Amanda de Oliveira Silva, Small Grains Extension Specialist
Last week, we kicked off our wheat plot tour season in Oklahoma, with our first stops in southwestern Oklahoma—Altus and Walters—and south-central Oklahoma in Chickasha. Plot tours are always a valuable opportunity to evaluate variety performance and visit with producers, and these first stops gave us an early look at the challenging conditions many wheat fields are facing across the state this season.
Figure 1. Wheat plot tour at the Dual-Purpose Wheat Variety Trial in Walters, where producers and OSU specialists evaluated variety performance and discussed the impacts of drought stress and early leaf rust development on the crop. Kinder Farms, April 20, 2026.
For anyone following the weather, the story is not surprising. Prolonged drought since last fall, combined with above-normal temperatures through winter and early spring, has taken a significant toll on the crop (Figure 2).
Across much of southwest Oklahoma, moisture has been extremely limited for months. Some fields never established properly, and in the driest areas, stands remain poor, thin, and uneven. In several cases, producers have already made the difficult decision to abandon fields or graze them out, as yield potential no longer justifies the cost of taking the crop to harvest, or in some cases, there simply is not enough crop there to harvest.
At our Walters dual-purpose and Altus stops, drought stress was impossible to miss (Figures 3 and 4). Short plants, reduced tillering, and accelerated development were common across fields. When wheat undergoes stem elongation and grain set under moisture stress and heat, the crop has less time and fewer resources to build and fill grain, directly reducing yield potential.
Figure 3. Dual-purpose wheat variety trial in Walters. This trial was planted on September 25, 2025, and grazed at a stocking rate of 154 lbs/ac. The crop has faced multiple challenges throughout the season, including armyworm and grasshopper infestations in the fall, brown wheat mite pressure in early spring, and persistent drought since planting. The first significant rainfall occurred during the first week of April (2.8 inches). Kinder Farms, April 20, 2026.
Figure 4. Wheat variety trial in Altus, planted on November 25, 2025. This trial received very limited rainfall after planting, resulting in poor stand establishment, as shown in the photo. Stand variability is high, plants are extremely short, and tillering is reduced due to prolonged drought stress. The center plot shown is representative of many fields in the region, where yield potential has been severely reduced, and some fields have already been abandoned for grain harvest. Altus, April 21, 2026.
Conditions in Chickasha were somewhat better compared to the southwest, but variability remains high. Planting date, soil type, and how much rainfall individual fields have received are making a big difference in how the crop is holding on.
The recent rains were certainly welcome and should provide some benefit to fields that are still in fair to moderate condition, especially those now entering grain fill. However, for many fields we are approaching a point of diminishing returns. Rain at this stage can help preserve yield potential, but it cannot fully restore what was lost from poor establishment and prolonged stress earlier in the season.
On top of drought stress, we are also seeing some disease pressure. Viral diseases such as Wheat streak mosaic and Barley yellow dwarf remain present in some areas, and leaf rust has begun to develop where conditions have turned favorable. While disease pressure is not the main driver of yield loss right now, it can add another layer of stress to an already compromised crop (Figure 5).
Figure 5. Wheat variety trials in Chickasha showing severe leaf rust infestation in susceptible varieties. Recent rainfall and favorable temperatures have improved crop conditions but also accelerated fungal disease development, increasing pressure on varieties lacking resistance. Chickasha, April 24, 2026.
At this point, yield prospects will depend heavily on how long the crop can maintain green leaf area and continue grain fill over the next few weeks. But overall, statewide yield expectations are trending below average.
Even with the challenges this season, our plot tours remain a valuable opportunity to see how varieties are performing under real field conditions, review the latest research from our programs, and talk through the conditions you’re seeing in your area.
We encourage you to join us at one of our upcoming stops (see schedule here). Every season teaches us something, and this year is another strong reminder of how dependent Oklahoma wheat production is on timely rainfall.
Reports from southwest Oklahoma indicate Bird Cherry Oat Aphid (BCOA) infestations in winter wheat. While these aphids are often present in Oklahoma wheat every year, heavy infestations—especially during the grain-fill stages or in fields intended for grazing—can lead to economic loss through direct feeding and the transmission of viral diseases.
Identification and Differentiation from Other Small Grain Aphids
The Bird Cherry Oat Aphid is relatively easy to identify if you know what to look for, but it can be confused with the Rice Root Aphid (RRA).
Bird Cherry Oat Aphid (BCOA), Rhopalosiphum padi:
Appearance: Small, pear-shaped, olive-green to greenish-black bodies. Tips of legs are black. “Old” aphids found in winter and early spring often are black but will give birth to more typically colored aphids in the spring.
Key Feature: A distinctive reddish-orange or “rusty” patch at the rear of the abdomen, specifically surrounding the base of the cornicles (tailpipes) (Figure 1).
Location: Primarily found on the leaves and stems in the lower to middle canopy and can be found throughout the wheat growing season. When in high numbers, feeding can result in honeydew.
Appearance: Very similar in color and possesses a reddish-orange patch.
Key Differences: The RRA has a hairy appearance with long & prominent hairs on its antennae and body (Figure 2)
Location: As the name suggests, RRA is typically found at or below the soil line on the roots or the very base of the crown. BCOA will stay on the green tissue above ground. RRA typically appear in the fall, soon after wheat emerges.
Figure 1. Bird cherry oat aphid (BCOA) adults and nymphs. Image courtesy of iNaturalist.Figure 2. Rice root aphid (RRA) adults can appear similar to BCOA. RRA are rarely economically damaging. Image courtesy Rick Grantham, OSU.
BCOA Biology
In Oklahoma and the southern Great Plains, BCOA populations consist entirely of females that give birth to live young (parthenogenesis). This allows for extremely rapid population growth when temperatures are mild. They can survive the winter as active nymphs and adults in the wheat canopy, though their development slows during extreme cold. As the wheat matures or populations become crowded, winged alates are produced to migrate to other fields.
BCOA Damage: Feeding and Disease
The impact of BCOA is twofold:
Direct Feeding Damage: BCOA are sapsuckers. Large numbers can cause leaf yellowing and stunting (Figure 3). In grazing systems, BCOA feeding can interfere with protein assimilation in the plant, potentially reducing the nutritional quality of the forage for cattle.
Viral Transmission: BCOA is a primary vector for Barley Yellow Dwarf Virus (BYDV).
Symptoms: Infected wheat displays brilliant yellow or reddish-purple leaf tips. Plants infected in the fall are often severely stunted and have significantly reduced root systems, leading to high yield loss (Figure 3). Spring infections are usually less severe but still impact test weights.
Figure 3. Heavy bird cherry oat aphid (BCOA) with honeydew accumulation and chlorosis/stunting. Image courtesy Angus Catchot, Mississippi State Extension.
Scouting Techniques Because BCOA often hides in the lower canopy or in the “whorl” of the plant, thorough scouting is essential. Method: Examine 25 randomly selected tillers across a zigzag transect of the field. Focus: Look closely at the underside of leaves and inside the leaf sheaths. Threshold: While wheat can tolerate a surprising number of BCOA, treatment is generally recommended if populations reach 20 to 50 aphids per tiller during the seedling to boot stages. If the wheat is under moisture stress or if the goal is to prevent BYDV spread in early spring, use the lower end of the threshold. Management Recommendations Natural Enemies: Before spraying, check for the “Three L’s”: Lady beetles, Lacewings, and Lysiphlebus (parasitic wasps). If you see aphid mummies, bloated, tan/bronze-colored aphid husks (Figure 4), the wasps are actively working. If natural enemy populations are high, they can often crash an aphid population without the need for chemicals. Based on recent observations, natural enemy numbers appear be on the low end this year. Chemical Control: Several insecticides are labeled for BCOA in wheat (Table 1). Organophosphates or pyrethroids are generally effective but be mindful of the flare risk: sometimes spraying for aphids can kill natural enemies and lead to a secondary surge of other pests like mites. We are having widespread reports of brown wheat mites across Oklahoma. BCOA can be spot sprayed with a ground-sprayer. Before spraying any insecticides consider the return on investment: Estimate yield loss: Calculate the average number of aphids per tiller from your scouting ( = # aphids/# tillers). Estimate crop value: Crop Value = Yield Potential X Price per Bushel Estimate control costs: Control Cost = Insecticide Cost + Application Cost Estimate preventable loss: Crop Value X Yield Loss from Aphid (0.07) Approximately 5-9% yield loss occurs when there are 20-40 BCOA per tiller, making average yield loss from BCOA to be 7% or 0.07. If preventable loss is greater than control costs, then treat! Cultural Control: For future seasons, delaying planting can reduce the window for fall BCOA migration and subsequent BYDV infection.
Figure 4. Bird cherry oat aphid (BCOA) and brown mummy. These mummies are a result of an aphid being parasitized by Lysiphlebus testceipes wasps.
Table 1. Some foliar insecticides for bird cherry-oat aphid (BCOA) in wheat. The mention, listing, or use of specific insecticides is not an endorsement of that product, nor is it a criticism of similar products not mentioned.
Always follow pesticide label directions, application sites, and rates. Be sure to read and follow the label for preharvest intervals (PHI) and restricted-entry intervals (REI). Use a minimum of 10 GPA by ground and 3 GPA by air (if labelled for aerial application) to ensure adequate coverage.
For assistance with aphid identification or treatment decisions, see OSU Fact Sheet EPP-7099 Small Grain Aphids in Oklahoma and Their Management, or contact your local OSU Extension office.
Ashleigh Faris, Cropping Systems Entomologist, IPM Coordinator
Following a period of dry weather, wheat growers in central Oklahoma are reporting activity of the Brown Wheat Mite (BWM). Unlike many other wheat pests, BWM thrives in drought conditions, and its damage can often be mistaken for moisture stress or nutrient deficiency.
Identification
The Brown Wheat Mite is small—about the size of a needle point—but is generally easier to spot than the Wheat Curl Mite because it is active on the leaf surface.
Appearance: BWM has a dark red to brownish-black, oval-shaped body (Figure 1).
Distinguishing Feature: Its front legs are significantly longer than its other three pairs of legs.
Behavior: They are most active during the day, particularly in the afternoon, and will quickly drop to the ground if the plant is disturbed (Figure 2).
Figure 1. Brown wheat mite (BWM).
Figure 2. Brown wheat mites (BWM) on wheat. Image courtesy L. Galvin, OSU Extension.
Biology and Life Cycle
BWM populations consist entirely of females that produce offspring without mating (parthenogenesis), allowing for extremely rapid population growth under dry conditions. The BWM has a unique life cycle in that it can lay two types of eggs. Environmental conditions dictate when these two types of eggs are laid:
Red Eggs: Laid during the growing season and hatch in about a week when conditions are favorable.
White (Diapause) Eggs: Laid as temperatures rise and the crop matures. They are highly resistant and allow the population to survive the summer heat, hatching only when cooler, wetter weather arrives in the fall.
Damage
BWM damage is caused by the mites piercing plant cells and sucking out the plant nutrients.
Symptoms: Initial damage appears as “stippling” (fine white or yellow spots) on the leaves. As feeding continues, leaves take on a silvery or bronzed appearance (Figure 3).
Tipping: Heavy infestations cause the tips of the leaves to turn brown and die.
Weather Interaction: Damage is most severe when plants are already under drought stress. Because both BWM damage and drought cause yellowing/browning, it is essential to confirm the presence of mites before treating.
Figure 3. Brown wheat mite (BWM) damage
Scouting
Because BWM is highly mobile and drops when disturbed, careful scouting is required:
Timing: Scout during the warmest part of the day when mites are most active on the upper leaves.
The Paper Test: Gently but quickly shake or tap wheat plants over a white piece of paper or a white clipboard. Look for tiny dark specks moving across the surface.
Economic Threshold: While thresholds vary based on crop value and moisture stress, research suggests a treatment threshold of 25 to 50 brown wheat mites per leaf in wheat that is 6 inches to 9 inches tall is economically warranted. An alternative estimation is “several hundred” per foot of row. If the wheat is severely stressed, the lower end of that threshold should be used.
Management Recommendations
The “Rain” Factor: A significant, driving rain is often the most effective control for BWM. Rain can physically knock mites from the plant and promote fungal pathogens that naturally reduce the population.
Chemical Control: If populations exceed the threshold and no rain is in the forecast, chemical intervention may be necessary. Know the cost of the treatment and value of your wheat so you can determine if an application is a worth return on investment.
Effective Ingredients: Organophosphates (such as Dimethoate) have historically provided better control than many pyrethroids, as the latter can sometimes result in mite “flaring” or simply fail to provide adequate residual control.
Coverage: High water volume is critical to ensure the insecticide reaches the mites, especially if they have moved toward the base of the plant.
Cultural Practices: Since BWM thrives in dry, dusty conditions, maintaining good soil moisture and vigorous plant growth can help the crop tolerate feeding. Here’s to hoping for some rain soon in the forecast; we could really use it for lots of reasons in Oklahoma.
Temperatures dropped below freezing across parts of the state. Here is how growth stage, temperature, and duration of the freeze influence potential wheat injury.
Amanda de Oliveira Silva, Small Grains Extension Specialist
Several areas across Oklahoma experienced freezing temperatures overnight, with some locations recording multiple hours below freezing (Figures 1 and 2). There is potential for freeze injury, especially in drought-stressed wheat that has reached jointing or later growth stages. If wheat is still before jointing, the growing point remains below the soil surface and is more protected from freezing injury.
However, with the warm conditions we experienced earlier this spring, the crop is running slightly ahead of schedule, and some fields have already reached or passed the jointing stage. At this stage, the developing head has started to move up the elongating stem and is no longer protected.
In the coming days we may start to see additional symptoms of freeze injury. The extent of the injury will depend on several factors, including the growth stage of the plants, how low the temperature dropped, and how long temperatures remained at those levels. Brief freezes often cause little damage, but several hours below critical temperatures during jointing or reproductive stages can reduce yield (Figure 3).
Figure 1. Minimum air temperature (in Fahrenheit) over the past 24 hours at each Mesonet station. Figure courtesy Oklahoma Mesonet.Figure 2. Number of hours spent at or below freezing (32°F) over the past 48 hours at Mesonet station. Figure courtesy Oklahoma Mesonet.
What are the temperatures that can damage the wheat plants?
The potential for freeze injury depends largely on the growth stage of the crop. Anecdotal evidence sometimes suggests varietal differences in resistance to spring freeze injury, but this is often due to differences in plant maturity at the time of the freeze event. Earlier-maturing varieties are more likely to be injured during spring freezes simply because they are typically more advanced in development.
The susceptibility of wheat plants to freeze injury steadily increases as the crop progresses from jointing to heading and flowering.
Figure 3 below provides a general guide to temperature thresholds and their potential impact on yield. Keep in mind that these values are not exact, but they serve as useful rules of thumb.
Temperatures closer to the soil surface may be slightly higher than those recorded by weather stations located about one meter above the ground, especially when soil moisture is present. Because each freeze event is unique, it is difficult to define exact thresholds. For example, a field at the jointing stage exposed to 24°F for two hours may experience similar injury to wheat exposed to 28°F for a longer period of time.
Figure 3. Temperatures that can cause injury to winter wheat at different growth stages. Source: Kansas State University publication C646: Spring Freeze Injury to Kansas Wheat.
How long should I wait to assess the injury?
Patience is important when evaluating freeze damage. The full extent of injury is usually not visible within the first day or two after the freeze event.
If warm temperatures return quickly, symptoms may become evident within 5–7 days. If temperatures remain cool, it may take 10–14 days before the extent of the injury can be properly assessed.
What freeze injury symptoms should I look for?
One common symptom is leaf tip burn, where leaf tips turn yellow and necrotic (Figure 4). This type of damage is often cosmetic and may not significantly affect yield.
More severe freeze damage may cause entire leaves to turn yellow or white, and plants may lose their turgidity and appear flaccid (Figure 5). In some cases, a “silage” smell may be noticeable several days after the freeze event.
Figure 4.Leaf tips that have turned necrotic due to freezing temperatures. Photo taken in March 2017 courtesy of Josh Bushong, OSU Northwest Area Extension Agronomist.
Figure 5.More severe freeze damage causing leaves to turn yellow-white and plants to lose turgidity. Source: Kansas State University publication C646: Spring Freeze Injury to Kansas Wheat.
The most important plant part to check: the developing head (growing point)
This is particularly important in areas where fields are more advanced in growth. Plants may appear healthy overall while the developing head has been damaged or killed.
To examine the growing point, carefully slice the stem lengthwise. A healthy growing point will have a firm, whitish-green appearance and remain turgid (Figures 6 and 7, left). Often you can lightly flick the head; if it bounces back and does not break, it is likely still healthy.
If the growing point is mushy, limp, breaks easily, or appears brown, it has likely been compromised (Figure 7, right). Another indication of damage is when the next emerging leaf becomes necrotic and lower stems appear discolored with lesions or enlarged nodes.
Figure 6. Close up of a healthy wheat head (growing point) above the second node showing whitish-green color and turgidity.
Figure 7. Plants that appear healthy may still have damaged heads. The photo on the left shows a healthy head, while the photo on the right shows a freeze-damaged head.
Freeze injury at later growth stages
Freezing temperatures at the boot stage may cause the head to become trapped in the flag leaf sheath, preventing proper head emergence (Figure 8). Whitish awn tips are often an indication that the head was exposed to freezing temperatures and that the flower parts may have been damaged.
Freezes during flowering may cause sterility due to damage to the anthers (the male reproductive organ), resulting in poor kernel set and yield losses (Figure 9).
Figure 8.Freeze injury at the boot stage may cause heads to remain trapped in the boot.
Figure 9. Freeze during flowering may cause sterility due to damage to the anthers, resulting in poor kernel set and yield loss.
Can wheat recover from freeze injury?
The percentage of damaged heads does not always translate directly into yield loss. At the jointing stage, wheat still has the potential to produce additional tillers or retain secondary tillers.
Whether these tillers can compensate for damaged primary tillers will depend on subsequent weather conditions. If growing conditions are favorable, late-emerging tillers may still produce grain. However, if the crop is already near flowering or later stages, recovery becomes much more limited.
Key points to keep in mind
• Every freeze event is unique. Injury must be evaluated on a field-by-field basis. Temperature thresholds are guidelines, not exact predictors of damage. In some cases, conditions may suggest severe injury but fields recover with minimal impact.
• The extent of injury depends on several factors, including growth stage, minimum temperature reached, and duration of freezing temperatures. Field conditions such as elevation, residue cover, and soil moisture can also influence canopy temperatures.
• Symptoms may take several days to appear. Damage may become noticeable over the next days or into the middle of next week. Healthy wheat heads will remain firm and green, while damaged heads may appear bleached, yellow, or brown and break easily when pressed.
Stay Connected!
Enroll in the OSU Wheat text update service by texting the word “wheat” to (855) 452-0486 to receive timely information throughout the wheat season.
If you start to observe freeze injury in your fields over the next several days, send us a text and let us know what you are seeing.
Ashleigh M. Faris, Cropping Systems Extension Entomologist
Wheat producers in central Oklahoma are reporting the presence of the greenbug,Schizaphis graminum, in winter wheat fields. Greenbugs are one of the most important insect pests of wheat in the southern Great Plains and can occur from fall through spring. These aphids feed on plant sap and inject toxins into wheat plants, causing characteristic leaf discoloration and plant injury.
Early detection through field scouting is essential to determine whether populations are increasing and if an insecticide treatment is justified.
Greenbug Identification & Biology
Key identifying characteristics of greenbug (Figure 1):
Small aphids (~1/16 inch long)
Pale to lime-green body
Dark green stripe down the middle of the back
Dark tips on antennae and legs
Found in colonies on the underside of wheat leaves
Figure 1. Greenbug nymphs and adults on wheat leaf. Greenbugs are distinguishable from other aphids based on their lime green bodies, dark green stripe down back, dark antennae, and dark leg tips. Image courtesy of https://databases.nbair.res.in/.
Greenbugs reproduce rapidly under favorable conditions (between 55° F and 95° F) and often occur in patches within fields rather than evenly distributed populations. During periods of cool weather, the greenbug may increase to enormous numbers, due to the absence of natural enemies, which develop significantly slower compared to greenbugs at such temperatures. On the other hand, cold weather can also influence aphid populations. However, this latest cold snap is not enough to eliminate greenbugs. It takes average temperatures below 20° F for at least a week to kill a substantial number of greenbugs in wheat.
Greenbug Damage in Wheat
Greenbugs damage wheat in two ways, through direct feeding and injection of toxic saliva. Greenbugs may also transmit barley yellow dwarf virus (BYDV), which can further reduce yield potential.
Typical early symptoms include small, reddish or copper spots on leaves (Figure 2) and yellowing around feeding sites. Advanced infestations will result in leaves turning yellow or orange, dead leaf tissue, stunted plants, and expanding patches of dead wheat. Heavy infestations may kill seedlings and reduce tillering, particularly during drought stress.
Figure 2. Early damage to wheat caused by greenbugs appears as yellow to reddish, coppery spots. Image courtesy of Alton Sparks, Kansas State Extension.
How to Scout for Greenbugs
The Glance-N-Go™ sampling system developed by Oklahoma State University can help determine whether aphid populations exceed economic thresholds. Download the Greenbug Glance N’ Go Sampler app for your smartphone. You will then input the control cost ($/Acre), crop value ($/Acre), and the Spring sampling window. Use a zig-zag or W-pattern (Figure 3) to scout your field, checking undersides of leaves at three tillers per stop for greenbugs and brown mummies. Use the app to record the numbers of these insects and sample until the app tells you to stop sampling or tells you treat. As temperatures warm, continue to scout regularly as greenbug populations may build.
Figure 3. Scouting pattern for greenbug. Walk a W-pattern across the field and examine plants at multiple locations. Inspect the underside of leaves and base of tillers for aphids and beneficial insects. Image courtesy of A.M. Faris, Oklahoma State University Extension.
Scouting recommendations without the Greenbug Glance N’ Go Sampler app:
Walk a W or zigzag pattern across the field.
Examine 10–20 plants at each stop.
Check:
Underside of leaves
Leaf midrib
Base of tillers
Record:
Aphids per tiller
Presence of aphid mummies (Figure 4)
Beneficial insects
Beneficial Insects
Natural enemies frequently control aphid populations. While scouting for greenbug you should also look for lady beetles, lacewing larvae, hoverfly larvae, and parasitized aphids (“mummies”) (Figure 4). If beneficial insects are abundant, aphid populations may decline without insecticide treatment. Where there are one to two lady beetles (adults and larvae) per foot of row, or 15 to 20 percent of the greenbugs have been parasitized, control measures could be delayed until it is determined whether the greenbug population is continuing to increase.
Based on current wheat scouting, it appears that parasitoid numbers are low this 2026 season so continuing to scout for greenbug will be critical in responding to populations that go unchecked by beneficials.
Figure 4. Brown mummy amongst greenbugs. The brown, inflated insect in the top let of the image is a greenbug that has been parasitized. Look for these mummies when making management decisions. Image courtesy of David Voegtlin, University of Illinois.
Economic Threshold Guidelines
The simplest way to determine if action needs to be taken against greenbugs is to utilize the Glance-N-Go™ sampling system developed by Oklahoma State University. Approximate guidelines historically used in Oklahoma wheat can be found in Table 1 below.
Table 1. Approximate guidelines historically used in Oklahoma wheat for greenbug.
Wheat Growth Stage
# Greenbugs per Linear Foot
Seedling wheat
50
3–6-inch wheat, 3 tillers or more
100 – 300
Late vegetative wheat
300 to 500
Thresholds are influenced by:
Wheat growth stage
Crop value
Cost of treatment
Presence of beneficial insects
Insecticides Labeled for Greenbugs in Wheat
Aphid feeding and insecticide performance are strongly influenced by temperature. Greenbugs tend to move higher on wheat plants during warm conditions but may move lower on the plant or below ground during cold weather, reducing exposure to insecticides. As a result, damaging populations are most often observed in late winter and early spring. Insecticides generally perform best when temperatures are above 50°F, and control may occur more slowly in cooler conditions (e.g., control at 45° F may take roughly twice as long as at 70° F). If applications must be made under cooler temperatures, use the highest labeled rate. Wheat grown under irrigation can typically tolerate higher greenbug populations than dryland wheat.
Table 2. Common foliar options for greenbug in winter wheat.
Active Ingredient
Example Trade Names
Dimethoate*
Dimethoate 4E
Chlorantraniliprole+Lambda-cyhalothrin
Beseige*
Lambda-cyhalothrin
Warrior II*
Gamma-cyhalothrin
Proaxis*, Declare
Zeta-cypermethrin
Mustang Maxx
Sulfoxaflor
Transform WG
Flupyradifurone
Sivanto Prime
*Greenbug is known to have many biotypes. Besiege and Proaxis Insecticides may provide suppression only. Use the maximum rate when treating greenbug.
Always follow pesticide label directions, application sites, and rates. Be sure to read and follow the label for preharvest intervals (PHI) and restricted-entry intervals (REI). Use a minimum of 10 GPA by ground and 3 GPA by air (if labelled for aerial application) to ensure adequate coverage.
For assistance with aphid identification or treatment decisions, see OSU Fact Sheet EPP-7099 Small Grain Aphids in Oklahoma and Their Management, or contact your local OSU Extension office.
Amanda de Oliveira Silva, Small Grains Extension Specialist
The first hollow stem stage indicates the beginning of stem elongation or just before the jointing stage. It is a good indicator of when producers should remove cattle from wheat pasture. This occurs when there is 1.5 cm (5/8”, or the diameter of a dime) of hollow stem below the developing grain head (see full explanation).
The latest FHS results from OSU forage trials in Stillwater (Table 1) and Chickasha (Table 2) are listed below. For an additional resource and wheat update on FHS, see the Mesonet First Hollow Stem Advisor.
OSU Small Grains Program monitors FHS occurrence on a twice-per-week basis
As in previous years, we will continue monitoring FHS occurrence in our wheat plots at Stillwater and Chickasha and share updates on this blog. In past years, our forage trials—where FHS samples are collected—were seeded early to simulate a grazed system, though forage was not removed. This method created an accelerated growth environment, allowing us to identify the earliest onset of FHS. Varieties that reach FHS earliest in these trials should be closely monitored in commercial fields.
This year, we are continuing with a new approach by simulating grazing with a mower in the forage trial in Stillwater. This will allow us to compare whether varieties reach FHS at different times when grazed versus non-grazed. We hypothesize that the simulated grazing treatment will likely delay FHS relative to the non-grazed treatment, with FHS differences among varieties becoming less pronounced. We also hypothesize that the amount of delay will vary among varieties, such that an early-FHS variety in the non-grazed environment may appear more intermediate in its FHS arrival with canopy removal. This comparison will provide insight into how canopy removal from grazing impacts the timing of reproductive development.
The latest FHS results for each variety planted in our forage trials at Stillwater and Chickasha are summarized below (Tables 1 and 2). All varieties have reached the 1.5 cm FHS threshold.
Table 1. First Hollow Stem (FHS) results for each wheat variety collected at Stillwater. Plots were planted on 10/10/2025, with one section left unclipped and the other clipped to simulate grazing. The FHS threshold is 1.5 cm (5/8″ or approximately the diameter of a dime). Reported values represent the average of ten measurements per variety. Varieties that exceed the threshold are highlighted in red. For the simulated grazing, plots were mowed on January 2nd and 13th, and on February 9th and 16th at a 3” cutting height, with the frequency representing a light grazing treatment.
Table 2. First Hollow Stem (FHS) results for each wheat variety collected at Chickasha. Plots were planted on 9/25/2025, with all sections left unclipped (i.e., not grazed). The FHS threshold is 1.5 cm (5/8″ or approximately the diameter of a dime). Reported values represent the average of ten measurements per variety. Varieties that exceed the threshold are highlighted in red.
Contact your local Extension office and us if you have questions.
Amanda de Oliveira Silva, Small Grains Extension Specialist
The first hollow stem stage indicates the beginning of stem elongation or just before the jointing stage. It is a good indicator of when producers should remove cattle from wheat pasture. This occurs when there is 1.5 cm (5/8”, or the diameter of a dime) of hollow stem below the developing grain head (see full explanation).
The latest FHS results from OSU forage trials in Stillwater (Table 1) and Chickasha (Table 2) are listed below. For an additional resource and wheat update on FHS, see the Mesonet First Hollow Stem Advisor.
OSU Small Grains Program monitors FHS occurrence on a twice-per-week basis
As in previous years, we will continue monitoring FHS occurrence in our wheat plots at Stillwater and Chickasha and share updates on this blog. In past years, our forage trials—where FHS samples are collected—were seeded early to simulate a grazed system, though forage was not removed. This method created an accelerated growth environment, allowing us to identify the earliest onset of FHS. Varieties that reach FHS earliest in these trials should be closely monitored in commercial fields.
This year, we are continuing with a new approach by simulating grazing with a mower in the forage trial in Stillwater. This will allow us to compare whether varieties reach FHS at different times when grazed versus non-grazed. We hypothesize that the simulated grazing treatment will likely delay FHS relative to the non-grazed treatment, with FHS differences among varieties becoming less pronounced. We also hypothesize that the amount of delay will vary among varieties, such that an early-FHS variety in the non-grazed environment may appear more intermediate in its FHS arrival with canopy removal. This comparison will provide insight into how canopy removal from grazing impacts the timing of reproductive development.
The latest FHS results for each variety planted in our forage trials at Stillwater and Chickasha are summarized below (Tables 1 and 2). Most varieties have reached the 1.5 cm FHS threshold.
Table 1. First Hollow Stem (FHS) results for each wheat variety collected at Stillwater. Plots were planted on 10/10/2025, with one section left unclipped and the other clipped to simulate grazing. The FHS threshold is 1.5 cm (5/8″ or approximately the diameter of a dime). Reported values represent the average of ten measurements per variety. Varieties that exceed the threshold are highlighted in red. For the simulated grazing, plots were mowed on January 2nd and 13th, and on February 9th and 16th at a 3” cutting height, with the frequency representing a light grazing treatment.
Table 2. First Hollow Stem (FHS) results for each wheat variety collected at Chickasha. Plots were planted on 9/25/2025, with all sections left unclipped (i.e., not grazed). The FHS threshold is 1.5 cm (5/8″ or approximately the diameter of a dime). Reported values represent the average of ten measurements per variety. Varieties that exceed the threshold are highlighted in red.
Contact your local Extension office and us if you have questions.
Amanda de Oliveira Silva, Small Grains Extension Specialist
The first hollow stem stage indicates the beginning of stem elongation or just before the jointing stage. It is a good indicator of when producers should remove cattle from wheat pasture. This occurs when there is 1.5 cm (5/8”, or the diameter of a dime) of hollow stem below the developing grain head (see full explanation).
The latest FHS results from OSU forage trials in Stillwater (Table 1) and Chickasha (Table 2) are listed below. For an additional resource and wheat update on FHS, see the Mesonet First Hollow Stem Advisor.
OSU Small Grains Program monitors FHS occurrence on a twice-per-week basis
As in previous years, we will continue monitoring FHS occurrence in our wheat plots at Stillwater and Chickasha and share updates on this blog. In past years, our forage trials—where FHS samples are collected—were seeded early to simulate a grazed system, though forage was not removed. This method created an accelerated growth environment, allowing us to identify the earliest onset of FHS. Varieties that reach FHS earliest in these trials should be closely monitored in commercial fields.
This year, we are continuing with a new approach by simulating grazing with a mower in the forage trial in Stillwater. This will allow us to compare whether varieties reach FHS at different times when grazed versus non-grazed. We hypothesize that the simulated grazing treatment will likely delay FHS relative to the non-grazed treatment, with FHS differences among varieties becoming less pronounced. We also hypothesize that the amount of delay will vary among varieties, such that an early-FHS variety in the non-grazed environment may appear more intermediate in its FHS arrival with canopy removal. This comparison will provide insight into how canopy removal from grazing impacts the timing of reproductive development.
The latest FHS results for each variety planted in our forage trials at Stillwater and Chickasha are summarized below (Tables 1 and 2). Some varieties have reached the 1.5 cm FHS threshold.
Table 1. First Hollow Stem (FHS) results for each wheat variety collected at Stillwater. Plots were planted on 10/10/2025, with one section left unclipped and the other clipped to simulate grazing. The FHS threshold is 1.5 cm (5/8″ or approximately the diameter of a dime). Reported values represent the average of ten measurements per variety. Varieties that exceed the threshold are highlighted in red. For the simulated grazing, plots were mowed on January 2nd and 13th, and on February 9th and 16th at a 3” cutting height, with the frequency representing a light grazing treatment.
Table 2. First Hollow Stem (FHS) results for each wheat variety collected at Chickasha. Plots were planted on 9/25/2025, with all sections left unclipped (i.e., not grazed). The FHS threshold is 1.5 cm (5/8″ or approximately the diameter of a dime). Reported values represent the average of ten measurements per variety. Varieties that exceed the threshold are highlighted in red.
Contact your local Extension office and us if you have questions.
Amanda de Oliveira Silva, Small Grains Extension Specialist
The first hollow stem stage indicates the beginning of stem elongation or just before the jointing stage. It is a good indicator of when producers should remove cattle from wheat pasture. This occurs when there is 1.5 cm (5/8”, or the diameter of a dime) of hollow stem below the developing grain head (see full explanation).
The latest FHS results from OSU forage trials in Stillwater (Table 1) and Chickasha (Table 2) are listed below. For an additional resource and wheat update on FHS, see the Mesonet First Hollow Stem Advisor.
OSU Small Grains Program monitors FHS occurrence on a twice-per-week basis
As in previous years, we will continue monitoring FHS occurrence in our wheat plots at Stillwater and Chickasha and share updates on this blog. In past years, our forage trials—where FHS samples are collected—were seeded early to simulate a grazed system, though forage was not removed. This method created an accelerated growth environment, allowing us to identify the earliest onset of FHS. Varieties that reach FHS earliest in these trials should be closely monitored in commercial fields.
This year, we are continuing with a new approach by simulating grazing with a mower in the forage trial in Stillwater. This will allow us to compare whether varieties reach FHS at different times when grazed versus non-grazed. We hypothesize that the simulated grazing treatment will likely delay FHS relative to the non-grazed treatment, with FHS differences among varieties becoming less pronounced. We also hypothesize that the amount of delay will vary among varieties, such that an early-FHS variety in the non-grazed environment may appear more intermediate in its FHS arrival with canopy removal. This comparison will provide insight into how canopy removal from grazing impacts the timing of reproductive development.
The latest FHS results for each variety planted in our forage trials at Stillwater and Chickasha are summarized below (Tables 1 and 2). Most varieties are still well below the 1.5 cm FHS threshold.
Table 1. First Hollow Stem (FHS) results for each wheat variety collected at Stillwater. Plots were planted on 10/10/2025, with one section left unclipped and the other clipped to simulate grazing. The FHS threshold is 1.5 cm (5/8″ or approximately the diameter of a dime). Reported values represent the average of ten measurements per variety. Varieties that exceed the threshold are highlighted in red. For the simulated grazing, plots were mowed on January 2nd and 13th, and on February 9th and 16th at a 3” cutting height, with the frequency representing a light grazing treatment.
Table 2. First Hollow Stem (FHS) results for each wheat variety collected at Chickasha. Plots were planted on 9/25/2025, with all sections left unclipped (i.e., not grazed). The FHS threshold is 1.5 cm (5/8″ or approximately the diameter of a dime). Reported values represent the average of ten measurements per variety. Varieties that exceed the threshold are highlighted in red.
Contact your local Extension office and us if you have questions.
Amanda de Oliveira Silva, Small Grains Extension Specialist
Soil moisture conditions are currently favorable for wheat planting across much of Oklahoma. Many of you may be eager to get seed in the ground, but before moving ahead, it is important to consider a few key points.
Planting date
For dual-purpose wheat (grazing + grain), the optimal planting window in most of Oklahoma is mid-September (Figure 1). Planting during this period provides the best balance between fall forage production and maintaining grain yield potential.
Early planting may increase fall forage production but also raises the risk of pests and diseases. It’s usually only recommended for wheat intended for graze-out or dual-purpose.
Grain-only wheat should generally be planted about 3-4 weeks later (mid-October, Figure 1) in many parts of the state. Our recent work shows there is more flexibility than we thought, and planting a little later can still work well depending on the weather.
Figure 1. Forage and grain yield potential in relation to the day of the year. Every 1,000 kg/ha is equal to approximately 900 lb/acre or 15 bu/acre. Ideal planting dates for dual-purpose wheat in Oklahoma are mid-September (i.e., approximately day 260). Planting for grain-only should occur at least 3-4 weeks after dual-purpose planting (i.e., mid-October or approximately day 285).
Watch for Fall Armyworms
Planting too early increases the chance of fall armyworm infestations. These pests are small and easy to miss, but you might notice “window-pane” feeding on leaves (Figure 2). Check beneath crop residue as well, since they often hide there during the heat of the day (Figure 3).
Figure 2. Symptom of “window paned” leaves shows severe feeding from the fall armyworm. Photo taken on October 2, 2019, at Canadian County by Amanda Silva.
Figure 3. Fall armyworms may be found under crop residue during the day. Photo taken on October 2, 2019 at Canadian County by Amanda Silva.
Volunteer wheat and Virus Risk
Early planting also raises the risk of wheat streak mosaic and Triticum mosaic viruses, spread by the wheat curl mite. Because seed treatments do not control these viruses and few varieties have strong resistance (i.e., Breakthrough), cultural practices are critical:
Control volunteer wheat and other grassy hosts as much as possible.
Ensure volunteer wheat is completely dead for at least two weeks before planting. This breaks the “green bridge” that mites use to move into new seedlings.
Planting a little later can also help lower virus pressure.
We saw significant wheat streak mosaic issues last year, making these steps especially important in 2025.
Other Planting Considerations
Before planting:
Soil test to guide fertility needs and reduce input costs.
Use high-quality seed to promote good germination and stand establishment.
Consider fungicide and insecticide seed treatments to protect against soilborne diseases and early pest pressure such as root rots.
Need More Information?
Your county OSU Extension office is a great resource for information. You can also reach out directly to us:
WORLD OF WHEAT 