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May 2014 Archives

Alfalfa Harvest Alert Data May 29, 2014 Update

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by Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties

Update May 31 about 2:45 for data for May 29 samples.  

Alfalfa Field Data 2014 05 29 Update 05 31.pdf

I'll aim to update this on Monday Evening with the early reports we get for Monday June 2.  

Harvest would be underway or close if fields were firm enough to get on with equipment and the weather offered a suitable opportunity. Farther north fields may not be quite harvest ready yet, depending on feed needs, but not farm behind now.

MAKE SAFETY A PRIORITY when fields and weather conditions are right for harvest.

For more U of M information about forages go to

Go to Midwest Forage Association if you'd like to order PEAQ Sticks:

The Wisconsin Extension Forage web page can be found at:


By Dave Nicolai, IAP Program Coordinator

The 2014 Field School for Ag Professionals will be held on July 30 - 31 at the University of Minnesota Agriculture Experiment Station, St. Paul Campus, University of Minnesota. The St. Paul Campus (located in Falcon Heights, MN next to the Minnesota State Fairgrounds at Larpenteur and Gortner Ave) is this year's site for the Field School for Ag Professional which is the summer training opportunity that combines hand-on training and real-world field scenarios that no winter program can offer.  The two-day program focuses on core principles in agronomy, entomology, weed and soil sciences on the first day to build a foundation for participants and builds on this foundation with timely, cutting-edge topics on the second day.

It is too early to know if black cutworm will be a significant problem in 2014 MN crop production. However, captures in a cooperative pheromone trapping network indicate vigilance is in order. We do not have complete coverage of the state with this network and cutworm infestations are always variable from field to field so it is best to err on the side of caution. Pay close attention to any leaf feeding, wilted or cut off corn plants as you scout.

There are at least two flights, April 28 and May 8, where larvae would be large enough show leaf feeding and may be large enough to cut corn in warmer locations. The highest, but not exclusive, risk for black cutworm infestations is highest from Faribault and Steele County in SC MN and a diagonal northwest up the Minnesota River to southern WC MN.

We do know that black cutworm larvae are present and active. I just received a report of black cutworm leaf feeding on corn near the Sibley/Renville County line (Curt Burns). In addition to corn, sugarbeets and several other dicot crops can be attacked.. Later planted weedy fields are were not tilled before cutworm moths arrived are most at risk. Depending on geography, weedy late worked fields may be common this year.

Scouting is important to determine if cutworms are a problem in you fields. Some corn hybrids and at plant insecticides provide control of black cutworm larvae. Insurance insecticide applications for black cutworm are not productive. For further information see: .

Alfalfa Harvest Alert Data May 29, 2014

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by Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties

1-800-964-4929 or 968-5077 if a local call to Foley

May 29 Evening

Here's the information we have so far from May 29.

Alfalfa Field Data 2014 05 29.pdf

I'll aim to update this on Friday evening with reports we get during the day on Friday May 30.

Heat Canker in Wheat, Barley, and Oats

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The last couple days the weather has given us some dry sunny weather with high winds. This has been great to have fields finally dry off and make strides with planting the crop. Unfortunately this also exposed young small grain seedlings to same conditions. The daytime heat at the soil surface has caused heat canker. The tender young tissue at the soil surface basically has been 'cooked' and this appears as a yellow band that is slightly constricted (Photo 1). As the leaf continues to grow, this yellow band (1/8 - 1/4") moves upward and away from the soil surface. If the hot and dry weather last for several days, repeated bands should become visible. The damage is nicely depicted on page 81 of the second edition of the Small Grains Field Guide. Because of the high winds, the tips of leaves may break off at the yellow band and give a field a very ragged appearance. Damage from heat canker is temporary and should not affect further growth and development.

Thumbnail image for 14 Heat Canker.jpeg
Photo 1 - Wheat seedlings with the yellow, constricted appearance symptomatic for heat canker (photo courtesy of Luke Steinberger)

Having experienced a very late spring as in 2013, we are also experiencing a similar start to the season when it comes to diseases in small grains as last year. Tan spot has made an appearance on wheat and barley around the state.

Tan spot is identifiable by the brown spots often surrounded by a yellow halo that appear Tan spot lesion.JPG

This may run together to form larger patches of yellowing and browning. Initial infections in young seedlings often result in yellowing of leaf tips as the seedlings react to the toxins produced by this fungus. Tan spot will be particularly prevalent on previous wheat ground. Be careful not to mistake nitrogen deficiency (see recent post to crop e-news by Dr. Jochum Wiersma on early season yellowing in small grains) or symptoms of BYDV for tan spot.

Scouting is really key with these diseases and results in early detection. As tan spot can go through multiple infection cycles in a season, it is important to control it as soon as it is identified. If left unchecked, this disease will continue to progress and may impact yield.
If you do see tan spot, you can use a tank mix of herbicide and fungicide to control this disease. With the young crop, we recommend using half the labeled rate of products containing active ingredients such as propiconazole (e.g. Tilt). This is because there is less biomass at this stage for the fungicide to cover. After application of fungicide, the lesions of tan spot will not disappear, but the fungus in these lesions will have been killed off. It is important to keep scouting new growth in fields to determine if new infections are occurring. If so, an application of fungicide later in the season may be necessary.

A number of different fungicides can be used for control of this disease (follow this link to the current fungicide efficacy table for small grains. ). Always remember to follow current labeling instructions for use.

This year, we are interested in collecting isolates of Tan Spot. So if found, please can you contact me at BEFORE you spray and we will try to collect a sample.

Early Seasoning Yellowing of Wheat, Barley, and Oats.

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Reports of yellowing in small grains have started to reach us. There are several reasons why young wheat, barley, or oat plants have a pale green/yellow color. Some of the common reasons for early season yellowing are:

  • Nitrogen deficiency
  • Sulfur deficiency
  • Early tan spot infection
  • Herbicide injury

The nitrogen (N) deficiencies can readily be identified as the symptoms are worst on the oldest leaves and start at the tip of the leaves, progressing towards the base as the deficiency gets worse. The causes of the N deficiencies are several, all which have common denominator, namely excess precipitation. Excessive rainfall causes:

  • Leaching
  • Denitrification
  • Inability of the plants to take up available N

Leaching is a potential problem in coarser textured soils. Saturated soils/standing water will cause both denitrification and inability to take up available N. Denitrification is a microbial process and slows down considerably as soil temperature decrease. According to Univ. of Illinois data (Hoeft, 2004), denitrification losses are 1-2% if soil temperatures are less than 55oF, 2-3% when soil temperatures are between 55 and 65oF, and 4 -5% once soil temperatures exceed 65oF. As soils are saturated, the plant's roots also are unable to take up N - even if available. Often the crop recovers quickly if the growing conditions improve and the excess water has drained.

If the N deficiency is severe, a supplemental application of N as either urea (46-0-0) or urea ammonium nitrate solution (28-0-0) can be advantageous. Research by George Rehm and Russ Severson in 2005 showed that 40 lbs of supplemental N at the 4 leaf stage yielded 7 bu/A extra over the untreated check.

Sulfur (S) deficiencies are generally found on coarser textured soils and can readily be identified as symptoms are worst on newest leaves and less on older growth. This is opposite to N deficiencies as can be explained by the difference in mobility of the element in the plant; N can be more readily be recycled from older growth and redirected to the younger leaves compared to S. Cool and dry conditions tend to make S more pronounced as less S becomes available from the breakdown of organic matter.

Cool conditions make some of the micro nutrients also less available to the plant. These symptoms are often first noted on the coarser textured soils. Again, George Rehm has chased this problem in the past and found that no single culprit was to blame. As soon as growing conditions improved, the symptomology would disappear.
Early season tan spot infection can also cause the young wheat and barley crop to turn a bright yellow. Especially young seedlings up to the 3 to 4 leaf are very sensitive to a toxin that is produced by the fungus. This yellowing affects the whole seedling. If tan spot is identified as the cause of the yellowing, an early season fungicide treatment is warranted. Additional details on how to effectively control early season tan spot can be found in a follow-up article by Dr. Madeleine Smith.

Although few if any acreage has received an herbicide to date, yellowing of the crop can also be caused by herbicides. Cool growing conditions make a number of our common small grain herbicides more prone to cause temporary injury. Especially the ACCase class of grass herbicides is more active with cool(er) growing conditions. This temporary yellowing will dissipate in one to two weeks after application with no effect on grain yield.

Hoeft, Robert. 2004. Predicting and Measuring Nitrogen Loss. University of Illinois Extension

Switching to Soybeans?

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by Seth Naeve, University of Minnesota Extension Soybean Agronomist

As June 1 looms in the not-too-distant future, large areas of land intended for small grains or corn remain unplanted in Northwestern Minnesota.  Likewise, there are localized areas in East-central and South-central Minnesota where the corn crop has not yet been planted.  With recent rainfall, and a May 31 crop insurance cut-off date around the corner, some producers are considering switching to soybeans.

Alfalfa Harvest Alert Data May 27, 2014

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by Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties or 1-800-964-4929 or 968-5077 if a local call to Foley

May 27 Evening - May 28 Evening Update

The crop has taken a pretty significant leap forward during the past week. It's probably time to take a yard stick out to most field in the area.

This report includes new data from Scott County on May 22, and on May 26 and 27 from McLeod, Meeker, Wright, Benton, Stearns and Morrison. Some NOTES ABOUT FIELD OBSERVATIONS are included  following the numbers.

Alfalfa Field Data 2014 05 27.pdf

This document will be revised in this posting on Wednesday evening May 28 with more lab reports.

New samples will be taken on Thursday Morning May 29, with the goal of having some of that posted on Thursday evening.

For more U of M information about forages go to:

Go to Midwest Forage Association if you'd like to order PEAQ Sticks:

The Wisconsin Extension Forage web page can be found at:

Alfalfa Harvest Alert Data May 22, 2014

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by Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties
May 23 Evening

This report includes data from Thursday May 22 in Carver, Wright, Stearns, Benton, and Morrison County. Some NOTES ABOUT FIELD OBSERVATIONS are include following the numbers.

Alfalfa Field Data 2014 05 22.pdf

The next report should be posted Tuesday Evening May 27.

Some sites are not tall enough to be sampled yet. We generally suggest starting field measurements and or lab sampling when the tallest stems are about 16 inches.

For more U of M information about forages go to

Go to Midwest Forage Association if you'd like to order PEAQ Sticks:

The Wisconsin Extension Forage web page can be found at:

Sauk Centre Hay Auction Summary May 15, 2014

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by Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties by phone, if a local call to Foley 968-5077 or 1-800-964-4929

This information is for the Sauk Centre Hay Auction held on May 15, 2014.

"Continue Reading" for Links to reports and other information - including the data from the Alfalfa Harvest Alert Scissors Cut Project.

There will be an auction again at Sauk Centre on June 5.


Alfalfa Harvest Alert Project 2014 Starts

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by Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties
May 20 Evening

The 2014 Alfalfa Harvest Alert Scissors Cut project has started this week with 3 samples taken on Monday May 19 in Carver County and 1 sample in Benton County. We generally suggest starting field measurements and or lab sampling when the tallest stems are about 16 inches.

With an unusual spring again this year, it's good to get an early look at a few samples to see what things are like.

"Continue reading" 1) to get the link for May 19 results with observations; 2) to get the link for a News Release that tells about the project and where listen to or read reports; 3) links to U of M Forage Information; and 4) link to Midwest Forage Association for buying a PEAQ stick

By Lizabeth Stahl and Lisa Behnken, Extension Educators in Crops  

Access to results for many of the U of MN crops research trials conducted across the state has now become streamlined with the launch of the new, U of MN Extension Crops Research website.  This one-stop shop can be accessed through the U of MN Extension Crops webpage at under "Research Reports".

The website contains results for small plot and on-farm crops research and demonstration trials conducted across Southern MN from 2003 to 2013.  You can also access research results for crops trials conducted at Research and Outreach Centers located across the state by clicking on the respective link.  Statewide results for weed science research can be accessed through the "Applied Weed Science" link, and results for the Minnesota hybrid and variety trials can be accessed through the "Minnesota Field Crops Variety Trials" link. 

The Research Reports webpage supplements U of MN Crops websites such as the "Corn", "Soybean", "Small Grains", "Forages", or "Sugarbeets" websites, or the "Nutrient Management", "Pest Management", "Ag Drainage", "Climate and Weather", and "Tillage" websites, where you can find research-based information and resources to help with specific crops-related decisions. 

By Robert Koch, Extension Entomologist

Recent cool and wet conditions may increase the risk of seedcorn maggot infestation in some soybean and corn fields. Seedcorn maggots are small (1/4 inch long), white maggots (fly larvae) that feed on germinating seeds. The maggots can tunnel into seed, which may result in seed death, and can injure the emerging plant tissues, which can affect plant growth or lead to damping off. Such injury can result in stand loss or weakened plants. For example, if the growing point of soybean is killed, "Y-plants" can result when branching develops at the cotyledons. Yield from "Y-plants" may be reduced if competing with neighboring healthy plants. Seedcorn maggot injury can be difficult to distinguish from other problems such as Pythium and other seedling diseases.
Fields at greatest risk are those with decaying organic matter, such as a recently incorporated cover crop or manure. Risk of injury is greater when cool and wet conditions slow germination and emergence, which increases the window of time plants are susceptible to attack. Rescue treatments are not available for this pest. However, preventative tactics can be utilized to protect seed and plants in high-risk situations. Seed-applied and soil insecticides can offer effective protection of germinating plants from seedcorn maggot (be sure to follow instructions on product label). In addition, degree-day models are available to guide decisions about adjusting planting date to avoid periods with high larval abundance (UW seedcorn maggot degree-days).
When significant stand loss occurs, replanting may be required, but this option should be considered carefully. Information is available to guide replant decisions in soybean (U of MN Extension soybean replant guide) and corn (U of MN Extension corn replant guide).

Black cutworm traps pick up significant flights

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Over the past couple weeks, cooperator-run pheromone traps indicate the potential for localized damaging populations of black cutworm in corn and other crops. Faribault, Lac Qui Parle, Swift and Waseca Counties have had significant captures. Cutting from the earliest of these flights is projected to occur after May 28.

Areas with delayed spring tillage and early season weeds are most attractive for migrant cutworms to lay eggs.

This does not mean insurance insecticide applications are warranted and insecticide rescue treatments work well where economic threshold populations occur.

2014 University of Minnesota Cooperative Black Cutworm Trapping Network newsletters with further information on cutworm biology, scouting, thresholds and control as well as maps of trap captures and cutting predictions can be found at:

Late Planting of Small Grains

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Wheat, barley, and oat are cool season annuals and are most productive when they grow and develop during cool weather. The yield potential of a crop is largely determined by the 6 leaf stage. Cool temperatures during this period are particularly important for the development of a high yield potential. For example, the number of tillers that ultimately produce grain at harvest declines as planting is delayed (Figure 1). The number of spikelets per spike is determined during the 4 to 5.5 leaf stage (Figure 2). Spikelet numbers are negatively correlated with temperature; spikelet numbers are greater when temperatures during the 4-5.5 leaf stages are cool.

14 Figure 1 Late Planting.jpg
Figure 1 - The effect of planting date for on number of heads per square feet of hard spring wheat at harvest in Langdon, ND (data and graph courtesy of Terry Gregoire, Area Agronomist, NDSU).

14 Figure 2 Late Planting.jpg
Figure 2 - The effect of maximum daily temperatures on the number of spikelets per spike that are initiated between the 4 and 5.5 leaf stage of spring wheat in Langdon, ND (data and graph courtesy of Terry Gregoire, Area Agronomist, NDSU).

Because of the expectation that average temperatures will be higher as we plant later, development of the crop will speed up too. The number of heat units required for a plant to move to the next phase of development will accumulate faster. This forces development along faster and causes the plant to have less time to grow. Plants end up with fewer tillers, smaller heads, and fewer and smaller kernels per head, cutting into our yields.

To improve the odds of high grain yields is to ensure that the tillering and head initiation phases occur during relatively cool temperatures is by planting early. Early planting is pivotal in this regard (Table 1)

Table 1 - The average seeding dates and last recommended seeding dates for small grains in Minnesota.
14 Table 1 Late Planting.JPG

Research has shown that, on average, yields decreased 1% per day when planting is delayed past the optimum planting date. Planting after the last possible date is not recommended because the odds that grain yield and quality (test weight) will be dramatically reduced due to heat stress.

You can partially offset this yield loss by increasing the seeding rate and ensuring that you have more main stems per unit area. The recommendation is to increase the seeding rate by 1 percent for every day after the optimum planting window.

The last possible date for planting is not chiseled in stone. The chances of a profitable crop just drop because of the anticipated weather and temperatures later during the growing season. Past the last possible date, you may want to consider an alternative crop, though economic reality might prevent this. If you stay with small grains past that date you will have to hope for a cool and dry summer. Point and case being the summer of 2013; weather conditions during grain fill last year proofed so favorable that, despite the late planting date, the State's average HRSW yield was the third highest ever reported. This feat was largely the result of the cooler nighttime temperatures. Figure 3 shows the difference in the minimum temperatures during the growing season in 2012 and 2013.

14 Figure 3 Late Planting.JPG
Figure 3 - The difference in daily minimum temperatures during the growing seasons in 2012 and 2013 in Devils Lake, ND. Day 56 marks the approximate beginning of grain fill.

Crusting and Emergence Problems

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Last week's heavy rains have caused widespread crusting problems. Dr. David Franzen , NDSU Extension Soil Scientist, summarized the options available to you in an article more than a decade ago. It has been reprinted here as a refresher.

Crusting results from rains breaking down soil aggregates into particles that cement into hard layers at the soil surface when drying occurs rapidly. In soils that have not been seeded, the crust prevents further soil drying by sealing off the underlying soil from the air. The crust also reflects sunlight, in effect insulating the soil and maintaining cooler soil temperatures that further slow drying.

Crusts in unseeded fields can be broken by working the fields very shallow, no deeper than the depth of the crust, with such tools as a rotary hoe, a field cultivator with narrow shovels or spikes, or a rigid harrow. Breaking the crust will help dry the field more quickly and warm the soil. Some compaction will result from the extra trip over the field, but the benefits of the tillage should outweigh the negatives.

In seeded fields that received heavy rains after seeding and developed crusts, breaking the crusts may be crucial for good stand establishment and to avoid reseeding. A rotary hoe is the best tool for breaking a crust. A spring-tooth harrow with the teeth set straight down instead of slanted back can sometimes be used. The circular motion of harrow teeth set in this fashion can be very effective at breaking a crust enough for young seedlings to emerge. A heavy rigid harrow should be avoided as too much soil movement may expose seedling roots. If neither of these tools is available, running over the field with and empty double disc drill will also break the crust.

The goal of any crust-breaking trip is to crack the crust into small pieces and move them around slightly to let air and light into the soil below. Seedlings trapped under a crust will try to grow and elongate below the crust until they run out of stored energy from the seed. The cooler the weather, the longer the seedling can survive, unless a seedling disease infects it. The warmer the temperature, the faster the seedling will try to grow and the sooner it will run out of energy. It is important to deal with crusts soon after they form.

With any crust-breaking method, some stand damage is likely. However, compared to the damage a crust can do, the damage done while breaking crust is usually much less than the crust itself causes.

Evaluating Winter Wheat Plant Stands

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One of the hardest decisions with growing winter wheat is evaluating the amount of winter kill and making the decision whether to keep a stand. Winter wheat is planted in the fall and develops in the spring during relatively ideal conditions for tiller development. Therefore the optimum plant stands of winter wheat can be less than that of spring wheat. A stand of 900,000 - 1,000,000 plants/acre or 21 - 23 plants/ft2 will be enough to maximize grain yield.

Some winter kill is to be expected in Minnesota. This past winter was cold even by Minnesota standards. The extreme cold, combined with little snow cover in parts of the state, and that the fact some of winter wheat was planted on prevent plant acres that had little or no standing stubble to collect the limited snow that fell, means that winter kill is very likely this year. Roots are generally less winter hardy than crowns and regrowth may be very slow, even if roots and shoots appear dead.

The very cool and wet weather to date has meant that fields have been very slow to green up and have just started to put on new leaves and tillers. This past week was probably the first time that evaluating surviving plant density was fairly straightforward. The problem that remains, however, is that winter survival in all likelihood will variable within a field and depending on topography (windblown hilltops having less stand than protected areas of the field). If stands are reduced uniformly across the field, stands of 17 plants/ft2 can still produce near maximum grain yields. Even stands as low as 11 plants/ft2 can still produce a 40 bu/A yield.

Given the lateness of the spring and the likelihood that anything else that is planted will be planted later than optimum creates another incentive to stick with a less than ideal stand of winter wheat. Consider interseeding spring wheat to fill large gaps but be prepared for the fact that spring wheat matures later than winter wheat so harvest will be problematic. Furthermore, mixing wheat classes can cause problems at the elevator. Planting winter wheat into large gaps can also be an option. Winter wheat planted in the spring will not vernalize so it will not produce a head (or there will be fewer late heads), but will provide ground cover until harvest.

Sauk Centre Hay Auction Summary May 1, 2014

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by Dan Martens, Extension Educator, Stearns-Benton-Morrison Counties by phone, if a local call to Foley 968-5077 or 1-800-964-4929

This information is for the Sauk Centre Hay Auction held on May 1, 2014.

Check "Continue Reading" for all the information.

Researchers at Cornell University recently discovered an isolate of Fusarium graminearum (the organism which causes Fusarium head blight (FHB)) with greatly reduced sensitivity to tebuconazole. Tebuconazole is the active ingredient (A.I.) in fungicides such as Folicur and one of the A.I.s in Prosaro. These fungicides are routinely used to control both leaf diseases and also for FHB suppression.
The researchers conducted a study to examine the sensitivity of 50 isolates of Fusarium to tebuconazole and another A.I , metconazole (the A. I. in Caramba). They found one isolate out of these 50 (designated TEB-R) so have such a reduced sensitivity to tebuconazole, they deemed it tebuconazole-resistant.

How has a tebuconazole resistant isolate of FHB arisen?

It's important to remember that fungicides themselves do not cause the mutations giving rise to the genetic variation mediating resistance. When fungicide applications are made over a period of time across a landscape, they create an environment where resistant isolates now have a competitive advantage over susceptible isolates. It's a classic case of survival of the fittest. This results in selection for resistant isolates at a much higher frequency in the population.
Interestingly, until recently, New York has been one of the few states where tebuconazole has not been widely used to suppress FHB. However, seed treatments containing tebuconazole have been commonly used throughout the state.

Is the discovery of a fungicide -resistant isolate surprising?

In a word, no. It is not uncommon to find fungicide resistant isolates occurring at low frequencies in natural populations of Fusarium, even before exposure to fungicides. Fusarium graminaerum is known for its wide genetic variability. Once surveys are conducted to measure sensitivity of isolates to fungicides, we would expect to find some with resistance to tebuconazole or other fungicides.

Should producers be changing management practices in light of this discovery?

These findings don't mean that we should drop fungicides from our control programs, but it does mean we need to be smart about our fungicide use. Deploying resistant varieties in combination with fungicides where different modes of action are used in rotation or in tank mixes all help to prevent causing a huge population shift in the fungus towards resistant isolates resulting in loss of efficacy of A.I.s. It is worth remembering that this isolate, although resistant to tebuconazole, was still susceptible to other A.I.s. In the absence of the selection pressure caused by tebuconazole, this isolate of Fusarium seemed to have no competitive advantage over other tebuconazole susceptible isolates.

So what is the impact of this finding?

Should we stop using tebuconazole to control fungal diseases? This discovery highlights the need for careful monitoring of fungal populations of FHB and other disease-causing fungi and establishing baseline sensitivities to commonly used A. I.s in these fungicides. This will allow an early warning if populations are shifting towards an increased number of isolates with reduced sensitivity or resistance. Until we are able to gain a broader picture of what is happening in our fungal populations, integrated management strategies utilizing the best resistant wheat and barley varieties available and judicious use of fungicides ( including tebuconazole) are still the best approach to control this devastating disease. Indeed, in many other wheat growing regions of the world where fungicide resistance is a problem for some diseases, A.I. management (rotation of A.I.s) is already practiced as a matter of routine across all cropping systems. The issue of fungicide resistance should garner as much as attention as the currently recognized problems with herbicide and insecticide resistance in the U.S.

For more information contact: Dr. madeleine Smith at: or Dr. Gary Bergstrom at:

Reference: P. Spolti et al. 2014 Triazole sensitivity in a contemporary population of Fusarium graminearum from New York wheat and competitiveness of a tebuconazole resistant isolate. Plant Disease.Vol 98: p 607-613

By Lizabeth Stahl, Extension Educator in Crops

Benefits of a preemergence (PRE) herbicide application in soybean were demonstrated through the "PRE Challenge" - a series of on-farm research and demonstration trials conducted across southern MN in 2012 and 2013. In these University of Minnesota Extension trials, made possible through financial support of the Minnesota Soybean Research and Promotion Council, cooperators compared a postemergence-only herbicide program to a program that included a PRE herbicide application.

by M. Scott Wells - Forage and Cropping System Agronomist

Being new to this state, I have been curious about how this spring compares to the previous year as it relates to precipitation. This time last year, much of Minnesota reported below normal precipitation (Figure 1a). However, across Southern Minnesota this year there has been greater than normal precipitation reported with some areas departing more than 6-inches from the normal (Figure 1b).

Screen Shot 2014-05-02 at 5.50.27 PM.pngFigure 1.Minnesota Monthly Departure from Normal Precipitation for April 2013 (a) and 2014 (b). NOAA - Advance Hydrological Prediction Services.

With the increase in precipitation this spring, coupled with cool temperatures, there could be greater risk of delayed corn planting. Like many of you, we at the University are waiting for the soil to dry and warm so that we can plant research crops. Across the Midwest, several states report less than 20% of their corn acreage planted. In Minnesota, only 4% of the corn has been planted which is similar to the spring of 2013 (Figure 2). Unfortunately, judging the weather report for the next few days, it doesn't look like there will be a significant jump in corn acreage planted.

Screen Shot 2014-05-02 at 6.17.47 PM.pngFigure 2. USDA's weekly crop progress estimates of percentage of corn acreage planted as of April 28, 2014.

Last year, corn planting was delayed and forage producers were faced with significant loses of alfalfa acreage due to winterkill. During our winter workshops, forage producers asked where they could find cover crop seed to plant as forages. Questions arose as to which cover crop species and seeding rates were most appropriate to use along with where to source the seed. Many producers commented that they were not able to find cover crop seed last year, even though there were seed suppliers in Minnesota that did have inventory last spring. Below is a list of seed suppliers in Minnesota that carry cover crop seeds along with information concerning planting date and seeding rates. The below list is meant to assist producers interested in planting cover crops, however, it is not comprehensive or endorsed by University of Minnesota Extension Forage Program. Additional information on prevent to plant cover crop options can be found at University of Minnesota Forages Extension website.

Albert Lea Seeds Albert Lea, MN 800-352-5247
Agassiz Seed & Supply West Fargo, ND 701-282-8118
Central Sota Buffalo, MN 763-682-1464
Cover Crop Solutions Robesania, PA 800-767-9441
Federated Coop Several Locations
FMX Turf Castle Rock, MN 651-463-8041
La Crosse Forage & Turf Seed, LLC La Crosse, WI 800-328-1909
Legacy Seeds, Inc. Scandinavia, WI 866-791-6390
Marty's Farm Service Several Locations
Millborn Seeds Brookings, SD 888-498-7333
Prairie Restorations Several Locations
Producer's Choice Seed Jordan, MN 877-560-5181
Shady Knoll Farm Redwood Falls, MN 507-640-0993
Waconia Farm Supply Waconia, MN 952-442-2126
Welter Seed and Honey Co. Onslow, IA 563.485.2762
Werner Farm Seed Dundas, MN 507-645-7995

Hopefully, May brings flowers and favorable planting conditions.

The continuous rainy weather that we've been experiencing can take an emotional toll on a farmer.  It's easy to feel a little helpless looking out at those soggy fields.  The common response is to keep active and begin to make contingency plans.  Some producers are beginning to get nervous about their variety choices and are calling on their seed dealers to inquire about sourcing earlier maturity soybeans. 

While this is a very normal response to the situation, it's important to remember that soybean maturities need not be adjusted for some time.  The standard University of Minnesota recommendations state that soybean maturities should not be adjusted until a target planting date of June 10 is reached.   We will have MANY good working days before then. 

There are two primary reasons why soybean maturities need not be adjusted for some time.  First, the soybean's reproductive development is much less impacted by heat unit accumulation than corn.  Shorter days help trigger flowering and maturation in soybean, so that even late planted - full maturity - soybeans tend to mature naturally, if only a day or two late.  Second, early May growth and development in Minnesota soybeans tends to be very slow.  Historically, soybeans planted in early May are only one or two leaves ahead of soybeans planted in late May due to the warm soil and air temperatures experienced by the later planted soybeans.

A secondary (but perhaps equally important) reason to delay maturity shifts relates to variety availability.  One should assume that they have already chosen the highest-yielding varieties for their farms.  Any swapping that occurs in the spring will result in producers accepting lesser varieties in trade.  Hold with your current varieties (at least) until a late May planting becomes imminent. 

Note:  Current University recommendations for late- and re-planting are based on antiquated research trials.  We know that farmers are planting much longer maturity soybeans today.  We know that this change will impact when soybean maturity switches should occur.  This is a research project that we hope to take on in coming years.


Seth Naeve, Extension Soybean Agronomist

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