Oomycete Diseases of Soybean and Current Management
by Jim Kurle, Department of Plant Pathology, University of Minnesota
December 2013

The complex of pathogens that causes seed, seedling, and root rots and damping off of seedlings is the most important cause of poor soybean plant stands and can significantly reduce soybean yields. The most important of these pathogens are the oomycetes, Phytophthora sojae and Pythium species.

Management of diseases caused by the oomycetes will be discussed with an emphasis on integration of resistance, chemical controls, and cultural practices.  View presentation on the Plant Management Network.

 

Study group focuses on new soybean virus
November 2013 by Matthew Wilde, Iowa Soybean Association Senior Writer

A relatively new and potentially destructive soybean disease has researchers on alert and searching for answers.

Soybean vein necrosis virus (SVNV) has been detected in 16 states and the province of Ontario, Canada, according to a recent report funded by the soybean checkoff. Little is known about the virus, but experts say it can reduce yields, especially when plants are stressed.

“Every field I walked into this year had it. Two years ago, it was in maybe 1 percent,” said Daren Mueller, an assistant professor in Iowa State University’s (ISU) Department of Plant Pathology and Microbiology. “Our message is soybean vein necrosis virus can potentially be a much more destructive virus than any other that we have studied.” Read the full article

 

Soil sampling in the fall is a good time to analyze for soybean cyst nematodes
October 2013 by Phil Kaatz, Michigan State University Extension

Each year, the largest single cause of soybean yield loss is the soybean cyst nematode (SCN).  This small, plant parasitic pest feeds on roots, removing plant nutrients and disrupting water and nutrient uptake. Plants  that have high SCN numbers have poorly developed root systems that may result in yellow, stunted plants, or may result in no above-ground symptoms at all.

Producers that have soybeans in their rotation should consider splitting their soil samples taken during the fall to be analyzed for soil nutrients to also test for SCN. The Michigan Soybean Promotion Committee  funds the cost of analyzing for SCN through the Soybean Checkoff.  [Several states in the north-central region offer this program. Check with your state soybean checkoff board].   Read the full article from Michigan University Extension

 

Soybean Aphids Moving To Buckthorn
September 12, 2013  by Janet J. Knodel, Extension Entomologist, North Dakota State University

Winged soybean aphids were observed moving to buckthorn, a small woody shrub. Buckthorn is common in our shelterbelts and woods in North Dakota (and throughout the North Central region). Soybean aphids overwinter as eggs on buckthorn.  Read the full article in the North Dakota Crop and Pest Report.

 

Soybean Diseases Starting to Wake Up
August 26, 2013 by Daren Mueller, Department of Plant Pathology and Microbiology, Iowa State University

After taking muchof the growing season off, soybean diseases are finally starting to wake up and make a bit of noise.  Read the full article in the Integrated Crop Management News

 

Assessing the Risk of White Mold (Sclerotinia Stem Rot) of Soybean in 2013
July 22, 2013 by Carl Bradley, University of Illinois

What does the risk of white mold look like for 2013?  This is not an easy question to answer since we have had fairly favorable weather for white mold initially with some stretches of non-favorable weather in-between.

In fields that were not planted late and have been in full-canopy for the last couple of weeks, it is likely that apothecia have developed and that some infections may have occurred already.  However, the progression of infection and disease development likely came to a stop with the hot and dry conditions observed last week.  Read full article in the Bulletin

It’s Time to Begin Scouting for Soybean Aphid
July 11, 2013 by Eileen Cullen, University of Wisconsin Extension Entomologist

Begin field scouting when plants reach late vegetative to beginning bloom (R1) soybean growth stages, making one or two visits per field each week. Continue scouting until aphid populations decline, usually mid to late August. Economic threshold is reached when a field average is 250 aphids/plant and populations are actively increasing.

To calculate a field average, count the number of aphids on each of 20-30 plants per field, from a sample representative of at least 80% of the field. In this video, Dr. Cullen briefly demonstrates how this is done.

 

Soybean Aphid : Do Higher Crop Values Mean a Lower Threshold?
June 2013, by Kelley Tilmon, Soybean Extension Specialist, South Dakota State University

This slide presentation addresses the question of whether the economic threshold for treatment of soybean aphid should be lowered or not in light of current high crop values.

By the end of the presentation, viewers should know more about the distinction between an economic injury level and an economic threshold, how the original soybean aphid threshold recommendations were determined, how the information from those studies relates to current threshold recommendations, and why most extension entomologists do not recommend adopting significantly lower thresholds as a cost-effective management approach.  View the slideshow on the Plant Management Network website

 

Common Issues with Soybean Germination and Emergence
May 15, 2013 by Shawn Conley, University of Wisconsin-Madison

In this video, common issues growers may have concerning soybean germination and emergence are discussed by Soybean and Wheat Extension Specialist Dr. Shawn Conley.  In an early spring field, Shawn gives tips on seeding depth, soil compaction issues, loss of cotyledon at emergence, frost damage, and general stand assessment.

 

Management recommendations for large soybean seed
April 1, 2013 by Mike Staton, Michigan State University Extension

Due to the 2012 drought, the size of the soybean seed available for planting in 2013 will be highly variable. In some cases, the drought reduced the size of the seed, but more often it created larger seeds.  Understanding the challenges of handling large seeds will improve seed performance in 2013.  Read full article

 

Identification and Management of Charcoal Rot of Soybeans
March 2013

This podcast presented by Doug Jardine, plant pathologist at Kansas State University, discusses charcoal rot of soybeans. Based on the most recent estimates, charcoal rot is the sixth most serious disease of soybeans in the United States, but its rank increases in years of extensive drought such as 2012.

Emphasis in the presentation is on both recognition of symptoms and practical management practices. View podcast on the Plant Management Network

Indiana farmer elected head of North Central Soybean Research Program
February 20, 2013

The North Central Soybean Research Program (NCSRP) is proud to announce Indiana farmer Trevor Glick as the president of the farmer-led organization. Glick, a seventh-generation soybean, corn, winter wheat and cattle farmer from Columbus, Indiana, previously served as vice president and replaces Ed Cagney of Scotts, Michigan.

As the first second-generation NCSRP board member, Glick says he’s excited to lead the organization and fulfill its mission. His father, Myron, was also on the board. “I’m honored to serve soybean farmers. (My father) valued the board and the progress they were making and I feel the same way,” Glick says, “Coordinating research efforts among states and universities sets the organization apart.” Read more

Developing Soybean Cultivars
February 5, 2013 by William J. Kenworthy, University of Maryland

This podcast presented on the Plant Management Network website will help growers and consultants in all regions understand the principles of genetic inheritance and how they are used in breeding programs.  A widely used classical breeding technique to develop new soybean cultivars will be diagrammed.

By the end of this presentation, the practitioner should have a better understanding of how soybean cultivars are developed and why some cultivar traits such as yield can vary across locations.  View podcast

 

Charcoal Rot in Soybean: Managing Disease with Resistance
January 22, 2013

Charcoal rot was a problem in the hot, dry 2012 growing season, especially for growers in Kansas and Missouri, where the root disease is well-known during hot, stressful growing conditions. Now even in the Upper Midwest, charcoal rot has been found affecting soybean with increased frequency in Illinois, Indiana, Iowa, Minnesota, North Dakota, and Wisconsin.

This has intensified efforts by a consortium of plant pathologists and breeders at southern and midwestern Universities and the USDA to identify host resistance to charcoal rot and to develop resistant soybean cultivars. In a series of coordinated checkoff-funded projects, the group has now identified several soybean lines with moderate resistance to charcoal rot, some of which have been incorporated into breeding programs. Seven promising lines, including one MG II line, were identified by screening hundreds of plant introductions from the USDA soybean germplasm collection. Seed of these lines is being increased for inclusion in multi-state field screening tests.

The first multi-state field screening program for charcoal rot is now in place, with sites in Illinois, Kansas, Missouri, Tennessee, and Arkansas. The goal of the screening program is to identify cultivars with resistance to charcoal rot, proven under standardized screening methods, across a range of environments and years. As of 2012, 17 lines from MG III to V have been identified with moderate resistance and four lines with very good resistance.  Read more about charcoal rot

 

New Options for Soybean Aphid Host Plant Resistance
December, 2012 by Michael McCarville, Erin Hodgson and Matt O’Neal, Department of Entomology, Iowa State University

The Department of Entomology at Iowa State University recently updated our Soybean aphid-resistant varieties for Iowa for the 2013 growing season. The publication lists currently available soybean seed with resistance to soybean aphid. The list is intended to assist farmers looking to adopt this new management tactic and possibly reduce their need for a foliar insecticide. The listing includes varieties in late maturity group 0 and maturity groups 1, 2 and 3. >Read newsletter article
>View list

 

Hundreds of SCN-resistant Soybean Varieties Available for 2013
November 17, 2012  by Greg Tylka,  Iowa State University

Each year, Iowa State University, together with the Iowa Soybean Association,  compiles a list of SCN-resistant soybean varieties that are available for the upcoming growing season. This year there are slightly fewer varieties available, almost all with PI 88788 SCN resistance. 
>View list

 

 

The Illinois Soybean Production Guide:  Systematic Strategies to Increasing Yields now available online
October 31, 2012

The Illinois Soybean Association and Illinois State University, together with the United Soybean Board,  has released a new soybean checkoff-funded booklet called Illinois Soybean Production Guide:  Systematic Strategies to Increasing Yields. 

The booklet provides key production recommendations related to seed selection, planting, pest and disease control, harvest and storage, and is available online  >View the Illinois Soybean Production Guide

 

Probability of a Return on Investment  for Soybean Seed Treatments
October 2, 2012 by Shawn P. Conley, State Soybean Extension Specialist, University of Wisconsin, Madison

This webcast provided by the Plant Management Network outlines the dramatic increase in soybean seed treatment use in the U.S., the various factors that go into seed treatment decisions, and provides a useful risk matrix that helps the user assess their probability of breaking-even on seed treatments  >View webcast

 

Seed Treatments for Soybean Nematodes
October 2, 2012 by Loren J. Giesler, Extension Plant Pathologist, University of Nebraska-Lincoln

This webcast reviews three currently-marketed seed treatment products for soybean nematode management, their active ingredients and modes of action. Dr. Giesler also summarizes the first year of a NCSRP-funded project on soybean cyst nematode treatments with 30 field trial locations in 2011  >View webcast

 

Pay close attention to reducing soybean harvest losses this fall
September 10, 2012 by Mike Staton, Michigan State University Extension

Reducing harvest losses is a simple and effective way to increase soybean yields and profitability.  Losses of 7.5 percent are common, but could be much higher this fall. With careful maintenance and operation, harvest losses can be maintained at 3 percent. Reducing harvest losses from 7.5 to 3 percent in a 45-bushel per acre soybean crop would increase the marketable yield by two bushels per acre >read the full article

 

Identifying the Cause of Yellow Patches in Soybeans
September 5, 2012 by Daren Mueller, Department of Plant Pathology, Iowa State University

Over the past week, we have observed yellow patches developing in soybean fields across Iowa. There are several different causes, including spider mites and soybean cyst nematode. However, we will look at three additional problems that are causing these patches: sudden death syndrome, charcoal rot and top dieback  >read the full article

 

Watch Fields for Soybean Sudden Death Syndrome and Soybean Cyst Nematodes
August 21, 2012 by by Bruce MacKellar, Michigan State University Extension

The next two weeks are the “sweet spot” of soybean scouting for sudden death syndrome and soybean cyst nematodes … read full article

 

Late Season Diseases Are Early This Year
August 13, 2012 by Anne Dorrance, Ohio State University

Based on visits to some fields and samples sent in to the lab here in Wooster, there are some late season diseases appearing…including Phytophthora root and stem rot, Diaporthe stem canker, Sudden Death Syndrome, Soybean Cyst Nematode (SCN), Charcoal rot, and Frogeye leaf spot.  At this stage the infections have taken place and fungicides will not prevent any further disease development.  Scouting fields to see where these problems are will greatly help identify what disease resistance package the variety should have in the field the next time … read full article

 

Possible Breakdown of SCN Resistance Topic of New Webcast
July 29, 2012 by Greg Tylka, Department of Plant Pathology and Microbiology

Because of widespread, repeated use of varieties with the same PI 88788 source of resistance, many SCN populations have developed increased reproduction on that type of resistance. It is no longer uncommon to see SCN females on roots of SCN-resistant soybean varieties in the Midwest … read full article

Read more on SCN:  Symptoms of SCN Damage Apparent Early, Yield Loss Likely Great in 2012

 

Do Dry-Weather Crops Still Need Fungicides?
July 20, 2012 by Carl A. Bradley, University of Illinois

Foliar fungal disease pressure will be low in water-stressed fields, so the likelihood that fungicide application will be profitable is low…read full article

Alternatives for Drought-damaged Soybeans – Bean Crop or Forage
July 16, 2012 by Stephen Barnhart and Andy Lenssen, Department of Agronomy, Iowa State University

How to evaluate the soybean crop in individual fields and plan when and how to harvest them to the greatest economic advantage.. .read full article

Soybeans, Insecticide/Miticide Applications, and Bees
July 10, 2012 by Ron Hammond and Andy Michel, Ohio State University

With the potential to have to spray insecticide/miticides on soybeans in the coming weeks during the flowering stages (R1-R2), we would remind growers of the concern with foraging bees.  With drought conditions, the likelihood of bees coming to soybeans to forage is higher than usual…read full article

 

Early Season Water Deficit Stress on Southern WI Soybeans
July 2, 2012 by by Shawn Conley, Extension Agronomist, University of Wisconsin

In soybean there are two growth periods for which soil moisture is critical for optimum growth and development: at planting and during the reproductive stages from bloom through pod fill. In Wisconsin the main reproductive growth in soybean occurs from early July to mid-September.  If a drought does develop and severely affects podset and seed fill, and if livestock feed is needed, soybeans can be harvested as a forage for ensiling...read full article

Soybean Response to Drought
June 22, 2012 by Andy Lenssen, Department of Agronomy, Iowa State University

Winter, spring and early summer precipitation has been below long-term average, and soybeans in some areas…are experiencing periodic water stress due to inadequate available water content in upper soil depths…read full article

Now is the Time to Look for Soybean Cyst Nematode Females on Soybean Roots
June 7, 2012 by Greg Tylka, Department of Plant Pathology and Microbiology, Iowa State University

The first generation of adult soybean cyst nematode (SCN ) females are appearing now.  So the next six to eight weeks (through July) are prime time to dig roots and check for SCN females in Iowa...read full article

 

Soybean Growth and Development
June 7, 2012 by Hans Kandel, Extension Agronomist Broadleaf Crops, North Dakota State University

Soybean seed, after it has absorbed water (about 50% of the seed weight) and under favorable growing conditions will start to germinate. The primary root will first emerge from the seed. As the germination process continues, the stem (hypocotyl) will emerge and pull the cotyledons toward the soil surface…read full article

Bean Leaf Beetle Thresholds: Where Do They Come From?
May 25, 2012 by Mike Gray, University of Illinois Extension

In a recent article, I mentioned that densities of bean leaf beetles typically must reach 39 or more per foot of row in soybeans at V2+ stages for economic damage to occur. In essence, large numbers of beetles are generally required in the spring to warrant a rescue treatment…So where did this threshold guideline come from?…read full article

 

New Weed ID Resource
May 24, 2012
Michigan State University Extension

The Michigan State University IPM Program has An IPM Pocket Guide for Weed Identification in Field Crops  on-line in pdf format. The guide is also available as a print pocket-sized guide designed for field use. Weeds can be located in listings by their common or scientific name as well as by identifying characteristics.

 

Bean Leaf Beetles are Moving to Soybean
May 17, 2012 byErin Hodgson, Department of Entomology, Iowa State University

Bean leaf beetle is easily disturbed and will drop from plants to seek shelter in soil cracks or under debris. Sampling early in the season requires you to be sneaky to estimate actual densities. In some cases, you may just see leaf defoliation and not the beetles...read full article

 

Slugs Causing Concern Earlier Than Normal
May 14, 2012 by  Ron Hammond and Andy Michel, Department of Entomology, Ohio State University

Slugs hatched out earlier than normal and have reached a size that can cause noticeable feeding injury much sooner.  For growers who have experienced slug issues in the past, it is critical that fields be scouted NOW. If plants have emerged and have leaves, look for the telltale signs of slug feeding. The growing point of soybeans is between the cotyledons as the plant emerges from the soil.  Thus, the slug is easily able to reach and feed on both the cotyledons and the growing point, making it much easier for slugs to kill the soybean plant as it emerges from the soil. For crops not yet or just now emerging, or yet to be planted, care should be taken to determine if slugs are present and lying in wait...read full article

 

Conservation System Management Considerations
May 14, 2012 by Mahdi Al-Kaisi, Department of Agronomy, Iowa State University  

Conservation tillage systems such as no-tillage have a positive impact on soil productivity…especially under extreme wet or dry conditions. Current research shows that the tillage system has little effect on N, P and K crop needs. However, the timing and method of application are vitally important to no-tillage success, especially in cold-wet soil conditions where mineralization of soil nutrients is much slower compared to conventional tillage ...read full article

 

Soybean Seedling Diseases – What to Look for in 2012
May 10, 2012 by Anne Dorrance, Department of Plant Pathology, Ohio State University

Soybean seed and seedlings are vulnerable to a number of soil borne pathogens in the early spring. The conditions for these diseases have been quite variable this year in Ohio, with some areas very dry and cool while other locations have been warm and wet…read full article

 

Entomological Musings This Spring
May 10, 2012 by Mike Gray, University of Illinois Extension

Bean leaf beetles. Just as producers transition from corn planting to soybeans, observations of bean leaf beetles are becoming more common, especially in central Illinois. Bean leaf beetles overwinter in protected areas (beneath plant debris), and survival this past winter was undoubtedly quite good. Favorite overwintering sites include wooded areas adjacent to stands of alfalfa. In the spring, dormancy of the adults is broken, and they often move initially into alfalfa. Soybean seedlings in early-planted fields are most at risk to intensive feeding by the overwintering population.

Rescue treatments for bean leaf beetles in seedling soybeans are typically not warranted given the densities required to cause economic losses: 16 beetles per foot of row for the early seedling stage and 39 for the V2 stage and beyond. In light of the mild winter, I encourage producers to scout fields carefully for bean leaf beetles this spring. Pay particular attention to soybean fields that are planted first in your area of the state…read full article

 

On-Farm Iron Deficiency Chlorosis Management Strip Trials
May 3, 2012 by Daniel Kaiser, University of Minnesota Soil Fertility Specialist

Four field trials have been conducted since 2010. At two of the locations there was severe yield reduction from IDC. In severe areas, in-furrow application of an EDDHA-Fe fertilizer significantly increased yield by an average of 5 to 6 bushels across the entire trial, and by as much as 10 bu/ac or more in the severe areas. The oats cover has also shown some positive yield benefits in severe IDC field areas. When comparing varieties, there was a large yield benefit with the variety that was less tolerant to IDC, but the tolerant variety still overall produced a higher yield level when IDC was present ...read full article

Despite valiant efforts by farmers and the seed industry to control SCN, it is still considered to be the #1 yield robber in soybean production. It invades roots, feeds, then reproduces 250-fold. It can reduce yield as much as 70 percent under severe infestations and drought conditions; under more moderate conditions it can cause 30 percent yield loss without visual symptoms.

An army of researchers funded with soybean checkoff dollars has been working to find that elusive solution to the $1.5 billion annual economic loss. The solution, improved genetic resistance, is a ways off but it is coming.

Plant breeders at Midwest universities, in partnership with the USDA have been searching the nation’s germplasm collection for novel genes to complement those in today’s varieties. Several breeding lines containing these new genes have been recently developed and are under rigorous testing. Commercial SCN-resistant soybean varieties containing these new genes could be available as early as 2017.

Until then, farmers will need to rely on improved management strategies including old school cultural practices and emerging technologies to limit yield loss to SCN.

Nematicide seed treatments are emerging as the next wave of options available to soybean farmers to manage SCN. That’s why the North Central Soybean Research Program is evaluating nematicide seed treatments across a 12 state region.

Using commercially treated seed, plant pathologists evaluated the effectiveness of this technology by determining the SCN population at planting and again in the same location, after harvest. The numbers tell the story—an uncertain story. There was no clear benefit to the seed treatments in the 2011 field trials. Keep in mind however; it is extremely difficult to get a clear picture of performance based on one year of field data so the study will be repeated in 2012 and 2013.

In other studies, researchers are looking at levels of SCN reproduction on roots of soybean varieties labeled as resistant. The results are surprising: Not all SCN-resistant soybean varieties manage SCN equally; some varieties still have a large number of SCN on the roots at harvest. Repeated use of these varieties allows the SCN population to continue to grow—and feed on soybean roots.  However, field studies also show that some of these same varieties remain high-yielding under pressure from SCN. More work is needed in this area to better understand this relationship. Meanwhile, check with your state Extension specialist for information on SCN reproduction on commercial soybean varieties to determine if your soybean variety is actually lowering SCN numbers.

Old school cultural practices like rotating soybean with corn or other non-host crops is still a great way to lower SCN populations. Many farmers have shifted to a soybean-corn-corn rotation strategy to benefit from higher margins realized from corn production. Older research clearly shows a decrease in SCN numbers when soybean is planted following one year of corn. It is unclear whether a long-term soybean-corn-corn management strategy significantly reduces SCN numbers—and increases soybean yield.

Until a genetic solution is discovered that eliminates SCN feeding and reproduction several management tactics will need to be employed to reduce yield loss from this pest. Seed treatments, planting SCN resistant varieties, crop rotation, and monitoring SCN numbers within fields are all critical.

That’s your soybean checkoff. Delivering results.

1.  Improve the quality of the root zone. This will improve water-holding capacity of the soil and plant resiliency. Healthy roots enable the vegetative portion of the plant to take full advantage of photosynthetic capacity.

• Manage SCN populations. This goes beyond purchasing seed labeled as SCN-resistant. Regularly test for SCN, rotate varieties grown in fields and sources of resistance to keep SCN numbers low.
• Use fungicide and insecticide seed treatments.  Research has shown that soybean seed planted with both yield more.
• Drain soils—tile is inexpensive.
• Reduce soil compaction
• Improve soil fertility levels. Be sure you have enough P, K, and micronutrients but be sensitive to environment.

2.  Variety selection.  If you are planting a variety that is two years old or more you may be giving up $13 or more per acre.

3.  Plant early to take advantage of as much of the growing season as you can. Delayed planting can cause 0.3 to 0.7 bushels/acre/day yield loss after May 10.

4.  Row spacing.  The greatest yield advantage is from 15- or 10-inch row spacing.  Yield gains of 4.5 bushels/acre have been proven for narrow rows compared to 30 inch rows in Midwest trials.

5.  Plant population.  Agronomists from several Midwest universities have shown that a final stand of 100,000 to 125,000 plants per acre will provide the best return on investment.

6.  Crop rotation helps reduce the severity of certain diseases and increases yield of soybean and corn crops.

7.  Manage weeds early.  Weeds compete with soybean for water and nutrients and sunlight.

• Use a combination of a pre-emergent herbicide for early weed control then go for one application of a post- emergent herbicide to clean up the rest.
• Use multiple modes of action to reduce the possibility of a herbicide-resistant weed population developing.

8.  Hire a crop advisor if you are not monitoring your fields yourself.  A good crop advisor will monitor your for yield robbing diseases, insects and fertility problems.  Crop advisors are always up-to-date on emerging problems and management recommendations.  Identifying problems early can save you big money.

9.   Strive for a clean harvest for both soybeans and corn.  Certain fungal pathogens like the one that causes Sudden death syndrome (SDS) survive on corn residue and dropped corn kernels.  A clean corn harvest may reduce the severity of SDS the following year.

10.  GET INFORMED!  Take advantage of production meetings sponsored by Extension educators.  These meetings are packed with the latest research findings and best management practices for producing corn and soybeans.

It’s a serious threat

Midwest farmers are faced with another harmful pest from Asia, the brown marmorated stink bug (BMSB). Its name describes its color pattern (marmorated, meaning marble-like or speckled) on its shield-like back, and what it smells like if it’s threatened or squished. However, its name does not tell the story of how this new pest is devastating parts of North America.

Over the past decade, the BMSB has moved into homes, fields and orchards in 33 states. It has a wide host range similar to Japanese beetle, including corn, soybean, fruits and vegetables. The BMSB is serious threat to agriculture and is wide-spread in the Eastern United States with additional known populations in California and Oregon. However, because of the BMSB’s recent detection in the Midwest, a thorough survey for this pest has not been conducted.

One thing is for certain, though: BMSB can take a toll on soybeans, although so far yield loss has been limited to the east coast. The insect, which is distinguished by white banding on the antennae and legs, a striped abdomen and a pale underside, tends to feed on soybean seeds through the pod, damaging the yield potential. During seed formation, BMSB can puncture tissue and cause deformations. The seed coat can be damaged, and overall the seeds are smaller and shriveled.

And while BMSB feeding appears to slow or delay development of soybeans, the insect’s appetite goes far afield. Corn is on its menu too. So are fruits and vegetables. In fact, there’s little it doesn’t attack with vigor, piercing and sucking leaves, stems, fruits, and seeds.

Scouting will reveal the presence of many species of stink bugs. While most stink bugs are herbivores, one sticks out as beneficial – that is, the BMSB’s cousin, the spined soldier bug, commonly found in Midwest soybean fields. Both the immature and adult stink bugs of this species are predatory, and will kill many soybean pests.

The entire agricultural sector is on a steep learning curve, working towards an integrated pest management program to control the BMSB. That’s a real challenge, because it’s different on so many levels.

1. Like another invasive pest, the multi-colored Asian lady beetle, the BMSB isn’t limited to the field. It survives the winter as an adult by entering houses and structures, and becoming a noxious pest.
2. Both the immature stage (nymphs) and adults feed on host plants.
3. Generations overlap and can feed throughout most of the summer.
4. Treatment thresholds have not been developed.

It’s unlikely that BMSB will show up in great numbers in soybean fields across the Midwest this summer. It usually takes two to three years to become problematic once it is introduced. They usually become problematic first in fruit trees and vegetables.  It is possible, that in the Midwest, they may target corn and soybean early in the summer because of the low abundance of other hosts. Scouting will prove or disprove that prediction.

If you find stink bugs in your soybean or corn fields, and you are not certain which species you have, contact your state’s Extension entomologist.  They will assist you in accurately identifying the insect and providing options for management.

Soybean yield is often limited by soilborne pathogens. The average United States soybean yield is 43.9 bushels per acre or only about 27 percent of known yield potential (160 bushels per acre). The difference between harvested yield and potential yield is lost to a plethora of environmental stresses such as heat and drought as well as a complex of poorly understood soilborne pathogens.  These pathogens invade plant roots causing tissue decay, a reduction in the number of root tips, a decrease in nodule size and loss of root function.

Major yield losses are found in areas where soils have high clay content or remain saturated for long periods of time. The key to improving soybean yield is to improve root health.

One aspect of improving root health is increasing the number of roots. Water and nutrients are absorbed into the root just behind the root tip, so increasing the number of roots means more water and nutrients can be absorbed.  Healthy roots trigger faster plant growth and seed development when environmental conditions are not growth limiting.

In addition to anchoring the plant, the soybean root is responsible for absorbing large amounts of water and nutrients and then transporting them to the stem and leaves. When roots are damaged the plant’s ability to obtain water and nutrients is greatly reduced. Preventing  damage to the root removes the stress and helps avoid unnecessary yield loss.

The most important pathogens associated with seedling root health include the soybean cyst nematode, Pythium species, Phytophthora sojae, Rhizoctonia solani, and Fusarium species. Iowa State University researchers found that each of these pathogens has been found to impair root health alone and in combination with each other.

Pythium species cause seed decay, pre-emergence damping off and early post-emergence seedling death. Seed infected with Pythium species may decay before germination and as they do, become soft and rotted. Phytophthora sojae also causes a soft, wet rot of seed or seedling tissue similar to that of Pythium species. Infected seedlings may die prior to emerging from the soil or shortly thereafter.

Symptoms of Rhizoctonia solani infection generally show up on seedlings as dry, dark reddish-brown lesions just above the soil line. Seedling loss from Rhizoctonia seedling blight is less common that from Pythium seed decay and Phytophthora root rot but when present, stand loss can be severe.

The traditional soybean-corn production system creates a monoculture that creates an environment that promotes the build-up of root-infecting pathogens.

Researchers at Iowa State University report that within the soybean- corn rotation, there may have an inadvertent increase of populations of root-infecting pathogens, thereby increasing root damage. For example, there are reports from Ohio State University that isolates of Pythium species and Rhizoctonia solani are becoming resistant to commonly used fungicide seed treatments. They suggest that if these isolates are pathogenic to both soybean and corn, it is likely the pathogen inoculum is also increasing in the field. Thus, an increased knowledge of the role of Pythium species and Rhizoctonia solani in the soybean-corn rotation is necessary for improving yield.

Improving root health

The first 10 to 14 days following soybean planting is the window of opportunity for Pythium and other soilborne fungi to infect the plant. Implement practices that promote quick germination and seedling emergence to prevent infection.

• Plant high quality seed and plant into a good seed bed
• Plant seed that has resistance to Phytophthora sojae. Specific resistance is controlled by major resistance genes such as Rps1k. In addition, select varieties with high partial resistance (tolerance) when possible.
• Plant where drainage is adequate, or improve drainage if possible. Avoid low areas of fields, especially if a field has a history of seedling or root rot problems.
• Consider that germination will be quickest when soil temperatures are greater than 65°F

What to do if seedling diseases are present

• If dead plants are scattered throughout the field, and no significant stand reduction is apparent, then no action is needed if the disease is Pythium or Rhizoctonia damping off.
• If seedling loss is severe, consult a certified crop advisor to determine if replanting is necessary. Replanting is not always necessary.
• Take good disease notes and use preventive measures such as seed treatment or resistant varieties to reduce the likelihood of a disease problem in the next soybean crop.

If replanting is necessary

If poor stands are due to diseases, fungicide seed treatments can be used in replanting to avoid further damping off, especially for Rhizoctonia and Phytophthora. If poor stands are due to a low germination rate, a seed treatment cannot improve seed germination rate or seed vigor.

No-till farming is a growing practice in many areas of the United States. An estimated 50 percent of the acres planted to soybeans in 2009 were done so without tillage according to a recent USDA Economic Research Service report. Farmers are adapting no-till soybean production at a faster rate than they are for corn, cotton and rice.

There are many motives for adapting no-till. Some see it as a “greener” way to produce a global food supply while conserving soil and water resources so generations to come will be able to enjoy the benefits we do. Others see it as building resiliency into a production system faced with challenges of floods, drought, diseases and pests influenced in part by changes in climate. No matter what the reason, no-till practitioners are emphatic in their belief that it contributes to the sustainability of soybean production.

Long time practitioners of no-till admit there is no one way of doing it. Soils respond differently to no-till, so no single piece of equipment or common practice guarantees success. Successful no-tillers admit, however, they’ve learned from their mistakes and from listening to others.

Jim Specht, University of Nebraska, professor of agronomy offers these words of advice for getting the most out of no-till soybean production systems.

Plant early - Iowa State University reports delayed planting of high yielding fields results in a yield loss of 0.3 to 0.7 bushels per acre per day with the largest yield reductions occurring after May 10.  In Nebraska, the yield penalty for delayed planting is between 0.3 and 0.6 bushels per acre per day of planting delay after May 1.

Choose soybean varieties wisely - Variety selection for field-specific problems such as diseases and SCN is important for success in no-till.  Loren Giesler, University of Nebraska Extension plant pathologist agrees and says, “Farmers who know they have SCN can gain, on average, five to six bushels per acre simply by planting a SCN-resistant soybean variety, according to yield trials.”

Use a fungicide seed treatment - There is no doubt that seed-applied fungicides improve stand establishment in cool soils common in no-till fields. This is especially important to famers who are planting fewer seeds per acre to reduce input costs without sacrificing yield. To them, every plant counts. To others, it’s insurance. University studies show that soybeans are very resilient and will compensate for a few missing plants.

The benefit of using an insecticide seed treatment is unclear. Some university research shows that an insecticide seed treatment alone doesn’t always improve yield. The research also shows yield increases are inconsistent when an insecticide/fungicide seed treatment is used. Although the industry doesn’t have a complete understanding of how to use this technology, the observed benefits can’t be ignored.

Consider strip tilling soybeans in heavy residue situations. For those soybean producers whose prior crop corn yields were high, there will be a lot of corn residue left behind.  Specht says, “For every pound of grain removed there is a pound of residue left behind so, a 250 bushel per acre corn crop leaves behind 14,336 pounds of residue per acre.” He suggests producers will get better planter soil closure over the soybean seed if a strip of corn residue has been cleared.  The soil in that strip also warms up faster, which benefits early planted soybeans.

Every year more farmers are seeing the wisdom and rewards — both economic and personal — in no-till soybean production systems. Because each farm is different, there’s no single formula for sustainable success in no-till, but these principles are a good place to begin.

This year, many Midwest farmers discovered first-hand the effect of root infection by the fungal pathogen that causes sudden death syndrome (SDS): yield losses of 40 percent were recorded in some fields. But it’s not just SDS that is limiting yield in soybean fields. Wounds caused by soybean cyst nematodes (SCN) and by maturing females serve as entry points for other soilborne pathogens. Brown stem rot (BSR) also infects roots of young seedlings and is often found in the presence of SCN.

Each disease can cause significant yield loss, up to 50 percent under optimal conditions. Even worse is the interaction between SCN and the fungal pathogens that cause SDS and BSR which can cause even more yield loss.

First discovered in 1971 in Arkansas, SDS has quickly spread throughout the Soybean Belt and is now found in areas of South Dakota and in 23 counties in Minnesota. It is likely spreading north with the movement of SCN; the SDS fungus is commonly found in the cysts. Because of this close association with between SDS and SCN, assume that if you have one or the other, you probably have both.

BSR has been found in nearly all Midwest soybean producing states. The increase in the incidence of BSR is thought to be a result of a monoculture created by the traditional soybean corn rotation which encourages a build-up of the BSR pathogen in the soil. Like SDS, the fungus that results in BSR infects the root early in the growing season and is favored by cool, wet soils.

Minimizing yield loss from SDS and BSR begins with managing SCN in fields where combinations of these stressors co-exist. SCN cannot be eliminated once it becomes established in a field, but its influence on other soilborne pathogens can be reduced with proper management.

A new publication is now available to help soybean producers manage SCN. The SCN Management Guide, fifth edition provides soybean producers with science-based information generated from many years of checkoff funded research that is proven to reduce SCN populations.

With currently available management options, it is much easier to keep low numbers low than it is to try and drive high SCN numbers down. By managing SCN you can:

• Improve soybean root and plant health and yield;
• Keep SCN numbers low; and
• Preserve the yield potential of resistant varieties

Because no single management practice will meet all three goals, you must use an integrated approach that combines several components. Chief among these are the use of varieties resistant to SCN and with good field tolerance to SDS and BSR, rotation with non-host crops when possible, maintaining a well-drained seedbed, use of fungicide and insecticide seed treatments to promote early seedling health.

Click on the Free Publications link above to receive your free print copy of the SCN Management Guide, or view online – see sidebar to the right.

Farmers will need to employ multiple tactics to improve soybean yield. The most important will be employing management tactics that improve soybean root health.

A healthy soybean root is an important component to soybean yield. A soybean plant with a healthy root system is more efficient in taking up water and nutrients, and can better withstand the effects of infection by soilborne pathogens and soybean cyst nematode.

This year, many Midwest farmers discovered first-hand the effect of root infection by the fungal pathogen that causes sudden death syndrome: yield losses of 40 percent were recorded in some fields.But it’s not just sudden death syndrome that is limiting yield potential in soybean fields. Soybean cyst nematode remains the most serious nematode pest of soybean in the United States.

For many years early soybean planting has contributed to soybean seedling damping off, which reduces stand establishment. Pythium, Rhizoctonia root and stem rot, Phytophthora root rot, and Charcoal rot are root and stem diseases caused by soilborne pathogens and all are known to cause significant yield loss. It is interesting to note that research conducted at Iowa State University discovered that some isolates of Pythium recovered from diseased soybean seedlings were also highly aggressive against corn. This suggests that management tactics to reduce the impact of Pythium species must be utilized in both the soybean and corn crops.

Reducing yield loss from these soybean diseases begins with improving root health. Improving root health begins with refining management tactics. Soilborne pathogens are best managed with a combination of improved soil drainage, fungicide seed treatments, planting high quality seed, crop rotation and tillage practices that minimize soil compaction zones. These management tactics reduce inoculum in the field and limit the amount of water available for the pathogens to germinate and infect.

The importance of a well drained soil became apparent this year as farmers noticed signs of SDS first in low lying field areas and along edges of water ways. Improving drainage in these areas will reduce the severity of SDS and also diseases caused by Pythium and Phytophthora. If drainage in these areas cannot be improved, farmers should consider planting them last.

The importance of managing SCN cannot be overstated. SCN feeding on roots creates openings for opportunistic infection by soilborne pathogens. Researchers recently found greater levels of Pythium species and Phytophthora sojae in roots of SCN susceptible soybean plants. Previous research showed that SDS was more severe in areas also known to be populated by SCN.

Fungicide seed treatments for soybean are an emerging tool that farmers can use to protect yield. Some data suggest that the combination of a fungicide and insecticide seed treatment produces greater yield than using either of the two alone. This suggests that the management tactics to control early season diseases and insects should begin at planting and not after emergence. In other words, Manage Soybeans from the Ground Up to increase soybean yield.

That’s your soybean checkoff. Delivering Results.

Sudden death syndrome (SDS) is ravaging many Midwest soybean fields.

Farmers watched anxiously as low-lying areas of some fields suspiciously turned brown then watched those small areas grow into much larger areas of dying plants. SDS is showing up on a scale not seen since it hit Illinois soybean fields in the early 1990s. This year’s yield losses to SDS are expected to exceed 20 percent in some fields.

The cause of the disease is a soil fungus that is widespread throughout the Midwest. It infects the soybean root early in the plant’s development; later, the pathogen rapidly kills the plant during pod set and pod filling. Infection of the soybean root is worsened by cool, rainy weather throughout the first half of the growing season as well as soil compaction and poor drainage.

Development of SDS depends upon many factors including planting date, tillage, variety of soybean, and the presence of other stresses such as SCN. Early planted soybeans tend to be more heavily damaged than later planted beans because of the more favorable conditions for infection by the soilborne fungus.

The impact of tillage on SDS remains unclear. Reduced tillage, including no-till, may influence the presence of the disease because corn residue causes slower warming and drying of the soil. Corn residue, including dropped corn kernels, harbors the fungus that causes the disease, possibly increasing the amount of the fungus in the soil. However, mature no-till fields tend to drain more quickly than conventionally tilled fields reducing the saturated seed zones that promote infection of the root by the fungus.

Crop rotation is of limited value. University of Illinois researchers report finding SDS in continuously grown soybeans, soybeans following one or two years of corn, and in fields that had been out of soybean production for many years. They reported that the fungus that causes SDS can persist in the soil for many years even without a host crop.

SDS can be more severe in field areas also infested with SCN. Feeding by the nematode on soybean roots adds additional stress that often increases the impact and severity of SDS. Researchers have discovered that cysts can contain the fungal pathogen that causes SDS. However, the two problems are known to exist independently.

Farmers planting maturity group II and I soybeans may be at greater risk of seeing SDS in their fields because soybeans in those maturity groups generally have lower levels of field tolerance to the disease. Although public and private plant breeders are working hard to improve the plant’s performance against the fungus, it will be another 5 to 10 years before greater levels of protection are in place in those maturity groups.

Checkoff-funded researchers throughout the Midwest are working feverishly to solve the SDS problem. Emphasis is being placed on the development of breeding lines with improved tolerance to SDS and screening and categorizing the response of commercial soybean varieties.

Soybean aphid is the most significant above-ground pest that farmers face today.

Aphids reduce soybean yield and farmer profitability. They may even transmit viral diseases that can reduce seed quality at harvest. They’re born pregnant so populations can explode almost as quickly as you can turn your head.

Farmers could be facing another year of heavy aphid populations. According to Matt O’Neal, Iowa State University soybean entomologist, he and his Midwest colleagues logged record numbers of aphids headed to overwintering sites in 2009. “The numbers of aphids found on buckthorn last fall were so high that leaves were falling off the plant,” says O’Neal. However, a follow-up visit to those same areas found very few eggs. “This is a bit of a mystery to us,” admits O’Neal. He also admits they’ve seen this before and if history repeats itself, farmers will be spraying for aphids in late July or early August.

“One well-timed foliar application applied after the aphid population exceeds the economic threshold will protect yield and increase profits in most situations,” says O’Neal.

Timing is very important, however.

“Adding insecticide to an early-season glyphosate application as ‘insurance’ doesn’t make sense, says David Ragsdale, University of Minnesota entomologist. Weeds need to be controlled early because they compete for water, nutrients and sunlight. However, aphid populations don’t reach the economic threshold until much later.

The timing of a fungicide application may overlap with the management of soybean aphid. However, many fungicides are toxic to naturally occurring fungi that attack aphids and their use could lead to a subsequent increase in aphid numbers. Farmers who apply fungicide either alone or in a tank mix should monitor those fields for aphid population growth.

Some marketing programs encourage the prophylactic use of fungicides and insecticides as a tactic for managing soybean. Although yield gains using this tactic have been recorded, the results have been inconsistent and thus the benefit this management tactic remains unclear. Ragsdale believes there is a better way.

“Aphid management requires multiple tactics,” states Ragsdale. He advises farmers against becoming too reliant on the “quick fixes” when making management decisions. “Using multiple tactics including cultural, chemical, and biological control is the most effective aphid management plan for long-term, profitable soybean production,” he concludes.

Both Ragsdale and O’Neal recommend regular scouting and a 250-aphid-per-plant threshold for spraying to conserve the natural enemies that prey on aphids. Scout once or twice a week beginning in late June or early July, no later than the R1 (beginning bloom) soybean growth stage, and continue through pod fill. Pay particular attention to late-planted fields, or fields under moisture stress.