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JenREES 7/18/21

Leaned plants with braceroot growth on leeward side.

Crop Update: Grateful that in general (beyond seed corn), greensnap levels were lower for the widespread area compared to what we saw in 2020. It appears many fields with leaned plants have been working to right themselves with brace roots growing like crazy to help stabilize plants. Ear development on bent plants will be something to watch going forward. With plants bending in the wind instead of breaking, sometimes extra stress occurs where the ear is developing. Sometimes we see ear abnormalities and sometimes the ears are fine. With fields with severe bending, once the plant reaches tassel, it will no longer try to right itself and will switch to putting resources into the ear. For those with storm damaged fields who were originally planning on more nitrogen through the pivot, last year we took tissue samples to assess that need.

For fields with uneven development with plants ranging from vegetative stages to tassel, particularly storm damaged and uneven emerging fields, one needs to be aware that various adjuvants added to an insecticide and/or fungicide application pre-tassel can cause ear abnormalities.

So, the conversation with those at western bean cutworm thresholds with only portions of fields tasseling was to consider not adding the adjuvant (the same applies for those applying fungicide). I wasn’t sure how efficacy would be for different products without them (that would be a conversation for the chemical reps), but we know that adjuvants such as non-ionic surfactants can cause ear abnormalities when applied pre-tassel.

Also had several conversations regarding foliar fungicide applications. Fields have very low disease pressure right now with bacterial leaf streak being the most prevalent, and a fungicide won’t help with it. Gray leaf spot is very low in fields. Southern rust has been found in a few counties in mid- to southern- Kansas. It has not been found in Nebraska. You can view the tracking map at: https://corn.ipmpipe.org/southerncornrust/. Yield increases with automatic VT applications aren’t consistently proven in Nebraska. The following are fungicide timing studies conducted in Nebraska.

Southern rust detected (red counties) as of 7/18/21.

In 2008-2009, a UNL fungicide timing trial was conducted near Clay Center on 2 hybrids (GLS ratings ‘fair’ and ‘(very) good’) with a high clearance applicator. Timing over the two years included: Tassel, Milk, Dough, 25%, 33%, 50%, and 100% Dent comparing the fungicides Headline, Headline AMP, Quilt and Stratego YLD.

  • 2008No yield difference on GLS hybrids rated ‘good’ at any of the timings (Tassel, Milk, 33% and 100% Dent) nor the check when Headline or Stratego YLD were applied. For the ‘fair’ hybrid, no yield difference for any application timing nor the check for the April 30th planting except for Headline applied at milk stage (increased yield). Low gray leaf spot pressure.
  • 2009No yield difference on GLS hybrids rated ‘very good’ or ‘fair’ nor the check on any timings (Tassel, Milk, and Dough) using Headline, Headline AMP, or Quilt. Moderate gray leaf spot disease pressure.

In 2020, Dr. Tamra Jackson-Ziems and her team did another fungicide timing trial at UNL’s South Central Ag Lab near Clay Center. Fungicides were applied at planting, R1, or R3. There were no clear yield differences between applying foliar fungicide at R1 vs. R3 for any of the products except Miravis® Neo. Sometimes a product didn’t show a difference between other products or even the untreated check. There’s a picture of the data at jenreesources.com. Hybrids vary in disease susceptibility (thus response to fungicide application). With last year being a heavy southern rust year, being able to wait till at least R3 (milk) to apply a fungicide provided some additional time for the residual to work when southern really came on. I know some had to apply a second fungicide application when they automatically applied at R1. That’s just tough from an economic and resistance management perspective, in spite of higher corn prices. Thus, why I recommend waiting until disease pressure warrants the application. The main ‘plant health’ benefit observed in Nebraska when disease pressure was low (ex. 2012) was stalk strength.

July 28 South Central Ag Lab Field Day will be held from 8:45 a.m.-4 p.m. (Reg. 8:30 a.m.), near Clay Center. For all those who’ve talked with me about planting green into rye, there’s an excellent study by Dr. Amit Jhala and grad student Trey Stephens. They compare the same herbicide program with rye termination 2 weeks prior to planting or 2 weeks after planting in both corn and soybean. It was really interesting to visualize the differences in May and I’d encourage anyone interested to take a look at this now in July. Additional topics include disease, insect, and nutrient management, cover crops, and irrigation. You can RSVP at https://enrec.unl.edu/2021scalfieldday

Every time a letter is the same, it means there’s 90% confidence that there’s no difference between those treatments. It’s kind of hard to understand this chart with all the letters. The highest yielding group containing “a” also often contain other letters, and those with an “a” occur at both R1 or R3, depending on the product. The only noticeable difference between applying at R1 vs. R3 occurred with the Miravis Neo product. The other noticeable difference was between the Xyway timing of at planting or planting+R1. Any product that does not have a “d” listed above it yielded significantly better than the untreated check in this study in 2020.

JenREES 3/14/21

March is a month where I spend some time planning on-farm research and other experiments. One topic that surfaced during our on-farm research meetings in February was potentially testing the fungicide product Xyway™. This product is unique in that it is applied in furrow and can be applied with starter fertilizer at planting. It moves systemically in the plant through the water carrying vessels (xylem). For growers who are near towns or locations where aerial applications are restricted, a product like this is intriguing and could have a unique fit.

There’s limited university research with the product, but the findings have been intriguing thus far. The LFR® and 3D versions (in furrow at planting) were tested in Kentucky compared to untreated check and foliar fungicide products (Lucento® and Headline AMP®) applied at R1 in corn. In 2019, Xyway™ LFR® and sometimes the 3D version also showed the same efficacy for northern corn leaf blight (NCLB) and even gray leaf spot (GLS) compared to products applied at R1. All the products had less disease severity compared to the untreated check. Xyway™ did not reduce southern rust disease severity. In 2020, low disease pressure in general was observed in the Kentucky locations. The Xyway™ still provided the same disease reduction to GLS as foliar products applied at R1, which were all significantly less than the check.

Every time a letter is the same, it means there’s 90% confidence that there’s no difference between those treatments. While it’s hard to understand, there was a yield difference between the Xyway at planting and the untreated check but not the Xyway + Lucento vs. the untreated check. Also, the only difference between applying at R1 vs. R3 occurred with the Miravis Neo product. Otherwise there were no differences between product pairs at those timings.

In 2020, Dr. Tamra Jackson-Ziems also had a study at UNL South Central Ag Lab near Clay Center. The study compared different application timings (at planting, R1 and R3) of different products compared to an untreated check. Xyway™ LFR® was applied with starter at 15.2 oz/ac at planting. This was compared to Xyway™ at planting + 5 oz/ac Lucento® applied at R1. A number of foliar fungicide products were applied at R1 and R3. The Xyway™ LFR® applied at planting showed no disease difference compared to the untreated check for southern rust. All the other products and timings reduced the amount of southern rust compared to the untreated check. Traditionally, we’ve seen fungicides provide improved standability. In 2020, there were no differences in lodging for any of the products or timings compared to the untreated check. Regarding yield, the Xyway™ LFR® at planting yielded better than the check, whereas there was no yield difference with the Xyway™ + Lucento® at R1. Looking at the data, there were no yield differences between applying foliar fungicide at R1 vs. R3 for any of the products except Miravis® Neo. And, sometimes a product didn’t show a difference between other products or even the untreated check. I show a picture of the data on my website jenreesources.com. With last year being a heavy southern rust year, being able to wait till R3 to apply a fungicide provided some additional time for the residual to work when southern really came on. I know some had to apply a second fungicide application when they automatically applied at R1; that’s just tough from an economic and resistance management perspective.

Because I’ve got nearly a handful of growers interested in testing Xyway™, I put together protocols at jenreesources.com if you’d also like to check them out. If you’re interested in testing any study via on-farm research, please contact me or your local Extension educator.

Solar Energy Webinars: These webinars are free and for anyone who is interested in solar. What is the payback for Solar PV systems? A common question with not such as easy answer. Farmers and businesses are receiving marketing materials to invest in solar, yet the economic feasibility of solar is not always clear. This webinar series will cover how solar electric systems work, how to determine the value of energy and how the complexity of subsidies and policy make general statements about feasibility more complex. This workshop will cover these issues in detail and provide participants with the information they need to speak confidently with farmers about solar electric systems. All webinars are held from 9:00-10:30 a.m. on March 30, Apr. 1, Apr. 6, Apr. 8. Registration at: https://unl.zoom.us/meeting/register/tJEod-qhrz0sHdYkpW9nRnfdsv0wlk78bW99. Those with specific questions can reach out to John Hay, Nebraska Extension Educator at 402-472-0408 or jhay2@unl.edu.

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