Sorghum Tips

This tip was provided by:

Calvin Trostle, Extension Agronomy, Lubbock, 806-746-6101, ctrostle@ag.tamu.edu

Statewide

Still “Free” Nitrogen for Grain Sorghum Production:  Revisiting Soil Profile N

It has been almost five years since I first mentioned this topic in Sorghum Tips. What has changed?—Nothing! Across Texas crop consultants, producers, AgriLife staff, etc. continue growing awareness of the potential for accumulating nitrate-nitrogen (NO₃-N) in the soil. This nitrogen has value for your sorghum and other crops. “Profile N” is readily available nitrogen accumulating below standard soil sampling depths (most often 6”). This accumulation is due to over fertilization (or underutilization in years when production is sub-par) with N, and the majority of the time producers are not aware of the presence of this N in the soil. Historically this N is not accounted for in supplying crop nutrient requirements, but it should be—all of it!

The level of N accumulation can vary greatly due to fertilization practices, downward percolating moisture from rains which carries the soluble and mobile nitrate, soil type, etc. Sometimes substantial N is found even below 3’ in the soil, but only deep rooted crops can tap that N. Texas A&M AgriLife’s Soil, Water, and Forage Testing Lab has updated their “Profile Soil Sample Information Form” (SP17) for 2017. This form pairs your standard 0-6” soil sample (analyzed for multiple nutrients including N, P, etc.; routine analysis is still only $10, the same as in 2012) with a second soil sample from below 6” to as deep as 24”. This paired soil sample is analyzed for nitrate-N only, $4/sample. The submitter marks the depth so a proper calculation of nutrient requirements can be made by the soil test lab

Is profile nitrate-nitrogen down to 24” deep 100% available to grain sorghum?

Yes. Even slightly deeper N is largely available. The Profile Soil Sample form for N credits all nitrate N at 6-24” to your crop requirement thus reducing fertilizer costs. Extension recommends that producers include at least some profile soil N sampling to establish whether there might be deeper N present.

Some producers disagree with crediting all nitrate-N in the 6-24” range to grain sorghum. In Texas across the state for different soil types, and yes, different crops, for all practical purposes you can credit all measured nitrate-N to your crop requirement. Many producers have never heard this. When I conduct Extension educational programs on this topic, I ask for a show of hands “How many of you think you can fully credit 100% of soil nitrate-N in the top 24” to your crop requirement?” (I deliberately emphasize ‘fully’ and ‘100%’). Normally about 10% of attendees say you can, and 20-30% say you can’t, and the rest are sitting on the fence. Yes, as noted above, “for all practical purposes…” Perhaps a producer is truly uncomfortable with this idea; if so, then credit 2/3 or ¾ of you soil test profile N—this is still a potentially significant cost savings. What do other states do in their soil testing labs do? They generally credit 100%, and in fact several states including Kansas now recommend a 24” soil sampling for all nutrient analyses.

The soil test lab I prefer doesn’t offer a profile soil test for N. What do I do?

Most labs in fact don’t have a separate form for nitrate-N only soil profile test. If you like the concept you can still submit your samples to that lab, just fill out one form for each sample then you will need to total the sum of nitrate-N. for all samples (above 3’) by your own hand.

The current Texas A&M AgriLife Extension Profile Soil Sample form is found at http://soiltesting.tamu.edu/files/profilesoil.pdf

I attended the Amarillo Farm Show on Wednesday. I have about 10 seed company catalogs that include grain sorghum hybrids. At first glance you would not know where to begin if you didn’t have your own track record of preferred grain sorghum hybrids—there are almost two dozen hybrids listed in some catalogs. Many of these catalogs are “national” in that they list all hybrids the company markets, including what you might plant in Nebraska, Missouri, Georgia, or Texas, for example. In most cases, however, I visited with company representatives and have circled in my catalogs their primary choices for dryland and irrigated hybrids for my region.

Texas A&M AgriLife Research is publishing every week additional 2016 grain sorghum hybrid trial results here (also note the “Archive” link for results from 2015 and previous years on the same page). None of the current trials have any data on sugarcane aphid observations.

As producers across Texas consider grain sorghum hybrids for 2016, your recent experience will color greatly the value you place on potential grain sorghum SCA tolerance. Producers in South & Central Texas have not had as much trouble the past two years as was probably feared after the first two years that SCA appeared. In contrast, in much of the Texas Panhandle and the northwest South Plains, growers in 2016 faced tremendous damage in this area of the state where SCA arrived the latest.

For hybrid trials that various states set up to test hybrid performance in the presence of sugarcane aphid, there are several types of data that you may find as these trials are published over the next 2 to 3 months. This data will include:

• SCA counts of aphids per leaf (including lower and upper leaves) and a reporting of how soon initial SCA infestation occurred and perhaps SCA counts at different growth stages throughout the season.
• Reductions in stand of younger plants if SCA killed seedlings (although it is likely it can’t be assumed that all trials had uniformity of planted seed having a seed treatment insecticide; most hybrids planted in these trials probably do).
• SCA damage ratings (likely on a scale of 0 to 9 or 0 to 10) taken later in the season.
• Percentage of lodged plants.
• Head exsertion (how far the heads emerged past the flag leaf; heavily damaged plants may not have the energy to push the head out very well).
• Yield—but not just regular yield. Yield is the bottom line, and the best trial results will compare yield of grain sorghum hybrids with and without SCA control. This enables comparisons of the total impact of SCA on hybrid performance.

Watch for trial reports that were conducted specifically to evaluate hybrid performance in response to sugarcane aphid. Texas A&M AgriLife has several forthcoming trials, and we will be interested in the same types of trials from surrounding states. United Sorghum Checkoff Program’s Dr. Brent Bean will be compiling numerous reports across states. I will let you know when these reports are reported.

A note about Sugarcane Aphid in South Texas—Robert Bowling’s 2016 Summary

Dr. Robert Bowling, Texas A&M AgriLife Extension entomologist, Corpus Christi, published his season-ending newsletter on Monday, Nov. 28. He discusses the “head scratcher” observations, e.g., sudden collapse of numerous SCA populations observed in many fields in 2016, as well as a potential fungal pathogen of the sugarcane aphid. See his most recent “Rolling with Bowling” post here.

This tip was provided by:

Ronnie Schnell, Cropping Systems – Statewide, College Station, ronschnell@tamu.edu

Statewide

Sugarcane Aphid Tolerant Grain Sorghum Hybrids

Seven commercially available grain sorghum hybrids were evaluated for tolerance to sugarcane aphids (SCA) at five locations in Texas during 2016. All were compared to a susceptible public check (Tx399 x Tx430). Late plantings (mid May) were used to increase the chance of pre-bloom SCA infestations. Given the late planting, yield from SCA trials were low and are not provided in this report. Results from College Station and Greenville have been reported.

SCA was present at both sites within 6 weeks of planting, although numbers remained below threshold (50 per leaf) through flowering. By Late July, the susceptible check had a mean number of SCA per leaf in excess of 200 and remained above 100 through harvest. In contrast, five commercial hybrids demonstrated consistent lower levels of SCA per leaf. DKS 37-07, AG 1203, BH4100, SP7715 and W7051 all remain below 50 SCA (mean per leaf) throughout the duration of the trial at College Station and Greenville. Performance of these hybrids at other locations is not available yet. Variation of timing, intensity and duration of SCA infestations may affect performance of these hybrids at other locations. However, these results suggest that these hybrids have some level of tolerance to SCA, which may reduce the number of insecticide applications or possibly the need for insecticide applications.

Is the maturity and yield potential of these hybrids appropriate for your farm? If so, including them among hybrids you plant may be appropriate. Maturity and yield information obtained from Texas A&M AgriLife trials in the Gulf Coast and Central Texas regions during 2016 are provided below. Yield differences for early maturing hybrids should be weighed against potential savings on insecticide sprays.

Sorghum Partners – SP7715

• Medium-Full
• Mean grain yield at Thrall, TX was 5,287 lbs/acre, +4% of trial mean yield.

Warner Seed – W7051

• Medium-Full
• No yield information available in the region for 2016.

BH Genetics – BH4100

• Medium
• Average yield from 4 trials in the Blacklands region of Central Texas was 4,708 lbs/acre, -3% of the regional trials mean yield.

Advanta – Alta Seeds AG1203

• Medium-Early
• Average yield from 15 trials in the Upper Gulf Coast and Central Texas region was 4,642 lbs/acre. Overall, was -5% of the trail mean yields.

Dekalb – DKS 37-07

• Medium-Early
• No yield information available in the region for 2016.

This tip was provided by:

Calvin Trostle, Extension Agronomy, Lubbock, 806-746-6101, ctrostle@ag.tamu.edu

Statewide

Grain Sorghum Hybrid Trials and Selection for 2017

I attended the Amarillo Farm Show on Wednesday.  I have about 10 seed company catalogs that include grain sorghum hybrids.  At first glance you would not know where to begin if you didn’t have your own track record of preferred grain sorghum hybrids—there are almost two dozen hybrids listed in some catalogs.  Many of these catalogs are “national” in that they list all hybrids the company markets, including what you might plant in Nebraska, Missouri, Georgia, or Texas, for example.  In most cases, however, I visited with company representatives and have circled in my catalogs their primary choices for dryland and irrigated hybrids for my region.

Texas A&M AgriLife Research is publishing every week additional 2016 grain sorghum hybrid trial results at http://varietytesting.tamu.edu/grain-sorghum/  (also note the “Archive” link for results from 2015 and previous years on the same page).  None of the current trials have any data on sugarcane aphid observations.

As producers across Texas consider grain sorghum hybrids for 2016, your recent experience will color greatly the value you place on potential grain sorghum SCA tolerance.  Producers in South & Central Texas have not had as much trouble the past two years as was probably feared after the first two years that SCA appeared.  In contrast, in much of the Texas Panhandle and the northwest South Plains, growers in 2016 faced tremendous damage in this area of the state where SCA arrived the latest.

For hybrid trials that various states set up to test hybrid performance in the presence of sugarcane aphid, there are several types of data that you may find as these trials are published over the next 2 to 3 months.  This data will include:

• SCA counts of aphids per leaf (including lower and upper leaves) and a reporting of how soon initial SCA infestation occurred and perhaps SCA counts at different growth stages throughout the season.
• Reductions in stand of younger plants if SCA killed seedlings (although it is likely it can’t be assumed that all trials had uniformity of planted seed having a seed treatment insecticide; most hybrids planted in these trials probably do).
• SCA damage ratings (likely on a scale of 0 to 9 or 0 to 10) taken later in the season.
• Percentage of lodged plants.
• Head exsertion (how far the heads emerged past the flag leaf; heavily damaged plants may not have the energy to push the head out very well).
• Yield—but not just regular yield.  Yield is the bottom line, and the best trial results will compare yield of grain sorghum hybrids with and without SCA control.  This enables comparisons of the total impact of SCA on hybrid performance.

Watch for trial reports that were conducted specifically to evaluate hybrid performance in response to sugarcane aphid.  Texas A&M AgriLife has several forthcoming trials, and we will be interested in the same types of trials from surrounding states.  United Sorghum Checkoff Program’s Dr. Brent Bean will be compiling numerous reports across states.  I will let you know when these reports are reported.

A note about Sugarcane Aphid in South Texas—Robert Bowling’s 2016 Summary

Dr. Robert Bowling, Texas A&M AgriLife Extension entomologist, Corpus Christi, published his season-ending newsletter on Monday, Nov. 28.  He discusses the “head scratcher” observations, e.g., sudden collapse of numerous SCA populations observed in many fields in 2016, as well as a potential fungal pathogen of the sugarcane aphid.  See his most recent “Rolling with Bowling” post at http://betteryield.agrilife.org/files/2016/07/Updates-on-the-SCA-and-Fungal-Pathogens.pdf

This tip was provided by:

Ronnie Schnell, Cropping Systems, College Station, ronschnell@tamu.edu

Statewide

Will Grain Sorghum Respond to Starter Fertilizers?

Stater fertilizer is defined as the application of small amounts of nitrogen (N) and phosphorus (P) near the seed at planting. In-furrow or “pop-up” applications apply small rates, usually less than 6 gallons per acre, directly in the seed furrow. Another option is to place the fertilizer about 2 inches to the side and 2 inches below the soil surface. This is referred to as a 2×2 application. Application rates can be increased for 2×2 placement due to greater separation from the seed. Rates may need to be adjusted (lowered) in sandy soils to prevent seedling damage.

Starter fertilizers have been investigated extensively for corn in northern latitudes. Results in corn have been inconsistent, many showing a positive yield response in less than 4 out of 10 years. Will grain sorghum respond to starter fertilizer in Texas? Limited information is available for grain sorghum. Research from Kansas in the 1990’s shows an 18% yield increase and 6- to 7-day reduction in bloom date with a 2×2 application of N and P compared to broadcast application of the same rate. Another study from Kansas in 2002 showed a 26% yield increase for starter fertilizers compared to no-starter checks and a 11-day reduction of days to mid bloom. Trials are underway in central Texas looking at starter fertilizers in grain sorghum in combination with nitrogen rate and timing. During the first year, grain yield was increased 14% with the 2×2 application (22-73-0/acre) compared to no starter or a lower rate in-furrow starter application (7-24-0/acre). Earlier flowering was observed with 2×2 starter application in Texas as well, although only a few days earlier than plots without starter. There certainly could be advantages to earlier flowering in Texas. However, more work is needed to determine the actual economic response to starter fertilizers in Texas.

Soil sampling should be conducted to determine P requirements for grain sorghum production. Soils with low levels of extractable P are more likely to see a response to starter fertilizers. Depending on soil test recommendations, in-furrow or 2×2 application of starter fertilizers are a convenient and efficient way to apply needed P. Also, there are many different sources of phosphorus fertilizer available today that can be used in starter fertilizer solutions. Polyphosphates, orthophosphates and various ratios of the two are found in many products today. Given current grain prices, using the product that provides the most nutrient for the best price is likely the best option.  Efficient timing, rate and placement will have greater impact than any particular source.

This tip was provided by:

Calvin Trostle, Extension Agronomy, Lubbock, 806-746-6101, ctrostle@ag.tamu.edu

Statewide

Grain Sorghum Stubble vs. Planting a Cover Crop

In past Sorghum Tips I have outlined several points regarding our management and understanding potential benefits that sorghum stubble may afford.  Access some of the previous information at http://texassorghum.org/sorghum-tips (at the bottom of the page you can click on earlier pages, they are arranged in reverse chronological order).  Regarding sorghum stubble three of these posts include:

• Grain Sorghum, Surface Residues, and Soil Organic Matter. July 24, 2012.  Grain sorghum stubble is a ‘blanket’ to protect the soil surface and minimize erosion.  Farming into stubble is increasingly a common practice across the U.S.  Learn how to manage the stubble and farm it with possible modifications to your equipment.  Tillage of sorghum stubble into the soil does not appreciably increase soil organic matter as some of the soil matter you already have is disturbed and lost (incorporating residues is an “exchange” of organic matter).  The best route to maintaining and improving stable long-term soil organic matter content is to leave the roots undisturbed.
• Baling Sorghum Stalks:  I—Loss of Nitrogen ($) from the Field.  November 19, 2014.  When sorghum stalks are removed from the field, a modest but significant amount of N (roughly 1% of the biomass) is nitrogen, which has a replacement cost that is often not factored into the price you receive.  Grain harvest or grazing remove much less N and is not a concern.
• Baling Sorghum Stalks:  II— Loss of Soil Cover Protection.  December 9, 2014.  Removal of sorghum stalks in baling means that you are selling an asset—and probably not getting compensated adequately for the intangible value of your “blanket.”

Cover cropping is a common topic across much of the U.S.  NRCS promotes cover cropping.  Several industry publications like No-Till Farmer and Dryland No-Tiller newsletter highlight producers using cover crop practices across the country.  I have attended several cover crop conferences, and I have some work on the topic myself in the Texas High Plains.  Much of the reporting on the successes of cover cropping come from regions of the U.S. that either have high rainfall (e.g. more than the annual crop requires) or lower evaporative demand (cooler conditions where 1” of moisture goes much further than it would in Texas).

A Cover Crop Caveat…

A caveat—and I assert a major one—is that outside of the areas noted above there is not a lot of data to date from universities, USDA Agricultural Research Service (in contrast to NRCS), etc. that clearly demonstrates value of cover cropping (and this type of data needs to be long-term to capture the potential benefits that can occur over time).  The primary concern in many drier areas, which would include much of Texas, is that there is not sufficient moisture to support investing some of your water resources in a cover crop.  This is a fair question though note that tillage practices are the culprit in significant potential moisture losses.

Cover crops have costs starting with the seed.  Some recommendations from seed companies can easily exceed $30/acre, usually for a multi-species blend.  For any area in Texas multi-species blends may be only 3 or 5 species (probably OK) vs. a shotgun approach with up to 15 species, several of which are quite possibly not well adapted and don’t grow (so why pay for them?).  Also, winter blends (think colder conditions of the Texas High Plains) will include a few legumes, but Texas A&M AgriLife observations are that most legumes don’t nodulate well (may not have a crop-specific Rhizobium or Bradyrhizobium inoculant) and if soils are cold there is little nitrogen fixation occurring—thus the purported benefit of adding N to the soil ecosystem is not realized.

Grain sorghum stubble vs. separate planting of a cover crop.  I believe this is an important consideration, especially in drier areas of Texas where grain sorghum is the only adapted summer annual crop you can plant that will generate much residue.  Do not overlook the value of this stubble.  It may preclude any need to consider costs associated with establishing a cover crop.  One selling point of cover crops is “A living root in the soil at all times” which fosters microbial activity thus contributing to nutrient cycling.  This is often mentioned as if to lead you and I to conclude that there is no biological activity if there is not a live root in the soil, and this is simply not true.  There is massive amounts of biological activity, and though it is somewhat less, soil microorganisms are busy decomposing root matter in the months after a root dies, and these populations of organisms will increase rapidly once live root matter returns to the soil.  Cover cropping may be viable for your farm, and I encourage Texas farmers to experiment.  But don’t overlook existing and “free” resources—like your remaining grain sorghum stubble—in terms of achieving some of the same goals that cover crops in principle may offer.

Wet field conditions during 2015 and 2016 disrupted many field operations and forced many activities to be performed when soil conditions were less than ideal. Traffic from tillage, planting, fertilizing, spraying and harvest activities can lead to soil compaction when soils are too wet. Soil compaction is the compression of soil volume, reducing the amount of pore space between soil particles. Reduced pore space limits movement and volume of air and water in the soil profile. Soil compaction can restrict root penetration, reduce water infiltration, reduce water and nutrient uptake and reduce yields for years. Yield loss can range from 5-30% depending on severity.

There are four types of compaction: surface crusting, surface compaction, tillage pan and deep compaction. Surface crusting is caused by the impact of raindrops on soils with weak aggregates. Surface compaction occurs near the surface within the normal tillage depth and is caused by any pressure applied to the soil surface. Surface crusting and surface compaction can generally be alleviated through normal tillage practices such as chisel plowing. Tillage pans and deep compaction develop below the normal tillage depth. Tillage pans develop when the same tillage depth is used year after year. Deep compaction is caused by axle load of field traffic (Figure 1). The severity of deep compaction is influenced by equipment weight, tire and axle number, tire inflation, soil moisture and number of passes. High axle loads from combines and grain carts can cause severe compaction.

The best approach is to prevent soil compaction from occurring. Tips for preventing compaction include:
• Avoid field activities if possible when soils are too wet.
• If working on wet soils, frequently empty combines and grain carts to reduce axle loads.
• Minimize traffic from tractor-trailers or other vehicles with high inflation pressure and small footprint.
• Reduce tire pressure, use floatation tires or tandem axles.
• Use smaller/lighter equipment when possible.
• Reduce axle loads below 10 tons.
• Control traffic patterns.

Alleviating deep soil compaction can be expensive and results are not guaranteed. Subsoiling may be required if compaction is obviously limiting yield. Subsoiling refers to tillage at a depth of at least 14 inches. Subsoiling should be performed to 1 inch below the compacted zone. Subsoiling should occur when the soil is dry enough for the compaction zone to be fractured. Subsoiling when it is too wet will not fracture the compacted layer. Excessive tillage or subsoiling can destroy soil structure making soil more susceptible to compaction in the future. Plans for preventing compaction are critical following subsoiling activites.

This tip was provided by:

Calvin Trostle, Extension Agronomy, Lubbock, 806-746-6101, ctrostle@ag.tamu.edu

Statewide

Wrapping up Grain Sorghum Crop In-Season Management Decisions for 2016

Grain sorghum across Texas ranges from harvested several months ago in South Texas to pre-bloom in the lower Texas High Plains.  The further northwest in Texas the more likely there are still significant management decisions remaining in the cropping season.  Here are three remaining in-season management issues for finishing the Texas grain sorghum crop:

• Sugarcane aphid.  Activity in the High Plains is mixed as some fields have hit thresholds with significant potential damage whereas other fields seem to have a prolonged duration of low levels of SCA that have not taken off.  Recent rains and cooler temperatures may be slowing SCA development, but as noted in earlier Sorghum Tips, this is no time to be complacent. Remember, all grain sorghum hybrids are susceptible to SCA at some level.  To review recent SCA information from Texas A&M AgriLife, re-visit the information and web links in the May 25, 2016 Sorghum Tip by entomologist Dr. Ed Bynum, see http://texassorghum.org/avoiding-complacency-about-sugarcane-aphid.html

• Irrigation termination.  With recent rains over most of the Texas High Plains irrigation needs to make yield goals have lessened, and later maturing dryland sorghum is in better shape provided N fertility is available to make yield.  Typically irrigation termination occurs by early soft dough if some soil moisture remains.  For a brief review of late-season grain sorghum irrigation see the Sorghum Tip from August, 2012, at http://texassorghum.org/irrigation-termination-for-high-plains-grain-sorghum.html

• Harvest aids.  We reviewed information for grain sorghum harvest aids in September 2015.  Evaluate cost of treatment and your yield potential and apply your assessment of A) lodging potential, and B) your ability to harvest in timely fashion rather than letting the crop sit for a long time in the field if you get busy with corn harvest, wheat planting, and cotton harvest.  See the prior information at http://texassorghum.org/harvest-aids-in-grain-sorghum-a-review.html

Bushland/Amarillo Forage Sorghum Field Day, September 8

Dr. Jourdan Bell, extension agronomist, Amarillo, will showcase the Texas A&M AgriLife forage sorghum hybrid research trials near Bushland on September 8, 9:00 AM-12:00 PM.  The tour will convene at the plots north of Bushland, plots north of Bushland at the intersection of Jim Line and Blessen Roads (35.205836, -102.041460).  This trial of commercial hybrids is among the largest of any kind in Texas—101 hybrids in 2016—and provides excellent multi-year data.  For further information contact the Amarillo AgriLife Center at (806) 677-5600, or e-mail Dr. Bell, jourdan.bell@ag.tamu.edu

This tip was provided by:

Calvin Trostle, Extension Agronomy, Lubbock, 806-746-6101, ctrostle@ag.tamu.edu

Statewide

“Feed Grain Outlook”—A Newsletter of AgriLife Extension Agricultural Economics

For this edition’s regular Sorghum Tip I am reminded that growing grain sorghum is not all about planting date, hybrid choice, seeding rate, your fertility program, and managing weeds and pests.  Your economics assessment of sorghum via your budget and market prospects are important, too.

Dr. Mark Welch, Texas A&M AgriLife agricultural economist, specializes in the study and reporting of grain markets and their trends in production, usage, pricing, and supply.  He captures this information in his weekly newsletter Feed Grain Outlook.  Dr. Welch perspective on the markets includes his experience as a farmer in the High Plains as well as a feedlot operator.  Though the majority of Dr. Welch newsletter discusses corn, grain sorghum is also a significant part of the newsletter.  Readers can review recent data for feed use, carryover stocks, the proportion of the grain sorghum crop going to ethanol (and what proportion of ethanol production is from grain sorghum vs. corn), and China sales.  Much of the information Dr. Welch discusses is from USDA.

If you would like to receive a weekly e-mail with the Feed Grain Outlook newsletter, e-mail Dr. Welch at jmwelch@tamu.edu (office phone 979.845.8011) to be added to the distribution list.  You may view recent editions of the newsletter at http://agecoext.tamu.edu/resources/market-outlook/feedgrain-outlook/

Some of this information may also be reported by Texas Grain Sorghum Association or National Sorghum Producers, but Dr. Welch adds an additional dimension in his weekly analysis.  He welcomes your inquiries and interest in grain sorghum across the state.

This tip was provided by:

Ronnie Schnell, Cropping Systems , College Station, ronschnell@tamu.edu

Statewide

Stalk Rots and Harvest

Stalk rots can occur in sorghum and often go unnoticed until significant lodging occurs. Yield loss can result from severe lodging but also from reduced head size and poor grain fill.  Two common stalk rots are charcoal rot and fusarium rot. Each are caused by different fungal pathogens. The fungus invades the plant through the crown roots and then continues to colonize and destroy (shredding) the tissue of the lower nodes. Fusarium rots will cause tan to reddish colored shredding while charcoal rots will cause grayish to black shredding. Often the tissue at the second or third node above the crown roots become so weak the plant will eventually lodge.

Moisture stress is a common contributor to the development of stalk rots although crop nutrition, insect damage and plant populations will contribute as well. Some hybrids are more susceptible than others but no hybrid is immune. Lower plant populations can help in two ways; reduce stress due to interplant competition for resources (water and nutrients) and greater stalk diameter. Larger stalks will stand better than thin stalks, especially when disease is present.

As harvest approaches, the presence of stalk rots should be considered when making decisions about harvest timing and use of harvest aids. Presence of the disease can be easily checked using a pinch test. Simply pinch the stalk between your thumb and index finger at nodes just above the brace roots. If the stalk tissue is soft, stalk rot is likely present. You can split the stalk open to confirm. The degree to which the fungus has destroyed the tissue will affect standability. Shredding across multiple nodes will increase the susceptibility to lodging. Harvest as soon as possible to avoid yield loss due to significant lodging. Additionally, dry down after harvest aids are applied can exacerbate lodging. Severely infected plants will likely fall regardless of application of harvest aids.

For information on grain sorghum or sorghum forages for your area, or for specific questions you have on sorghum, contact your local county agricultural Extension agent, an Extension crop specialist, Dr. Ronnie Schnell (ronschnell@tamu.edu) or Dr. Calvin Trostle, extension agronomist, Lubbock at (806) 746-6101, ctrostle@ag.tamu.edu  Your question will be relayed to the appropriate Texas A&M AgriLife staff as needed.