AGRONOMIC UPDATE – July 21, 2021….

Corn Fun Fact:  One acre of corn eliminates 8 tons of carbon dioxide from the air….that’s 1200T from a 150 acre field.

Topics:

– Growing Degree Day Update

– What’s going on in my fields?…..Corn Development, Disease, Crop Water Use….

– Corn/Soybean Insect Update

– Soybean Development – Disease and more…

As of July 21st, we have accumulated approximately the following for Growing Degree Days in 2021:

Planting Date     GDU’s2021          Average GDU     Departure from average

April 24               1569                        1424                      +145 (+6 days)

April 30               1515                        1387                       +128 (+5 days)

May 6                   1439                       1350                      +89 (+3.5 days)

Since the last update on July 9th, we continue to be a few days ahead of the average and the same, to slightly behind, 2020.  The cooler temperatures of the past couple of weeks has not cost us to much as far as time is concerned and the cooler temps meant less stress on the crop….which is ALWAYS a good thing.

The above maps are the latest 6-10 & 8-14 day forecast maps for temperature and precipitation.  You can see that above normal heat and below normal precip is predicted for the next two weeks and forecasts are calling for temps into the 90’s over the next 10-14 days.  This will move the crop along and increase crop water usage….more on this below.

WHAT’S GOING ON IN MY FIELD?…..Corn Development, Disease, Crop Water Use..

Most of the corn crop is in the R1 (silking) to Early R2 (Blister Kernel) stage.   So far I would estimate that most fields in the area are 50% to Done pollinating.   I would expect to see some uneveness in pollination/silking due to the uneven emergence we saw this past spring and from the willowing effect from the storms of July 9th.

  • Plant height on the corn crop this year is as high as I can remember for quite a few years….ear height as well.   This is across all hybrid families.   While not an indicator of yield, extra-tall plant height brings its own management issues.   Right now this is mainly connected to irrigation.   Irrigation coverage using drop nozzles will potentially not be as even if the nozzles extend to far into the canopy, watch for this over the upcoming heat that is predicted (I have seen years like this where it is wet on one side of the plant and dry on the other, and water never gets to the dry side the rest of the year).  Also, the upper canopy of the plant can become stripped up from irrigation equipment, potentially impacting grain fill.
  • A captured pollen grain takes about 24 hrs. to grow down the silk to the ovule where fertilization occurs and the ovule becomes a kernel.
  • At R1, potassium uptake is essentially complete, and nitrogen and phosphorous uptake are rapid.  Last round of N should be going on over the next 7-10 days.
  • Blister Kernel occurs approx. 10-14 days after Silking.  Starch has begun to accumulate in the watery endosperm and the kernels are beginning a period of rapid, steady, dry matter accumulation that will continue until physiological maturity in approx. 50-60 days after silking.
  • At Blister Kernel, maximum ear length is achieved.  Although not as severe as at Silking, stress over the next two weeks can still have a profound effect on yield through kernel abortion.
  • Kernel abortion from stress can occur through the Milk stage(18-22 days after silking), however when the plant reaches Dough, kernel abortion will no longer take place, and any yield reduction from then on out will be from lower test weight.
  • As far as sunlight is concerned, we are currently running about 10% percent below normal over the last 14 days, or from V14-Pollination.  Sunlight, of course, is now a much bigger yield factor, since we are now beginning the crucial grain fill period.   As such, how much sunlight and when it occurs during the grain-fill period, will play a role in overall yield and late-season plant health.   Lack of sunlight early in the grain fill period (i.e. right now)  can lead to the ear tipping back as well.
  • Extra stress will occur if sunlight is reduced and temps (especially nighttime) are higher than average.  This stress occurs because, since temps are high (especially nighttime temps) the energy demand on the plant is higher than average; couple this with reduced photosynthesis, and this leads to greater energy in the plant just going to maintain itself and not to filling the ear.  It is an axiom in corn production that when you have to run your air conditioner at night, it is not good corn growing weather.
  • Relative Humidity over the past two weeks has been 9% higher than normal, with a daily average of 81% RH during this time frame.   This, coupled with average high temps in the upper 70’s to low 80’s (average high temperatures have been 6 degrees below normal during this time period), increases the probability of seeing a greater incidence of leaf disease, especially Gray Leaf Spot and Northern Corn Leaf Blight.   We are just starting to see the first Gray Leaf Spot lesions this week.   This is about 7-10 days earlier than the last few years.   Currently we are seeing very low leaf disease pressure in area fields, however, the past two weeks has allowed good incubation of diseases and we would expect to see an outbreak occur over the next couple of weeks.  If we experience warmer temps and lower RH than forecasted, the potential for impact from diseases will be reduced.
  • The forecasted temperatures will also increase the potential for Northern Corn Leaf Blight, a disease we normally do not see here but that can blow up in cool temps.  https://www.pioneer.com/us/agronomy/northern_corn_leaf_blight_cropfocus.html
  • Keep an eye out for Southern Rust as well…..https://www.pioneer.com/us/agronomy/southern_rust_cropfocus.html
  • Fungicide application should be going on now and into next week, for best yield response.  You want to protect the plant when it is working the hardest, which is silking through milk stage.  Fungicide will not help control bacterial leaf streak.
  • The past two weeks have seen a daily average of .17-.19 in/day.  This is very much a reflection of the lower temperatures and higher relative humidity during this time frame.
  • The corn crop is now at its peak water usage, so expect average ET rates to be .25-.35 in/day through the Milk stage.  Maintaining an adequate soil moisture profile will be key over the next three weeks or so.   As you think about irrigation needs over the next two weeks, keep temperatures and relative humidity in mind as we move forward to see what actually occurs to help reduce potential water stress or potential over watering.  If dew points are low (dry mornings), that means relative humidity is low, and ET rates will ramp up quickly and be higher than normal.  On the flip side, if heat indices are high in which a 95 degree actual temperature feels like 110 degrees, then relative humidity is high and ET rates will be average to below average.  Forecasts for next few days are calling for low dew points meaning potentially higher ET rates than normal.

SOYBEAN UPDATE

  • Much of the crop is in the late-R2(full flower) to R3(pod set) stage of growth.
  • Peak water use, nutrient demand, and overall energy demand in the plant occurs at R3 and into R4 stage….i.e. right now and into the next few weeks!
  • ET rates in soybeans reach peak at R3 stage (.30+ in/day) and will continue to stay high through R6(full seed).    See comments above on corn ET rates, as the same applies for soybeans.  One will need to be careful not to water constantly to help reduce disease potential (see below on white mold) due to a constantly ‘wet canopy’.   If White Mold becomes a problem, it will be best to water at night and leave off during the day so the canopy has some chance to dry out.    In heavy soils, when irrigation is needed, we recommend running a heavy irrigation amount (.80 to inch) and then leaving it sit for a while.
  • R3 is the prime growth stage for fungicide/insecticide applications….some early planted and early maturity fields are in this stage right now.  Same goes for any nutrient application such as N, as well.  Now and into next week will be excellent time for application.
  • We saw our first infected plants with White Mold earlier this week.   This is about two weeks ahead of the last couple of years.  Weather conditions of the past two weeks have been very conducive for White Mold to occur.  White Mold infestations could be on the severe side this year.   Any 2nd treatments for White Mold need to go on at R3 and should be going on now and into next week.   See the attached link for White Mold management.    http://www.pioneer.com/us/agronomy/managing_white_mold_soybeans.html    We recommend Aproach or Delaro fungicide for any white mold control.   High temps and dry mornings will slow the disease down.

INSECT UPDATE – Corn & Soybeans

  • Keep scouting for Western Bean Cutworm larvae.  Moth flight has been somewhat erratic over the past week.  From GDU data, we expect that the flight is 75% complete.  However, I do think light numbers will continue to fly over the next few weeks, leading to a potential slow buildup of infestation levels.  However, any potential treatments should be on, or going on ASAP, as we are now finding small larvae on the ear tips, at top of the silks.  Any delay in treating, and they will be too far into the ear tip for control.  Overall infestation levels are not super high, but many sandy fields still have the potential to have infestation levels that will cause economic damage.
  • Corn Rootworm pressure has been much higher this year than the past few years.  Adult rootworm beetle control should already be on, or going on now if planned….Steward insecticide by FMC is an excellent choice for control
  • Overall insect pressure in soybeans has been very light.   Begin scouting next week for Bean Leaf Beetles as they will begin feeding on developing pods over the next few weeks.  So far we are not seeing much for Soybean Aphids.   If you have made an insecticide application already, this should give you season long control unless a severe outbreak of one of these insects occurs.
  • Dectes Stem Borer – be on the lookout for this insect starting now and into harvest.  This is a new insect that borers into the stem and we saw our first case of this insect in August last of 2019.  Watch field edges first and let us know if you are seeing wilted and dying plants as they move in from the grassy edges.   https://www.pioneer.com/us/agronomy/stem-borer-dectes.html
  • Seeing very small colonies of Corn Leaf Aphids(dark green aphid) in area corn fields.   They tend to proliferate under cooler and damper conditions, so we may see their numbers increase in the area.   They are not an economic concern, but you may begin to notice them as you walk through your fields.
  • We are just starting to see our first Spider Mite colonies…..very small and on the very bottom leaves.   However, if temperatures turn out as forecasted and relative humidity stays lower than average, infestation levels will increase.  Keep an eye out for this insect over the next month or so.

PIVOT BIO

Pivot Bio announces their next generation product!   With Pivot Bio’s next generation product for corn, PROVEN 40, farmers can turn to a more dependable nitrogen. Learn more about this revolutionary offering here:  https://blog.pivotbio.com/press-releases/series-d  We are excited to see what Pivot Bio has to offer and what performance we may see as we move towards harvest….we have many trials out in our area.   

Reminder that the Pioneer Annual Customer Appreciation Supper is Friday, August 20th…..it’s our 25th Anniversary, and we ask you, our customer to help us celebrate!!   Invite will be coming out soon!

Please contact us with any questions or comments you may have!   Thank you for your business!!

Starman Seed Service, Inc.

/by

AGRONOMIC UPDATE – July 9, 2021….Sex in the Corn Field….

I knew that title would generate some interest…..it’s not what you are thinking!

Fun fact: A single tassel produces approximately 5+ million pollen grains….

Topics:

– Growing Degree Day Update

– What’s going on in my fields?…..Corn Development, etc. 

– Fungicide/Disease in Corn

– Insect Update

– Soybean Development

As of July 9th, we have accumulated approximately the following for Growing Degree Days in 2020:

Planting Date     GDD’s2021          Average GDD     Departure from average

April 24               1294                        1159                      +135 (+3 days)

April 30               1240                       1141                       +98 (+2 days)

May 6                   1161                        1099                      +67 (+2.5 days)

 We have lost a couple of days compared to normal since the last update at the end of June.   Other than over the 4th of July weekend, temperatures have not been as warm as predicted and humidity levels have been more like normal for this time of year.   So far we have been lucky to dodge any storm damage….hopefully this trend will continue.

Based on the above numbers, when can we expect to silk?  If we look at P1366 genetics we see that it takes approx. 1380 GDU’s to silk, this means that we would be looking at a potential silk date around July 12-15.  Hybrids such as P0622 (1270 GDU’s to silk) are close to tasseling and should be pollinating next week.   In other words, we can expect to see most all fields begin tasseling next week, with heavy pollination shed occurring mid-next week into the following week.   This is slightly ahead of the average and of last year.

What’s going on in my field?….

  • Overall much of the corn crop looks very good!  Very good color and uniformity for the most part.  Much of the corn crop is in the V14-V16 leaf stage, with some tassels beginning to poke out along tree lines, etc., depending upon hybrid and planting date.  This is slightly ahead of last year.   From V10-VT, corn gains a new color every 50 GDU’s, or about every other day.   
  • Kernels per row began around V12 and is continuing through and up to tassel stage
  • Nitrogen needs will continue to grow through tasseling and into early reproductive stages.  Nitrogen uptake in corn – very rapid now through tassel (up to 4-8 lbs per day).  Today’s hybrids use nitrogen later in the growing season and into the reproductive phases.  You will want to keep that last shot of N available for after tasseling.    This year so far, we haven’t experienced conditions that usually lead to N loss from leaching or denitrification….overall color looks great!   Expectations are that more N is potentially available in the soil profile.
  • We are now into the rapid growth and accumulation of dry matter by the plant.  The window for brittle snap is still open over the next 7-10 days.
  • Under field conditions, pollen shed usually occurs in the late morning and early evenings.
  • Pollen shed will extend for one to two weeks, but if field is uniform in plant emergence and height, pollen shed is 80% complete in 5-7 days from full tassel emergence.
  • At tassel, vegetative development is now complete; maximum plant height and root depth is achieved.
  • VT overlaps with R1 (silking stage) when visible silks appear before the tassel is fully emerged.  By definition, growth stage R1 (Abendroth et al., 2011) for an individual ear is defined when a single silk strand is visible from the tip of the husk. An entire field is defined as being at growth stage R1 when silks are visible on at least 50 % of the plants. This whole field definition for growth stage R1 is synonymous with the term “mid-silk”.
  • A captured pollen grain takes about 24 hours to grow down the silk to the ovule for fertilization.
  • Peak pollen shed usually occurs in mid-morning.   Some research indicates that pollen shed decreases after temperatures surpass 86F.   A second “flush” of pollen often occurs in late afternoon or evening as temperatures cool.   Pollen shed may occur throughout most of the day under relatively cool, cloudy conditions….. https://www.pioneer.com/us/agronomy/corn_pollination_success_cropfocus.html
  • Weather conditions influence pollen shed.  If the anthers are wet, the pores will not open and pollen will not be released.   Thus, on an average summer morning following a heavy evening dew, pollen shed will not begin until the dew dries and the anther pores open.  Similarly, pollen is not shed during rainy conditions.   Cool, humid temperatures delay pollen shed, while hot, dry conditions hasten pollen shed.
  • Generally 2-3 days are required for all silks on a single ear to be exposed and pollinated, with the silks on the butt of the ear emerging first.  The silks will grow from 1-1.5 inches each day and will continue to elongate until fertilized.  If not pollinated, silk elongation stops about 10 days after silk emergence due to senescence of the silk tissue. Unusually long silks can be a diagnostic symptom that the ear was not successfully pollinated.
  • Silk emergence and growth is dependent upon turgid pressure within the plant, in other words how much water is available in the plant to cover all of its needs.   If this is limited, (ie. dryland, low-gallon wells, etc.) silk emergence will be slowed and delayed with potential to miss the pollen shed.   Under severe water stress conditions pollen shed will still take place like normal, however, silks can be delayed, which means potential for poor pollination.
  • It takes approximately 55-60 days from silking to physiological maturity.  So if a field is silking on July 15th, it will need until September 15th to reach maturity, given average weather.  Current 6-10 and 8-14 day forecasts call for slightly above normal temperatures, which should give us a GDD accumulation of 26-27 GDU’s per day.
  • High nighttime temperatures (ie. any stress) begin to play a role in final yield during grain-fill as this causes the plant to work harder to maintain both yield and overall plant health.

Corn Leaf Disease/Fungicide

  • The next four to six weeks will be critical for disease infestations and fungicide applications.
  • Begin scouting now and through the next few weeks for disease infestations.  So far, leaf disease load in area cornfields is very low, mainly bacterial leaf streak (see attachment below).  Bacterial Leaf Streak incidence is the lowest we have seen over the past few years.   However, overall temps and humidity levels the past couple of weeks have been conducive for an increased development of leaf diseases.
  • If you are planning on only one fungicide application, the best timing for this application is after pollination as the crop is working the hardest and has the highest demand for energy at this time.  We want to protect as much of the leaf surface as possible in this time frame, which is from pollination and the two weeks after.   Corn on corn acres are always a good place to start with fungicide applications.
  • While any hybrid can have a response to foliar fungicides, hybrids such as P0589, P0950, P1138, P1244, P1185, P1138 & P1366, are hybrids to focus on first for higher probability of response from foliar fungicides, especially if gray leaf spot infestations are high…..Fungicide response probabililty….This attachment is a list of Pioneer hybrids and their potential response to a fungicide application for Gray Leaf Spot and Norther Corn Leaf Blight.  The chart also shows staygreen and stalk strength ratings for each hybrid.   This chart can help with fungicide management decisions.
  • See attachments on disease and fungicide management – https://www.pioneer.com/us/agronomy/maximizing_foliar_fungicides_corn.html and https://www.pioneer.com/us/agronomy/bacterial-leaf-streak.html
  • https://crop-protection-network.s3.amazonaws.com/publications/fungicide-efficacy-for-control-of-corn-diseases-filename-2021-03-09-163332.pdf.   This attachment shows efficacy by active ingredient for different leaf diseases, for the current fungicides on the market

Water Management

Below are some key water management tips to keep in mind:

  • The greatest yield loss from moisture stress occurs in the period two weeks prior to two weeks after pollination.  For the next two weeks, the corn crop will be at its peak water usage, with ET rates of .30+ inches per day – higher when temps are in the mid-90’s and higher yet when combined low humidity.
  • ET rates over the past week or so have been normal to slightly above normal.  Thankfully we have received some timely rainfall in this period.  However, we are now fast approaching peak water use in corn, and with the potential higher temps forecasted for the next couple of weeks, it will be important to stay on top of overall water needs by the crop.
  • At present, we are seeing fairly good root depth according to the soil moisture probes….sandier soils are 16-28” (better than average) and heavy soils are 20-32+” (somewhat below average) depending upon plant date, conditions and soil type.  Remember that maximum plant height and root depth are achieved once the plant tassels.

Insect Update

Western Bean Cutworm egg masses can be found in area, sandy fields.  Keep these tips in mind over the next few weeks:

  • To scout for this insect, check the sandier fields first and look on the upper side of the leaf for a white, or purple, egg mass.  These will be found on the upper 1/3 of the plant.
  • We will again have the pheromone moth traps located west of Elgin.   We caught our first moths at end of this week.   Check back on this website, under Grower resources, for updated moth flight counts.
  • Treat when the fields are 95% tasseled.  Use high rates of a Capture-like product to give you 3-4 weeks of residual control.
  • WBC are attracted to those fields that are closest to tasseling.
  • Once a field has been tasseled, any egg masses that hatch will see the larvae head straight to the ear tip, so treatment soon after tasseling is critical.
  • AML versions of Pioneer hybrids offer control of WBC/Corn earworm.  No need to treat these hybrids for WBC – these include P0622AML, P1138AML, P1366AML, P1563AML, P2042AML and P2089AML.

Corn Rootworm pressure appears to be higher this year versus the past few years.  Adult beetle emergence is occurring right now, and will continue over the next few weeks.  Monitor your continuous corn acres for adult beetle populations to:

  • prevent high numbers interfering with pollination through silk-clipping.  There is a higher potential for this to occur this year than past years due to timing emergence of the adults and potential for high overall numbers of beetles.
  • help with rootworm control in your continuous corn acres.  Strongly recommended to use Steward insecticide (by FMC) for control of adult beetle populations to help with next year’s control of rootworm.  This product has shown excellent results for both kill and residual, upwards of 30 days.

Grasshoppers….seeing light feeding in both corn and soybeans from small grasshoppers.   Keep monitoring for this insect if conditions stay dry.

So far we are not seeing much insect activity in soybeans.  Gall Midge in Soybeans – There is a continued increase of reports of Gall Midge in the counties to the east of us.  I would assume that we have this insect somewhere in our area in very light numbers.  Keep an eye out for plants dying on the edges of your field, or in the end rows, as this insect is most common on field borders.   See attachment for more info.   https://www.pioneer.com/us/agronomy/Gall-Midge-New-Pest-In-Soybeans.html

Soybean Development

  • Most of the soybeans in our area are at late R1 (Beg flower) to mostly R2 (Full flower).  I would not be surprised to see early R3 (pod set) on some fields next week.   Most fields are finally coming around and growing….some fields are still showing leaf cupping…..crop growth is also uneven in some fields in those areas with high crop residue.
  • Soybeans should be nodulating heavily at this stage.   At the beginning of the reproductive stage, soybeans will still put on 50% of their vegetative growth.
  • Crop water use in soybeans starts to increase rapidly at full flower, peaks at R3 and will stay high through R6, or full seed  Flower stage is usually the time when the soybean plant begins to pull from the deeper root zones.
  • We continue to see a yield response from a fungicide application in soybeans, either at R1 for white mold (applications of which should be on already) and/or a later R3 (pod set) stage of growth.  Environmental conditions over the next two months will determine disease incidence and overall level of disease infestation.  In 2019 we saw a lot of Frogeye Leaf Spot occur in soybeans, keep an eye out on this disease as well.  See attachment for more info on this disease….https://www.pioneer.com/us/agronomy/frogeye_leaf_spot_on_soybeans.html     Not all fungicides control this disease, so make sure you check the label to see if this disease is controlled.  Much like in corn, we are not seeing much for leaf disease pressure in soybeans at the moment.
  • White mold attachment:  https://www.pioneer.com/us/agronomy/managing_white_mold_soybeans.html

Thank you for your business!!   Please let us know any questions or concerns you may have!!

Starman Seed Service, Inc.

/by