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6/30/2008 - 7/6/2008

What About Foliar Fertilization for Soybean This Year?

By Antonio P. Mallarino, Department of Agronomy

This year soybean was planted late or replanted in many fields due to excess rainfall and late spring temperatures were colder than normal.  Therefore, some producers wonder if foliar fertilization could help improve soybean growth and grain yield.  The short answer is that it may, but probably not in fields that have been well fertilized or where growth is limited by factors other than nutrient supply.  This short article reviews major issues involved, provides a brief summary of many studies conducted in Iowa during the last few years, and provides some recommendations.

Foliar Fertilization at Late Reproductive Growth Stages

Prior to the 1990s research had focused on foliar fertilization at late soybean reproductive stages (R4 to R7).  There were hundreds of field experiments during the middle 1970s and early 1980s in Iowa and other regions that included nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and other nutrients.  The soybean plant has a sharp decline in root activity during late seed development stages with large nutrient translocation from leaves and pods into the developing seed.  Researchers theorized that if nutrients were applied to the foliage at this time, leaf senescence and “seed starving” could be alleviated and grain yields would increase.  A few early experiments in Iowa suggested that spraying the soybean canopy with a mixture in a ratio 10-2.3-3.6-0.5 N-P2O5-K2O-S between the R5 and R6 growth stages could increase yields by 7 to 8 bu/acre.  However, more than 200 subsequent trials in Iowa, the Midwest, and Southern states from the late 1970s to the middle 1980s showed inconsistent results, responses varied from a maximum increase less than 5 bu/acre to a yield decrease up to 6 bu/acre.  More recent work in the Midwest under rain-fed conditions showed similar results, and often yield decreases when N sources were sprayed alone or in a mixture.  The more positive results were observed under very high yield conditions and irrigation in Kansas.  Therefore, these results have discouraged further research and adoption of foliar fertilization of soybean at late reproductive stages.

Foliar Fertilization at Vegetative to Early Reproductive Stages

Small amounts of nutrients sprayed onto soybean foliage at early stages could supplement inadequate pre-plant fertilization and increase nutrient supply at a time when roots and N fixing root nodules are not well developed.  Furthermore, foliar fertilization could enhance growth if soil conditions limit nutrient uptake when soil levels are adequate.  About 100 replicated field trials were conducted from 1994 until 2006 to evaluate these possibilities by spraying foliar fertilizers with or without mixing it with glyphosate herbicide or a fungicide at the V5 to R3 growth stages.  The products tested (not all products were included in all trials) included the low-salt fluid fertilizer 3-18-18 (N-P2O5-K2O) and 10-10-10 (N-P2O5-K2O) both with or without S and with or without the micronutrients boron (B), iron (Fe), and zinc (Zn); and also 8-0-8 (N-P2O5-K2O).  Product rates ranged from 2 to 6 gal/acre applied once or twice (spaced 8 to 10 days).  The fields were managed with no-till, ridge-till, or chisel-plow tillage.
 
Figure 1 summarizes results from 66 trials that compared three sets of six treatments.  The majority of fields tested Optimum or higher for P and K according to Iowa State University interpretation class but there were also low-testing soils in some trials.  Each graph shows averages across all fields and averages for fields where at least one treatment was statistically different from the control.  Foliar fertilization increased yield in 15 to 30 percent of the fields depending on the set and year.  The average response to the best treatment (3 gal/acre of 3-18-18), which was common to the three sets of trials, across all trials was 0.7 bu/acre but the average response across the responsive trials was 4.1 bu/acre.

Foliar Fertilization Chart


Figure 1. Average soybean grain yield response across three sets of trials to several foliar fertilizers. The different bars represent yield responses across all trials and only the responsive trials for each set of experiments.

Differences between treatments were not consistent across fields but responses tended to be higher for a rate of 3 gal/acre of 3-18-18.  Adding S or micronutrients did not produce higher yield.  The highest rate of 10-10-10 (with or without S) and 8-0-8 fertilizers reduced yield in a few fields (some leaf burn was observed).  Double applications were statistically similar to single applications.  Responses were observed in low-testing fields and also in fields testing Optimum or higher.

Reasons for positive responses in fields testing Optimum or higher in P and K were difficult to identify.  Complex multivariate statistical analyses were used to understand the relationship between yield response and soil-test values, soil type, tillage system, nutrient uptake at early or late growth stages, rainfall, temperature, planting date, etc.  These analyses did not support strong conclusions but suggested conditions in which a response to foliar fertilization was more likely.  In some years, responses were higher and more frequent in ridge-till and no-till fields compared with chisel-plow tillage.  In general, the responsive fields had slower early plant growth and P or K uptake than non-responsive fields because of low-testing soil, cool early temperatures, and excessive rainfall.  Therefore, conditions that inhibit root growth and/or nutrient uptake early during the growing season (except drought) increase the likelihood of a yield response.  Unfortunately there is no simple “absolute yardstick” that can be used to identify these conditions that increase chance of response to foliar fertilization in producers’ fields.  For example, this project and others could not identify a useful critical or optimal nutrient concentration in young plant tissue.

Twenty-three additional trials were conducted in conventional small-plot trials or replicated strip trials. These were simple comparisons of 3 gal/acre of 3-18-18 to a control because this was the fertilizer and rate most effective in the first 66 trials.  The results of these trials showed a response in about 15 percent of the trials.  Grain quality analysis of soybean grain showed no effect of foliar fertilization on oil or protein concentrations.

Five field trials were conducted in 2005 and 2006 to study foliar fertilization and fungicide application alone or in a spray mixture.  Eight treatments were a non-treated control, four foliar fertilization treatments without fungicide (a single application of 3 gal/acre of 3-18-18 at the V5 and R2 to R3 growth stages, a double 3-18-18 application at V5 and R2 to R3 stages, and 3.3 gal/acre of 28% UAN at the R2 to R3 stages), and three fungicide (Headline®) treatments at the R2 to R3 growth stages (alone and in combination with 3-18-18 or UAN fertilizer).  On average the fungicide increased yield by 2.9 bu/acre, although the responses were statistically significant at only three fields.  The fungicide delayed leaf senescence at most fields, although disease control by the fungicide was observed only for Brown Spot in three fields.  Spraying soybean with 3-18-18 fertilizer did not affect yield at four fields and increased it slightly at one field.  Spraying with UAN did not affect yield at two fields, increased it slightly at one field, and decreased it at two fields.  The UAN application caused moderate leaf burning and the 3-18-18 application caused very minor or no burning.  An important result was that there was no interaction between foliar fertilization and fungicide application at any field.  Mixing the two fertilizers used in this project with the fungicide did not cause problems or an additional yield response compared to the products alone.

Recommendations

Foliar fertilization of soybean will not be cost-effective in Iowa when applied across all fields because the expected average response is less than 1 bu/acre.  The probability of a larger yield increase is 15 to 20 percent.  Except for too high rates of products with high salt content, N, or S that produced leaf burn and sometimes decreased yield, research has shown inconsistent differences between nutrient ratios or frequencies of application.  However, a single application of 3 gal/acre of 3-18-18 usually produced the highest and more consistent yield responses.  Mixing this fertilizer with glyphosate for early applications or with Headline® fungicide for mid-season applications caused no problems but did not increase the efficacy of either product.  The probability of a yield response that offset costs will be increased by targeting fields for spraying.  These include fields with low soil nutrient levels due to insufficient pre-plant fertilization and conditions where soil or climate factors limit nutrient uptake in late spring and early summer.  Unfortunately these conditions often cannot be easily identified in the field.

Antonio P. Mallarino is a professor of agronomy with research and extension responsibilities in soil fertility and nutrient management.

Corn Following Corn in 2008

By Mahdi Al-Kaisi, Roger Elmore, Antonio Mallarino, Palle Pedersen, Alison Robertson, John Sawyer, and Jon Tollefson

Corn following corn is in rough shape in areas across Iowa. Many wonder what is happening. The crop’s condition in general is not normal for this time of year. For example, last Sunday the USDA rated this year’s Iowa corn crop as 54 percent in ‘Good’ to ‘Excellent’ condition and 15 percent is ‘Poor’ or ‘Very Poor.’ Last year 72 percent was rated ‘Good’ to ‘Excellent’ and 5 percent was in ‘Poor’ or ‘Very Poor’ condition during the same week. Average plant height as of Sunday was 24 inches compared to 40 inches at end of the same week last year. Growing Degree Days continue to lag behind normal all over the state.

Corn Following Corn
FIGURE 1. Plant height differences between corn following soybeans (left) and corn following corn (right) in the Long-term Nitrogen Study conducted by John Sawyer and Dan Barker. Nitrogen application rate on both plots was 240 lbs/acre, spring applied. Thus, N is not limiting plant growth. Iowa State University. Photos taken on 30 June 2008 by Roger Elmore.

Certainly, plant heights and crop conditions in late June are not necessarily correlated with yield. There is a lot of the growing season to go yet. In baseball language, although the crop is only perhaps in the 3rd inning, it really hasn’t had a lot of chance to bat. Warmer weather in the last week has helped immensely.

So why is the corn following corn in this condition?

Yields – what can we expect?

First remember why we rotate corn and soybean: crop rotation usually results in maximum yield of both crops. In the very best of years corn following corn will yield as well as corn following soybean. In the worst of years lower yields occur when corn follows corn. These are years with climatic stresses – most notably dry years and those with wet springs.

Over the last eight years, Iowa corn yields following corn have ranged from almost the same to 27 percent less than yield of corn following soybeans. The eight-year average is 14 percent less (Table 1). Crop rotation is an important tool for us to maximize yield and profitability. Planting corn after corn usually results in reduced yield which results from a less than ideal growing environment.

Elmore Table 1

Table 1. Corn yields following soybean (SC) and following corn (CC) across multiple Iowa locations. To insure N was not limiting, the yields for each rotation are at the maximum yield response to applied N. Iowa State University, 2000-2007.
 

Agronomics

Reasons for lower yields (Table 1) when corn is planted after corn are multifaceted. Many publications are available on the subject (for one example, see ICM news, Feb. 12, 2007, in the archives). Some of these reasons include: allelopathy, autotoxicity, increased residue, residue breakdown products, organic acids, nitrogen, N, issues, lower soil temperatures especially with no-till in poorly drained soils, reduced plant stand, and slower early vegetative growth. Slower growth could result in tasseling and silking occurring during drier periods, as well as delayed maturity with an increased risk of fall frost damage.

Regarding nitrogen (N) issues, N immobilization, low soil inorganic N, and inadequate N to meet early corn N needs (either applied before or at planting), can all result in poorer performance of corn following corn. More information on N fertilization for corn following corn and an N-rate calculator are available.

The beneficial effects of starter N and Phosphorus are more likely for corn following corn than for corn following soybean. This is especially true in areas with large residue accumulation, resulting from reduced tillage systems, and with excessively wet and cool soils.

Continuous corn can impact soil biological diversity by limiting microbial biomass. The microbial biomass is essential for nutrient cycling. Production of corn following corn often encourages the use of intensive tillage due to the increased residue production. More intensive tillage affects microbial diversity and the soil’s physical, chemical, and biological condition.

Seedling Diseases

An increase in the prevalence of seedling disease may be another reason why corn following corn looks so bad this year. The risk of disease in corn following corn fields is always greater than in fields that have been rotated to nonhost crops because of increased amounts of inoculum. Many corn pathogens survive in infested corn residue. Continuous-corn fields, in particular those with crop residues left on the surface, are more prone to seedling diseases due to higher inoculum pressure and cooler, wetter soils. This year the very wet and cool start to the growing season has further favored the development of seedling diseases.

Infection by seedling pathogens results in seed rot, root rot, and mesocotyl rot. Affected seedlings are stunted, off-color, and/or lack vigor. Why? Because the developing seedling relies on the seminal roots and mesocotyl for water and nutrient uptake up until around growth stage V6, then the crown roots become active. Thus, it is possible that the poor looking corn we are seeing in continuous corn fields is in part a result of increased seedling disease.

Insects

Insects are another possibility as we ponder the reason why corn following corn looks worse than when it is grown following soybeans. Corn rootworms have adapted to crop rotation, but they still are more serious pests when corn is grown continuously. The above-ground effects of their root feeding, and their impacts on yield, will be more severe when continuous corn is under stress. Early growing conditions many of us have experienced, saturated soils and cool temperatures, will magnify their impact. Heavy amounts of rain filled the soil with water resulting in shallower root systems. Cool temperatures cause slower root growth and regrowth after insect feeding injury. Remember also that the corn rootworm eggs will be distributed in clumps in the fields.

Finally, none of the control options, insecticides or genetically-modified rootworm corn, will control all of the larvae. Consequently as you search for a reason for patches of uneven, short, yellow corn make sure you look at the root systems for corn rootworm larval feeding. Larvae root pruning could cause the symptoms you are seeing.

Risk Management

Remember the corn and soybean rotation as a system and not as two separate crops. Consider risk, especially when we have such small profit margins with our crops. By alternating corn and soybean, we minimize risk compared to a two-year corn and one-year soybean rotation or similar combinations. Many producers think corn will never fail because of the high yields we have experienced within the last five years. Nonetheless, anything is possible when dealing with our current volatile weather systems. Alternating corn and soybean is likely still the most profitable rotation sequence to maximize profit for most farmers in Iowa. Information to help make the most profitable decisions regarding crop rotation can be found on the Ag Decision Maker website.

Summary

The poor performance of corn under continuous corn system is very complex and multifaceted. Yield reductions are often associated with continuous corn due to the host of factors that are listed above as compared to corn following soybean or any extended crop rotation.


Additional links:
Yield penalty when corn follows corn

Mahdi Al-Kaisi is an associate professor in agronomy with research and extension responsibilities in soil management and environmental soil science.
Roger Elmore is a professor of agronomy with research and extension responsibilities in corn production.
Antonio P. Mallarino is a professor of agronomy with research and extension responsibilities in soil fertility and nutrient management.
Palle Pedersen is an assistant professor of agronomy with research and extension responsibilities in soybean production.
Alison Robertson is an assistant professor of plant pathology with research and extension responsibilities in field crop diseases.
John Sawyer is a professor of agronomy with research and extension responsibilities in soil fertility and nutrient management.
Jon Tollefson is a professor of entomology with responsibilities in field crop pest management.

Improving glyphosate performance in Roundup Ready soybean

By Bob Hartzler, Department of Agronomy

Although glyphosate resistant weeds have been documented in states surrounding Iowa, at this time our only confirmed glyphosate-resistant species is horseweed/marestail (Conyza canadensis).  However, over the past decade we have selected for a weed spectrum that possesses a higher level of tolerance than was present at the start of the Roundup Ready era of weed management.  Because of this, glyphosate control failures are more common now than they were ten years ago.

There are several ways to reduce performance issues when using glyphosate for postemergence weed control.  The most important is to apply the herbicide in a timely fashion.  The majority of control failures are at least partially caused by spraying weeds that exceed four inches in height.   Lambsquarter, waterhemp, horseweed and giant ragweed are species where timeliness is especially critical in obtaining consistent results.

The second factor resulting in inconsistent results is too low of rate.  Base the rate on the most difficult to control weed in the field.  The third factor, and least understood, is the influence of environmental conditions on herbicide efficacy.   Light, temperature, soil moisture, relative humidity and numerous other factors all interact to influence the susceptibility of a plant to any herbicide.  Lambsquarter is particularly responsive to environmental conditions, and under certain conditions becomes almost immune to postemergence applications. Timely application to small weeds greatly reduces the impact of the environment on weed response to postemergence herbicides.

Persons who have experienced inconsistent results in the past typically are interested in additional materials to add to the tank to minimize problems.  The types of additives recommended for use with glyphosate varies among products, although all glyphosate products recommend the use of AMS or other nitrogen sources.  A variety of AMS alternatives (water conditioners) are marketed for use with glyphosate, but many do not provide enough active ingredient to reduce the antagonistic effects of salts present in the carrier.  The specific recommendations for surfactants vary among glyphosate products and should be followed.  The use of surfactants with ‘fully loaded’ formulations has not consistently overcome problems associated with spraying large weeds or weather-related issues.

In certain situations addition of a second herbicide to glyphosate may improve weed control. There should be a specific purpose for adding a second product to the tank rather than arbitrarily adding something in the hope of improving performance. Control of big giant ragweed can be improved with the addition of an ALS herbicide (cloransulam – First Rate/Amplify;  clorimuron – Classic) or a PPO inhibitor (Flexstar, Phoenix, Cobra).   Addition of Harmony GT or a PPO inhibitor has been shown to improve the consistency of wild buckwheat control.   Cloransulam, chlorimuron or a PPO inhibitor can improve the control of annual morningglories. There are no products for use in soybean that will consistently improve the performance of glyphosate on lambsquarter and waterhemp.

In summary, glyphosate remains the most effective herbicide we have to control weeds in soybean and corn.  However, consistent results can only be obtained through good management of the product.  Proper rate selection and timing of application are the most important steps.

Bob Hartzler is a professor of weed science with extension, teaching and research responsibilities.

Will Foliar Diseases be a Problem on Corn This Year?

By Alison Robertson, Department of Plant Pathology

Should I consider spraying a fungicide to protect yield?

Beginning this time last year the droning of airplanes could be heard in Iowa as acre upon acre of corn was sprayed with fungicides.  Today the skies are quiet.  Why?  The corn crop is two to three weeks behind in crop development compared with last year, a result of the cool and very wet start to the growing season.  Across most of Iowa we will be lucky if the corn really is “knee high by the 4th July.”  Last year corn was starting to tassel across the state; this year tasseling will likely occur sometime in mid-July. 

So what does this mean in terms of foliar disease?  Common rust is usually the first disease to appear on corn in Iowa.  We usually start to see symptoms around the beginning of July.  I have yet to see or hear of common rust so far this season.  Gray leaf spot and Northern corn leaf blight usually start to appear towards the end of July when the weather becomes become favorable for infection and disease development (high humidity and very warm temperatures (greater than 85 degrees F)).  During this period, spore levels of the gray leaf spot fungus also start to increase exponentially so inoculum pressure is greater. 

Research has shown that the earlier in the grain-fill process that disease develops, the greater the impact on grain yield.  This year, because tasseling and silking are delayed, grain filling will occur in late July through August, and may coincide with increased disease pressure assuming  we have “typical Iowa State Fair weather” – hot and humid with blankets of fog hanging over corn fields late into the morning.  Thus the impact of foliar diseases on corn yields may be greater this year, since disease could become a problem earlier in grain fill.

Fungicides can be used to manage foliar diseases of corn and protect yield.  With the volatile markets and with yield potential already taking a knock from the floods, the use of a fungicide to protect every bushel might sound even more appealing, and indeed this year could be a good year to spray a fungicide--but there are several factors that need to be considered before pulling the trigger. 

Carl Bradley at the University of Illinois discussed all of those factors in an article posted on July 3, 2008, but I would like to highlight a few of factors that are particularly important for Iowa producers to consider this year:

  1. What’s lost is lost:  Because of the weather we have already lost yield potential in many fields.  No fungicide application can recover that yield.  If producers are to spray, it would be best to target those fields that have the highest yield potential.
  2. Growth stage of the crop: Uneven plant stand is evident in the majority of corn fields across Iowa.  Growth stages in a single field can range between 2 and 4 leaf stages.  Last year, applications of fungicide prior to VT were implicated in deformed ears and reduced yield.  This may or may not be a factor this year, as temperatures at the time of application directly affect phytotoxicity of many fungicides.
  3. Fungicide effective period: Most of the fungicide products registered for corn are only effective for 14-21 days.  Since the grain fill period ranges from 55-65 days, timing of fungicide applications will be crucial to ensure maximum effectiveness of the product and thereby maximize yield protection.
  4. Hybrid susceptibility and disease pressure:  In Iowa, fungicide applications are not recommended on hybrids that have good resistance to foliar disease.  Fungicide applications to intermediate hybrids and susceptible hybrids should be based on disease pressure, forecasted weather conditions and previous crop history. 

This growing season, scouting will be crucial to determine if a fungicide should be applied or not and when it should be applied.  Fields should be scouted to ensure that all plants are at least at VT (tasseling) before a fungicide is applied.  The level of disease in the field also needs to be determined starting a VT, and then one to two-weeks later if necessary.  If disease is present on the 3rd leaf below the ear leaf or higher, and a susceptible hybrid is being grown, a fungicide application may be warranted.  On intermediate hybrids, if the forecast is for hot and muggy weather, the previous crop is corn, or the field has a history of disease, a fungicide application may help protect yield.

A final note on applying fungicides to hail damaged corn--unfortunately there is very little data to support the use of fungicides on hail damaged corn.  In Carl Bradley’s article he discusses a simulated hail-fungicide trial he conducted at Urbana, Ill.

Alison Robertson is an assistant professor of plant pathology with research and extension responsibilities in field crop diseases.

Hail Damage Across a Large Part of Iowa

By Palle Pedersen, Department of Agronomy

Last week was certainly an eventful week in terms of weather across the state. Unfortunately, in several of those heavy rainfall areas hail also occurred, adding a whole new dimension to our stressful crop conditions this year. Along with the flooded fields that will reduce plant stands, the damage caused to the plant by hail will also have to be considered when making replant decisions. It is essential to make good estimation of plant health and accurate stand counts in order to determine the need for replanting.

Soybean is sensitive to hail damage because as soon as the plant emerges the growing point is above ground and extremely sensitive to adverse weather events such as hail. In the case of hail, the plant is considered dead if it is in the cotyledon stage and it is cut off below the cotyledons, or if it is damaged by hail to such a degree that they have no green leaf tissue or regrowth.

The reason is that nutrients and food reserves in the cotyledons supply the needs of the young plant during emergence and for about seven to 10 days after emergence, or until about the V1 stage. Cotyledons are the first photosynthetic organs of the soybean seedling and are also major contributors for seedling growth. Unlike corn, whose growing point is below ground until it reaches V5-V6, the growing point for soybeans is between the cotyledons and moves above the soil surface at emergence.

This makes soybean particularly susceptible to damage from hail, frost, insects like bean leaf beetles, or anything that cuts the plant off below the cotyledons early in its life. Stand reductions are therefore likely to follow hailstorms. Overall, we do not see hail damage to be as critical early during the vegetative growth stages. However, plant injury tends to be much greater during reproductive growth stages.

Some of the hail storms last week had 60 mph wind and hail with the size of baseballs leaving plants with broken stems and completely defoliated. I started a project with Purdue University in 2003 to assess the effect of node removals at different growth stages. This project was funded by the National Crop Insurance Service and we are still doing the research today. Last year we summarized the first three years of the study and here is a short summary of the Iowa data.

We had six treatments of node removal (0, 20, 40, 60, 80, and 100%) and three node removal timings (V2, V6, and R3). Averaged over node removal treatments, yield was 24.9 and 46.1% greater at the V2 than the V6 and R3 node removal timings, respectfully. Seed mass was 3.2% greater when comparing the V2 to the V6 or R3 node removal. Soybean oil content response was variable, but generally decreased as percent node removal increased. Protein content was largely unaffected. Our results suggest that node removal timing was a significant factor to consider when estimating soybean grain yield loss and oil content adjustments may need to be considered to properly compensate growers. 

More information about replant decisions can be found at www.soybeanmanagement.info

Hail Damage Table


Palle Pedersen is an assistant professor of agronomy with research and extension responsibilities in soybean production.

Pre-harvest Intervals for Foliar Fungicides on Wheat

By Daren Mueller, Department of Plant Pathology

EPA has notified the Iowa Department of Agriculture and Land Stewardship that some problems with compliance with pre-harvest intervals for fungicides applied to wheat in Kansas were discovered this year. Some wheat was embargoed until tests could be completed to determine residue levels. Although Iowa has a small number of wheat acres compared with Kansas and other nearby states, pesticide applicators and growers should check the pre-harvest intervals (PHIs) for any wheat fungicides that have been applied.

Table 1.  Wheat Pre-Harvest Intervals for Fungicides Registered in Iowa

Preharvest intervals for wheat fungicides

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

Degree Days Continue to Lag

By Rich Pope, Department of Plant Pathology

Another week of slightly cool days with scattered storms has Iowa farmers facing uneven stands in many fields. Cumulative heat during the week of June 23 lagged behind long term averages by 10 to 25 degree days in Iowa. The cool temperatures and still wet soils provide stresses to struggling crops, and those stresses are showing up in poor growth.  As we get more heat the corn and soybean should recover, but this early summer has predisposed the crops to future stresses.

Accumulated degree days through June 29

That said, some fields that got planted by mid-May have escaped the onslaught of flooding and ponding and are doing quite well. 

The first 2008 report of soybean aphid in Iowa was by ISU field agronomist Brian Lang in Winnesheik County on Saturday, June 28. The infestation was reported as scattered clusters of small (5-30 aphids per soybean plant).

Rich Pope is an extension specialist with responsibilities in the Corn and Soybean Initiative.



This article was published originally on 7/7/2008 The information contained within the article may or may not be up to date depending on when you are accessing the information.


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