May was a month we all might want to forget. The data below was captured by my weather station near Centerburg.
Click here for .pdf report 2025 May
May was a month we all might want to forget. The data below was captured by my weather station near Centerburg.
Click here for .pdf report 2025 May
Soybean seedling diseases are often the cause of reduced stands and can cause significant economic losses on an annual basis. Diseased seedlings are often less vigorous and severe stand loss may require replanting of affected areas. So far, this spring, the persistent wet weather we have been experiencing has created ideal conditions for the onset of early-season soybean seedling diseases. Diagnosing seedling diseases in the field can be difficult since the symptoms of various seedling blights are similar, and seedlings often decompose quickly. Since it’s too wet to plant, now is a great time to scout your existing emerged fields for stand issues.
Fusarium Root Rot
Many Fusarium species reside in the soil and can infect soybean. Infected plants may be stunted and spindly with brown or black lesions on the roots and poorly developed root systems.
In severe cases, seedlings may die before emerging. Species of Fusarium can infect plants under a wide variety of environmental conditions. Fusarium root rot is often associated with stressed plants.
Rhizoctonia Seedling Blight
Is caused by the fungus Rhizoctonia solani. The characteristic symptom of Rhizoctonia seedling blight is a reddish-brown lesion on the lower stem or hypocotyl, usually at the soil level. Lesions on the diseased stem appear sunken (canker-like) and dry, and can girdle the hypocotyl. Continue reading Soybean Seedling Disease
Source: Agronomy eUpdates
If corn has been planted, standing water or saturated soil conditions in areas of a field can produce impacts now or later for corn. Periods of early-season water saturation can cause immediate problems for small corn plants and can have season-long implications as well. Hopefully, the affected areas are small and confined to spots that are low-lying or poorly drained. While heavy rains and respective standing water have been limited to areas of northwest, northeast, and southeast Kansas, the coverage is expected to increase into mid-May. Precipitation is forecasted across most of the state with an emphasis on western Kansas, where upwards of 2-3 inches is possible. In addition to this above-normal moisture, temperatures will be cooler than normal with extensive periods of clouds. Thus, the extent of inundated corn may potentially increase as a result.
Factors affecting flood damage to corn include
Saturated soil after corn emergence
After corn emerges, saturated soils inhibit root growth, leaf area expansion, and photosynthesis because of the lack of oxygen and cooler soil temperatures. Yellow leaves indicate a slowing of photosynthesis and plant growth. Leaves and sheaths may turn purple from the accumulation of sugars if photosynthesis continues but growth is slowed. Corn plants can recover with minimal impact on yield if the plants stay alive and conditions return to normal fairly quickly.
Although root growth can compensate to some extent later in the season, a saturated profile early in the season can confine the root system to the top several inches of soil, setting up problems later in the season if the root system remains shallow. Corn plants in this situation tend to be prone to late-season root rot if wetness continues throughout the summer, and stalk rots if the plants undergo mid- to late-season drought stress. Plants with shallow root systems also become more susceptible to standability problems during periods of high winds.
Tolerance of young corn plants to full submersion
Young corn plants can tolerate only a few days of full submersion. In some cases, symptoms and stand problems seen late in the season may trace back to flooding when the plants were young. Before V6, when the growing point is at or below the soil surface, corn can survive only 2-4 days of flooding. The chances of plant survival increase dramatically if the growing point was not completely submerged or if it was submerged for less than 48 hours. After 48 hours of soil saturation, soil oxygen is depleted, and critical plant functions (photosynthesis, water uptake, and nutrient uptake) are impaired.
Thus, young corn plants are more susceptible than corn beyond the V6 stage, when the plants are taller and the growing point is above the surface. Research has demonstrated yield reductions from early-season flooding ranging from 5% to 32%, depending on soil nitrogen status and duration of flooding.
Complicating factors
Temperatures can influence the extent of damage from flooding or saturated soils. Cool, cloudy weather limits damage from flooding because growth is slowed and because cool water contains more oxygen than warm water. Warm temperatures can increase the chances of long-term damage.
Silt deposition in the whorls of vegetative corn plants can inhibit the recovery of flooded corn plants. Enough soil can be deposited in the whorl that the emergence of later leaves is inhibited. A heavy layer of silt on leaf surfaces can potentially inhibit photosynthesis or damage the waxy surface layer of the leaf (cuticle), making the leaves subject to drying out. New leaves should not be affected if they can emerge normally. Ironically, what is often best for the silt-covered plants is to receive a small shower to help wash off the leaves.
In some instances, the soil in the whorl may contain certain soft-rotting bacteria. These bacteria can cause the top of the plant to rot. The whorl can easily be pulled out of a plant infected with these soft-rotting bacteria. In addition, a rather putrid odor will be present. These plants will not recover.
Disease considerations
Flooding can increase the incidence of moisture-loving diseases like crazy top downy mildew. Saturation for 24 to 48 hours allows the crazy top fungus spores found in the soil to germinate and infect flooded plants. The fungus grows systemically in the plant, often not causing visual symptoms for some time. Symptom expression depends on the timing of infection and the amount of fungal growth in the plant. Symptoms include excessive tillering, rolling and twisting of upper leaves, and proliferation of the tassel. Eventually, both the tassel and ear can resemble a disorganized mass of small leaves, hence the name “crazy top.”
Other concerns: Denitrification, cold weather crown stress, green snap, and root lodging
Saturated soils can also cause loss of N fertilizer by either denitrification (loss of N to the atmosphere, mainly as nitrous oxide gas) or leaching (movement of N beyond the rooting zone). For any of these losses to occur, N should be present in the mobile nitrate (NO3–) form. Depending on the fertilizer application time and source, most of the N may still be in the stable ammonium (NH4+) form. However, the conversion to nitrate happens quickly as soil temperature continues to increase. Under wet spring planting conditions, corn may respond to in-season N applications if a large portion of early-applied N is lost to these processes. If corn remains N deficient later in the season, expect considerably higher levels of stalk rot.
Another condition associated with extended periods of cool, wet soils is commonly referred to as cold weather crown stress. Internal stalk cells in the crown nodes can become “leaky” when cell membranes become chilled and oxygen is limited because of the saturated soils. Hybrids with “southern” genetics are more susceptible to this problem than are northern types. Plants may recover from this damage, but they will be much more susceptible to stalk rot later in the season if hot, dry temperatures occur, since water and nutrients cannot be efficiently moved through the damaged crown.
Source: Agronomy eUpdates
Figure 1. Sidewall and seed zone compaction in heavy clay soil.
Conducting field work — including planting, tillage, or traffic in general — after wet weather can cause soil compaction, particularly sidewall compaction in the seed furrow. The worst cases of sidewall compaction are seen after a field has been planted when the soil was too wet, followed by a period of dry weather. If the soil stays moist, the roots can usually grow through the walls of the seed furrow. However, if the soil gets dry, the roots can have a harder time growing through that seed furrow wall, and instead grow along the furrow, resulting in what is referred to as sidewall compaction.
With corn, the plants might look fine for a while, but the symptoms of this problem will probably show up after the plants reach several inches tall. Symptoms can mimic drought stress, nutrient deficiency, or both.
Since there are not any good ways to fix sidewall compaction once it exists, the best practice would be to avoid creating the problem in the first place. This means waiting until soils are dry enough to plant. The way to test for this is to dig down to the desired planting depth and make a ball with the soil. Next, see if the ball will crumble or crack apart, or if it deforms like molding putty. If it crumbles, it is ready to plant. If it deforms, it would be best to wait before resuming field operations. Even waiting as little as half a day could make a big difference.
Other considerations
It looks like we are mirroring our 5-year average … so far.
Mother Nature is finally cooperating, and planting is off to a great start. A common question is, “After planting how long before I can see corn?” Once corn is in the ground, you can expect to see emergence around 100 growing degree days after planting. The Table below lists the approximate growing degree days for various corn growth stages.
New this year! I will have a weather station set up by some of our research plots near Centerburg. Click here to access our local weather data. This weather data should be able provide information to assist with many of your daily activities such as: spraying records, crop growth & development, insect scouting, anticipated disease pressure, and many more.
I have installed a weather station by some of my on-farm research trials near Centerburg. This station records weather data every 5 minutes.
The following summary list the various types of weather data i am able to collect.
If you need local weather data to update your records, click the link below.
The Science For Success team is hosting a two-part webinar series focused on some of the biggest challenges in soybean production: the ever changing environmental and economic landscape. The webinar series is free and open to anyone. Certified Crop Advisers can earn 1.0 CEU in Crop Management by attending the webinar.
Register at: https://soybeanscienceforsuccess.org/webinars-and-events/
Part 1: Climate Challenges in Soybean Production
Part 2: Economic Insights for Uncertain Times
About Science for Success: Science For Success is a national team of soybean Extension Specialists from Land-Grant Universities. We collaborate to bring you sound research information on soybean Best Management Practices (BMPs). Science for Success is funded by the United Soybean Board through the checkoff program. To learn more about Science For Success, please visit our new website: https://soybeanscienceforsuccess.org/
Join us on February 27th for the 5th annual virtual Corn College and Soybean School presented by the Ohio State University Extension Agronomic Crops Team. The program will run from 9:00 AM to 4:00 PM and feature OSU Extension field and state specialists with updates and topics relevant for the 2025 growing season. CCA CEU credits will be available upon viewing the live presentations. Talks will also be recorded for later viewing on the Ohio State Agronomy YouTube channel, https://www.youtube.com/@OSUAgronomicCrops.
Please register by February 26th at noon. To register, visit https://osu.az1.qualtrics.com/jfe/form/SV_bKLRxGoOPaOkBka or scan the QR code below. There is a $10 registration fee for this event, which goes directly to support the activities and efforts of the OSU Agronomic Crops Team.
2025 Speaker and Topic Lineup