Cotton and Soil Planting Temperatures

               Today we are experiencing record high temperatures in the Plainview area, in the low 90’s.  With such warm weather, it can be difficult to fight the urge to head to the field with the planter.  Most cotton producers seem to be holding off with another blast of cold air and one more chance for some snow on the way later this week. 

                Cotton gets off to its best start when planted in a recommended 68°F consistent temperature soil (roughly 64°F bare minimum).  This spring the soil temperature has followed the trends of the air temperature fairly closely.  Higher moisture content in the soil usually slows the soil’s response to air temperatures, but that just is not the case today.  The best time to take your soil temperature is between 7 AM and 10 AM.  That early morning period is when the soil temperature should be at its lowest, guaranteeing that the soil will remain consistently at that minimum temperature. 

                Out of curiosity, and to answer several producer presented questions, I took some soil temperature readings in several locations during the heat of the day today.  Please keep in mind that these readings are during the heat of the day, and another cold front is expected soon.  Temperatures will not rebound to these levels until several days following the eventual return of warm weather.

-          66°F.  Two miles southwest of Hale Center, Texas.  Potential cotton field / plowed / very dry topsoil / under a pivot.

-          63°F.   Two miles southwest of Hale Center, Texas.  Current wheat field / recently irrigated under a pivot.

-          69°F.  One mile east of Edmonson, Texas.  Potential cotton field / plowed / pre-watered / dry topsoil / furrow irrigated.

-          66°F.  Two miles east of Edmonson, Texas.  Potential cotton field / no-till (2012 cotton ground) / pre-watered / moist topsoil / under pivot.

 

By my best estimation, sometime between May 8^th and May 12^th should be near ideal soil temperatures for planting cotton.  Please feel free to call if I can be of any assistance.

Blayne

Hale & Swisher Wheat Update

         

         

          Evaluating the extent of freeze damage to our area wheat is still the main issue for wheat producers.  Just about the time producers, crop consultants, and advisors are ready to make a solid freeze assessment another round of freezing weather moves in.  As of April 23, it is difficult for me to find irrigated wheat fields in the area with no freeze damage whatsoever to the growing point or stalk.  The severity of damage sustained looks highly variable from area to area, field to field, and also across individual fields.  Areas irrigated shortly before any one of the recent cold snaps seem to be in the worst shape.  Many times ice from the recent pivot irrigations formed on and over the plants in a sheet causing serious damage to that area of the field.  Fields already experiencing serious drought stress had less crop canopy to ‘blanket’ the heads and growing points and have significant freeze damage also.  Damage generally seemed more prevalent the farther north I moved across Hale and Swisher counties.  Exceptions to this observance can be found, both better and worse, just about anywhere across both counties.  Experience does show that we should never count wheat completely out until the heads actually emerge.  Many fields are moving into flag and boot stages now.

Of the fields I have looked at this week, the percent damaged heads ranges from 5% to 60%, with most irrigated fields averaging about 15% in Hale and 25% in Swisher.  This is not a 1:1 head damage to yield loss relationship.  Historically, that relationship is more 2:1 in nature.  Secondary tillers, if healthy, can help compensate in yield and grain weight.  It remains debatable what the yield potential of the area wheat crop was before the recent frost events occurred with so many detrimental factors working against the crop. 

If present, freeze damage to the stalk will be much more severe in economic terms than damage to the head or growing point.   Fields with this type of damage are very likely to lodge as the grain matures and become un-harvestable for hay or grain.  In addition, that stalk becomes limited in the amount of grain fill it is capable of.  Symptoms of freeze damage to wheat stalks include a brownish-red discoloration and are easily collapsed compared to healthy green stalks.  I have noted a few low lying fields already lodged well before boot and have had several producers report the same.  In these cases, the wheat is lost to any use other than grazing or cover.

Greenbugs and other aphids can still be found in most area wheat fields, but appear to have run their economic course.  Area insecticide treatments seem to have worked well where applied.  Many producers opted not to treat for economic infestations of greenbugs this season due to the already bleak wheat situation and economic outlook.  In fields where greenbugs were allowed to run their course significant pest damage has occurred, but predators and parasitoids are now working their way through the aphid populations and look to have the pest on the downward slope.  I urge producers and consultants to remain vigilant in their pest and plant monitoring efforts.  Each field is likely to have unique populations and situations and the threat of economic damage from greenbugs are still present.  

On April 12, Monti Vandiver, CEA – IPM in Bailey and Parmer counties, released his findings confirming a few pocketed populations of chlorpyrifos resistant greenbugs surviving 1 pt/ac. applications in those two counties.  One ray of sunshine on an otherwise bleak assessment of the current wheat situation is that several area producers opted not to treat their greenbug problems.  This offers a chance for our likely susceptible or at least less exposed populations of greenbugs to survive and possibly help stem the encroachment of resistance into our area and perhaps ease the pressure on those producers nearby. 

I welcome any thoughts or questions you may have regarding your wheat situation and I encourage consultants to share your field observations with us too.  Thanks,

Blayne

 

Wheat & Greenbug Situation

The wheat situation as of April 12, 2013, remains a tough one to grasp, but that could be because we might not really want to.  The wheat this season has been through a lot.  Top upon the list of wheat woes is the current drought.  Add to that a fairly common occurrence of mosaic viruses, several nights of prolonged cold weather recently, and a spotty but heavy greenbug situation and the prognosis for area wheat cannot be too exciting.  There are a few exceptional fields in the area, but these tend to be fields where wheat is the producer’s primary crop and are fairly rare.

                In my on-site wheat inspections this week I still find a substantial number of greenbugs in most fields.  I urge consultants and producers alike to get an eye in any questionable fields as populations are variable from field to field.  In many cases these greenbugs are well over the economic threshold in remarkable numbers, in other cases the predators seem to be controlling them well.  The ‘greenbug clouds’ that myself and several area entomologist reported seeing last week seem to have subsided.  The aphid situation might be stabilizing, but if a field has an economic pest population and that field’s economic situation still looks to have some potential, now is the time to act.    

                To check for wheat aphid pests, I prefer to use a drop cloth or clipboard in a beat sheet type method during the hottest part of the day, on an already warm day.  Aphids will be harder to find on cool or cold days or mornings.  The darker the color of the clipboard or cloth the better the aphid pests will stand out and be seen.  I fold the drop cloth so it is roughly the size of a clipboard and lay the cloth (or clipboard) on the ground along planted ‘row’ or wheat as flat as possible.  Then I vigorously pop the wheat onto the drop cloth, shaking the aphids onto the cloth trying no to do much harm to the aphids, while still shaking them loose.  Once you feel all aphids are off the wheat, get a full count of all aphids and good species identification.  Don’t forget to get a good evaluation of the beneficial arthropods at this time.  Even with some pretty high existing aphid numbers, a good population of ladybug larva, parasitic wasps, and lacewing larva give can adequate control if present in high enough numbers.  I also like to make at least a cursory look over the wheat plants just utilized in the drop sample for pest damage and the presence of mosaics.   Often I will dissect several plants while I am there to check for cold damage and head size at this time too.                 

A full explanation of greenbug and other aphid wheat pest economic thresholds can be found in the Texas A&M AgriLife Extension wheat pest publications.   A good rule of thumb I have used is; if your field is averaging 70-100 greenbugs per clipboard sized beat sample, and few predators can be found, you might be near ET for that field.  This is roughly based upon Extension data, but does not take into account grain price.

I feel a larger question remains for many area wheat producers… Even if my field is at ET for any pest aphids, is it really worth spraying? 

That is a good question, but one that can only be answered on a field by field basis.  This next week we will have several decisions to make.   Another question is… Did your field receive cold injury this last week? 

Unfortunately it will not be until next week before we will be able to tell if a field has sustained economic cold injury to the head and main growing point.  To give us a hand with that, Dr. Calvin Trestle, Agronomist – Texas A&M AgriLife Extension – Lubbock, will be making a whirlwind tour of the District 2 wheat growing areas on April 17^th.  He will be stopping at the Street Community Gin in Claytonville, Texas at 5PM on that date.  Wheat producers are encouraged to bring samples from your fields for him to dissect and to train producers on how to do it themselves.  I will be out of town next week until the 19^th.  At that time, I would be more than happy to help determine the viability of any wheat field, aphid pressure, or any other IPM question you may have.

 

Blayne

 

Greenbug Update

As recently as Wednesday last week I had announced that the predators should be able to handle the greenbug population I currently find in our area wheat. What a difference a few days make. Starting Thursday, March 28th I began receiving phone calls in earnest about possible heavy greenbug infestations in wheat north of Tulia in Swisher County that were already severe and on the increase. Since that time I have been able to confirm all reports with several on-site inspections.

In these areas, I find very few predators to control an already economic and growing population of greenbugs. Upon occasion, I also found some pockets of Russian Wheat Aphids, and some spotty but heavy populations of Brown Wheat Mites intermixed with the greenbugs. The Brown Wheat Mites are very small, but rarely an economic concern.

What is alarming is that this population of aphid species is still on the increase and has begun dispersing. A very high percentage of these aphids found were of the winged biotype. Myself and multiple entomologist and Texas A&M AgriLife Extension Agents from Tulia north to at least Amarillo, have now noted heavy greenbug flight and movement. During the heat of the day, these winged aphids are dispersing and moving, being carried by winds in huge numbers. Personally, I have not witnessed these greenbug ‘clouds’ near Plainview in Hale County, but they are now quite notable just to the north of Kress in southern Swisher. I strongly suggest that all area wheat producers and consultants be on the lookout for aphid pests as you evaluate your wheat this week for frost damage, mosaics, etc. Even proactive wheat producers that made insecticide applications just two to three weeks ago in conjunction with herbicide applications could be looking at a re-infestation problem here in April.

On March 28, Dr. Ed Bynum, Texas A&M AgriLife Extension Entomologist, Amarillo, released the latest issue of Panhandle Pest Update. In this issue Dr. Bynum reported some possible area problems with these aphid pests, gave identifying characteristics of these pests, discussed economic thresholds, and listed relevant insecticide products. Most wheat producers should find this issue very helpful. A link to that newsletter is provided here. http://amarillo.tamu.edu/files/2010/11/PPU-2013-v5i1-3-27-2013.pdf

I do urge wheat producers to take into account the full economic picture when making decisions about this spring’s wheat aphid pest treatment options. Soil water availability, irrigation costs, and cost return on investment can easily become an issue for area wheat producers this season, as can some possible freeze damage from recent weather events. Another factor to consider is the presence or absence of plant disease. As I scouted area fields these past two weeks I noted a higher than expected and consistent amount of mosaic present in the majority of wheat fields. There are four differing types of wheat mosaic that can infect or area wheat, but identifying which type is actually present in your field requires samples to be sent to a lab. Many times, identification of which type of mosaic that is present in your field is a moot point once disease symptoms are noticeable. These mosaics are normally transmitted to wheat by the Wheat Curl Mite in the fall from green native grass, summer growing volunteer wheat, or corn. Early spring virus transfer might also be possible by other aphid species. All management options for spring control of these mosaics are: few known and none that have proven to work on a severe and widely dispersed infection of these viruses across a full wheat field.

If all of these factors, insect, drought, and mosaic combined in one wheat field, it can be difficult to justify spending much capital with little hope of return on investment. Unfortunately, several area wheat fields might be in this situation. In many cases, other options, such as grazing, utilizing the wheat as cover, or possibly hay are all options is necessary.

If I can help you identify a problem, or for more information, please give me a call anytime.

Blayne