About Me

osuwheat

osuwheat

Since 2004 I have served as the Small Grains Extension Specialist at Oklahoma State University. I work to improve the profitability and sustainability of small grains production in the southern Great Plains through improved management and variety selection. Most of my work focuses on dual-purpose and grain-only wheat production.

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Greenbug infestations reported

By Tom Royer, OSU Extension Entomologist

I received several reports of treatable greenbug infestations in winter wheat in Major County. This means it is important to scout your fields for greenbugs. I encourage you to use the “Glance n’ Go system, as it is easy to use.

Greenbugs on wheat

Greenbugs on wheat

There are several things that make Glance ‘n Go sampling a desirable way to make such a decision. You only have to “Glance” at a tiller to see if it has greenbugs (no counting greenbug numbers). You can make a decision to treat “on the Go” because you stop sampling once a decision is reached (no set number of samples). Finally, you can account for the activity of the greenbug’s most important natural enemy, Lysiphlebus testaceipes. Aphid Mummies

The Glance ‘n Go system be accessed in two ways. One is to set up an account with the myFields platform: http://myFields.info and sign up for a personal account. This system will allow you to sample a field with a smart phone in the field. To use it, you must have cell phone connectivity. You can then select the Glance n’ Go tool, plug in your cost inputs, and start sampling. Once you sign up, you can scout multiple fields and myFields will keep track of all your sampling information.

Glance-N-Go using the myFields platform

The second way is to access the Cereal Aphids Decision Support Tool on your computer http://entoplp.okstate.edu/gbweb/index3.htm . You can customize the threshold and selecting the Greenbug Calculator. Put your inputs in and it will select a threshold for your field. You can then download a paper Glance n’ Go form; take it to the field and start scouting.

Cereal Aphids Decision Support Tool

Cereal Aphids Decision Support Tool

By answering a few simple questions, you can determine an economic threshold for controlling greenbugs. This threshold is based on the estimated cost of treating the field and the estimated price of wheat. Once a threshold is calculated, you can print a Glance ‘n Go scouting form, take it to a field and record your sampling results. The form will help you to decide if the field needs to be treatment for greenbugs.

When scouting with the Glance ‘n Go system, keep a running count of tillers that have one or more aphid mummies and a running count of tillers that are infested with one or more greenbugs. The Glance ‘n Go form directs you to look at your total number of infested tillers and tillers with mummies after 5 stops. You will be directed to treat, not treat, or continue sampling. If there is enough parasitoid (mummy) activity, you will be directed to stop sampling and DON’T TREAT, even if you have exceeded the treatment threshold for greenbugs! Why? Because research showed that at that level of parasitism, almost all of the healthy-looking greenbugs have been “sentenced to death” and will be ghosts within 3-5 days. If they have received their “sentence” you can save the cost of an unnecessary insecticide application.

aphid mummies

aphid mummies

I accessed the Glance n’ Go tool to determine a “general” threshold that you can use for a Spring infestation, based on a wheat price of $5.50 per bushel and an application cost of either $4, $6, and $8 per acre. You can go directly to the website and download a paper form (Greenbug Spring Infestation) directly. The threshold is 3 greenbugs per tiller if your application costs are $4 per acre or 2 greenbugs per tiller for application costs of $6 or $8 per acre.

Contact your local County Extension Agricultural Educator for more information. If a field needs to be treated, check with Current Report CR-7194, “Management of Insect and Mite Pests in Small Grains”.

First hollow stem update 03/16/15

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). To monitor first hollow stem, we measure hollow stem for the 56 lines in our September-sown wheat forage plots at Stillwater each year. Almost all varieties are well past first hollow stem. Full results are posted in the table below. Varieties with no value for first hollow stem reached first hollow stem on a previous measurement date.

This will be the last first hollow stem update of the 2015 season. You can check progression of first hollow stem around the state by using the First Hollow Stem Advisor on the Oklahoma Mesonet site

First hollow stem measured in wheat sown 09/16/2014 at Stillwater, OK. Varieties with ‘-‘ reached first hollow stem on a previous measurement date
Variety cm of hollow stem 03/16/15
Endurance 0.9
Deliver 1.7
Pete 0.3
OK Rising 1.1
Billings -
Ruby Lee 2.1
Garrison 1.9
Duster -
Gallagher -
Iba -
Centerfield 1.0
Doublestop CL Plus 1.5
NF 101 -
Everest -
1863 -
KanMark 3.0
Oakley CL 2.1
KS061406 -
Sy Llano -
Sy Southwind -
Greer -
Jackpot -
Sy Monument 2.1
06BC722#25 -
AP09T7631 -
WB-Cedar -
WB-Redhawk -
WB4458 -
WB-Grainfield -
Winterhawk -
T153 -
T154 -
T158 2.4
LCS Mint -
LCS Wizard -
LCS Pistol -
LCH13DH-20-87 6.0
LCH13DH-14-91 -
TAM 112 -
TAM 204 -
TAM 113 -
TAM 114 -
CO11D174 .
Byrd -
Brawl CL Plus -
OK09125 -
OK1059060-2C14 -
OK10126 -
OK11D25056 1.8
OK11231 -
OK12621 3.9
OK13625 -
OK0986130-7C13 -
OK08P707W-19C13 3.8
OK10728W -
OK11755W -

 

 

Wheat disease update – 16 March 2015

Wheat disease updates are written by Dr. Bob Hunger, OSU Extension Plant Pathologist

Oklahoma:  The leaf rust I saw around Stillwater in February seems to have “died out.”  The cold weather we had from late February into early March killed the lower leaves where leaf rust was active and conditions did not allow spread to younger leaves.  Dr. Brett Carver (OSU Wheat Breeder) confirmed this to me this morning as he indicated late last week he did not see any rust (leaf or stripe) around Stillwater or at his nurseries in Lahoma and Marshal.  This also is the case for northern and northwestern OK, as well as for KS (see Dr. De Wolf’s observations under “Other States” below).  Dr. Tom Royer and I visited variety trials at Cherokee and Alva last week.  No foliar diseases were observed but Dr. Royer did find a small greenbug colony on wheat in the field surrounding the Alva trial.  However, with mild temperatures and moisture predicted for the coming week and with inoculum to the south of us in Texas and southern Oklahoma, foliar diseases should be increasing in incidence and severity across central and northern OK.

Leaf and stripe rust are active in Texas (see Dr. Ron French’s observations below), and southern and central Oklahoma.  Mark Gregory (Area Extn Agron Spec – Duncan, OK) has reported seeing both leaf and stripe rust (but more stripe rust) across much of south-central and southwestern OK – especially around Grandfield, OK located north of Wichita Falls, TX.  Similar reports have come from Aaron Henson (Extn Educator; Tillman Cnty) and Gary Strickland (Exten Educator; Jackson Cnty).  Incidence has ranged from scattered to many “hot spots” of stripe rust, and from light to intermediate incidence of leaf rust.

Some of these fields (especially if it is a susceptible variety) will merit an early application of fungicide to curtail foliar disease activity (especially the stripe rust).  Be aware that applying a fungicide now will not last the entire season, and a second application toward head emergence also may be needed if weather continues to be favorable for foliar diseases.  For an early season application I recommend using a full rate (as opposed to a half rate) of a less expensive fungicide because there is so much time left in the growing season.  Then a later season application with a more expensive fungicide may or may not be needed.  Also be sure to not exceed the maximum amount of fungicide applied and to rotate chemistries to prevent resistance. Also consider your variety.  A variety like Ruby Lee that has good yield potential should be protected from early and late stripe or leaf rust, but a variety such as Duster may show some leaf rust early but still has good resistance to this rust.  However, stripe rust on Duster may merit control.  ALSO, in no-till fields watch for incidence of diseases such as tan spot, septoria, and powdery mildew as these diseases likely will be more common in fields with wheat residue and may merit an early season fungicide application.

Reports/excerpts of reports from other states:

Texas  Dr. Ron French (Ast Prof & Extn Plant Pathologist, Texas A&M AgriLife Extension Service, Amarillo) 9-Mar-2015:  “Last week, I was visiting the lower Coastal Bend of Texas (around Kingsville/Corpus Christi) and the Lower Rio Grande Valley of Texas (along the southernmost part of the Texas-Mexico border area). In Weslaco (Hidalgo County, Lower Rio Grande Valley), I visited sentinel plots (21 lines-winter wheat, spring wheat, barley…).”

“In Weslaco (March 4), Puccinia graminis f. sp. tritici, the causal agent of stem rust, was found on leaf tissue only, at trace levels to 1% severity in six 6 lines including  Morocco,  Marvelous, Kyto (CI 8250) and Line B (1% severity). Last year, stem rust was first observed on Siouxland, Panola, and  Morocco but observations were done the week of April 7, 2014.”

“Stripe rust (March 3)on wheat was observed  in 5 lines, ranging from  trace levels in Siouxland  to 25% incidence and 40% severity on Sisson.  Leaf rust was only observed at trace levels in lines such as Siouxland, Panola, and Sisson.  Powdery mildew was only present in the lower canopy of barley  Hypana, Morex DPH, and Hyproly.  Some wheat was already in the boot stage (Morocco, Line B).”

“Last year, dry conditions (little or no rain) were present in this area when stem rust was first observed. This year has seen more rain during the past three weeks, with temperatures ranging from as low as 38° F to as high as 84°F (lower on average for that area). With rain and warmer weather expected this week, disease pressure may be more conducive to seeing more disease development for all rusts.”

“No stem rust was observed in wheat in  the lower coastal bend around Kingsville, approximately 110 miles north of Weslaco. Fields did have stripe rust (up to 20% severity) but had already been sprayed with a fungicide and trace levels of leaf rust could also be observed.”

Kansas  Dr. Erick De Wolf (Prof & Small Grains Extn Pathologist, Kansas State Univ) 11-Mar-2015:  “We did some scouting for rust diseases near Manhattan (Northeastern KS).  We were checking on research plots where rust had been noted last fall but were unable to detect leaf rust in these plots so far this spring.  We noted severe tip die-back of the leaf tissue in these plots and suspect that this winter injury has removed much of the leaf rust from this location. Bethany Grabow, Ph.D candidate with KSU detected a trace of leaf rust on wheat in an adjacent field.  Incidence of disease was <0.01% with only a few pustules detected. This wheat was planted later than the aforementioned plots and did not experience the winter injury to the leaf tissue.  We also noted small colonies of aphids in the research plots with each colony having 3-5 aphids a few winged aphids were also observed near the colonies. We will continue to monitor the diseases this spring and provide more updates soon.”

Wheat leaf rust

Wheat leaf rust

Wheat stripe rust

Wheat stripe rust

First hollow stem update 03/12/15

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). To monitor first hollow stem, we measure hollow stem for the 56 lines in our September-sown wheat forage plots at Stillwater each year. In spite of the recent cold snap many varieties are progressing towards first hollow stem. The small grains extension crew split ten stems from lines tested in our program today and Billings, Duster, Iba, Oakley CL, Hot Rod (formerly KS061406), WB Greenfield, and LCS Wizard join the list of varieties at or past first hollow stem. Full results are posted in the table below. Varieties with no value for first hollow stem reached first hollow stem on a previous measurement date.

We will take another set of measurements early next week and report the results on this blog. You can check progression of first hollow stem around the state by using the First Hollow Stem Advisor on the Oklahoma Mesonet site.

 

First hollow stem measured in wheat sown 09/16/2014 at Stillwater, OK. Varieties with ‘-‘ reached first hollow stem on a previous measurement date
Variety cm of hollow stem 03/12/15
Endurance 0.2
Deliver 1.0
Pete 0.6
OK Rising 1.1
Billings 1.6
Ruby Lee 0.9
Garrison 1.2
Duster 1.8
Gallagher -
Iba 1.7
Centerfield 0.8
Doublestop CL Plus 1.4
NF 101 -
Everest -
1863 -
KanMark -
Oakley CL 2.0
Hot Rod 2.8
SY Llano -
SY Southwind -
Greer -
Jackpot -
SY Monument 1.2
SY Flint -
SY Drifter -
WB-Cedar -
WB-Redhawk -
WB4458 -
WB-Grainfield 2.0
Winterhawk -
T153 -
T154 -
T158 0.9
LCS Mint -
LCS Wizard 1.5
LCS Pistol -
LCH13DH-20-87 2.6
LCH13DH-14-91 -
TAM 112 -
TAM 204 -
TAM 113 -
TAM 114 -
CO11D174 -
Byrd -
Brawl CL Plus -
OK09125 1.9
OK1059060-2C14 1.6
OK10126 -
OK11D25056 1.1
OK11231 -
OK12621 1.2
OK13625 -
OK0986130-7C13 -
OK08P707W-19C13 1.3
OK10728W -
OK11755W -

 

 

 

First hollow stem update 03/09/15

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). To monitor first hollow stem, we measure hollow stem for the 56 lines in our September-sown wheat forage plots at Stillwater each year. In spite of the recent cold snap many varieties are progressing towards first hollow stem. The small grains extension crew split ten stems from lines tested in our program today and KanMark, Sy Southwind and Greer join the list of varieties at or past first hollow stem. Full results are posted in the table below. Varieties with no value for first hollow stem reached first hollow stem on a previous measurement date.

We will take another set of measurements later this week and report the results on this blog. Given the warm forecast for the coming week, I predict that all varieties will be well past first hollow stem by Friday. You can check progression of first hollow stem around the state by using the First Hollow Stem Advisor on the Oklahoma Mesonet site.

 

First hollow stem measured in wheat sown 09/16/2014 at Stillwater, OK. Varieties with ‘-‘ reached first hollow stem on a previous measurement date
Variety cm of hollow stem 03/09/15
Endurance 0.2
Deliver 0.2
Pete 0.3
OK Rising 0.7
Billings 1.0
Ruby Lee 0.6
Garrison 0.9
Duster 0.9
Gallagher -
Iba 0.8
Centerfield 0.5
Doublestop CL Plus 0.6
NF 101 -
Everest -
1863 -
KanMark 1.5
Oakley CL 0.9
KS061406 1.2
Sy Llano -
Sy Southwind 2.6
Greer 2.1
Jackpot -
Sy Monument 0.7
06BC722#25 -
AP09T7631 1.5
WB-Cedar -
WB-Redhawk -
WB4458 -
WB-Grainfield 0.8
Winterhawk -
T153 -
T154 -
T158 0.8
LCS Mint -
LCS Wizard 0.6
LCS Pistol -
LCH13DH-20-87 1.0
LCH13DH-14-91 -
TAM 112 -
TAM 204 -
TAM 113 -
TAM 114 -
CO11D174 2.2
Byrd -
Brawl CL Plus -
OK09125 1.3
OK1059060-2C14 0.9
OK10126 -
OK11D25056 1.1
OK11231 -
OK12621 1.1
OK13625 -
OK0986130-7C13 -
OK08P707W-19C13 1.4
OK10728W -
OK11755W -

 

Army cutworms reported in some Oklahoma wheat fields

This article is provided by Dr. Tom A. Royer, OSU Extension Entomologist

Sug Farrington, Extension Educator in Cimarron County received a sample of “worms” that were collected by a producer in his wheat field. They turned out to be army cutworms.

Unlike the fall armyworm, this caterpillar overwinters in Oklahoma, tolerates cold and feeds throughout the winter months. Adult army cutworm moths migrate to Oklahoma each fall from their summer residence in the Rocky Mountains. They seek bare or sparsely vegetated fields (like a newly prepared field ready for wheat planting, or a field that was “dusted in” and had not yet emerged) and lay eggs from August through October. The eggs hatch soon after being deposited, which explains why a producer might see different sizes of larvae in a field. Army cutworms feed throughout the winter and molt seven times before they turn into pupae in the soil. Most larvae will be gone by late March and adult moths begin emerging in April and fly back to the Rocky Mountains to spend the summer.

Army cutworms. Photo courtesy Sug Farrington, Cimarron County Extension Educator.

Army cutworms can cause severe stand loss of wheat if not controlled. Cutworm damage often goes unnoticed through the winter because the caterpillars grow slowly and don’t get big enough to cause noticeable damage until temperatures warm in the spring. Unfortunately, that is also an indication of poor growing conditions due to drought (which cutworms also like), so it becomes important to check the fields for cutworms. If you notice a field at this time of year with a numbers of starlings or black birds feeding in a concentrated area of your wheat field, they are likely feasting on army cutworms!

Army cutworm injury in wheat. Photo courtesy Sug Farrington, Cimarron County Extension Educator.

Army cutworm injury in wheat. Photo courtesy Sug Farrington, Cimarron County Extension Educator.

Sample a field by stirring or digging the soil to a depth of two inches at 5 or more locations. Also, turn over those dried up cow patties, as they are a favorite hiding place for army cutworms. The cutworms will be “greenish grey”, and will probably curl up into a tight “C” when disturbed. A suggested treatment threshold is 2-3 caterpillars per foot of row when conditions are dry (like we are experiencing this winter) or 4-5 caterpillars per row-foot in fields with adequate moisture. Control suggestions are listed in Current Report-7194 Management of Insect and Mite Pests in Small Grains.

Army cutworms are also a potential pest of canola. Scout fields just as you would in wheat. The suggested treatment threshold for cutworms in canola is 1-2 per row-foot. Current recommendations for control of army cutworms in canola are listed in CR-7667, Management of Insect and Mite Pests in Canola.

First hollow stem update 03/05/15

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). To monitor first hollow stem, we measure hollow stem for the 56 lines in our September-sown wheat forage plots at Stillwater each year. In spite of the recent cold snap many varieties are progressing towards first hollow stem. The small grains extension crew split ten stems from lines tested in our program today and1863, LCS Mint, TAM 204, TAM 113, TAM 114, and Byrd join the list of varieties at or past first hollow stem. Full results are posted in the table below. Varieties with no value for first hollow stem reached first hollow stem on a previous measurement date.

We will take another set of measurements later this week and report the results on this blog. Given the warm forecast for the coming week, I predict that all varieties will be well past first hollow stem by next Friday. You can check progression of first hollow stem around the state by using the First Hollow Stem Advisor on the Oklahoma Mesonet site.

 

First hollow stem measured in wheat sown 09/16/2014 at Stillwater, OK. Varieties with a “-” reached first hollow stem on a previous measurement date
Variety cm of hollow stem 03/05/15
Endurance 0.2
Deliver 0.2
Pete 0.1
OK Rising 0.2
Billings 0.7
Ruby Lee 0.6
Garrison 0.5
Duster 0.5
Gallagher -
Iba 0.5
Centerfield 0.2
Doublestop CL Plus 0.3
NF 101 -
Everest -
1863 1.6
KanMark 1.1
Oakley CL 0.6
KS061406 1.0
Sy Llano -
Sy Southwind 0.9
Greer 1.1
Jackpot -
Sy Monument 0.1
06BC722#25 2.8
AP09T7631 1.1
WB-Cedar -
WB-Redhawk -
WB4458 -
WB-Grainfield 0.8
Winterhawk -
T153 -
T154 -
T158 1.3
LCS Mint 1.5
LCS Wizard 0.7
LCS Pistol -
LCH13DH-20-87 1.1
LCH13DH-14-91 -
TAM 112 -
TAM 204 1.6
TAM 113 1.6
TAM 114 1.9
CO11D174 1.1
Byrd 1.7
Brawl CL Plus -
OK09125 0.8
OK1059060-2C14 1.4
OK10126 -
OK11D25056 0.9
OK11231 -
OK12621 0.8
OK13625 -
OK0986130-7C13 -
OK08P707W-19C13 1.3
OK10728W 1.5
OK11755W -
Average 1.0

 

First hollow stem update 03/02/15

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). To monitor first hollow stem, we measure hollow stem for the 56 lines in our September-sown wheat forage plots at Stillwater each year. In spite of the recent cold snap many varieties are progressing towards first hollow stem. The small grains extension crew split ten stems from lines tested in our program today and NF 101 and Brawl CL Plus join the list of varieties at or past first hollow stem. Full results are posted in the table below. We will take another set of measurements later this week and report the results on this blog.

The numbers reported from Stillwater are likely behind those being observed in southern Oklahoma and ahead of those observed in northern Oklahoma. You can check progression of first hollow stem around the state by using the First Hollow Stem Advisor on the Oklahoma Mesonet site.

 

First hollow stem measured in wheat sown 09/16/2014 at Stillwater, OK.
Variety cm of hollow stem 03/02/15
Endurance 0.5
Deliver 0.4
Pete 0.1
OK Rising 0.1
Billings 0.4
Ruby Lee 0.2
Garrison 0.1
Duster 0.4
Gallagher .
Iba 0.1
Centerfield 0.1
Doublestop CL Plus 0.1
NF 101 1.5
Everest .
1863 0.6
KanMark 0.4
Oakley CL 0.6
KS061406 0.7
Sy Llano .
Sy Southwind 0.2
Greer 0.8
Jackpot .
Sy Monument 0.4
06BC722#25 1.3
AP09T7631 0.4
WB-Cedar .
WB-Redhawk .
WB4458 .
WB-Grainfield 1.1
Winterhawk .
T153 .
T154 .
T158 0.5
LCS Mint 0.8
LCS Wizard 0.9
LCS Pistol .
LCH13DH-20-87 0.8
LCH13DH-14-91 .
TAM 112 .
TAM 204 1.4
TAM 113 1.2
TAM 114 1.4
CO11D174 0.9
Byrd 0.7
Brawl CL Plus 1.8
OK09125 0.5
OK1059060-2C14 0.7
OK10126 .
OK11D25056 0.7
OK11231 2.2
OK12621 0.9
OK13625 .
OK0986130-7C13 .
OK08P707W-19C13 1.2
OK10728W 1.0
OK11755W .
Average 0.7

 

Wheat disease update – 27 February 2015

Wheat disease updates are written by Dr. Bob Hunger, OSU Extension Plant Pathologist

Oklahoma:  As indicated in the Texas reports below, both leaf rust and stripe rust are present across Texas with stripe rust appearing to be the most prevalent and severe.  This also seems to be the case in Oklahoma – at least across central to southern Oklahoma.  John Fenderson (Monsanto) indicated yesterday that on a recent trip he took across central to southern Oklahoma he saw “clean” wheat around Chickasha but along highway 70 going west to Frederick he saw lots of stripe rust and some leaf rust.  In a few places he saw the ground colored orange from stripe rust spores indicating a stripe rust “hot spot.”  In fields such as this (especially if there are many hot spots), application of a fungicide to control the stripe rust should be considered.  In addition to helping to control the stripe rust, there could be the benefit of also limiting leaf rust, powdery mildew and possibly tan spot/septoria.

Around Stillwater, I have not seen much change since two weeks ago.  I have not confirmed any stripe rust, but have seen leaf rust.  However, we have been mostly quite cold with only slight moisture but stripe rust may also be starting.  I will wait until it warms up a bit before I look again.

Wheat leaf rust

Wheat leaf rust

Wheat stripe rust

Wheat stripe rust

Reports/excerpts of reports from other states:

Texas 

Dr. Amir Ibrahim (Prof, Small Grains Breeding and Genetics, Texas A&M AgriLife Research) 26-Feb-2015:  The wheat crop in South Texas is at now at Feekes stages 5-6 [start of node elongation/first node detectable at base of tiller] depending on the line.   Leaf Rust (P. triticina) is spreading in our trials at College station (Brazos County) and both ‘Baldwin’ catch plot and ‘TAM 110’ are 100S.  As for stripe rust (P. striiformis), the ‘Sisson’ catch plot is 70S whereas the ‘Patton’ border is 100S.  It is noteworthy that we reported stripe rust on Patton near Ennis (Ellis County) on January 29, 2015.

Leaf rust is easy to find, but severity is very low at Bushland (Potter County) in Texas High Plains and Chillicothe (Hardeman County) in Texas Rolling Plains.  Unconfirmed reports also indicated spread of stripe rust in Brady (McCulloch County) in the heart of the state. Reports also indicated that ‘Redhawk’ was especially susceptible there and that some producers are already applying fungicides. Both leaf and stripe rusts are also present in Wharton County in South Texas.

If conditions continue to prevail, we can have significant leaf and stripe rust levels compared to last year, in my opinion.

Dr. Ron French (Ast Prof & Extn Plant Pathologist, Texas A&M AgriLife Extension Service, Amarillo) 25-Feb-2015:  Update on wheat rust in Texas- some commercial fields.  Leaf rust had been reported in Texas in fall 2014 as far north as Hansford County (Texas Panhandle, bordering the Oklahoma Panhandle) and throughout NW Texas, especially the Texas Panhandle. In early winter 2015, leaf rust was still found around the Amarillo area. This winter in Amarillo, we have had temperatures as low as 3°F  and will still be as low as 12°F and not much higher than the mid- 50s F for the next week, including snow.  In some cases when temperatures have dropped this much, some fields with trace levels of leaf rust no longer exhibited leaf rust for a while, whether that meant inoculum did not survive, was not active, or had new inoculum come in to that field. I visited some random fields today in the Amarillo area and was not able to find any leaf rust. This does not mean that leaf rust is not present but that it may be present at really low trace levels.

Last Wednesday, February 18, I did find leaf rust in one wheat field in Wichita County at trace levels in very few plants and only in the lowest two leaves. The biggest wheat in that field was at Feekes 4. Wichita County is in the Texas Rolling Plains and borders Clay, Wilbarger, and Archer Counties in Texas, and Tillman and Cotton Counties in SW Oklahoma. With high temperatures expected not to be higher than 63°F and as low as 25°F for the next seven days, could disappear, as observed in previous years when leaf rust was first observed in mid-to-late March.

Unlike 2014, no leaf rust has been observed so far in the lower Coastal Bend of Texas around Kingsville and Corpus Christi by this time. Some days have been cooler than normal and they have had more rain than in some previous years.

Stripe rust has been present as far west as Tom Green County in west Central Texas, where the city of San Angelo is located. Stripe rust was first observed at the very end of January and beginning of February. Stripe rust levels were significant in lower leaves only and the ground was covered in orange spores. A few fields that were sprayed with Tilt on February 16th had taken advantage of the fact that topdressing of nitrogen was being done on the wheat. Within a week, fields looked great and new growth looks “excellent” (probably a combination of topdressing, moisture from overhead pivot irrigation, root growth, and the fungicide application). At time of spraying, the wheat was fully tillered. Some varieties with some level of stripe rust include TAM 113, Coronado, Greer, Redhawk, Cedar, and TAM 304.

The farthest north I have seen stripe rust is in Wichita County at low trace levels, on February 18th.  The biggest wheat in that field was at Feekes 4. Although normally dry, this area may be getting some snow and rain in the next week or so, so there could be an increase in inoculum. But since temperatures are expected to range from 25° to 41°F on the low side, and between 32-63°F on the high side for the next seven days, this may not be conducive to stripe rust increase or establishment. Time will tell. Other fields in that area have not had stripe rust so far from what I gathered today.

Other locations with stripe rust include fields around De Leon, in Comanche County, located in Central Texas. The application Tilt in February is not uncommon in some locations in southern Texas as powdery mildew can be an issue. This year, applications of Tilt have occurred due to stripe rust concerns and in many cases, taking advantage of top dressing of nitrogen on wheat.

First hollow stem update 02/26/15

First hollow stem is the optimal time to remove cattle from wheat pasture (full explanation). To monitor first hollow stem, we measure hollow stem for the 56 lines in our September-sown wheat forage plots at Stillwater each year. In spite of the recent cold snap many varieties are progressing towards first hollow stem. The small grains extension crew split ten stems from lines tested in our program today and Gallagher, Everest, Jackpot, Winterhawk, T153, T154, LCS Pistol, and TAM 112 join the list of varieties at or past first hollow stem. Full results are posted in the table below. We will take another set of measurements the first of next week and report the results on this blog.

The numbers reported from Stillwater are likely behind those being observed in southern Oklahoma and ahead of those observed in northern Oklahoma. You can check progression of first hollow stem around the state by using the First Hollow Stem Advisor on the Oklahoma Mesonet site.

First hollow stem measured in wheat sown 09/16/2014 at Stillwater, OK. Varieties in red are at or past first hollow stem.
Variety cm of hollow stem 02/26/15
Endurance 0.0
Deliver 0.6
Pete 0.0
OK Rising 0.1
Billings 0.5
Ruby Lee 0.4
Garrison 0.1
Duster 0.1
Gallagher 2.0
Iba 0.1
Centerfield 0.2
Doublestop CL Plus 0.0
NF 101 1.0
Everest 1.6
1863 0.7
KanMark 1.1
Oakley CL 1.0
KS061406 0.8
Sy Llano -
Sy Southwind 0.6
Greer 0.8
Jackpot 1.9
Sy Monument 0.0
06BC722#25 0.8
AP09T7631 0.1
WB-Cedar -
WB-Redhawk -
WB4458 1.7
WB-Grainfield 1.0
Winterhawk 1.9
T153 1.5
T154 2.3
T158 0.1
LCS Mint 1.4
LCS Wizard 0.7
LCS Pistol 1.7
LCH13DH-20-87 0.8
LCH13DH-14-91 -
TAM 112 1.9
TAM 204 1.3
TAM 113 1.4
TAM 114 1.2
CO11D174 1.1
Byrd 0.7
Brawl CL Plus 0.9
OK09125 0.9
OK1059060-2C14 0.9
OK10126 2.3
OK11D25056 1.5
OK11231 1.4
OK12621 0.6
OK13625 -
OK0986130-7C13 -
OK08P707W-19C13 1.0
OK10728W 1.0
OK11755W 2.2
Average 1.0

 

 

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