July 8, 2008


Tayor, Callahan, McCulloch, and Runnels County wheat variety tests have been harvested. As soon as the information is available it will be sent out to you. Concho and Gillespie Counties will be thrashing their samples in the near future. As the summaries from these tests are completed, I would appreciate receiving a copy. These summaries are sent to the companies that market the seed so they can determine which varieties preform best in each region. The companies that receive summaries early tend to support our programs favorably each year.

August 19 is the date of the Big Country Wheat Conference that will be held at the Taylor County Extension Office. The conferences target audience is mid- to upper-level wheat producers. This meeting will be useful in increasing their knowledge in wheat production and marketing. An agenda for this meeting will be sent to you in the near future. Make your plans now to attend.


Hot, dry and windy are factors that impacted the cotton crop through most of June. These weather conditions are a challenge to most crop managers. Producers that usually make a side-dress application of fertilizer, may choose not to spend the money. If a side-dress application is made, it needs to be completed before the 1/3 grown square stage. Foliar application of nitrogen can begin once the crop starts blooming.

The late emerging cotton crop will require special management in order to produce a moderate yield with desirable lint fiber quality. Historically, July and August are our hottest and driest months, if we don't get into a period of frequent rainfall this crop is done before it gets started. If a wet pattern does develop, our phones will be ringing off the wall with producers wanting to know how to maximize production on a crop that had a late start.

Our daily heat unit accumulation has been good. I would prefer that the maximum air temperature be in the 92 to 95 degree range, to reduce plant stress. It is going to be very important to set all the squares we can until first bloom. After boll set begins, it will be important to maintain as many bolls as possible for the first three weeks. Other bolls will be retained by the cotton plant and will contribute to yield, but the quality of lint from the later retained bolls is a concern. The bolls that develop in the later part of the season will accumulate less heat units than would be needed for quality fiber development. It is not uncommon to have a discount of 10 cents per pound for low micronaire cotton.

If July and August are hot, the plants with a week root system will suffer. Factors causing the greatest concern are: 1) plants with a lot of leaf surface area that transpire water through the natural openings in the leaves faster than the roots can meet the demand, 2) the root system is not adequately developed and can't extract moisture and nutrients from the soil fast enough to meet demand, 3) even though adequate soil moisture and nutrients exist, once the plant begins blooming and setting fruit the root system's development is slowed greatly due to the plants normal processes of boll development. So the best opportunity to develop a more extensive root system is before blooming begins. Producers can encourage root development by making sure that adequate nutrients are available. If soil applied nitrogen was not applied before the one-third grown square stage, then foliar application will need to be delayed until blooming begins.

Two of the 23 tests established this year have been lost due to weather conditions. If you loose a plot please let me know, seed company representatives often want to visit the tests during the summer.

Grain Sorghum

If producers plant grain sorghum late, the application of nutrients should be made prior to the seven- to ten-leaf stage (depending on maturity group). Application at this time could increase the number of seed per head and the size of the seed. If nutrients are applied late, then seed size is the only variable of yield that can be increased.

Is it to late to plant grain sorghum? It just depends on how big a gambler you are. If you plant a 100 day grain sorghum on July 1 you may or may not have enough time. It will depend on the temperatures at the end of the season and when it freezes. If you do plant grain sorghum late, the application of nutrients should be made prior to the seven- to ten-leaf stage. Several producers have called asking about varieties of grain sorghum to plant. Refer to the message from Calvin Trostle to answer those questions.

A note from Calvin Trostle, Extension Agronomist, Lubbock

Dear Colleagues:

Linked is a PDF file "2008 Alternative Crop Options after Failed Cotton & Late-Season Crop Planting for the Texas South Plains." It details replant and late plant crop options (often after failed cotton) for grain sorghum, sunflower, guar, sesame, summer annual forages, black-eyed peas and other short-season vegetable crops, and lesser replant options like soybean, peanuts, corn. It is on the Lubbock Center website at: http://lubbock.tamu.edu/cotton/pdf/cropreplantoptions08.pdf

In addition, linked is a copy of last recommended planting dates for individual sorghum hybrids, as well as, a "Pick's" list of grain sorghum hybrids for the Texas High Plains which is based on the AgriLife Research Crop Testing Program (there are many other good hybrids, but I don't have A&M System data on them--I do get flack for this document sometimes; CEAs may wish to use this for yourselves, but not distribute it).

I believe the information attached will answer many of the inquiries that you will receive.

Linked is a list of companies that sell grain sorghum. Most of the web sites provide information on the varieties. The producers will be selecting varieties with a medium maturity.

Failed out cotton planted back to grain sorghum is having a problem with volunteer cotton starting to emerge. Linked is a quick reference of post emerge herbicides for grain sorghum. Several limitations need to be considered: 1) the height of the cotton or cotton age when herbicides can be applied, 2) the use of surfactants may cause leaf burn to the grain sorghum plant, and 3) the replant interval before you can come back to cotton. After these considerations are made only a few of the herbicides remain that can be used.

Forage Sorghum

I have had several questions about nitrate and prussic acid poisoning concerns due to forage being baled as hay or eaten by livestock. Linked is information on nitrate and prussic acid poisoning.

Pesticide Recertification Training

On July 14, there will be a training conducted at Abilene for producers needing to obtain a Private Applicators License. For more details and to register for the meeting call Robert Pritz at (325) 672-6048.

Weed Identification and Control

I have had several Extension Agents and producers indicate that Roundup has not been working well in controlling weeds this season. That is probably due to the environmental conditions that exist at the time the chemicals are applied and the size of the weed being treated. Weeds that developed under heat and moisture stressed conditions will prove to be a challenge due to the cuticle becoming thick and waxy. This makes getting the herbicide into the plant difficult. If the herbicide being applied allows for a crop oil concentrate to be used, that would be a better choice than a surfactant due to the improved penetration through the cuticle. Early morning applications of herbicides are also important wind speeds are lower and relative humidity is higher. Try to complete herbicide applications before the temperature gets above 80 degrees F and the relative humidity drops below 30 percent. Due to the hard water in our region, it is important to use ammonium sulphate in the tank-mix. About 8 to 17 pounds per 100 gallons of mix is recommended. Applying a herbicide to weeds that are moisture stressed or mature will generally result in a poor level of control, so it should be avoided. This combination of steps should improve the level of weed control achieved by producers.

Producers will have a difficult time controlling Johnsongrass that is in a stressed condition. In tests conducted under similar conditions the level of control obtained ranged from 15 to 75 percent. Even the high level of control left a lot of grass and the producers felt like they had wasted their money.

Monthly Calendar


July 2, District 7 Office, Extension Agent Training
July 7, Disrtict 7 Office, Interview with Agronomy Candidate #1
July 10, Glasscock County, Turnrow Meeting
July 16, District 7 Office, Interview with Agronomy Candidate #2
July 22, Tom Green County, Producers Meeting


August 4 - 6, Comal County, Specialist Association Meeting
August 12, Brown County, Food Plot for Wildlife Presentation
August 13, Gillespie County, Hay Show and Small Grain Production Meeting
August 14, Tom Green County, Silver Clover Banquet
August 19, Taylor County, Big Country Wheat Conference


Billy E. Warrick, Ph.D.
Professor and Extension Agronomist
Texas AgriLife Extension Service
Texas A&M System