JenREES 6-7-20
*The York and Seward County Extension offices are now open to the public. We ask that visitors please wear a mask when entering the buildings.*
This past week was interesting to say the least! For those who experienced hail and/or wind damage, the following site provides guidance via information and videos for early-season hail damage: https://go.unl.edu/u5ns. We do say to be patient and wait 4-7 days to determine recovery and warm temps can help. For home owners, there was also a great deal of tree and plant damage. Make clean pruning cuts and don’t treat/paint over cuts, don’t add fertilizer, and leave as much leaf area as possible.
Most of this week’s questions centered around soybeans. The past two weeks, the
Sensitive soybean variety to PPO-inhibitor herbicide. Notice stunting, chlorotic appearance, leaf abnormalities.
majority of my soybean questions have been around emergence problems. Two common things I’m finding: many were planted around May 18-19 and they have a great deal of PPO-inhibitor injury to hypocotyls. In touching base regarding what we were seeing, John Mick with Pioneer shared that some soybean varieties are more sensitive to PPO-inhibitor injury. ‘Sensitive varieties’ means later on plants appear stunted and chlorotic in appearance. These plants also tend to have wavy leaves with some leaf cupping, which may have been mis-diagnosed as off-target growth regulator injury in the past. I’ve seen those symptoms for several years but just told people the plant was working to metabolize the pre-emergence herbicide and it was most likely taking longer due to the environmental conditions at the time. So, in a way, it was correct, but now we can all be more aware there are sensitive varieties to PPO-inhibitors. Thus, it’s important to talk with your seed dealer/agronomist about their variety ratings (if they exist). If planting a sensitive variety, it’s better to apply your pre-emergence application a week or so before planting to reduce the herbicide load on that germinating seedling. I’ve put a lot more explanation and pictures in this CropWatch article and the pics also on my blog.
The pre-emergence products did a great job for the most part. Thus, a common
Source: UNL Guide for Weed, Insect, and Disease Management.
question/discussion this week was around spraying essentially ‘contact’ herbicides in the absence of weeds. Could appreciate those thoughts. Regardless if the farmer wanted to apply glyphosate, liberty, or dicamba, we did talk about the importance of spraying earlier than one thinks is necessary and the need for residual products. I was going to share more about that here, but Amit Jhala wrote a very good article in this week’s CropWatch at: https://go.unl.edu/y3r8. He explains which products are options to consider at this point depending on if you have emerged weeds or not, what growth stage they can be applied, and some label restrictions. There’s a picture on my blog for soybean development stages. The cotyledons are not counted. The unifoliolates are counted as V1 only when the trifoliolate leaf edges above them are no longer touching. This continues up the plant. New nodes with leaves will be produced every 3.75 days. Note that early planted soybean may flower soon; they don’t have to wait till June 21 (longest day of year) to do so.
Because of that, for those near the 45 day window for post-dicamba application to soybean, be sure to check fields as the label states 45 days after planting or R1 (at least 1 flower on any node), whichever occurs first. Follow label instructions and I’m also recommending documenting development stage via picture/video on all post- applications to crops this year. Regarding use of soybean dicamba, Nebraska Dept. of Ag Director Steve Wellman stated, “The Nebraska Department of Agriculture has not issued a stop sale order and will enforce the sales and applications of these products as they are currently registered in Nebraska.”
Thistle caterpillars are being observed in some early planted soybean fields. Threshold for pre-flowering is 30% defoliation.
Corn post-herbicide applications: Said I’d share on this, but ran out of room; I
Leaf collar correlating to split stalk method. Courtesy L. Abendroth, Iowa State University.
wrote a CropWatch article here: https://go.unl.edu/jz9v. Recommendations for any applications this year: Go into the field (beyond the endrows) and document growth stage of the plant via picture/video using the leaf collar method and/or split stalks (once reach V6 due to leaves sloughing off). Do this before any applications are made to the field. If the growth stage isn’t correct for the application, don’t spray. How I explain the split-stalk method of development staging: The growing point emerges above ground around V6. Dig a plant without breaking the stalk. Carefully split the stalk down the middle through the root ball. At the base of the stalk is an inverted triangle that contains Nodes 1-4 (but they can’t be differentiated). Next look for the white area above that (about ½-3/4”) followed by the next visible band. The white area is the internode with the band being the 5th node (V5). There’s about an inch of internode between V5 and V6. After that, internode length is more dependent upon air temperature instead of soil temperature. Every leaf is attached to a node. Pull off the fully collared leaves and follow them back to where they break off at a specific node. Count the nodes on the stalk to the highest collared leaf that breaks off at a node to determine the growth stage.
My concern with some of these plants is them becoming brittle and potentially breaking off at some point in the season.
There’s been mis-diagnosis/confusion about PPO-inhibitor injury vs. ILeVo ‘halo’ effect which shows the seed treatment is working. ILeVo causes no burning to the hypocotyls and the effect isn’t seen on leaves other than cotyledons.
Also been confusion between PPO-inhibitor injury and Phytophthora. Phytophthora will have discolored root and lesion from soil line upward. PPO-inhibitor won’t cause discoloration/rotting of the root. We have seen burning of stem near soil line due to rain/irrigation splash from PPO-inhibitor, so dig up seedling to check the roots for root rot.
JenREES 5-31-20
Corn: I really enjoy this stage when corn is just tall enough to give the fields a green cast when looking at them from an angle. There continues to be discussion and questions about uneven corn emergence. Like many, I wasn’t anticipating seeing uneven emergence after having great soil conditions (right moisture and a warming trend of temps) for planting. Variations in soil temp, depth, and moisture can delay germination from a few days or longer. Residue blowing back over the row explained much difference in emergence this year. I wish I would’ve noted the days on my calendar, but there’s a couple warm days in late April during planting where it just seemed like the moisture rapidly left the soil surface. And, in conversations it seems as if others noticed that too. So I think moisture around seed was another factor as was fertilizer burn in some situations. Purdue University has some research which showed yield reductions of 6-9% for plants emerging 1.5 weeks later than a uniformly emerging stand. They also found yields of uneven stands to be similar to planting the stand 1.5 weeks later.
If you’re side-dressing nitrogen and interested in testing different rates, we have some on-farm research protocols available at: https://go.unl.edu/tv63.
With warmer temperatures anticipated, corn will grow rapidly. This week we wrote an 
article in CropWatch regarding proper growth staging of plants; this will be extra critical once we hit V6+. Remember to use the leaf collar method and this is how I explain it. A collar develops at the leaf base near the stalk after each leaf fully expands. Think about collars like the collar on a button-down shirt. The collar flares slightly at one’s neck, just as a true exposed leaf collar flares at the base of the leaf at the stem. Start counting leaves at the base of the plant with the smallest rounded-tip leaf with a collar as #1. From there count every leaf with a true collar. Leaves that are still wrapped in the whorl around the main stem without exposed leaf collars are not counted. I recommend taking a picture inside the end rows to document the growth stage of your field prior to the post-application of herbicide. Next week I will share my experiences with proper growth staging to avoid ear abnormalities. Also be aware of potential off-target movement with dicamba products and higher temperatures.
Soybean: In most cases, soybeans are looking really good. There have been situations this week with herbicide damage to beans that may have been cracking when irrigation or rainfall event occurred allowing some pre-emergent herbicide to enter the row. Pre- herbicides can also rain splash onto cotyledons and first leaves making them look bad, but usually doesn’t kill them unless the weather stays cold and wet. If the plants end up severely pinched below the cotyledons, they won’t survive. Otherwise, keep watching them as they may continue to grow (warm weather will allow them to grow and metabolize the chemical better). I think we’re also possibly seeing some environmental effects from the cold conditions that occurred after planting/emergence when we can’t always explain the appearance of injury on the plant by herbicide. The ‘halo’ effect of ILeVo is another thing that is being mistaken as herbicide and/or environmental injury but it doesn’t last past the cotyledon stage.
Coronavirus Food Assistance Program for Crop Producers Webinar: There will be a webinar on June 4th at Noon (CST) to learn more. Registration is required at the following site: https://go.unl.edu/wj0e. In the meantime, Dr. Brad Lubben has put together an article with more information at: https://go.unl.edu/h3aq. All webinars are also archived at that same web link.
Irrigation Scheduling Equipment: It’s also a great time to get irrigation scheduling equipment installed! I decided to make a quick video instead of writing; it can be found at: https://youtu.be/4r5gn2pvvB4.
Sensors prepped and ready for 2020 on-farm research projects!
Gardeners: For all of you gardening for the first time, congrats! Some tips: keep soil moisture even by ensuring plants have around 1” of water/week (Best to water at base of plant; if use sprinkler, do so in early morning). Mulching gardens with leaves, grass clippings, straw, newspapers aids in conserving moisture, reducing weeds, and maintaining stable soil temperature. If herbicides were added to grass clippings, make sure to read the label for if/when they can be applied to a garden. In general, many labels will say grass clippings are safe after 4 mowings.
JenREES 5-21-20
This Memorial Day will be different not gathering to honor those who have gone before us. Grateful for those who paid the ultimate sacrifice for our freedom! May we still take time to honor them.
Crop Update: Several weeks ago we were seeing large numbers of seed corn maggot
flies. This past week have seen and heard reports of seed corn maggots attacking soybean seed/seedlings. Typically insecticide seed treatments provide protection; the exception is with high densities such as what we’re experiencing this year. They’re attracted to cover crop fields, fields with manure application, and tillage. There’s several generations but we shouldn’t have to worry about it again unless we experience replant situations. Fly emergence for the first three generations occurs when 354, 1080, and 1800 growing degree days have accumulated, respectively since January 1. There’s an updated article in CropWatch this week sharing more. They can reduce stands, but soybeans can withstand a great deal of stand loss. We recommend to leave a stand of at least 50,000 plants per acre with fair uniformity. That goes for anything that can reduce a soybean stand such as crusting, hail, herbicide damage, insects, disease, etc. We have research showing that the early planting will out-yield a replant. I realize there’s other considerations such as weed control and Dr. Shawn Conley at Wisconsin suggested putting the dollars into weed control instead of replant. They only found 2 bu/ac yield difference in stands of 50,000 plants/ac vs. optimal stands of 100,000-135,000 plants/ac. If you do consider replanting for any reason, we’d recommend going in next to the old stand with a similar maturity and proving it to yourself. Here’s a protocol if you’d like to test it yourself: https://go.unl.edu/wq24.
Post-Herbicide Applications: At pesticide training, I talk about the importance of overlapping residual. Ag industry partners talk about this too. It means aiming to apply the post-herbicide before the residual from the pre wears out. Many of us have seen fields that are clean one week with a flush of weeds the next. Sometimes it then rains, delaying post-applications. Dry conditions created difficulty getting pre-herbicides activated, allowing some weed escapes. Depending on the product, soil conditions, weather conditions, Dr. Stevan Knezevic shared that pre-products can last anywhere from 4-8 weeks. Page 24 of the 2020 Weed Guide also provides guidance on potential residual (also known as persistence in the soil) of herbicides if you’d like to check that out.
Bagworms: I haven’t spent time looking at evergreen trees to see if bagworm larvae
Bush with a severe bagworm infestation in 2018. Hard to see the bags in the brown part, but you can see them to the right in the green foliage.
have emerged yet or not. If you have last year’s bags on your trees that are sealed (don’t have an open hole at the top), you can pick off some bags, place them in a ziplock bag, and place it outdoors on the south side of your house. When you see larvae emerge, it’s a good indication to start checking your trees in the next weeks. Each bag can hold 500-1000 eggs. The larvae are really small and hard to see. Stand still and watch the tree. If bagworm larvae are present, you will see very tiny movements as they begin the process of building new bags. I have pictures and a video at: https://jenreesources.com/2015/06/27/bagworms-in-evergreens/. Egg hatch is from mid-May to early June, depending on the year. Some caterpillar larvae remain on the same trees containing the bags from which they hatched. Others are blown by the wind to area trees allowing for new infestations to occur. For homeowners with small trees or only a few trees, bags can be picked from trees now and drown in soapy water or burned. In the summer, they can be squished, drowned, or burned. I have a great memory of visiting Grandma in the care center with my family. Grandma was concerned about the spruce in the courtyard. Seeing bagworms, I turned it into a science lesson for my nieces/nephews. They had a blast making quick work of picking off bags and squishing them to the delight/disgust of the residents watching (and their parents) 🙂 That’s not feasible for most situations though. We recommend waiting to treat trees until bags reach around 1/2” in size to ensure egg hatch is complete. Good coverage is needed when treating trees. With ground sprayers, we say to spray to the point of runoff. Bt products are effective early on. Most often I recommend a permethrin or bifenthrin product. Aerial application may also be an option for windbreaks. For more info., please see: https://go.unl.edu/rgju.
JenREES 5-17-20
Congratulations to all who graduated from college or high school the past few weeks! You’ve experienced much challenge, change, and loss. Good can come from difficulty! May this experience better equip you for the future! Also wish to congratulate and welcome three new team members to the York and Seward county offices! Tanya Crawford will begin as the 4-H Educator in York County May 18. Emily Hemphill began as the 4-H Assistant in Seward County May 1. Kara Kohel will begin as the new Learning Child Educator in Seward County June 1.
Crop Update: Grateful for the recovery experienced on many frost/freeze damaged crops throughout the State! The worst damage I saw on corn in this part of the State resulted in exposed leaf tissue dying with new growth coming out of the ground within 5 days. Soybeans fared well in the area to which I’m extra grateful with the large number of early planted soybean acres this year!
There’s been some talk about uneven emergence in some fields. Most really aren’t too bad, just worse in fields that were worked or extra cloddy. And most often, seedlings are still coming when digging in the gaps. They’re just behind most likely due to depth or soil moisture variation. You may also want to check out an article on Early Season Insects in this week’s CropWatch at cropwatch.unl.edu. Also seeing and hearing of ammonia burn to roots of corn seedlings, mostly in strip till situations, due to the dry conditions. An inch or two of rainfall or irrigation can help dilute the salt concentration in the root zone and allow for growth of roots to resume. I realize this doesn’t help those without irrigation and we keep praying for rain. In a 2009 trial at UNL South Central Ag Lab near Clay Center, Dr. Richard Ferguson documented those plants being shorter in stature and appearing to have a purple color early in the growing season before later recovering.
For those asking about replanting, we have two articles to aid in decision making in this week’s CropWatch at cropwatch.unl.edu. I haven’t seen situations warranting this around here yet. It takes quite a stand loss. For example in corn, if there are 25,000 plants per acre and the field was initially planted on April 27 and you cannot replant until May 20, it would be better to leave your present stand, which has 95% yield potential, than to replant on May 20 when the yield potential for a stand of 30,000 would be 86%. Make sure you consider replant costs in your decision. Next week I’ll address thoughts on post applications to crops.
Lawn Update: As lawns grow, it’s important to not remove more than 1/3 of the height. During the spring and fall, cool season grasses such as bluegrass and fescue are also building their root reserves. Removing too much growth at once or continually mowing shorter than 3” puts more stress on the plant and doesn’t allow for as deep of roots for when the summer heat comes. UNL turf research found that lawns actually grow faster when they are scalped than when they are mowed at a taller height. So, if your lawn gets away from you like mine did last week, do your lawn a favor and raise your mowing height that one time and then go back to mowing at 3”.
Youth Learning Opportunities: There are a number of virtual and self-paced fun, learning opportunities for youth and families upcoming in the month of June! Many of the activities that were provided during the school year will be continuing with new sessions. You can check them all out at: https://4h.unl.edu/virtual-home-learning.
Building Better Babysitters Virtual Training: Additional childcare may be needed this summer. Babysitting is a big responsibility and it’s not for everyone. Youth ages 11 and up who are interested in building skills as a babysitter may be interested Nebraska Extension’s state-wide virtual babysitting training. Register by going to https://cvent.me/d4gWeD.
Adding some pics on frost recovery:
Same growth stage but showing the environmental variability associated with frost damage.
Seedling affected by frost on 3/9/20. Leaves watersoaked and wilted two days later. Splitting open stem reveals a healthy growing point (not brown or mushy) and green, healthy tissue below the wilted tissue. Thus, plants like these will likely recover, but it’s best to continue watching them for regrowth.
Same field 5 days later. A little sunshine and plants are recovering nicely! The frost-damaged tissue is now brown, dead and will typically slough off with the wind. Sometimes, it wraps around the seedling making it more difficult for new growth to push through at first, but it will.
Emerged beans were essentially unaffected in anything I looked at for this part of the State and are looking great now!
JenREES 5-10-20
The anticipated cool temps and potential for frost damage were on the minds of several towards the end of last week. The warm spring planting conditions allowed for more soybean emerged in Nebraska and the mid-west than I’ve ever seen before at this time-frame. From UNL small plot and on-farm research, it’s warm springs such as this that have provided the larger yield increases when soybean was planted early. As I’m writing this, low temperatures varied throughout the State Saturday night with more anticipated lows tonight. What should one look for in regards to frost/freeze recovery? First, we’d say to wait 3-5 days post frost to look for signs of regrowth. It may take up to 7 days depending on weather conditions following a frost event. I’ve provided photos in my blog at jenreesources.com to aid in what to watch for and will continue to add photos. Have learned a lot by flagging plants at different growth stages and taking pictures of their recovery. Would encourage you to do the same. One thing we’re always provided is the opportunity to learn!
Survival partly depends on how low temperatures got. Air temperatures of 28°F or less for at least two hours may result in damaged tissue and even death if the growing point is affected in corn and soybean. Air temperatures around 32°F typically don’t result in freeze of plant tissues. Why is this? Plant cells have solutes in the cytoplasm and just outside the cell membrane that act like a modest anti-freeze. Thus, the actual tissue temperature has to reach 28-30°F for frost damage to occur.
It also depends on stage of growth. For emerged corn, the growing point is still in the ground. Frost damage can appear as leaves discoloring and wilting due to plant cells rupturing. Eventually they will turn brown and slough off if new growth pushes through. It will be important to look at the growing point and make sure it’s white/yellow and firm and not discolored and soft. Warmer temps after frost event will help in reducing disease impacts from bacterial pathogens.
Soybeans that are just emerging with the hypocotyl hook exposed at or just above ground level, can be the most at risk for damage. The hypotcotyl hook is the area of the stem below the soybean cotyledon. Anything that impacts it will result in seedling death. Watch for plants that have soft, mushy, or pinched hypocotyls. These are situations where soybean seedlings tend to die. I’ve seen survival in seedlings with light scarring on the hypocotyl and cotyledons where there’s no pinching of the hypocotyl. Cotyledons just at the soil surface or above often will survive due to their high water content. They may have some light scarring yet they tend to survive. Look for the plumule (first true leaves from the shoot) within 7 days post-frost to ensure the growing point wasn’t injured. If unifoliolates were exposed, I’ve seen mixed results (depending on air temperatures and location in the field). Sometimes the unifoliolates will wilt and die but if the axiliary buds by cotyledons survive, new growth will occur.
For wheat, look for any splitting of the stems near the base of plants. Make sure the growing point looks healthy. Damage to wheat in jointing stage occur at 24°F for 2 hours and 28°F for 2 hours at boot. Impacts to wheat later on can also be seen at heading in white awns and spikelets and heads sometimes having difficulty to emerge from the boot (or being twisted). This CropWatch article shares more.
Low areas of fields, fields with coarser soil texture, and lower soil moisture contents can result in more frost damage. Fields receiving rains and wind prior to these cold temperatures may have aided in some protection. There’s often things I can’t explain when assessing frost damage. Sometimes a couple plants in a row will succumb while others around them at the same growth stage are fine. There’s just microclimate things that can’t always be explained. Here’s hoping most fields in the area are ok!
It’s also time to scout for alfalfa weevils and you can see more information and table of thresholds depending on growth stage in this CropWatch article: https://go.unl.edu/a7jw.
Rhubarb and Frost: If rhubarb leaves are not damaged too much and the stalks remain firm, it is still safe to eat. If the leaves are severely damaged or the stalks become soft or mushy, do not eat these stalks. Remove and discard them. New stalks can be harvested and eaten.
These are pics I took in 2019. The soybeans in the left photo had cotyledons just at the soil surface at time of frost. They survived. The upper right-hand photo shows a seedling with light scarring on the hypocotyl and cotyledons. However, the hypocotyl wasn’t pinched and you can see the plumule between the cotyledons is alive and healthy. The lower right-hand photo shows the hypocotyl was damaged on these seedlings causing pinching. Thus these seedlings didn’t survive.
This is what a healthy growing point looks like on a healthy plant not impacted by frost.
Corn impacted by frost on 3/9/20. Leaves watersoaked and wilted two days later. Splitting open stem reveals a healthy growing point (not brown or mushy) and green, healthy tissue below the wilted tissue. Thus, plants like these will likely recover, but it’s best to continue watching them for regrowth.
Plants impacted by frost (first and last) while middle two at same growth stage are not impacted. I see this often and have no explanation!
The beans next to this corn field look really good with light scarring of the cotyledons and healthy plumules.
JenREES 5-3-20
Planting season has rolled on this year with large planting progress made in short time! I’m grateful for the general warming trend with no cold snaps unlike so many recent years. Like many of you, am also praying for rain. For pre- herbicides, it is important to have 0.5-0.75” of moisture within a week of applying them for activation. That was a topic of concern I was hearing from both growers and ag industry last week, thus why it was recommended that some start pivots. I’m starting to see grass and broadleaf weeds coming through on ground that didn’t receive moisture to get the herbicide activated. Corn and soybean are also emerging fairly quickly with these warmer temps. The latest in pheromone trapping cutworm counts across the State can be found at: https://go.unl.edu/jdd3.
Some have asked about interseeding covers into early vegetative corn or soybean. Perhaps the three biggest things we’ve learned are to make sure the seed is in the ground vs. broadcast, plan to seed between V2-V5, and think about your herbicide program before trying this. An easy to understand site for herbicide impacts to covers is at: http://interseedingcovers.com/herbicide-options/. That whole website holds good information. There’s an Upper Big Blue NRD soil health project with partners of The Nature Conservancy, NRCS, and Extension where we will have 6 on-farm research studies and several other demos of interseeding this year. Growers are looking at impacts of different mixes, corn populations, row direction, and number of rows interseeded (1 vs. 3) between the corn rows. Looking forward to these additional studies to add to the research base which we talked about in this CropWatch article last year: https://go.unl.edu/4nh7.
My prayers go out to livestock and poultry producers; I just can’t imagine. There are a number of resources at https://animalscience.unl.edu/swine for emergency depopulation of livestock facilities. Such a hard time all around in ag. Free farm finance and legal clinics for May can be found at: https://go.unl.edu/joos. Nebraska Farm Hotline/Rural Response Hotline: 800-464-0258.
Evergreen Tree Diseases: The wet springs the past several years have led to an increase of needle blights. Spring is the time to be spraying trees with preventive fungicides with timing depending on the disease. None of the options I list are exhaustive and not meant as endorsement. For windbreak situations of cedars and pines, some ag retailers have carried Tenn-Cop 5E or Camelot. For home-owner use for trees in landscapes, I will share what I’ve seen sold in our local stores. It’s important to read the product label to ensure it’s safe to use on the specific plant/tree you wish to treat as some copper products can harm plants. In Austrian and Ponderosa pines, tip blight (where tips die) and dothistroma needle blight (where needles turn brown and die) can be prevented with fungicide applications. Tip blight is best prevented in late April-early May with active ingredients of Propiconazole (found in Fertiloam liquid systemic fungicide), Copper Salts of Fatty & Rosin Acids (sometimes listed as copper soap such as Bonide liquid copper fungicide and other liquid copper formulations), or Bordeaux mixture. Dothistroma needle blight can be prevented in mid-May and a second application in mid-June with Copper salts of fatty and rosin acids and Bordeaux mixture. In spruces, needle cast can cause the yellow to reddish brown color of needles in the fall that remain that way in the spring. Fungicide should be applied when the new growth is half grown with a second application 3-4 weeks later. If your tree is severely infected, it may take applications like this for 2-3 years in a row. Chlorothalonil (found in Daconil and Fung-onil) is commonly recommended. Fungicides containing azoxystrobin, mancozeb, propiconazole, copper salts of fatty acids, and copper hydroxide are also effective at controlling this disease if the product is labeled for use on spruce. You can learn more about evergreen diseases, how to identify them, and more products for management at: https://go.unl.edu/rbcc.
It’s too early for bagworm control. I’ll share more on what to look for next week.
JenREES 4-26-20
Crabgrass Preventer: Warm season annual grasses such as crabgrass and foxtail germinate when soil temperature at the 0-2” depth is consistently between 60-70F. Thus, we often say that reasonably, crabgrass preventer can be applied when soil temps at the 0-2” depth are consistently around 55F. Our CropWatch soil temperatures are measured at a 0-4” depth (https://cropwatch.unl.edu/soiltemperature). Based on them, it may be time to apply or at least getting close in the York area. If you’d like to determine the soil temp of your site locally, you can use a temperature probe or a meat thermometer (that you won’t use for cooking). Make a mark at 2” from the base and it will give you an idea. Remember to blow off or sweep lawn clippings and fertilizer from the sidewalks back onto lawns!
Moths: Our Extension entomologists are also starting to see black cutworm, variegated cutworm, and true armyworm moths in pheromone traps throughout Nebraska. You can see pictures and the counts (which will be updated) in CropWatch at https://go.unl.edu/jdd3.
Planting Green: Been receiving a number of questions throughout the state on this. We wrote a planting green article for CropWatch this week https://go.unl.edu/ysyi. We have minimal research but in the article, we explain more regarding herbicide considerations, what the research shows regarding allelopathy, and considerations based on growers’ and our observations and experiences. We haven’t found any wheat stem maggot flies in rye yet in Clay, York, or Seward counties. The flies we’re getting questions on are small brown flies and also seed corn maggot flies. Having an insecticide seed treatment on corn and beans will help against seed corn maggots. More info. from Iowa State: https://crops.extension.iastate.edu/cropnews/2020/04/seedcorn-maggots-flying-iowa
Seed Treatments for SDS: Continuing from last week, the summary is that ILeVO is an 
effective seed treatment in fields with high sudden death syndrome (SDS) pressure. However, not all areas of the field have the same amount of pressure, making it difficult to justify the cost field-wide. Three Nebraska on-farm research studies were conducted in soybeans in 2017 with a multi-hybrid planter. Soybeans with a farmer’s choice base seed treatment (check) were compared to the base seed treatment plus ILeVO. The goal was to look at site-specific application of ILeVO to reduce input costs while still effectively managing sudden death syndrome (SDS) pressure. Management zones were created using historical yield maps to show which zones were conducive to SDS pressure (SDS zone) and which weren’t (standard zone). Check strips and ILeVO treated strips were compared in both zones. Two of the locations showed no difference between the base treatment and base treatment + ILeVO in the SDS or the standard zones. At one location, SDS was not present in the field. In the other, the ILeVO treatment had significantly lower disease levels than the standard treatment and overall disease incidence was considered low. At the third site, the standard + ILeVO treatment yielded higher than the standard treated seed in the SDS zone. There was no difference in treatments in the standard zone. The SDS zone was around 50 acres and along a creek that ran through the field (Figure 1). Additional ILeVO studies were conducted in 2015-2016 via on-farm research in Dodge, Clay, and Nemaha Counties where an untreated check, base seed treatment, and base + ILeVO were compared. SDS incidence ratings were taken in addition to soybean cyst nematode samples. In two of the six fields, there was a yield difference between the base + ILeVO and other treatments, even though disease incidence was low. Two sites also had a significant decrease in SDS pressure with the ILeVO treatment, but it didn’t correlate in increased yield. These studies found ILeVO to be effective in reducing SDS pressure, but yield response and profitability depends on disease development and how widespread in the field. SDS pressure was found to be higher in frequently ponded soils or areas of the field with creeks or intermittent streams. We have no on-farm research data on Saltro although we have a York Co. study on it this year.
JenREES 4-19-20
Freeze Events: With last week’s cold spell, it’s hard to know exactly how it will impact flowering trees, shrubs, and fruit trees. It really depends on the bud/flowering stage at the time of the freezing temperatures. I’ve also received a number of questions regarding wheat and how bad it looks due to frost right now. In some cases, the injury may look worse due to leaf burn from fertilizer and/or fertilizer + herbicide applications shortly before the freeze events. We need to be patient and allow time with anticipated warmer temps to watch recovery. Ultimately, wheat in the tillering stage is quite tolerant of frost with minimal yield impact expected down to 12F for 2 hours. Once the wheat begins jointing (growing point moves above ground), temperatures like what we experienced of 24F for 2 hours can moderately to significantly impact yield. While upper leaves may be burned off from frost, there’s actually a micro-climate effect within the wheat canopy which is warmer closer to the ground (depending on the wheat stand). If the soil had quite a bit of moisture prior to freeze events, it also helps buffer the soil temperatures, reducing freeze injury. What I look at: is the wheat in tillering or jointing stage? Do you notice any splitting of tillers at the base of the plants? If the wheat is jointing, split the stem to look at the growing point (I use a box cutter for wheat this small). Is the growing point white and healthy or yellow/brown and mushy? Wheat can tolerate much, but I can also appreciate how many of you are trying to make decisions. You can also check out the freeze to wheat article in CropWatch and more localized to our area, Nathan Mueller’s blog: http://croptechcafe.org/multiple-spring-freeze-events-impact-winter-wheat/.
Regarding alfalfa, it’s another ‘wait and see’ situation. Please see this week’s CropWatch
Check the upper-most cluster of buds to determine any affects. This is where the growing point is located. If this cluster is froze off, look at axillary buds along main stem and new buds from crown for new growth.
at cropwatch.unl.edu for more info. The more growth actually results in potential for increased damage and it also depends on the air temperature and duration of freeze. New seedlings can be pretty resilient due to being close to warm soil, protected by companion crops like oats, or due to natural seedling tolerance. Damage can range from upper stems and leaves wilting and turning brown to a hard freeze causing plants to completely wilt down and fall over. What I watch for are new buds…buds that are within the canopy that weren’t exposed to frost, new axillary buds that develop from upper stems that have frozen off, and new crown buds. In 2007, some chose to remove the dead plant material from the plants to stimulate growth. Dr. Bruce Anderson found the plants reacted to the killed tops from frost the same as they would from a normal cutting. Thus, we’d recommend observing how the alfalfa responds and ultimately doing nothing for the time being. Cutting alfalfa for hay with only 6” of growth in most fields wouldn’t be practical and can weaken plants. Anticipate first cutting to be delayed as a result of these multiple freeze events.
Planting: While you might not share this sentiment, I was grateful last week was so clearly not the right conditions to plant for this area of the State! It seems extra tempting when there’s a couple of really nice days prior to a cold snap. Outside of ‘is it ok to plant’ or ‘should I plant corn or beans’, my main planting question is regarding soybean seeding rates. We now have 13 years of on-farm research from this part of the State in 15” (planted not drilled) and 30” rows in silt loam/clay loam soils showing no yield benefit to planting greater than 120,000 seeds/acre. These studies included a seed treatment when soybean was planted in late April/early May. Otherwise, no yield differences were achieved from 120K to 180K regardless if seed treatment was used. We share more in this week’s CropWatch. With sudden death syndrome being bad in 2019, I’ve also received questions on seed treatments such as Ilevo® or Saltro® for it. I will share the research next week. Bottom line: economically I would only consider this if you have a history of SDS. Even so, environmental conditions don’t always favor SDS. You could consider using SDS treated seed along areas with a creek or intermittent stream running through the field or lower areas of the field where water ponds and using non-SDS treated seed in the rest of the field. Early planting doesn’t automatically favor SDS. Water during flowering and levels of soybean cyst nematode can favor it. Will share the data next week. And, a reminder to check your seed tag regarding proper PPE to wear when handling any treated seed. Here’s wishing you a safe planting season!
JenREES 4-12-20
Happy Easter! This will truly be one to remember and hope you were able to still connect with family and friends in some way. For fruit trees and freeze temp. thresholds, please check out this resource: https://www.canr.msu.edu/uploads/files/PictureTableofFruitFreezeDamageThresholds.pdf. With planting having started for some or anticipated in the next few weeks, wanted to share some things I’ve been thinking about and some questions I’ve received.
As much as we have more physical distance in ag, it may be wise to have some plans in place in the event someone becomes sick with COVID-19 in your crop or livestock operation. Things such as disinfecting equipment and a sample 0-2 month plan with contact phone numbers are available in this week’s CropWatch at cropwatch.unl.edu. There’s also information on the CARES Act explaining the numbers. A series of Farm/Ranch COVID-19 free economic webinars are upcoming from UNL AgEcon. The first is this Thurs. April 16th at 3 p.m. CST. and features Nathan Kauffman, with the Federal Reserve Bank of Kansas City, presenting on COVID-19 Economic Developments and U.S. Agriculture. Details and recordings will be posted at https://go.unl.edu/manage2020.
Planting Considerations: It was nice to see equipment out in fields this past week! With tight economics, it’s important to make wise decisions with the factors we can control during planting season; it sets the stage for the rest of the year. One factor to consider is planting windows instead of planting dates. While this week is mid-April, it may not provide the best opportunities for planting. Be sure to check soil temps and plant at proper depth, not mudding in seed, and plant as close to 50F soil temps as possible when there’s a warming trend. Avoid planting when there’s potential for a cold rain/cold snap within 48 hours for corn and at least 24 hours for soybean. It’s also best to get seed in the ground 1.5-2” deep. For corn, this is critical in helping with nodal root establishment. For soybean, this aids in buffered soil moisture and temperature and helps delay emergence to aid against potential frost. Numerous research studies have proven the yield benefit to early planted soybean. Outside of the genetics, it’s the top way to improve soybean yields. When we conducted these studies via on-farm research, we also had planting date X planting rate studies. Those studies showed no yield difference when planting 120K vs. 180K in April vs. May beans. All the planting date studies had an insecticide + fungicide seed treatment and I have no data without it. Our soybean planting rate studies did not always have a seed treatment and now 13 years of that data still shows 90-120K planted seeds being the most economical while 120K is what we’d recommend for yield.
In this week’s CropWatch, I wrote an article with Jim Specht on soybean germination. The imbibition phase (water uptake) is the critical phase for potential seed chilling. Once the imbibition phase is complete, the soybean going through the osmotic phase can tolerate 35-40F soil temps as long as soil is not saturated. The reason why we say at least 24 hours for soybean vs. 48 hours for corn (regarding cold snap/cold rain) is because the soybean seed imbibes water much faster than corn. You can prove this to yourself! Put a soybean seed and corn seed in water and watch what happens. When teaching youth ag literacy, I put soybean seeds in water to show them the seed coat, root and first leaves. Granted, we’re not planting soybean into water, but it helps one see the difference in how the seeds imbibe water. Studies from journal articles showed the imbibition phase could complete in as little as 8-12 hours. However, it all depends on the beginning soil moisture, soil temperature, quality of the seed (no nicks in the seed coat, free of wrinkles from wet/dry cycles, higher seed moisture of 13-16%). There have also been experiments to suggest that soybean can be planted in 45F soil temps if soil moisture is stable and no cold rains occur during the imbibition period.
I’ve also received a few questions regarding rye rapidly growing and what to do. I have no research-only observation and talking to others. I’m still a fan of planting green. However, have noticed difficulty with residual herbicides applied to tall rye (above 12”) and getting down to the soil, thus weed escapes. So, a few thoughts. If you’re concerned about the rye, you can always terminate a few weeks before planting. Otherwise, consider splitting your residual with half on when you kill rye after planting with other half later or putting on your residual in a second pass after killing rye. Would welcome others’ thoughts/experiences of what’s working for you!
Dicamba Webinar: The National Ag Law Center is hosting a free webinar titled ‘The Deal with Dicamba: An Overview of Dicamba-Related Litigation’ on April 15th at 11 a.m. CST. It will discuss various lawsuits filed in response to crop damage allegedly caused by herbicides containing dicamba. Details: https://bit.ly/3e2LvGX.
JenREES 4-5-20
Youth/Family Support: Last week I shared this link for many hands-on learning activities: https://4h.unl.edu/virtual-home-learning. Two more resources that may be helpful for families right now: Helping Children Cope with stress and change: https://child.unl.edu/helping-children-cope and Reading for Resilience which helps children cope with storybooks: https://child.unl.edu/read4resilience.
Checking grain bins: A local farmer suggested to share a reminder to keep checking on grain with temps warming up and much grain in storage. It’s also so important to be safe with grain handling. The following is from Dr. Ken Hellevang with North Dakota State University (full article at: https://www.ag.ndsu.edu/news/newsreleases/2020/march-23-2020/proper-spring-grain-drying-and-storage-critical). “The stored grain temperature increases in the spring not only due to an increase in outdoor temperatures but also due to solar heat gain on the bin. Solar energy produces more than twice as much heat gain on the south wall of a bin in spring as it does during the summer.
Hellevang recommends periodically running aeration fans to keep the grain temperature near or below 30 degrees until the grain is dried if it exceeds recommended storage moisture contents, and below 40 degrees as long as possible during spring and early summer if the grain is dry. Night air temperatures are near or below 30 degrees in April and 40 degrees in May. Soybean oil quality may be affected in less than four months if even 12% moisture soybeans are stored at 70 degrees.
Cover the fan when it is not operating to prevent warm air from blowing into the bin and heating the stored grain. Hellevang also recommends ventilating the top of the bin to remove the solar heat gain that warms the grain. Provide air inlets near the eaves and exhausts near the peak or use a roof exhaust fan… Grain temperature should be checked every two weeks during the spring and summer. Grain also should be examined for insect infestations. Check the moisture content of stored grain to determine if it needs to be dried. Remember to verify that the moisture content measured by the meter has been adjusted for grain temperature.
Corn needs to be dried to 13% to 14% moisture for summer storage to prevent spoilage. Soybeans should be dried to 11% to 12%, wheat to 13%. The allowable storage time for 13% moisture soybeans is less than 100 days at 70 degrees. Corn – For natural air-drying, assure that the fan’s airflow rate is at least 1 cubic foot per minute per bushel (cfm/bu) and the initial corn moisture does not exceed 21%. Start the fan when the outdoor temperature averages about 40 degrees. Soybeans – Use an airflow rate of at least 1 cfm/bu to natural air-dry up to 15% to 16% moisture soybeans. Start the fan when the outdoor temperature averages about 40 degrees.”
Burndown and pre-plant herbicide apps: Anticipating this week’s nicer weather, I’ve also received several questions on burndown and pre-plant herbicide applications and weather impacts on control. Dr. Amit Jhala wrote two articles in this week’s UNL CropWatch at https://cropwatch.unl.edu. Sunny days with temperatures above 40F for day and night, and even better when temps are climbing to the upper 50s and above provide better control than if it’s cooler than 40F. Glyphosate works faster during sunny conditions when it is 60-75F and remains there a few hours. The articles also list rain-fast period and planting interval restrictions (as would the product labels). If you’re looking for a general idea on potential residual activity of herbicides for overlapping residual, check out pages 23-24 of the 2020 Guide for Weed Management.
My colleague Dr. Nathan Mueller shared in his blog: http://croptechcafe.org/should-you-control-winter-annual-weeds-early/, “A 2007-2009 UNL study conducted in Lincoln and Clay Center found that in 5 of the 6 site-years (2 site per year for 3 years is 6 site-year) that not controlling winter annual weeds prior to corn and soybean planting resulted in greater than a 5% yield loss and a 10% loss in 4 of the 6 site years.”
Sharing some encouragement from my neighborhood to yours 🙂 Individuals within farm families could also write messages to each other!
JenResources 