Thursday August 14 Ag News - Managing Stock Tank Algae - Fall Armyworm Potential - SDS and Suthern Rust in IA - and more!

 What does it take?
Alfredo DiCostanzo, NE Extension Beef Systems Educator

The 103rd edition of the Cuming County Fair closed Sunday under a sunny sky with temperatures in the 80’s. If you would ask anyone, fairgoer, exhibit participant, vendor, volunteer, or organizer, how they think the fair went, I believe the answer would be a resounding “darn good” to “extremely well.”

Might there have been glitches, setbacks, failures, etc.? Of course, the answer is yes. There always are.

Yet, despite this, everyone was in a good mood, likely tired but extremely satisfied with their role in it.

From any angle you look at it, the Cuming County Fair is every bit like the most successful state fairs, yet it is scaled to the size and reach of a county of only 9,000 people. Though statistics are not in for 2025, the Cuming County Fair regularly sees 30,000 people come through its entrance. In a short four days, the population of the county increases more than three times.

So, the question is: what does it take to have a successful county fair?

The simple answer is an unimaginable amount of love. Because it is love for many things, including family, neighbors, and the place we call home that drives everything.

The proof is in the dedication, effort, and hard work children and their families have done for nearly a year preparing their 4-H exhibit. It is also evident in the organization and work fair board members and other volunteers do before, during and after the fair.

If anyone wishes to see evidence of this, I ask them to think for a minute how it is possible that a 1,300-lb steer is led by a 75-lb 4-H exhibitor in front of a large and loud crowd, and yet, this young person manages to keep their animal on task and tend to the judge’s evaluation during shows that might extend over hours.

Who is not wowed by watching shows where young people compete by demonstrating skills, they trained their horses or dogs? It does not take much to recognize the time and effort it took these young people to get these animals to respond to their commands.

These children could not have done all of this by themselves. Their parents, siblings and extended family, their club volunteers and even neighbors and friends all have supported this endeavor in one way or another. A minute at the fair watching their support network brings a smile and the satisfaction that life is as it should be.

Beyond the shows, volunteers keep the fair running smoothly and on time. Without their dedication and hard work, concerts, rodeo, tractor pull, turtle races, polka dance, 4-H shows, 4-H Country Kitchen, fair events, vendor sales or parade would not take place.

Volunteers give their time for the whole Cuming County Fair to exist.

So, I am not sure what other response to give to what it takes to run a successful County Fair other than love. For only from love we can draw the dedication and devote time to making the Fair a gem of Cuming County.



Stock Tank Algae
Ben Beckman, NE Extension Educator

Keeping clean water in front of animals during the summer is important. However, sunlight and warm temperatures can often lead to stock tanks overrun by algae. Let’s look at how we can address these issues.

The first step to stopping algae growth in a tank is preventing a habitat algae will love. Keep animals from getting into larger tanks to limit unwanted nutrient loading. When possible, keep water from becoming warm and stagnant by matching tank size to herd demands. Finally, shade the tank to reduce sunlight, which algae needs to grow.

One control method that often gets lumped in with options that kill algae is barley straw. While studies have shown barley straw does not kill algae, 0.75 oz of straw per square yard of tank area submerged in a loose bag or container should be enough to limit growth up to 6 months.

Sometimes, algae growth can still become an issue despite our best efforts. If your tank is small enough, regular scrubbing can keep algae at bay. For larger tanks, commercial algicides, most using copper sulfate, can be effective. Just follow instructions carefully, especially when sheep are involved which are sensitive to copper.

Other often cited control options are goldfish and bleach. North Carolina State researchers recommend up to 2 oz of bleach per 50 gallons of water mixed well. Keep animals away while mixing to ensure no concentrated areas remain. Or you can try 4-6 goldfish per 100 gallons of water – just provide them with cover and cool water.

Clean water is vital for animal health, especially during summer. Prevent algae growth through proper tank placement, cleaning, and options like barley straw. If needed, consider copper sulfate, bleach, or goldfish.



Fall Armyworm Awareness
Samantha Daniel, NE Extension Educator

In previous years, portions of eastern Nebraska have seen significant numbers of fall armyworm caterpillars feeding on alfalfa, brome regrowth in pastures, and newly seeded small

grain crops such as wheat, triticale, and rye. While reports of armyworm damage have not been received so far this year, it is a good idea to keep an eye out for this insect.

Fall armyworm caterpillars can be distinguished from other Lepidopterans by markings on the head that resemble an inverted “Y” and four spots on the last abdominal segment that form a square. This insect does not overwinter in Nebraska, but rather migrates north from Texas, Florida, and Mexico when populations build up in late summer. Once caterpillars are ¾ inch, they can do considerable damage in a few days. Because of this, it is important to scout fields and pastures in the early morning and late afternoon, when caterpillars are most active, to spot them when they are small.

A reasonable treatment threshold is finding 3 or more caterpillars per square foot within a field or pasture. The application of a pyrethroid insecticide, given the larvae are smaller than ¾ inch, will provide adequate control. For forage crops be sure to check the grazing restriction and post-harvest interval. Keep in mind, caterpillars ¾ inch or longer are close to maturity and can be harder to control with an insecticide.

Fall armyworm feeding declines with cooler temperatures and the adult moths eventually migrate south. In the meantime, plan to keep an eye on your pastures and newly seeded fields for any sign of infestation.



Sudden Death Syndrome Showing Up Across Iowa
Daren S Mueller, ISU Extension Plant Pathologist 

We are seeing sudden death syndrome (SDS) in soybean fields across Iowa. Caused by the soilborne fungus Fusarium virguliforme, SDS is among the most destructive soybean diseases in the state. There are no in-season management options, but documenting where the disease occurs and noting how different cultivars perform will be valuable for making future management decisions.

It’s important to confirm that symptoms are SDS and not a look-alike disease such as brown stem rot(BSR) or red crown rot (RCR).
    BSR can look similar to SDS from above, but splitting stems will reveal a brown discoloration in the pith, which does not occur with SDS.
    RCR causes reddish discoloration at the crown and small red structures (perithecia) on the lower stem.

Important: Red crown rot has not been identified in Iowa. If you suspect RCR, please contact Daren Mueller at dsmuelle@iastate.edu and/or send a plant sample to the ISU Plant and Insect Diagnostic Clinic for confirmation.

Correct diagnosis is essential for tracking disease distribution and making future management decisions.



Southern rust continues to develop across Iowa
Alison Robertson, ISU Extension Field Crops Pathologist 

Southern rust has continued to spread across Iowa and increase in severity since the disease was first reported in mid-July. This is not surprising considering the weather we have been having. July was warm and extremely wet across the state, and the precipitation has continued through this first 10 days of August.

Southern rust thrives in warm (77-82°F), wet (dew, rain) conditions. At least 6 hours of leaf wetness is required for infection to occur. Under these conditions, the time between a spore infecting a leaf to the production of a pustule filled with new spores is 7 to 10 days. Compare this to tar spot (14-21 days) and gray leaf spot (14 days).  Consequently, southern rust epidemics can develop very quickly. Once we get into the cooler days of fall, southern rust development should slow.

Is it too late to apply a fungicide? 
According to this resource from the Crop Protection Network, applying a fungicide through R3 (milk) is likely to be beneficial. Only with severe disease pressure would a fungicide application be recommended at R4 (dough). I would consider severe southern rust disease pressure to be southern rust present on the ear leaf or in the upper canopy on most plants in the field at approximately 1% disease severity.  I’ve heard lots of chatter that southern rust is severe in the lower canopy.  Remember that the ear leaf and canopy above are filling grain. These are the leaves we need to apply a fungicide to and protect yield.

For folks who have already applied a fungicide, a second application is likely unnecessary. Your decision should depend on the product you used, the amount of disease in the upper canopy and the growth stage of your crop.  It goes without saying that at today’s grain prices, a second application of fungicide input is unlikely to result in an output (ROI).

How effective are fungicides against southern rust?
Fungicides vary in their efficacy against southern rust based on observations from corn pathologists across the U.S. Newer products, with VG-E efficacy, will protect leaves from new infections for 35-42 days, based on my experience. Older products and generics are likely protecting the leaves for 21 days.

Is southern rust going to be another disease we need to manage every year?
The southern rust pathogen is different from the pathogens that cause tar spot, gray leaf spot and northern corn leaf blight in that it will not survive the winter in Iowa.  All rust pathogens are obligate parasites, which means they can only survive on a living host. Rusts are, in a way, “snowbirds”. They survive on living hosts in Central America during our winter. Then each growing season, their spores are blown up to Iowa on southerly winds. Consequently, each new growing season starts with a clean slate when it comes to southern rust.



Weekly Ethanol Production for 8/8/2025

According to EIA data analyzed by the Renewable Fuels Association for the week ending August 8, ethanol production picked up 1.1% to 1.09 million b/d, equivalent to 45.91 million gallons daily. Output was 2.0% higher than the same week last year and 5.0% above the three-year average for the week. The four-week average ethanol production rate ticked up 0.1% to 1.09 million b/d, equivalent to an annualized rate of 16.71 billion gallons (bg).

Ethanol stocks retreated 4.7% to 22.6 million barrels, the lowest volume since mid-December 2024. Stocks were 3.0% less than the same week last year and 3.3% below the three-year average. Inventories thinned across all regions except the Rocky Mountains (PADD 4), which remained even with the prior week.

The volume of gasoline supplied to the U.S. market, a measure of implied demand, ebbed 0.4% to 9.00 million b/d (138.35 bg annualized). Demand was 0.5% less than a year ago and 0.9% below the three-year average.

Refiner/blender net inputs of ethanol climbed 0.8% to an 11-week high of 929,000 b/d, equivalent to 14.28 bg annualized. Still, net inputs were 0.3% less than year-ago levels and even with the three-year average.

Ethanol exports expanded 6.0% to an estimated 123,000 b/d (5.2 million gallons/day). It has been more than a year since EIA indicated ethanol was imported.



Fertilizer Prices Continue Mixed

Retail fertilizer prices tracked by DTN for the first week of August 2025 were mixed. No fertilizer price was substantially higher or lower than a month ago for the ninth week in a row. DTN designates a significant move as anything 5% or more.

Four fertilizers had slightly higher prices. DAP had an average price of $822/ton, MAP $892/ton, potash $484/ton and UAN28 $421/ton. 

Four fertilizers were slightly lower looking back to the prior month. Urea had an average price of $646/ton, 10-34-0 $669/ton, anhydrous $765/ton and UAN32 $498/ton.

On a price per pound of nitrogen basis, the average urea price was $0.70/lb.N, anhydrous $0.47/lb.N, UAN28 $0.75/lb.N and UAN32 $0.78/lb.N.

Seven fertilizers are now higher in price compared to one year earlier. 10-34-0 is 5% higher, MAP is 9% more expensive, DAP is 11% higher, anhydrous is 13% more expensive, UAN28 is 25% higher, urea is 28% higher and UAN32 is 32% more expensive looking back to last year. 

The remaining fertilizer price continues to be lower. Potash is 4% lower compared to last year.



BASF, Corteva Agriscience and M.S. Technologies, L.L.C. sign agreement to bring industry-first soybean trait stack to market 

BASF, Corteva Agriscience and M.S. Technologies, L.L.C. today announced that they have entered into a trait licensing agreement to bring BASF’s novel nematode resistant soybean (NRS) trait with Enlist E3® soybeans and Conkesta E3® soybeans to farmers in Brazil. The NRS trait offers the first ever biotech solution for effectively managing root lesion nematodes (Pratylenchus brachyurus) and soybean cyst nematodes – difficult-to-control microscopic pests that damage soybeans and threaten yields. 

“This novel trait has demonstrated more than 90% control of root lesion nematodes in more than 160 field trials over the past seven years,” said Adolfo Vitorio Ulbrich, Regional R&D Seeds Director at BASF Agricultural Solutions in Latin America. “We are excited to cooperate with Corteva and M.S. Technologies, L.L.C. to bring to Brazilian farmers the first commercially available biotechnology trait for soybeans to provide a critical management tool against nematodes.” 

The Enlist® weed control system is a U.S. industry-leading system for soybeans, corn, and cotton. Enlist E3 soybeans are tolerant to 2,4-D choline, glyphosate and glufosinate herbicides, giving growers additional herbicide options to manage resistant and hard-to-control weeds. Conkesta E3 soybeans additionally incorporate two Bt proteins (Cry1F and Cry1Ac) for the management of the main caterpillar pests in soybean crops, a tailored option for farmers in Latin America.  

“We’re pleased about the opportunity to combine our Enlist E3 and Conkesta E3 soybean technology with the nematode resistant soybean (NRS) trait from BASF to offer growers across Brazil a critical new tool to help protect against Pratylenchus brachyurus and soybean cyst nematode,” said Christian Pflug, Licensing Director, Brazil and Paraguay, Corteva. 

The transgenic soybean event in Enlist E3 soybeans and Conkesta E3 soybeans is jointly developed and owned by Corteva and M.S. Technologies, L.L.C. 

“Since the beginning, M.S. Technologies, L.L.C. has been focused on developing the industry’s highest-performing soybean genetics,” said Joe Merschman, president of M.S. Technologies, L.L.C. “Pairing Enlist E3 and Conkesta E3 genetics from M.S. Technologies, L.L.C. with this new NRS trait developed by BASF represents a step change in value protection for soybean growers in South America.” 

BASF, Corteva, and M.S. Technologies, L.L.C. anticipate commercial varieties containing BASF’s innovative NRS trait in Enlist E3 soybeans and Conkesta E3 soybeans will be available to farmers in Brazil by the end of the decade or early next decade, pending applicable regulatory reviews and completion of field testing. Additional countries remain a possibility. 

Terms of the agreement were not disclosed.