Posts filed under ‘soybeans’

Strategies to Control Marestail

This is easily one of the worst marestail years I have seen. Marestail is a weed that can follow a winter or summer annual life cycle. Marestail plants start out as a rosette, generally bolt in April/May, flower in July, and set and disperse seed from August to October. Each plant can produce up to 200,000 seeds that travel via the wind.

For those of us who deal with marestail, we know that post-emergence control of many marestail populations is close to impossible. As such, the goal of a marestail management program is to ensure that the combination of fall and spring burndown and residual herbicides results in a weed-free seedbed at the time of soybean emergence, and little to no emergence of marestail between soybean emergence and crop canopy closure. But keep in mind that even the most effective marestail management programs can fail to completely achieve this, but they often keep the populations low enough in the soybeans that they are not problematic.

For marestail control suggestions, OSU Extension Weed Specialist Dr. Mark Loux suggests the following as one possible approach:

Apply a combination of glyphosate and 2,4-D in the fall, followed by application of residual herbicide in the spring prior to soybean emergence. At the time of soybean planting, the field is likely to be infested with marestail that emerged earlier in spring, so include effective burndown herbicides to control emerged plants. Keep in mind these plants can be very small and not noticeable.

The idea here is to apply an herbicide treatment in the fall that adequately controls emerged marestail, but does not break the bank and allows use of residual herbicide in the spring. Canopy herbicide can also be used in the fall, but use of metribuzin in the fall preserves the option to plant corn the following spring. Follow the OSU Extension CORN newsletter for the latest updates at


September 7, 2010 at 3:04 pm 1 comment

How Soybean Sudden Death Syndrome Looks at the Root

Most agronomists and farmers are good at identifying soybean Sudden Death Syndrome (SDS) through leaf symptoms (below image courtesy of Glen Arnold, OSU Extension Putnam County):

Click image for full view


However, there is another diagnostic feature that can be used as well.  OSU’s Anne Dorrance will also use blue spores of the SDS fungus on a soybean tap root as a diagnostic feature.  This avoids incorrect diagnosis, that is, diagnosing brown stem rot or interveinal chlorosis from nutrient deficiency as SDS.

Click image for full view


Full podcast here:  

August 24, 2010 at 12:07 pm 1 comment

Insect Damage to Soybeans? Nah… It’s Wind Damage.

Winds in excess of 40 mph on August 4 left a few soybean leaves in tatters. A few who walked into their soybeans the next morning immediately thought ‘insect damage’.

Overview image showing torn, tattered soybean leaves in the upper trifoliates.

Another view showing torn, tattered soybean leaves.

Here's a closeup shot. Notice the irregular shape of leaf damage.

An indication that this isn't insect damage is that insect damage would not be so 'jagged'.

Final clue that this isn't insect damage. Wind damaged pieces of torn soybean leaf on the soil under soybean plants.

More torn soybean leaf pieces on the ground.

Nah, not insect damage. This was a clear-cut case of wind damage to soybeans (soybean stage R2).

August 6, 2010 at 8:15 am

Soybean Rust – Close to Ohio in 2009 but no Cigar

Dr. Anne Dorrane, OSU Extension Pathologist, recently discussed how close soybean rust came to Ohio in 2009. Excerpted from the January 12, 2010 CORN Newsletter:

Soybean rust was a big topic again at the end of 2009. First detections in Kentucky were in early September and followed a month later on late planted soybeans in Southern Indiana. What was most impressive this year – was the amount of rust that built up in the southern states at the end of the season. A limited number of Mississippi producers had yield losses directly due to soybean rust based on reports from Dr. Tom Allen, their field crop pathologist. In addition to the soybean, the amount of kudzu that was also infected is also becoming an issue. The good news is that again, not all kudzu is susceptible to the current strains of soybean rust we have right now. And the kudzu patches that are Susceptible are getting placed on maps to make the scouting easier in the future.

The biggest announcement that was made at the 2010 APS National Soybean Rust Meeting held in December was that the sentinel plot system would change. And this is a good thing. We know more, we can be more efficient at scouting now that we know where to look and those of us in the north can get better and knowing when to look. There is no point in searching in Ohio, if the southern states are negative. For 2010, we will again be monitoring the maps and commentary from our southern colleagues at the Soybean Rust website ( We will continue to monitor in Ohio as soybean rust continues to approach the middle tier of states. Hopefully it will continue to miss us or arrive to late to have an impact.

January 20, 2010 at 8:15 am

Soybean Aphid 2010 Early Prediction for Ohio

The below article is reblogged from an article written by Hammond et al for the CORN newsletter.

Soybean aphids did become a problem in parts of Ohio as predicted, with the worst problems being in the northeast counties and a few locations long Lake Erie. We also saw large, near economic populations in southern Ohio, especially along the Ohio River. We would mention that similar populations were observed in parts of Kentucky, southern Indiana, and southern Illinois.

The large flights of aphids seen in an outbreak year were much later than expected, more into mid-to-late August.  These late flights resulted in extremely large populations of aphids on buckthorn, the aphid’s overwintering host.  Although we expected to see large egg numbers on buckthorn, this did not happen. It appeared that a fungal pathogen infected the aphid population causing significant mortality. It was not unusual to see large numbers of brown, dead unwinged aphids along with winged aphids that seemed to “melt” on the leaf surfaces. Subsequently, we have observed very few eggs on the buckthorn this fall as we had projected.

What does this mean for Ohio in 2010? At this time, we have to admit we do not know. Normally when we see late flights and large numbers of aphids on buckthorn, we predict that we will see significant problems the following summer. But the large mortality we observed with the corresponding lack of egg deposition questions that assumption.  We recommend that growers maintain extra vigilance next summer until we see trends in what the soybean aphid population is doing. We would remind growers that the OSU Extension C.O.R.N. newsletter will be the best source of information during the summer months of 2010.

Full podcast here:

December 2, 2009 at 8:30 am

Kixor Based Products

BASF has introduced three new products based on a broad-spectrum broadleaf weed herbicide, Kixor (saflufenacil). The three new products include: Integrity, a premix of dimethenamid (Outlook) and saflufenacil for field corn and popcorn; Sharpen, which contains just saflufenacil and is labeled for corn, soybeans, and wheat; and Optill, a premix of saflufenacil and imazethapyr (Pursuit) for soybeans.

For soybeans, Sharpen is labeled at the rate of only 1 oz/A, because soybeans have less tolerance compared with corn. The lower rates for soybeans result in reduced residual broadleaf weed control, to the point that Sharpen should not be expected to provide substantial residual broadleaf weed control unless mixed with another residual herbicide.

Sharpen has activity on emerged weeds in addition to preemergence activity, and is apparently being promoted as a replacement for 2,4-D ester in preplant burndown treatments. OSU research shows that while Sharpen applied alone has some foliar activity, it will not adequately control emerged weeds in no-till fields unless mixed with another herbicide that has effective foliar activity (glyphosate, Ignite), and is likely to contribute more activity on annual weeds than on biennials or perennials.

Sharpen does have considerable activity on marestail, and while OSU needs additional data in this area, mixtures of Sharpen with glyphosate or Ignite have effectively controlled marestail. This provides an option for burndown of marestail (and other weeds) in fields where a grower is unable or unwilling to wait 7 days between application and planting. BASF is apparently positioning the combination of Sharpen, glyphosate, and Scepter as a replacement for combinations of glyphosate, 2,4-D ester, and other broadleaf PRE herbicides such as Valor XLT, Sonic, etc. in fields with marestail.

This article was condensed from the November 24, 2009 CORN newsletter at:

Full podcast here:

November 25, 2009 at 9:00 am

2010 Ohio Corn, Soybean and Wheat Enterprise Budgets

This article was written by Barry Ward, Production Business Management, OSU Department of Agricultural, Environmental, and Development Economics:

Budgeting helps guide you through your decision making process as you attempt to commit resources to the most profitable enterprises on the farm. Crops or Livestock? Corn, Soybeans, or Wheat? We can begin to answer these questions with well thought out budgets that include all revenue and costs. Without some form of budgeting and some method to track your enterprises’ progress you’ll have difficulty determining your most profitable enterprise(s) and if you’ve met your goals for the farm.

Budgeting is often described as “penciling it out” before committing resources to a plan. Ohio State University Extension has had a long history of developing “Enterprise Budgets” that can be used as a starting point for producers in their budgeting process.

Newly updated Enterprise Budgets for 2010 have been completed and posted to the Farm Management Website of the Department of Agricultural, Environmental and Development Economics. Updated Enterprise Budgets can be viewed and downloaded from the following website:

Enterprise Budgets updated so far for 2010 include: Corn-Conservation Tillage; Soybeans-No-Till (Roundup Ready); Wheat-Conservation Tillage, (Grain & Straw).

Our enterprise budgets are compiled on downloadable Excel Spreadsheets that contain macros for ease of use. Users can input their own production and price levels to calculate their own numbers. These Enterprise Budgets have a new look with color coded cells that will enable users to plug in numbers to easily calculate bottoms lines for different scenarios. Detailed footnotes are included to help explain methodologies used to obtain the budget numbers. Starting this year we will be updating these Enterprise Budgets periodically during the year is large changes occur in price or costs. Budgets will include a date in the upper right hand corner of the front page indicating when the last update occurred.

November 2, 2009 at 9:05 am

Purdue: Soybean Rust Confirmed in Indiana

From: Purdue Plant & Pest Diagnostic Lab (

Soybean rust was confirmed in Indiana September 30th on soybean leaves collected in southeast Posey county.  Posey County is in the extreme southern and western part of Indiana. The soybean field where rust was found was at R7 and rust was detected at very low levels. Pustules were observed on 14 out of 100 leaves. Severity was low, with 1-2 pustules on each infected leaf.

In 2009, soybean rust has been found in 14 states and 293 counties in the United States, and in two states and five municipalities in Mexico.

Soybean rust was found in 392 counties in the United States in 2008. This is the highest number of counties reporting the disease since it was first discovered in the continental U.S. in 2004.

Unfortunately, there are additional hosts that can serve as overwintering reservoirs for the pathogen and allow for build-up of inoculum, in those environs free from freezing temperatures. The pathogen is well adapted for long-distance dispersal, because spores can be readily carried long distances by the wind to new, rust-free regions.

Although impossible to find symptoms this late in the year in Ohio (thanks to the October 1 killing freeze) the latest soybean rust information can always be found at

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October 7, 2009 at 11:37 am

Graphical Display of Major US Crops, 2009

Please click on the image for a larger view:

Major US Crops

October 5, 2009 at 1:00 pm 4 comments

Lookalike Soybean Diseases: Brown Stem Rot

Brown Stem Rot is one of the lesser abundant diseases in my area, and is often easily confused with soybean Sudden Death Syndrome (SDS).  I had the chance on September 11 to spend a few minutes in the field with Dr. Anne Dorrance while we examined my brown stem rot plots. Foliar symptoms, when present, consist of wilting, chlorosis, and browning of the tissue between the veins. These foliar symptoms are very similar sudden-death syndrome. Generally, the two diseases can be distinguished by looking at the soybean pith. With brown stem rot, a brown to reddish brown discoloration of the stem pith occurs and can be continuous throughout the stem from the base of the plant upwards.  If the pith appears healthy at first, give a second look for discoloration at the nodes.

When this disease does develop it tends to be in fields that have been in continuous soybeans, short rotations, reduced tillage, or no-till. When disease is severe, yield reductions from 10 to 38% have been reported. The fungus, Phialophora gregata, only infects soybeans and is also residue borne.

Crop rotation and soybeans with resistance are two of the main tools used to combat brown stem rot in soybeans.  Dr. Dorrance’s factsheet on the subject is available here:

Anne Dorrance rating brown stem rot in soybeans-Van Wert County September 11, 2009

Anne Dorrance rating brown stem rot in soybeans-Van Wert County September 11, 2009

September 14, 2009 at 8:15 am

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