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Ag Reflections from 2014

Happy New Year!  Wishing all of you and your families a wonderful 2015!  As I look back at 2014, there are several ag-related observations that I noted throughout the year.

tornado damage in Sutton

Cleanup after the tornado in Sutton on Mother’s Day 2014.

The first observation continues to be the way communities and people in this County/area pull together in difficult times.  Whether after tornadoes/wind storms or helping other farm families who had an injured family member or had lost a family member, it’s just a blessing to see the way people pull together to help each other in time of need.  It was also a blessing for many who were unable to harvest in 2013 due to the August 1st storm, to harvest fields in 2014, and for many in the area to experience really good irrigated and dryland yields this year.

The dry winter of 2013/14 allowed for very mellow ground during planting time.  Often seeding depth ended up ½-1” deeper than intended.  The dry winter also didn’t allow for good residue decomposition leading to problems during planting and ensuing stand emergence.  Cutting off residue and high rains in May led to unintended consequences of replant situations when residue was moved off of farmers’ fields onto neighboring fields, suffocating emerged plants in portions of fields.  I’m not sure what the solution is for the future other than it really needs to be something worked out with neighboring farmers, but perhaps mentioning it here opens an opportunity for future conversations.

Cover crops have been incorporated into more operations in recent years, yet the ultimate goal for using them remains important in determining what species/crops are used in the fields.  We also realized the importance of determining amount grazed prior to turning cattle into fields (whether for grazing cover crops or crop residue), as high winds in winter 2013/14 in overgrazed fields led to soil blowing throughout the winter.

Systemic Goss Wilt Clay Co-Rees

Systemic Goss’ wilt showed up in some fields that were hail and/or frost damaged by V6.

The May frost showed us emerged soybeans at the cotyledon stage held up well to the frost compared to the corn.  We also again watched Goss’ wilt show up systemically by 6 leaf corn that was injured early by frost or hail in fields where Goss’ wilt had been a problem in the past.  We need more research/understanding of this disease.  Wheat continues to show us its resiliency as it winterkilled in portions of fields, withstood drought-stress, and then made up yield in the last 4-6 weeks.

Perfect pollination conditions coupled with high solar radiation, low night-time temperatures, and timely rain events were keys to the bountiful corn crop we experienced this year.  Soybeans were more of a mixed bag. In walking fields and in conversations with farmers, I think the disappointment in some irrigated yields could be attributed to early/over-irrigation, disease problems, and planting date.  UNL on-farm research showed on average a 3 bu/ac yield increase when soybeans were planted in late April to first week of May (regardless if growing season was warm/dry or cold/wet like it was this year) and those I’ve talked to who achieved 80+ bu/ac in the area this year planted in that time-frame.  I’m curious if there’s something to planting a 2.4-2.5 maturity early vs. a 3.0+ maturity early as some area producers are seeing strong yields from a shorter season hybrid planted early the past few years.  So if you’ve also seen this and/or are interested, that will be an on-farm research project to try next year.  Please let me know if you’re interested!

Here’s wishing you a healthy and prosperous 2015!

Crop Update 8/1/14

Southern rust of corn confirmed in Clay County July 31.  This was found on one leaf in a field near Trumbull.  Just because southern rust has been found in the area, we don't recommend automatically spraying.  Scout your fields and consider disease pressure, growth stage, and economics.  Long season corn and late-planted fields have the potential for most damage.

Southern rust of corn confirmed in Clay County July 31. Very small, tan-brown lesions on upper surface of the leaf, usually in clusters.  Spores inside the pustules are typically orange.  This was found on one leaf in a field near Trumbull. Just because southern rust has been found in the area, we don’t recommend automatically spraying. Scout your fields and consider disease pressure, growth stage, and economics. Long season corn and late-planted fields have the potential for most damage.  Secondary common rust sporulation has also been confused as southern rust as the secondary pustules tend to look like this.  It’s important to obtain microscopic confirmation to know for sure if you have southern rust in your fields.

Spores of southern rust appear elongated vs. common rust appear as near perfect circles.

Microscopic Observation:  Spores of southern rust appear elongated vs. common rust appear as near perfect circles.

Another common problem is old common rust lesions being confused as gray leaf spot.  The color of this lesion is a tan-gray, typical of gray leaf spot.  Using backlighting or a handlens, you can see the pustules within this lesion confirming it is common rust and not gray leaf spot.  I've had many calls that gray leaf spot was up the entire plant in their fields and after looking at fields, have found it to be common rust in most situations.  It's important to know what disease you truly have to make the best decision on fungicide application.

Another common problem is old common rust lesions being confused as gray leaf spot. The color of this lesion is a tan-gray, typical of gray leaf spot. Using backlighting or a handlens, you can see the pustules within this lesion confirming it is common rust and not gray leaf spot. I’ve had many calls that gray leaf spot was up the entire plant in their fields and after looking at fields, have found it to be common rust in most situations. It’s important to know what disease you truly have to make the best decision on fungicide application.

Have also received questions on soybeans, particularly in dryland.  Soybeans are drought stressed-often showing it in pockets within dryland fields right now.  Closer observation shows plants aborting pods and losing lowest leaves.  Spidermites can also be viewed on leaves in some of these patches.

Have also received questions on soybeans, particularly in dryland. This photo is showing drought stressed soybeans-often occurring in pockets within dryland fields right now. Closer observation shows plants aborting pods and losing lowest leaves. Spidermites can also be viewed on leaves in some of these patches.

Dryland corn showing stress as well.  June rains were making for dryland crops with potential, but also led to shallow rooting.  Crops could use a drink right now....but would prefer no more ice and hail.  The storm that hit Clay County so hard occurred one year ago today.

Dryland corn showing stress as well. June rains were making for dryland crops with potential, but also led to shallow rooting. Crops could use a drink right now….but would prefer no more hail and tornadoes. The storm that hit Clay County so hard occurred one year ago today.

Corn Disease Look-Alikes

Physoderma brown spot

Physoderma brown spot on corn. While the small, speckled lesions may look like southern rust, under hand lens or microscopic observation, there are no raised pustules as would be the case with southern rust. Also notice the brown/purple discoloration on the midrib which is also noticed on the stalk as well where the leaf color meets the stalk.

Fair week tends to be time for tasseling in corn and considerations for watering and fungicide application are being made.  Regarding diseases in corn, there has been confusion about a few diseases, particularly about a disease called physoderma brown spot which some have confused for southern rust.  The fungus causing physoderma brown spot feeds on pollen and debris on leaves and does not cause harm to the corn plants themselves.  Because the spores of this fungus move via water (it’s closely related to oomycetes), numerous lesions can appear on leaves in bands or areas where water collects.  While the lesions may look like early southern rust, there will be no pustules present and often purple colored lesions will also be observed in the midrib, leaf sheath, stalk, and outer husks.

Differentiating Rusts:

2013-07-30 09.31.26

Southern rust in corn. We currently have not seen southern rust in Nebraska in 2014. Notice how you can see raised pustules in this picture compared to the photo of physoderma brown spot above.

When differentiating between southern rust vs. common rust, there are several criteria to consider and this NebGuide is a great resource.  Typically common rust will have brick-red pustules randomly scattered on the upper and lower leaf surfaces that are larger in size.  It is common rust that we are currently seeing in our fields.

Bacterial leaf blight showing up heavily in some hybrids.  The UNL Plant and Pest Diagnostic Lab is determining species and we will share more information in the future.  There is no control for this disease at this point.

Bacterial leaf blight showing up heavily in some hybrids. The lesions are red-brown in color, long and skinny and mostly vein-limited.  Older lesions spread outside the veins and are buff in color-sometimes they are being confused as gray leaf spot.  The UNL Plant and Pest Diagnostic Lab is determining species and we will share more information in the future. There is no control for this disease at this time of the season.

Southern rust in our area tends to have very small, raised, tan-orange pustules on the upper leaf surface of leaves in localized areas on mid-upper leaves.  These pustules are tightly clustered on the leaves. However, color and size are relative as sometimes the two diseases can look alike.  Microscopic observation is the best way to differentiate the two diseases.  Fungal spores from Puccinia sorghi causing common rust will be near perfect round circles whereas fungal spores fromPuccinia polysora will be oblong in shape.

We do have some gray leaf spot in the lower canopies and I haven’t seen much northern corn leaf blight in the fields.  But we do

have a bacterial leaf blight that is affecting quite a bit of leaf tissue on some hybrids.  These lesions are long and skinny appearing at first to be limited to the veins.  There’s been concern about these lesions being severe gray leaf spot but it’s not and there’s nothing you can do about the bacterial disease.  Please don’t mistake this bacterial disease as a fungal one and trigger a fungicide application too early.

Fungicide Application Timing

We tend to see southern rust in our part of the State each year; it’s a matter of time.  Triggering a fungicide application too early may result in no residual for when you need it if/when southern rust occurs.  Every year some producers make more than one fungicide application due to blanket applications at tassel or shortly after followed by another fungicide application when southern rust occurs later in the year.  Consider good fungal resistance management and apply fungicides when disease pressure warrants them in your fields and also consider economics for your situation for proper fungicide application timing.

Nebraska On-Farm Research Network Testimonials

Listen to the value of on-farm research to these participants!  Sound interesting to you?  Learn more by checking our our On-Farm Research website or contacting any of our faculty involved!

Sprouting Corn Kernels on Hail-Damaged Ears

The latest event in the Clay County storm occurring August 1st has become germination of “good” kernels left on the ears that have been damaged by"Good" side of hail-damaged ear is now sprouting before black layer. hail.  This event of kernel germination prior to harvest is also called “vivipary”.

Typically we wouldn’t see this occur before black layer because of the hormonal balance within the kernels-particularly the balance between gibberellin and abscisic acid.  According to a study by White, et. al (2000), Gibberellin production with the lack of ABA allowed for kernel germination while less Gibberellin and more ABA deterred kernel germination.  At full maturity, very little ABA is left in the kernel (in both corn and soybeans) which allows them to germinate in correct conditions after harvest.  But this can also allow for sprouting in the ear after black layer when corn is still drying down, particularly in tight-husked, upright ears with conditions of high humidity or rain after black layer.  Sprouting under those conditions typically occurs at the base of the ear first.

Why are kernels sprouting before we’ve reached black layer?

That’s a good question.  I haven’t found much in the way of scientific explanation other than the thought that the hormonal balance of the kernels can be altered by physical damage from hail, bird feeding, and grain mold.  Some ear mold fungi also produce gibberellic acid which can lead to a hormonal balance shift in these ears stimulating germination.  I also haven’t observed that this is hybrid-dependent and am finding as much as 25-50% sprouted ears in various areas of hail-damaged fields.

What can you do now?Ear damage by hail and sprouting occurring before black layer.

Make sure your crop insurance adjuster is aware of the situation and make sure to submit samples for kernel damage due to mold, sprouting, and check for mycotoxins prior to harvest.

The local co-op may or may not choose to accept the load depending on percent damage and the standards they need to follow.  If the load is rejected, contact your crop insurance agent to determine your next step.  DO NOT bin the grain on your farm until you contact your insurance agent as they have specific rules that need to be followed in the case of grain rejected due to mycotoxins or kernel damage from storms.

Sprouted kernels lead to higher kernel damage and more fines in a load.  Keys for harvest will include harvesting early, getting corn dried down to 14%, potentially drying at a high temperature to kill the sprout, screening out fines, and monitoring stored grain closely for hot spots, mold, and additional sprouting grain.

You can also choose not to take it to grain right now, and honestly, that may be the best option for several of the hail-damaged fields.  Silage is still an option and it would be recommended to sample the green chop going into the silage pit for potential mycotoxins.  Mycotoxin level does not change with fermentation so cattle feeders would have a good idea of any mycotoxin levels if sampling was done in this manner.  See this post for additional information on making silage.

Additional information:Diplodia and other ear mold fungi on hail-damaged ears.  Now sprouting is occurring before black layer.

Du-Pont Pioneer.  (2007).  Field Facts:  Pre-mature Germination of Corn Kernels.

Nielsen, R.L. (2012).  Premature Corn Kernel Sprouting (aka Vivipary).  Corny News Network, Purdue University.

White et. al.  (2000).  Gibberellins and Seed Development in Maize. II. Gibberellin Synthesis Inhibition Enhances Abscisic Acid Signaling in Cultured Embryos.  Plant Physiology Vol. 122 no. 4 pg. 1089-1098.

Wiebold, B. (2009). Wet Weather Can Cause Seeds to Sprout before Harvest. Integrated Pest & Crop Management Newsletter, Univ of Missouri.

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