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First hollow stem update 03/04/2016

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). This will be the last of the 2016 first hollow stem updates, as the vast majority of varieties are at or well past first hollow stem.

Keep in mind that the numbers reported from Stillwater are likely behind those being observed in southern Oklahoma and ahead of those observed in northern Oklahoma. The First Hollow Stem Advisor can provide an estimate of first hollow stem progress in your neck of the woods.

First hollow stem measured in wheat sown 09/15/2015 at Stillwater, OK. Varieties with ‘-‘ reached first hollow stem on a previous measurement date
Variety cm of hollow stem 03/04/16
Endurance 1.5
OK Rising
Billings
Ruby Lee
Duster
Gallagher
Iba
Bentley
Doublestop CL Plus 1.57
NF 101
WB-Cedar
WB4458
WB-Grainfield
Winterhawk
WB4515
WB4721
WB4303
SY Monument 1.5
SY Flint
SY Llano
SY Drifter
SY Wolf
SY Razor
SY Grit
Everest
1863
KanMark
Oakley CL 1.74
Larry 1.8
Zenda
Tatanka 1.81
Joe 1.1
LCS Pistol 1.68
LCS Wizard 1.43
LCS Mint 2.08
LCS Chrome 1.84
T158 1.5
Long Branch 1.73
TAM 112
TAM 204
TAM 114
AG Robust
Byrd
Brawl CL Plus 1.26
Avery 1.97
OK1059060-3 1.91
OK10126 1.41
OK11D25056 1.55
OK12621 2.18
Stardust 2.24
OK12716R/W 1.16
OK11231 1.26
OK09915C-1 1.32
OK12912C 1.17
OK12DP22002-042
OK118036R/W

First hollow stem update 02/29/2016

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). We measure first hollow in our September-sown wheat forage plots at Stillwater each year, and normally have approximately 50% of varieties at or past first hollow stem by March 1st. I have posted first hollow stem measurements from samples taken from these plots on 02/29/16 in a table at the end of this blog. Most wheat varieties are now at or well past first hollow stem.

Keep in mind that the numbers reported from Stillwater are likely behind those being observed in southern Oklahoma and ahead of those observed in northern Oklahoma. The First Hollow Stem Advisor can provide an estimate of first hollow stem progress in your neck of the woods.

First hollow stem measured in wheat sown 09/15/2015 at Stillwater, OK. Varieties with ‘-‘ reached first hollow stem on a previous measurement date
Variety cm of hollow stem 02/29/2016
Endurance 1.0
OK Rising 1.5
Billings
Ruby Lee 2.0
Duster 2.0
Gallagher
Iba
Bentley
Doublestop CL Plus 1.4
NF 101
WB-Cedar
WB4458
WB-Grainfield
Winterhawk
WB4515
WB4721
WB4303
SY Monument 1.0
SY Flint
SY Llano
SY Drifter
SY Wolf 2.7
SY Razor
SY Grit
Everest
1863
KanMark 1.5
Oakley CL 1.3
Larry 0.9
Zenda
Tatanka 1.1
Joe 0.8
LCS Pistol 1.1
LCS Wizard 1.3
LCS Mint 1.4
LCS Chrome 1.2
T158 1.1
Long Branch 1.2
TAM 112 1.6
TAM 204 1.7
TAM 114 1.6
AG Robust
Byrd 1.7
Brawl CL Plus 1.1
Avery 1.1
OK1059060-3 1.4
OK10126 0.8
OK11D25056 1.1
OK12621 1.1
Stardust 1.0
OK12716R/W 1.1
OK11231 1.0
OK09915C-1 0.8
OK12912C 1.1
OK12DP22002-042 1.6
OK118036R/W

First hollow stem update 02/26/2016

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). We measure first hollow in our September-sown wheat forage plots at Stillwater each year, and normally have approximately 50% of varieties at or past first hollow stem by March 1st. I have posted first hollow stem measurements from these plots in a table at the end of this blog. WB-Grainfield and AG Robust have reached first hollow stem since our last update.

Keep in mind that the numbers reported from Stillwater are likely behind those being observed in southern Oklahoma and ahead of those observed in northern Oklahoma. The First Hollow Stem Advisor can provide an estimate of first hollow stem progress in your neck of the woods.

First hollow stem measured in wheat sown 09/15/2015 at Stillwater, OK. Varieties with no hollow stem value reached first hollow stem on a previous measurement date
Variety cm of hollow stem 02/26/16
Endurance 0.9
OK Rising 1.3
Billings
Ruby Lee 1.3
Duster 1.2
Gallagher
Iba
Bentley
Doublestop CL Plus 1.3
NF 101
WB-Cedar
WB4458
WB-Grainfield 1.6
Winterhawk
WB4515
WB4721
WB4303
SY Monument 0.9
SY Flint
SY Llano
SY Drifter
SY Wolf 1.1
SY Razor
SY Grit
Everest
1863
KanMark 1.4
Oakley CL 1.3
Larry 0.8
Zenda
Tatanka 1.0
Joe 0.7
LCS Pistol 0.9
LCS Wizard 1.2
LCS Mint 0.9
LCS Chrome 1.0
T158 1.0
Long Branch 1.1
TAM 112 1.2
TAM 204 1.3
TAM 114 1.3
AG Robust 1.6
Byrd 1.2
Brawl CL Plus 0.6
Avery 0.7
OK1059060-3 1.3
OK10126 0.7
OK11D25056 0.8
OK12621 0.8
OK10728W 0.8
OK12716R/W 0.6
OK11231 0.8
OK09915C-1 0.6
OK12912C 1.0
OK12DP22002-042 1.2
OK118036R/W  
Average 1.0

First hollow stem update 02/23/2016

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). We measure first hollow in our September-sown wheat forage plots at Stillwater each year, and normally have approximately 50% of varieties at or past first hollow stem by March 1st. I have posted first hollow stem measurements from these plots in a table at the end of this blog. As of Monday the varieties, Billings, Gallagher, Iba, Bentley, NF101, WB-Cedar, WB4458, Winterhawk, WB4515, WB4721, WB4303, SY Flint, Sy Llano, SY Drifter, SY Razor, SY Grit, Everest, and Zenda were all at or past first hollow stem at Stillwater. Please note that WB4515 was incorrectly labeled as WB4455 in the past couple of posts. Also note that experimental line OK0728W has been released as Stardust hard white winter wheat. We will take another set of measurements at the end of this week and report the results on this blog.

Keep in mind that the numbers reported from Stillwater are likely behind those being observed in southern Oklahoma and ahead of those observed in northern Oklahoma. The First Hollow Stem Advisor on the Oklahoma Mesonet can provide an indication of where varieties are regarding first hollow stem in your area.

First hollow stem measured in wheat sown 09/15/2015 at Stillwater, OK.
Variety cm of hollow stem 02/22/2016
Endurance 0.8
OK Rising 1.3
Billings 2.1
Ruby Lee 1.2
Duster 1.1
Gallagher 2.0
Iba 1.9
Bentley 1.8
Doublestop CL Plus 1.2
NF 101 2.5
WB-Cedar 1.5
WB4458 1.9
WB-Grainfield 1.3
Winterhawk 1.5
WB4515 1.6
WB4721 1.5
WB4303 2.1
SY Monument 0.8
SY Flint 1.5
SY Llano 2.8
SY Drifter 1.5
SY Wolf 1.0
SY Razor 2.9
SY Grit 1.7
Everest 1.5
1863 2.1
KanMark 1.4
Oakley CL 1.0
Larry 0.7
Zenda 1.6
Tatanka 0.9
Joe 0.7
LCS Pistol 0.8
LCS Wizard 1.2
LCS Mint 0.8
LCS Chrome 0.8
T158 0.8
Long Branch 1.0
TAM 112 0.9
TAM 204 1.2
TAM 114 0.7
AG Robust 1.0
Byrd 0.6
Brawl CL Plus 0.6
Avery 0.5
OK1059060-3 1.3
OK10126 0.6
OK11D25056 0.6
OK12621 0.7
Stardust 0.7
OK12716R/W 0.5
OK11231 0.6
OK09915C-1 0.5
OK12912C 0.9
OK12DP22002-042 0.9
OK118036R/W 2.0
Average 1.2

 

 

First hollow stem update 02/19/2016

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). We measure first hollow in our September-sown wheat forage plots at Stillwater each year, and normally have approximately 50% of varieties at or past first hollow stem by March 1st. I have posted first hollow stem measurements from these plots in a table at the end of this blog. No varieties are currently at first hollow stem at Stillwater, but given the warm conditions and the estimates from the first hollow stem advisor on the Mesonet, I anticipate we will have some varieties past first hollow stem by next week. Note that while no varieties are currently at first hollow stem, the overall average first hollow stem measurement increased as compared to 02/16/15.  Dillon Butchee reported early sown Gallagher in the Altus area was at first hollow stem.

Keep in mind that the numbers reported from Stillwater are likely behind those being observed in southern Oklahoma and ahead of those observed in northern Oklahoma. The First Hollow Stem Advisor on the Oklahoma Mesonet indicates that  early varieties in southern Oklahoma are likely past first hollow stem and that early varieties in central Oklahoma will reach this point within a week. Jim Johnson with the Noble Foundation reported that the estimates on the first hollow stem advisor were matching closely with his observations in the field around the Ardmore area. My advice is to start looking for a home for cattle on wheat pasture.

 

 

First hollow stem measured in wheat sown 09/15/2015 at Stillwater, OK.
Variety cm of hollow stem 02/19/16
Endurance 0.6
OK Rising 0.5
Billings 1.3
Ruby Lee 1.2
Duster 1.1
Gallagher 1.4
Iba 1.1
Bentley 0.7
Doublestop CL Plus 0.6
NF 101 1.1
WB-Cedar 0.7
WB4458 0.8
WB-Grainfield 1.0
Winterhawk 0.9
WB4455 0.6
WB4721 1.3
WB4303 1.2
SY Monument 0.6
SY Flint 1.3
SY Llano 1.0
SY Drifter 0.8
SY Wolf 0.4
SY Razor 1.4
SY Grit 1.3
Everest 0.6
1863 0.9
KanMark 0.7
Oakley CL 0.7
Larry 0.4
Zenda 1.1
Tatanka 0.4
Joe 0.6
LCS Pistol 0.6
LCS Wizard 0.6
LCS Mint 0.7
LCS Chrome 0.6
T158 0.7
Long Branch 0.9
TAM 112 0.7
TAM 204 0.6
TAM 114 0.4
AG Robust 0.7
Byrd 0.6
Brawl CL Plus 0.5
Avery 0.4
OK1059060-3 0.5
OK10126 0.3
OK11D25056 0.5
OK12621 0.4
OK10728W 0.6
OK12716R/W 0.4
OK11231 0.4
OK09915C-1 0.4
OK12912C 0.7
OK12DP22002-042 0.8
OK118036R/W 1.1
Average 0.7

 

First hollow stem update 02/16/2016

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). We measure first hollow in our September-sown wheat forage plots at Stillwater each year, and normally have approximately 50% of varieties at or past first hollow stem by March 1st. I have posted first hollow stem measurements from these plots in a table at the end of this blog. No varieties are currently at first hollow stem at Stillwater, but given the warm conditions and the estimates from the first hollow stem advisor on the Mesonet, I anticipate we will have some varieties past first hollow stem by the end of the week. We will take another set of measurements at the end of this week and report the results on this blog.

Keep in mind that the numbers reported from Stillwater are likely behind those being observed in southern Oklahoma and ahead of those observed in northern Oklahoma. The First Hollow Stem Advisor on the Oklahoma Mesonet indicates that  early varieties in southern Oklahoma are likely past first hollow stem and that early varieties in central Oklahoma will reach this point within a week. Jim Johnson with the Noble Foundation reported that the estimates on the first hollow stem advisor were matching closely with his observations in the field around the Ardmore area. My advice is to start looking for a home for cattle on wheat pasture.

Current first hollow stem estimates for early maturity wheat varieties

Current first hollow stem estimates for early maturity wheat varieties

One week projection of first hollow stem for early maturity wheat varieties

One week projection of first hollow stem for early maturity wheat varieties

Two week projection of first hollow stem for early maturity wheat varieties

Two week projection of first hollow stem for early maturity wheat varieties

 

First hollow stem measured in wheat sown 09/15/2015 at Stillwater, OK.
Variety cm of hollow stem 02/15/16
Endurance 0.0
OK Rising 0.1
Billings 0.4
Ruby Lee 0.3
Duster 0.1
Gallagher 0.7
Iba 0.8
Bentley 0.6
Doublestop CL Plus 0.3
NF 101 0.4
WB-Cedar 0.4
WB4458 0.7
WB-Grainfield 0.0
Winterhawk 0.0
WB4455 0.1
WB4721 0.3
WB4303 1.2
SY Monument 0.0
SY Flint 0.7
SY Llano 1.0
SY Drifter 0.1
SY Wolf 0.2
SY Razor 1.4
SY Grit 0.4
Everest 0.2
1863 0.8
KanMark 0.0
Oakley CL 0.2
Larry 0.0
Zenda 0.8
Tatanka 0.0
Joe 0.0
LCS Pistol 0.0
LCS Wizard 0.2
LCS Mint 0.1
LCS Chrome 0.1
T158 0.3
Long Branch 0.2
TAM 112 0.3
TAM 204 0.4
TAM 114 0.0
AG Robust 0.2
Byrd 0.1
Brawl CL Plus 0.1
Avery 0.2
OK1059060-3 0.0
OK10126 0.1
OK11D25056 0.1
OK12621 0.0
OK10728W 0.2
OK12716R/W 0.4
OK11231 0.0
OK09915C-1 0.0
OK12912C 0.4
OK12DP22002-042 0.1
OK118036R/W 0.3
Average 0.3

Is this the year for split fungicide application?

The stripe rust epidemic of 2015 is still fresh on the minds of many wheat farmers. Reports of active stripe rust on wheat in southern Oklahoma has producers now wondering if we are in for a repeat in 2016. While it is too early to tell if environmental conditions will favor a stripe rust outbreak in 2016, having active rust on wheat in the area satisfies at least one of the requirements for an epidemic. Most Oklahoma wheat producers will still be best advised to monitor the situation and make the fungicide decision based on yield potential and likelihood of infection when the flag leaf is emerging. Those with fields already showing heavy infection of foliar disease, however, might also benefit from a two-pass fungicide system. A few talking points and items to consider for those considering a two-pass system are posted below. A fact sheet on the topic of split application of fungicides can be found at www.wheat.okstate.edu

When to apply – The first pass in a two-pass fungicide system should be applied just after jointing. Please note that this is well after topdress nitrogen should be applied. For this and other reasons (see Dr. Arnall’s blog), tank mixing fungicides with nitrogen is generally not a good practice. Remember that the purpose of the early fungicide application is to keep disease in check until you come back with a flag leaf application in April. Going too early can result in too large of a gap between applications and enough time for disease to re-establish. Going too late can reduce the return on investment. Timing is everything with fungicides.

How much to apply – Back in the day, the discussion around split fungicide application centered on half rates for the first application. This recommendation was because of cost savings rather than disease management. The availability of low-cost, generic fungicides, though, has changed our philosophy, and a full rate of a low cost fungicide is the standard for split applications.

Which product to choose – Product choice is at the discretion of the consumer. If you are considering how to best spend your season-long fungicide budget, however, I would strongly recommend saving your “best” and perhaps most expensive product for the flag leaf application.

Watch season-long restrictions – As always, please read labels carefully and make note of season-long application restrictions. You don’t want an early fungicide application to remove the ability to apply your preferred product at flag leaf.

Wheat stripe rust

Wheat stripe rust

This overhead shot of the 2015 Chickasha intensive and standard wheat variety trials illustrates the severity of stripe rust in the region. The intensively managed trials on the left was treated with a fungicide just prior to heading. The standard trial on the right has the exact same varieties but no fungicide. The "middle" replication between the two studies is a border of Ruby Lee that is 1/2 treated 1/2 non treated.

This overhead shot of the 2015 Chickasha intensive and standard wheat variety trials illustrates the severity of stripe rust in the region. The intensively managed trials on the left was treated with a fungicide just prior to heading. The standard trial on the right has the exact same varieties but no fungicide. The “middle” replication between the two studies is a border of Ruby Lee that is 1/2 treated 1/2 non treated.

Don’t let armyworms waylay your wheat or canola

By Tom Royer, Extension Entomologist

Heath Sanders could not have made a more prophetic statement for this Extension Entomologist than when he said: “we learn something new about canola every year”. I have learned something new every year that I have been working with canola, and this year is starting to confirm his “prophesy” once again.

This has been a banner year for fall armyworms. They built up populations early, and migrated into Oklahoma earlier than “normal”, attacking sorghum and pasture grasses. Now, they are ready to attack wheat (once it emerges) and possibly, are marching in to graze on newly emerged canola. Dr. Angela Post, OSU Extension Weeds specialist reported that there were caterpillars that appeared to be either beet armyworm or fall armyworms attacking canola. We are getting confirmation on their identity, but regardless, producers need to be vigilant and protect their fields.

I have already discussed their management in wheat http://entoplp.okstate.edu/pddl/pddl/2015/PA14-41.pdf, but now need to alert canola producers about them attacking seedling canola and eliminating stand.

Look for “window pane” damage in young canola plants and/or cut plants. At this time, with canola so small, armyworm and cutworm caterpillars cannot be allowed the chance to reduce stand. The suggested treatment threshold is 1 or more armyworms per row-foot.

Look for window pane damage in young canola plants. Treatment threshold is one or more worms per foot of row.

Look for window pane damage in young canola plants. Treatment threshold is one or more worms per foot of row.

Consult CR-7194 Management of Insect and Mite Pests of Small Grains and CR-7667 Management of Insect and Mite Pests in Canola for specific insecticides that are registered for control. Keep in mind that beet and fall armyworms can sometimes be difficult to control, so vigilance is needed by follow-up scouting following an application to make sure control is achieved.

Q & A regarding PVP seed laws

Stories about seed law violations and fines have sprung up occasionally in the farm press over the past few years. These stories have tended to focus on the “penalty” part of the law and the magnitude of the fines rather than how the law protects Oklahoma farmers’ investments in wheat variety development and the provisions in the law that allow farmers to save seed for replanting. The purpose of this article is to answer some of the most frequently asked questions regarding the PVP law.

What is PVP?
The Plant Variety Protection Act (PVP or PVPA) is a federal seed law designed to protect the intellectual property of plant breeders, seed producers, and those who have funded variety development (in our case OSU and Oklahoma Taxpayers). The PVP law that you read about in the news today was enacted in 1994 and was an amendment to a law originally passed in 1970. The law prohibits the sale of farmer-saved seed without the variety owner’s permission. This protection lasts for 20 years for most crops. The ‘Title V’ you sometimes see tacked on to the end of PVP, refers to an amendment to the federal seed act stating that the variety can only be sold as a class of certified seed and by variety name.

Can I save seed from PVP-protected varieties?
Yes. You can save seed from PVP-protected varieties to plant on land you own or rent. You just cannot sell or trade the seed for planting purposes. A comparable example is an audio cd. You can make extra copies of an audio cd for your own use, such as an extra copy for the truck, without creating any problems. However, if you placed copies of the latest Sturgill Simpson cd for sale on Ebay, you would likely be contacted by the owners of the music regarding your unauthorized sale of their intellectual property.

Can I save seed of Clearfield varieties?
No, because Clearfield varieties are protected by a utility patent which protects a specific gene within the cultivar. Other examples of crop seed with genes protected by a utility patent include Roundup Ready, Bollgard, and Liberty Link. Wheat farmers will likely be seeing greater use of utility patents in the future but to my knowledge Clearfield varieties are the only hard wheat cultivars currently protected by a utility patent.

What about selling variety not stated (VNS) seed?
Not allowed. As indicated earlier, Title V of the federal seed act states that PVP-protected varieties can only be sold by variety name as a certified class of seed. This is one of several “ways-around-the-law” type questions that I am frequently asked at meetings and the answer is almost always no, you cannot do that. Other examples of violations would include: selling feed wheat, trading seed, giving seed away, and selling the standing crop of a PVP-protected variety and saving the seed.

The law just applies to the seller, right?
No. If there is a violation, then all parties involved can be included in the lawsuit. This includes the buyer, seller, seed conditioners, and even the entity spreading/planting the seed for the farmer.

How do I know if a variety is protected?
Certified seed of a protected variety will be clearly marked as such on the seed tag or the bulk label. The OSU Wheat Variety Comparison Chart indicates which varieties are PVP-protected and can be found at www.wheat.okstate.edu under Variety Testing, then under Variety Characteristics. Most varieties are now PVP-protected.

OSU is a public institution, why are they PVP-protecting varieties?
First and foremost, OSU acquires PVP-protection for new wheat cultivars to protect our (OSU, farmers, and taxpayers) collective investment in variety development. It takes 10 – 15 years to develop a wheat variety and this is not a cheap process. Without PVP protection others could reproduce an OSU wheat variety and profit from its sale without any benefit returned to farmers or OSU. PVP-protection ensures that when you buy an OSU variety, you are getting exactly the variety you are paying for and OSU has ensured quality-control standards through the certification process. It also ensures that a portion of the purchase price is returned to OSU for re-investment in the wheat breeding program where it is used to develop well-adapted varieties and ensure that the public sector remains competitive in wheat variety development.

Where can I find more information?
I am an agronomist, not a lawyer, so this article was meant to only hit the high points. A complete copy of the law (45 pages) can be found with a Google search of ‘plant variety protection act’. Texas AgriLife Extension also has a good summary of the law that can be found with a Google search for ‘plant variety protection act TAMU’.

Disease and insect issues to consider prior to planting

Planting date:  Much of the winter wheat in Oklahoma is sown with the intent of being used as a dual-purpose crop. In this system wheat is grazed by cattle from late October to early March, and then harvested for grain in early summer.  In a grain-only system, wheat is generally planted in October, but in a dual-purpose system wheat is planted in early to mid-September to maximize forage production.  Planting wheat early significantly increases the likelihood that diseases such as mite-transmitted viruses, the aphid/barley yellow dwarf complex, and root and foot rots will be more prevalent and more severe.  For more detailed information on planting date and seed treatment considerations on wheat, see CR-7088 (Effect of Planting Date and Seed Treatment on Diseases and Insect Pests of Wheat)

Mite-transmitted virus diseases.    These include wheat streak mosaic (WSM), wheat mosaic (formerly called high plains disease), and Triticum mosaic (TrM).  All are transmitted by wheat curl mite (WCMs).  WCMs and these viruses survive in crops such as wheat and corn, as well as many grassy weeds and volunteer wheat.  In the fall, WCMs spread to emerging seedling wheat, feed on that seedling wheat, and transmit virus to the young wheat plants.  Wheat infected in the fall is either killed by the next spring or will be severely damaged.  Seed treatments are not effective in controlling these virus diseases.  However, planting later in the fall (after October 1 in northern OK and after October 15 in southern OK) and controlling volunteer wheat are two practices that provide some control.  It is critical that volunteer wheat is completely dead for at least two weeks prior to emergence of seedling wheat because WCMs have a life span of 7-10 days.  Thus, destroying volunteer wheat at least two weeks prior to emergence of seedling wheat will greatly reduce mite numbers in the fall.  In addition to these cultural controls, two winter wheat varieties (RonL from Kansas and Mace from Nebraska) have resistance to WSM; however, their adaptation to production is limited to northwestern Oklahoma.  For more information on mite-transmitted virus diseases, see OSU Fact Sheet 7328 (Wheat Streak Mosaic, High Plains Disease and Triticum Mosaic:  Three Virus Diseases of Wheat in Oklahoma)

Aphid/barley yellow dwarf (BYD) complex:  Viruses that cause BYD are transmitted by many cereal-feeding aphids.  BYD infections that occur in the fall are the most severe because virus has a longer time to damage plants as compared to infections that occur in the spring.  Several steps can be taken to help manage BYD.  First, a later planting date (after October 1 in northern Oklahoma and after October 15 in southern Oklahoma) helps reduce the opportunity for fall infection. Second, some wheat varieties (e.g., Duster, Endurance, Gallagher, Iba, Doublestop CL+, Bentley, Everest, Winterhawk, Redhawk) tolerate BYD better than other varieties; however, be aware that no wheat variety has a high level of resistance to the aphid/BYD complex.  Third, control aphids that transmit the viruses that cause BYD.  This can be done by applying contact insecticides to kill aphids, or by treating seed before planting with a systemic insecticide.  Unfortunately, by the time contact insecticides are applied, aphids frequently have already transmitted the virus(es) that cause BYD.  Systemic seed-treatment insecticides including Gaucho (imidacloprid) and Cruiser (thiamethoxam) can control aphids during the fall after planting.  This may be particularly beneficial if wheat is planted early to obtain forage.  Be sure to thoroughly read the label before applying any chemical.

Hessian fly:  Hessian fly infestations occur in the fall and spring.  Fall infestations arise from over-summering pupae that emerge when climate conditions become favorable.  Delayed planting (after October 1 in northern Oklahoma, and after October 15 in southern Oklahoma) can help reduce the threat of Hessian fly, but a specific “fly free date” does not exist for most of Oklahoma as it does in Kansas and more northern wheat-growing states.  This is because smaller, supplementary broods of adult flies emerge throughout the fall and winter.  Some wheat varieties are either resistant (e.g. Duster, Gallagher, SY-Southwind, LCS Wizard, Winterhawk) or partially resistant (e.g. Everest, Iba, Jackpot, PostRock, Ruby Lee, SY-Gold, T-153, Tam 304, WB-Stout) to Hessian fly infestations.  Hessian fly infestations can be reduced somewhat by destroying volunteer wheat in and around the field at least two weeks prior to emergence of seedling wheat.  Seed treatments that contain imidacloprid or thiamethoxam will also help reduce fly fall infestations, especially if combined with delayed planting and volunteer destruction.  For more information on Hessian fly, see OSU Fact Sheet: EPP-7086 (Hessian fly Management in Oklahoma Winter Wheat)

Root and foot rots:  These include several diseases caused by fungi such as dryland (Fusarium) root rot, Rhizoctonia root rot (sharp eyespot), common root rot, take-all, and eyespot (strawbreaker).  Controlling root and foot rots is difficult.  There are no resistant varieties, and although fungicide seed treatments with activity toward the root and foot rots are available, their activity usually involves early-season control or suppression rather than control at a consistently high level throughout the season.  Often, there also are different “levels” of activity related to different treatment rates, so again, CAREFULLY read the label of any seed treatment to be sure activity against the diseases and/or insects of concern are indicated, and be certain that the seed treatment(s) is being used at the rate indicated on the label for activity against those diseases and/or insects.  Later planting (after October 1 in northern Oklahoma and after October 15 in southern Oklahoma) also can help reduce the incidence and severity of root rots, but planting later will not entirely eliminate the presence or effects of root rots.  If you have a field with a history of severe root rot, consider planting that field as late as possible or plan to use it in a “graze-out” fashion if that is consistent with your overall plan.  For some root rots, there are specific factors that contribute to disease incidence and severity.  For example, a high soil pH (>6.5) greatly favors disease development of the root rot called take-all.  OSU soil test recommendations factor in this phenomenon by reducing lime recommendations when continuous wheat is the intended crop. Another practice that can help limit take-all and some of the other root rots is the elimination of residue.  However, elimination of residue by tillage or burning does not seem to affect the incidence or severity of eyespot (strawbreaker).

Seed treatments:  There are several excellent reasons to plant seed wheat treated with an insecticide/fungicide seed treatment.  These include:

  1. Control of bunts and smuts, including common bunt (also called stinking smut), loose smut, and flag smut (for more information on flag smut, go to end of this report).  The similarity of these names can be confusing.  All affect the grain of wheat, but whereas common bunt and flag smut spores carryover onseed or in the soil, loose smut carries over in the seed.  Seed treatments are highly effective in controlling all three of these bunts/smuts.  If common bunt (stinking smut) was observed in a field and that field is to be planted again with wheat, then planting certified wheat seed treated with a fungicide effective against common bunt is strongly recommended.  If either common bunt or loose smut was observed in a field, grain harvested from that field should not be used as seed the next year.  However, if grain harvested from such a field must be used as seed wheat, treatment of that seed at a high rate of a systemic or a systemic + contact seed treatment effective against common bunt and loose smut is strongly recommended.  For more information on common bunt & loose smut, see: http://www.entoplp.okstate.edu/ddd/hosts/wheat.htm and consult the “2015 OSU Extension Agents’ Handbook of Insect, Plant Disease, and Weed Control (OCES publication E-832),” and/or contact your County Extension Educator.
  2. Enhance seedling emergence, stand establishment and forage production by suppressing root, crown and foot rots.  This was discussed above under “Root and Foot Rots.”
  3. Early season control of the aphid/BYDV complex.  This can be achieved by using a seed treatment containing an insecticide.  Be sure that the treatment includes an insecticide labeled for control of aphids.
  4. Control fall foliar diseases including leaf rust and powdery mildew.  Seed treatments are effective in controlling foliar diseases (especially leaf rust and powdery mildew) in the fall, which may reduce the inoculum level of these diseases in the spring.  However, this control should be viewed as an added benefit and not necessarily as a sole reason to use a seed treatment.
  5. Suppression of early emerged Hessian fly.  Research suggests that some suppression can be achieved, but an insecticide seed treatment has little residual activity past the seedling stage.

A final consideration for fall 2015:  In the text above, I made reference to “flag smut,” which is a smut of wheat I have not mentioned previously.  Flag smut occurs in the U.S., in particular, the Pacific Northwest.  It also has been reported in the Plains States, being first reported in Kansas in the 1920s.  However, flag smut has not been observed in the Central Plains for many years until this past spring when it was found in around 20 counties in Kansas from April-June.  No flag smut was observed on wheat in Oklahoma in 2015, but much of the wheat in Oklahoma had been harvested when I found out about flag smut occurring in Kansas.  Flag smut is similar to common bunt (stinking smut) in terms of its disease cycle, but spores of this fungus erupt through the leaves rather than replace the wheat grain as with common bunt.  Additionally, leaves and tillers infected with flag smut often are twisted and deformed.

For more information on flag smut, please go to the following links.  The first link is to a press release made in mid-July, 2015 on the finding of flag smut in Kansas.  The second link is a KSU fact sheet on flag smut.

http://www.ksre.ksu.edu/news/story/wheat_smut071515.aspx

http://www.bookstore.ksre.ksu.edu/pubs/MF3235.pdf

By: Dr. Bob Hunger, Extension OSU Wheat Pathologist and Dr. Tom Royer, OSU Extension Entomologist