus banding P in a continuous wheat system considering the impacts that lime cost, wheat price and yield goal has on the comparison. This work compared the net present value (NPV) of lime and banded P. The study considered yield goal level (40 and 60 bu/ac) as well as the price of P2O5 fertilizer and Ag Lime. The price of P2O5 used in this study was $0.43 lb-1 while lime price was dictated by distance from quarry, close to quarry being approximately $43 ton-1 and far being $81 ton-1. For all intents and purposes these lime values are equivalent to total lime cost including application. Wheat prices utilized in the study were $5.10 bu-1 and $7.91 bu-1. It is important to note that baseline yield level was not considered sustainable under banded P management in this analysis. This resulted in a decrease in yield of approximately 3.2 bu ac-1 per year. This is attributable to the expected continued decline in pH when banding P is the management technique of choice.
The analysis in this work showed that lime application is cost prohibitive in the short term (1 year) when compared with banding P regardless of lime cost, yield goal level, and wheat value (within the scope of this study). This same result can be seen over a two-year span when yield is at the lower level (40 bu ac-1). While in the short-term banding P was shown to be a viable alternative to liming, as producers are able to control ground longer lime application becomes the more appealing option, especially when producers can plan for more than 3 years of future production. In fact, under no set of circumstances did banding P provide greater economic return than liming regardless of crop value, yield, or liming cost when more than 3 years of production were considered and only under one scenario did banded P provide a higher NPV in a 3-year planning horizon.
While historically banding P was a profitable alternative to lime application for many wheat producers the situation has likely drastically changed. At the time of writing this blog (09/17/2021) Diammonium Phosphate (DAP) at the Two Rivers Cooperative was priced at $0.78 lb-1. of P2O5. This is a drastic increase in P cost over the last year or so since Cho et al. was published in 2020. With P fertilizer prices remaining high it will be important for producers to continue to consider the value of liming compared to banded P. This is particularly crucial for those producers who can make plans over a longer time frame, especially those more than 3 years.
Addendum: As fertilizer prices have continued to rise a quick analysis utilizing the $0.78 lb-1 of P2O5was completed to consider the higher P fertilizer cost. Under this analysis an estimated decrease in NPV of approximately $38 an acre for P banding occurred. When considering this change in NPV, lime application becomes the more profitable option for alleviation of soil acidity symptoms even in the short term (assuming lime price values are equivalent to the previous analysis). This underlines the fact that it is imperative to consider the impact on profitability of the liming vs. banding P decision in the current economic climate for agricultural inputs.
Link to the Open Access Peer Reviewed publication “Banding of phosphorus as an alternative to lime for wheat in acid soil” https://doi.org/10.1002/agg2.20071
Down and Dirty with NPK 