AGRONOMIC UPDATE: September 19, 2025….Harvest fast approaching….

   

Topics:

  • GDU/Weather Update
  • Corn – Soybean condition
  • What to look for heading into harvest….

TEMPERATURES & GDU ACCUMULATION:

As of September 18th, we have accumulated approximately the following for Growing Degree Units in 2025:

Planting Date     GDD’s2025          Average GDD         Departure from average

April 17                  2756                           2621                              +135 (+8 days)

April 24                 2704                           2575                              +129 (+8 days)

May 1                     2658                           2528                              +130 (+8 days)

Corn – Soybean Conditions…

  • From the above numbers, we see that GDU accumulation has gained a few days since the last update on the 9th. We are at now reaching GDU numbers that get us close to black layer.  The early and mid-maturity hybrids planted in April are basically at black layer, with the fuller season hybrids at 7/8 milk line or beginning black layer, which is matching the GDU numbers above.  The end-of-April and first-part-of-May planting dates still need some time yet, as they are 2/3-3/4 milk line, another 7-10 days yet. Any delay in emergence at planting will delay maturity by a few days compared to the above numbers. Temperatures for September have been average to slightly above normal.  This allowed the crop to gain some ground.  Current long-term forecasts are predicting average temperatures through September with above-normal for October into November. Last year at this time, we saw warmer temperatures, dry conditions and very low humidity throughout harvest….it appears that the 2025 harvest will not see these conditions to the near the extent seen in 2024.  Considering the growing season, we can be glad much of our crop got planted by first week of May….
  • Corn fields in the area are starting to lose their color.  This is happening earlier than past years. This is due to, one, natural senescence as the plants reach maturity, and two, from disease and stress from growing season, with this having the biggest impact. Plant staygreen will vary from field-to-field, and from hybrid-to-hybrid (even within a hybrid family itself), as the next weeks progress. Monitor plant staygreen over the next few weeks.  Monitor those fields that lose color the quickest over next few weeks (a few area fields are already there) as they will be the first ones to go after for harvest.  Due to the increased stress the crop experienced this year, we expect stalk quality to be poor come mid-to-late October (in some cases in next couple of weeks)….rapid color loss is still the key indicator for potential problems with stalks, etc., and they should be at the top of your harvest priority.  Monitor those fields that lose color the quickest over next few weeks as they will be the first ones to go after for harvest. Late leaf disease pressure and overall stress, will lead to potential harvestability issues even on those fields where a fungicide was applied….timing of application and what product used will play a much bigger role this year than past years for staygreen and late-season standability….
  • Disease and Harvest: Leaf disease has been heavier than normal once again this year. Southern Rust was heavy throughout the area and is impacting plant health.  However, disease from Tar Spot is having the biggest impact on late plant health over the last two weeks.  Impact on plant health from Tar Spot has increased greatly since the first of the month, mostly seen in loss of plant staygreen…some area fields have really ‘turned’ over the past 7-10 days.  We do see separation on Tar Spot tolerance across seed companies versus Pioneer. As observed in the past few years in the eastern states, Pioneer has shown increased tolerance to Tar Spot versus many competitors….see photos below:
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  • These photos show difference in P1413AM versus 113 day competitor.  Middle photo is from satellite imagery taken on September 13th. Photos of the plants and from  drone were taken September 18th.  All from same field.  Video link is from this field:  P1413AM vs 113 day Competitor – late-season health
  • The above phots were taken in a plot on September 12th.  P13777 family has shown good tolerance to Tar Spot so far this season.
  • Below are a couple more photos showing late-season plant health and impact of Tar Spot.  Both photos taken September 18th.  First photo is a field completely dead, with tops breaking out, and hand shelled @ 20% (not a Pioneer hybrid).
  • Late-season plant observations:
  • P13777PCUE plant health
  • P14830AML plant health
  • Please keep in mind that these are local, field specific, observations and not indictive of the area as a whole.  However, they do show trends for plant health and potential stalk issues as the season progresses.  Bottomline, have harvest equipment ready to go now and be flexible to move from field-to-field depending upon late-season health, etc.  2025 harvest looks to be one to get done quicker than past years. There is increased potential to have some corn fields needing to be harvested before soybean harvest is completed….
  • Ear Molds: Wet and damp conditions of the past few weeks has led to ear molds starting in most corn fields. As to what level of molds we will see, and to what impact they will have on yield and harvest, remains to be seen; however, potential is significant to see higher ear molds than past few years. We need dry, low humidity, and breezy conditions (also needed for crop drydown) over next few weeks to slow the progression of these molds; however, once they are present, they will remain on the ear, even with drier conditions….any new spell of moisture will allow them to increase again.  Those hybrids which keep a closed husk into harvest will be the most prone for increased ear molds….as well as those fields shutdown early due to disease or stress….
  • There is some very good corn in many area irrigated fields, as kernel depth and color looks good as we move into the later half of September.  We still expect to see more variability in irrigated yields overall this year versus past few years, mainly from the growing season we had, especially in the sand versus heavier soils.  One potential on yield for 2025 will be ‘can we get it our before it wants to fall apart?’  As mentioned above, we expect to have more standability issues this year than we have seen over the past number of years.
  • Grain moisture drydown is dependent upon temperature and ear husk structure.  Starting to see some husks begin to open in fields now.  On average, it takes 15-20 GDU’s to lower grain moisture each point from 30% down to 25%, 20-25 GDU’s per point of moisture from 25% to 22% and 25-30 GDU’s per point from 22% to 20%.  A high of 75 degrees and a low of 55 degrees equate to 15 GDU’s, which should roughly take a point of moisture out per day when grain moisture’s are 25%+.  So temps in the mid-70’s for highs and mid-50’s for lows should take corn from 30% to 25% in a week’s time.  Forecasted temperatures for the next 7-10 days will give us 12-16 GDU’s/day….drydown will be on the slow side for the rest of September by the looks of it.
  • Soybean harvest moisture: There is an average yield reduction of 7-8% when going from 13% moisture to 8% moisture soybeans.  This means an average loss of 6 bushels/acre (using an 80 bu yield) just in moisture, along with potential reduction from header loss, etc.   The below chart shows the average yield lost from lower harvest moisture and delayed harvest over five year on-farm study from Pioneer.
  • Weather conditions as of late, along with future forecasts, is leading to a slower development of soybeans getting ready to harvest….as well as a delay in harvest overall.  Forecasts do not look to be conducive for much harvest in September….
  • All for now.  As harvest progresses, we will text out plot info and updates.  Have a safe and successful harvest!!

Starman Seed & Supply, Inc.

 

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AGRONOMIC UPDATE: September 10, 2025….Approaching the Finish Line….

Topics:

  • Growing Degree Unit Update/Weather Forecast
  • Corn/Soybean Update
  • Prioritizing Harvest….
  • New Corn Hybrids for 2026…

TEMPERATURES & GDU ACCUMULATION:

As of September 9th, we have accumulated approximately the following for Growing Degree Units in 2025:

Planting Date     GDD’s2025          Average GDD         Departure from average

April 17                  2577                           2488                              +89 (+5 days)

April 24                 2526                           2442                              +84 (+5 days)

May 1                     2479                           2395                              +84 (+5 days)

GDU accumulation has been below normal since the last update on August 19th.  However, we continue to be ahead of the average, though we did lose 3 or so days since the 19th of August.  Considering how cool it has been, this is not as big a loss as what was to be expected.  This did give the crop a break, which was much needed back in August.  Since the last update, we have accumulated average of 15 GDU’s/day, which is 4-5 GDU’s less/day than average.  We should potentially see another 300+ GDU accumulation over the next 14 days if temps stay as forecasted. If this holds true, this means we will have accumulated 2700-2900 GDU’s by September 24th, which would mature most all hybrids regardless of planting dates….

Current Corn Conditions…..

  • Current stage of much of the corn crop is as follows:  Most fields are following the above GDU accumulation.  105 day and earlier hybrids planted before April 24 are 3/4 milk line – fuller season hybrids are 1/2-2/3 milk line.  May 1 planting dates are 1/4-1/2 milk line.  Most fields will take another 10 days (April planting dates) to 20 days (May planting dates) to finish, using average-to-above average temperature forecasts over this time period.  The current 10-14 day forecast looks conducive for development, but it will be interesting to see how the hot temperatures and breezy conditions predicted over this period will affect overall plant health and staygreen. Both grain color and kernel depth look very good at present; however, these next two weeks will still be important for final test weight and kernel depth. Silage harvest is getting underway, and early indications are normal to above-normal tonnage….
  • Below are a couple of photos showing impact of kernel depth and test weight on final yield….
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  • Note the second photo showing size of ears.  Note that all the ears are same rows around and kernel count, however kernel depth and weight is much different between the ears, with corresponding reduction in yield. We are still impacting kernel depth and test weights over the next couple of weeks….keep this in mind for last irrigations, etc…
  • Sunlight:  Solar radiation for all of the grain fill period, beginning in mid-July, has been below normal. We saw good sunlight in mid-August, but since the last week of August and into September, we’ve seen much below again. Sunlight plays a key role in kernel depth and test weight, as well as overall plant health. September 2024 saw much above normal sunlight which played a role in the good late-season plant health that we saw last year. So far in September this year, we are not having that luxury. This increases the potential for a negative impact on stalk integrity later into harvest for 2025, due to reduced photosynthesis going to overall plant health….this will be exacerbated by the high levels of disease present in most fields this year.
  • Disease:  As we saw in 2024, overall leaf disease pressure has been high this year….mainly Southern Rust; however, Tar Spot is starting to takeoff in some area fields. Most all corn fields in the area are ‘marked up’ with leaf disease.  Even fields with fungicide are marked up to some degree, though much reduced versus no fungicide applied.  The biggest drivers of disease right now is Southern Rust and Tar Spot. The cooler weather as of late has slowed Southern Rust down some, but it is still active and will increase in activity with the increasing warmer temperatures that are forecasted.
  • While the 2025 crop is ahead in development versus 2024, it seems like area fields are losing their color a little earlier than last few years.  This color change is due to crop maturity, but is also a reflection of the overall disease pressure and severity within the fields. Southern Rust does not overwinter here, so it is not usually a concern, however, if we get a lot of southerly winds, and/or hurricane outflow, we have a greater chance for this disease to develop.  Southerly trade-winds were very active all summer which drew the disease into our area.
  • As was to be expected, we have seen higher levels of, and earlier appearance of, Tar Spot in the area versus last year. Early infestation levels of this disease were low, but we are now seeing this disease really takeoff in some fields (and hybrids) over the past 10 days or so, and we would expect this disease to increase in infestation levels as the growing season reaches an end. While not having much impact on overall yield, this disease will be a big factor in late-season standability across hybrids and fields.
  • This set of photos was taken September 9th, all from the same field. They show differences in Tar Spot tolerance across three Pioneer hybrids. We are seeing the P13777 family show very good tolerance to Tar Spot. For Tar Spot, Pioneer offers some of the leading tolerance, across their hybrid lineup, within the seed industry. We continue to see Pioneer show better tolerance than many competitive hybrids and brands. Besides the irrigated acre, keep this in mind for the dryland and more marginal acres, that do not see a fungicide every year…
  • Due to the high incidence of disease pressure in 2025, we expect to see an impact on area corn acres this year, most likely in late-season plant health.  See Prioritizing Harvest below for more info.
  • Irrigation demand is slowing down, and we can see the end, but with the warmer temps coming it is still needed in the sandy soils and on the later planting dates (end of April & May)….even in the heavy soils, as black layer is still 2+ weeks away on these later planted fields. Keep in mind that 1/2 milk line corn requires 2.5″ – 3″ to finish….more in hot weather.  ET rates will approach .30-.40+ over next few days as temps warm up and breezy conditions prevail. Keep this in mind over the next 5-7 days. If irrigation is planned, better to water earlier than later….Don’t shutoff too early….the longer it stays green, the better yield and plant health. 

Current Soybean Conditions…..

  • Soybeans are starting to turn in much of the area.  Most fields are in mid-R6 to early R7.  The early group II soybeans are really starting to turn now.  Forecasted heat over next 5-8 days should move things along….
  • Disease:  Sudden Death Syndrome (SDS) is present in much of the area, with some fields showing heavier levels of infestation.  White Mold infestations have been very light this year….caught a break here. Overall disease pressure in soybeans has been much reduced this year compared to prior few years.
  • Irrigation: Fields in the late-R6 to early-R7 stage need approximately 1.5-3″ of moisture to finish.  For reference, the chart below shows soybean stage of growth at R6-R7.  Don’t give up on that last watering…..
  • Dectes Stem Borer.  This insect enters the plant at a node and proceeds to ‘hollow out’ the stem leading to early plant death.   So far not much one can do in the way of management for this insect yet. However, as with past few years, we expect this insect to be present in area fields. Keep this in mind as harvest begins and progresses. For more info see the following link….Dectes Stem Borer in Soybeans

Prioritizing Harvest!

The extremes in weather (very dry conditions at planting and emergence, consecutive days of high winds at V4-5, wet and cool summer with intermittent heat spells, reduced sunlight during grain fill, high disease pressure) in 2025 have the potential to impact late-season stalk quality.  As mentioned above, diseases like Southern Rust & Tar Spot will have some of the biggest impact on stalk quality.  Heavy fields of Southern Rust and late Tar Spot will be very likely to have poorer late-season stalk quality.  Stalk rots appear each year with varying degrees of severity. They are caused primarily by fungi and bacteria, but they can also result from environmental stresses. When these diseases or conditions happen, they weaken or destroy vascular tissue in the stalk, and the plant cannot transport water or carbohydrates effectively, which ultimately results in premature plant death and reduced grain fill.  The environmental stresses this year are putting more pressure on plant health.  Watch for those fields that lose staygreen quickly, or that have ears drop suddenly, as these are signs of premature plant death.  See photo for ‘ghost stalk’…..

The longer the plant stays green, the better the standability will be as harvest progresses.  Bottom line….there is a higher probability for the 2025 harvest to have significantly more issues with stalk integrity as harvest progresses, especially if sunlight stays reduced through September, limiting overall photosynthesis.  This is one year where you want to be ready ‘to go’ at the first opportunity….equipment, labor, etc.

New Corn Hybrids:

         

 

The above photos are some of the new hybrids for 2026 with a couple of the leader products from the show plot.  For 2026, Pioneer has over seven new corn hybrids across the 105-115 day maturities.  The photos above show some of these new products.  Please contact for more information on these products.

In 2024, Pioneer introduced the new Powercore Enlist, Powercore Ultra Enlist and Vorceed Enlist technology in corn. All new hybrids from Pioneer, starting in 2025, will have the Enlist technology, with Powercore providing above ground protection like the current AM products, Powercore Ultra providing above ground protection like the current AML products, and Vorceed is the new corn rootworm protection with RNAi performance. These hybrids offer excellent drought tolerance (one new AquaMax hybrid) as well as good disease tolerance package, with very good staygreen and improved brittle and root scores.  These are some numbers to watch as harvest progresses.

Please let us know any questions, or concerns, or comments you may have.   Let us know how we can help as harvest gets going!  Stay safe! Thanks for your support!

Starman Seed & Supply, Inc.

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