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12/1/2008 - 12/7/2008

Collaborative Training Results in Safer, Wiser Pesticide Use

By Paul Brown, Assistant Director Agriculture and Natural Resources
With crop out of the fields and snow in the air, farmers and Iowa State University Extension are turning their focus to winter trainings. ISU Extension provides the educational component required to become state certified manure and pesticide applicators.

“The pesticide applicator trainings that start showing up on ISU Extension calendars in December are the result of collaboration between Extension and Iowa Department of Agriculture and Land Stewardship,” said Gerald Miller, director of ISU Extension to Agriculture and Natural Resources. “The trainings are planned centrally and delivered by ISU Extension specialists at locations convenient to the applicators.”

Certified private pesticide applicators – people who apply a restricted-use pesticide in the production of an agricultural commodity on land they manage – must meet educational requirements to maintain their certification. Extension field agronomists provide training in all of Iowa’s counties. In 2007, Extension held 290 private pesticide continuing instructional courses, training more than 17,000 applicators.

Commercial pesticide applicators – people who enter into contracts or agreements to receive payment for applying a pesticide or who are employed by such an entity – meet their certification educational requirements by attending video conferences and Web casts that feature campus-based ISU Extension specialists. Last year, ISU Extension trained nearly 8,000 commercial applicators.

To learn about private pesticide training opportunities, contact an ISU Extension county office or visit the ISU Extension calendar and select the appropriate pesticide applicator training category. The Pest Managment and the Environment Web site lists the commercial applicator trainings. Information about pesticide testing is available at the IDALS site .

“Farmers take very seriously their responsibility to protect Iowa’s soil and water and Extension’s effort to make sure applicators have the most up-to-date information is vital,” Iowa Secretary of Agriculture Bill Northey said.  “The training materials clearly outline the current regulations that are in place to promote safety, environmental protection and efficient and appropriate use of pesticides.”

As a direct result of educational material presented during trainings, Iowa applicators know and are practicing proper recycling of used pesticide containers. In the state that ranks fourth in the number of pounds of empty containers, proper handling of material that would otherwise be considered hazardous waste has tremendous rewards.

“We are also seeing a better use of pesticides; atrazine is a great example,” said Miller. “We are seeing changes in use patterns of atrazine as a result of targeted training. At one time, there were high instances of residual atrazine in ground and surface waters because of heavy usage. In trainings, we talked about geographic considerations, where to and where not to apply atrazine, and the effectiveness of lower application rates. We now have about the same amount being applied in Iowa, but at lower rates and in more appropriate geographic areas – and the result is less evidence of residual atrazine in the environment.”


Paul Brown is the Extension to Agricultural and Natural Resources, assistant Director.

Soil Sample Results Can Reveal if SCN Management is Working

By Greg Tylka, Department of Plant Pathology
Fall soil sampling has been promoted for many years as an effective way to detect the soybean cyst nematode (SCN) in fields.  But many Midwestern soybean producers already know which fields are infested with SCN and have been growing SCN-resistant soybean varieties for numerous years to manage SCN population densities.  The key to profitable long-term soybean production in SCN-infested fields is to prevent SCN population densities (numbers) from increasing.

Recently, data from Iowa and surrounding states have shown that reproduction of SCN populations is increasing on the PI 88788 source of SCN resistance, the source of resistance used in most every SCN-resistant soybean variety.  Increased SCN reproduction on resistant soybean varieties will lead to increases in SCN population densities.

How would you know if the SCN population densities are building up in your fields?  Compare the results of soil samples collected and analyzed for SCN population densities in the fall after every third or fourth soybean crop to know whether SCN numbers are increasing. 

Comparing results of soil samples collected 6 to 8 years apart requires good record keeping and also consistent soil sample collection methods.  Accurate and detailed notes of when and how samples were collected are needed so the same methods can be used in future years.  Details should include the specific areas of fields that are sampled, the numbers of cores that are collected and their depth, the specific sampling date, whether samples are collected before or after a soybean or other crop, and which laboratory processes the samples.

Other general soil sampling guidelines for this purpose
• Collect soil samples in the fall after the previous crop has been harvested or in the spring, before the new crop is planted.
• The more soil cores collected and the smaller the area sampled, the more accurate the results will be.
• Soil cores should be from the upper eight inches of soil.
• If corn or some other nonhost crop was last grown in the field, it doesn’t matter if soil cores are collected in the previous crop’s row.
• It is better to collect soil cores after the previous corn or other nonhost crop’s rows have been destroyed by tillage.
• If soybeans were last grown in the field, collect soil cores from under the old crop rows.
• If sampling conventionally (not grid sampling), collect 15 to 20 soil cores in a zigzag pattern from no more than 20 acres.  The 20-acre parcels of the field do not need to be square or rectangular; samples can be collected from zones according to the agronomic features of the field.
• If grid sampling: collect one or two soil cores from every grid cell sample and combine these extra cores from the number of cells that represent approximately 20 acres.

zig zag soil sampling pattern

Collect 20 or more soil cores from areas in the field no larger than 20 acres.

soil sampling by area

The 20-acre sampling areas can be according to the agronomic features of the field.


It is important to note what SCN life stage is reported in the soil sample results. The Iowa State University Plant and Insect Diagnostic Clinic and most other soil test laboratories in Iowa count and report the number of SCN eggs.  But some laboratories report results as numbers of SCN cysts or juveniles in the soil.  Also, laboratories may report results as numbers per 100, 250 or 500 cubic centimeter of soil.  When comparing the results of soil sampling for SCN over years, be sure the same volumes of soil and the same SCN life stages are being compared.

Numerous private soil testing laboratories in Iowa offer SCN analysis of soil samples.  Additionally, the Iowa State University Plant and Insect Diagnostic Clinic tests soil samples for SCN.  Mail samples to:
         Plant and Insect Diagnostic Clinic
         327 Bessey Hall, Department of Plant Pathology
         Iowa State University
         Ames, IA 50011-1020
The current fee for SCN analysis at the ISU Plant and Insect Diagnostic Clinic is $15 per sample for samples from Iowa. Samples sent to the Plant and Insect Diagnostic Clinic should be accompanied by a completed Plant Nematode Sample Submission Form.


Greg Tylka is a professor of plant pathology with extension and research responsibilities in management of plant-parasitic nematodes.

Fall is Ideal Time to Check for Presence of SCN

by Greg Tylka, Department of Plant Pathology
The soybean cyst nematode (SCN) continues to be a serious yield-reducing pest of soybean in Iowa and throughout the Midwest.  But damage from SCN is almost always less noticeable in growing seasons with adequate to excess moisture, which much of Iowa experienced in 2008.  There can be 30 percent yield loss or more without the soybean crop looking noticeably damaged during the growing season.  Very serious soybean yield losses due to SCN are expected the next time Iowa experiences a very dry growing season.

Scouting fields to check for SCN is essential because it allows infestations to be discovered when SCN population densities are still low.  Fall is an ideal time to collect soil samples from fields to check for SCN.  It often makes most sense in the fall to sample fields in which soybeans will be grown the following growing season.  However, sampling fields in which soybeans were grown this year also makes sense, especially if the soybean yields were lower than expected with no apparent cause.

To effectively check fields for the presence of SCN, soil must be collected from many different places within the area being sampled.  Entire fields can be sampled or samples can be collected from “high risk” areas that often are the first places that SCN infestations are discovered.

If sampling entire fields, limit the area represented by a single composite soil sample, ideally, to no more than 20 acres.  That is, collect at least 20 soil cores from each 20-acre section of the field and combine those soil cores to represent the 20 acres.  With this approach, more than one composite 20-core soil sample will need to be collected from fields larger than 20 acres.  

If sampling “high risk” areas, collect 5 to 10 soil cores from each “high risk” area and combine those soil cores into one sample.  With this approach, the more cores collected from the smaller the area, the less the chance of missing SCN in the sample if it is present in the field.

“High risk” areas include the area near the field entryway (where soil from other fields may be introduced), along fence lines (where wind-blown soil from other fields may accumulate), in low spots and areas that have flooded (and had soil introduced from other fields), and in areas of the field where soil pH is 7.0 or greater.  Low-yielding areas of the field and areas where weed infestations are difficult to control are other places where SCN are highly likely to be found.

SCN hot spots

Areas of a field where SCN is more likely to be first discovered.


Other general guidelines for fall soil sampling for SCN include:
• Soil cores should be from the top 8 inches of soil.
• Mix multiple soil cores very well before placing mixed soil into a bag.
• Keep soil samples at room temperature or cooler until shipped.
• Send samples to a private soil testing laboratory for analysis or send to:
         Iowa State University
         Plant and Insect Diagnostic Clinic
         327 Bessey Hall
         Ames, IA 50011

The current fee for SCN analysis at the ISU Plant and Insect Diagnostic Clinic is $15 per sample for samples from Iowa. Samples sent to the Plant and Insect Diagnostic Clinic should be accompanied by a completed Plant Nematode Sample Submission Form.

View a video in the CSDLive section of the Corn and Soybean Digest Web site to see how to collect fall soil samples to detect SCN.  Also, available in the CSDLive section of the Corn and Soybean Digest Web site is a video showing how to check fields for the presence of SCN during the growing season.


Greg Tylka is a professor of plant pathology with extension and research responsibilities in management of plant-parasitic nematodes.

Crop Market Outlook

By Chad Hart, Department of Economics

The delays in planting led to delays in crop development and conclude with delays in harvesting.  As of Nov. 23, 86 percent of Iowa’s corn was harvested, roughly 12 percent behind normal.  The harvesting backlog, in combination with higher fertilizer prices, has fall fertilizer application behind as well.  Normally, over half of fall fertilizer applications are done by this point in the year. Currently, we are at 32 percent.  The delays of the 2008 crop are slowing the prep work for the 2009 crop.

Prices in the crop markets have dropped dramatically over the past five months, in combination with declines in energy prices and stock indexes.  Concerns about the U.S. and world economies are being reflected in reduced demand for many products, including agricultural products.  As corn and soybean prices rose earlier this year, we could point to strong export demand, growing biofuel demand, and significant feed demand.  Now, all three of those demand sectors have shown signs of weakness. 

Export demand has backed off with the strengthening of U.S. dollar versus many of the world’s currencies and the resurgence of alternative feed grains, especially feed wheat.  Feed demand for corn in the U.S. is projected to decline by 700 million bushels as the livestock industry continues through its consolidation.  And the biofuel industries have seen lower fuel demand and prices over the past several months and continue to face tight operating margins.

The decline in prices comes at a time when farmers are also facing the prospects of higher input costs.  Fertilizer and fuel costs have led the way, but the costs for seed, equipment, and land have also been on the rise.  Preliminary estimates for 2009 production costs show breakeven prices above $4 per bushel for corn and near $10 per bushel for soybeans.  Figures 1 and 2 display Iowa average corn and soybean prices and estimated production costs from Iowa State University Extension. 

Iowa corn prices and production costs


iowa soybean prices and production costs

The rise in crop prices and the subsequent rise in production costs we are experiencing now is somewhat like what happened in the early 1970s.  Prices rose and stayed higher than the historical average.  Costs rose to offset within a couple of years.  With prices at or below projected costs, producers need to watch their bottom lines, know their own breakeven prices, and take advantages of marketing opportunities that cover their costs when they are available.

Factors indicate price strengthening for 2009 crops
While demand and prices are down, there are reasons to think prices will strengthen for the 2009 crops.  One of the key factors is the continued growth of the biofuel industry.  In 2009, the Renewable Fuels Standard calls for 11.1 billion gallons of renewable fuels.  Biodiesel is to make up at least 500 million gallons of that target and corn-based ethanol could be used for 10.5 billion gallons of the standard.  Figure 3 show the Renewable Fuels Standard for the next 3 years and translates the conventional biofuels portion into potential corn demand via ethanol. 

Over the next few crop years, ethanol will continue to require more corn.  And the standard may be providing some support for crop prices even today.  Over the past couple of years, corn and soybean prices have tracked with crude oil prices.  But within the past couple of months, that linkage has weakened as crude oil price has dropped more quickly than crop prices.  During the last half of October, crude oil prices continued to slide as corn and soybean prices somewhat stabilized.  One possible reason for the change in the relationship between oil and crop prices is the standard and the need to maintain biofuel and crop prices at a level where the standard will be met.

renewables fuel standards

Many of the factors influencing crop prices today will continue to affect crop prices throughout the 2008 and 2009 marketing years.  The condition of the general economy will be a major driving factor.  Corn and soybean stocks remain tight in the U.S., leaving us with little cushion in case of production shortfalls.  The biofuel industry continues to build out and the livestock industry could continue its consolidation.  Agriculture has expanded to meet food, feed, and fuel demand.  In doing that, agriculture has also taken on the volatility that comes with the energy sector.  And we are seeing that volatility in our crop prices, input costs, and land values.



Chad Hart is a grain markets specialist and an assistant professor of economics with research and outreach responsibilities in grain and bioenergy crop marketing.

Soybean Rust - 2008 in Review

Daren Meuller, Department of Plant Pathology

While 2008 will be known for its early season rains, this did not translate into soybean rust arriving in Iowa. Soybean rust was reported in Alabama, Florida, Louisiana, Mississippi, Texas and Mexico in January. However, dry weather during early spring in southern Texas and Gulf Coast states helped keep soybean rust from building up inoculum and spreading early in the season. 

Since January 2008, soybean rust has been reported in 396 counties in the U.S. and Mexico, which is more than any previous year (Table 1). However, many of these finds were late in the season, more so than in previous years.

     2008 soybean rust summary table

Another bullet dodged
So what happened? Why did soybean rust once again fail to infect soybeans and cause yield loss in Iowa? Soybean rust overwintered in the right (or wrong, depending on your perspective) places and we had plenty of rain. There were hurricanes and other storm systems coupled with cooler-than-normal temperatures for portions of the summer that provided ideal conditions for disease establishment and development. We even had a late-planted crop and a season that lagged about two to three weeks behind, extending the vulnerable period for yield loss into early September.

Despite all of these factors that increased our chances for getting soybean rust, we didn’t.  In most of the places where the pathogen overwintered, it petered out as spring became summer. Disease did not spread or completely disappeared in the overwintering sites in Alabama, Mississippi, Louisiana and Texas. The infected crops in Mexico were harvested. Bottom line, the inoculum did not build up in the south like it did in 2007. So all of the storms that would have been major problems in 2007 were not, as there was little to no inoculum to transport. 


      soybean rust leaves

      Soybean rust on leaves.


Website and Fast Track System Overhauled
The Iowa State University Soybean Rust Web site was redesigned in 2008. The new site highlights weekly messages written throughout the growing season that provide up-to-date information on soybean rust. Individuals can sign up to have these reports e-mailed to them. The website also provides the basics and management of soybean rust, as well as fast facts about soybean rust.

In 2004, the Soybean Rust Fast Track System was put in place to ensure rapid identification of soybean rust through first detectors. Since then, more than 700 individuals were trained as first detectors. One of the main responsibilities of the first detectors was to screen samples suspected of being infected with soybean rust that were clearly infected with other foliar diseases, not rust. However, because of the difficulty in identifying soybean rust in the field, the function of the Fast Track System was changed. First detectors no longer are asked to filter out samples with other soybean diseases. The new role of first detectors is to serve as a conduit to get samples submitted properly to Iowa State University Plant and Insect Diagnostic Clinic.

Update on fungicide labels
Only two Section 18 labeled foliar fungicides (PunchTM and TopguardTM) remain for soybean rust treatment in Iowa and full registration decisions are expected in 2009 for these products. Alto®, CarambaTM, Folicur®, OriusTM, Quadris® Xtra and UppercutTM had Section 18 labels for soybean rust and received a full label for soybean in 2008. ProlineTM did not have a Section 18, but was registered for use on soybean in 2008. In 2009, the active ingredient in ProlineTM is expected to be combined with trifloxystrobin and marketed as Stratego Pro. 



Daren Mueller is an extension specialist with responsibilities in the Corn and Soybean Initiative.

This article was published originally on 12/8/2008 The information contained within the article may or may not be up to date depending on when you are accessing the information.

Links to this material are strongly encouraged. This article may be republished without further permission if it is published as written and includes credit to the author, Integrated Crop Management News and Iowa State University Extension. Prior permission from the author is required if this article is republished in any other manner.