York and Seward County Fairs: Here’s wishing the best to all the youth competing in the York and Seward County Fairs this week!
Crop Update: It’s unfortunately not hard to find southern rust in fields anymore as I’m finding it in every field I walk into. Incidence is mostly confined to lower canopies with the highest I’ve seen so far on the ear leaf. What’s concerning to me is the amount of rust I’m seeing (ear leaf and below) in canopies of fields that have already been sprayed. Some fields sprayed in mid-July will be out of residual soon, which is also concerning to me. Physoderma brown spot, which moves with water and isn’t a significant pest, can be confused with southern rust. While it can look bad, a major difference with Physoderma is that there’s no raised pustules (bumps) on the leaves. I haven’t seen gray leaf spot at ear leaves or above yet. I’ve added pictures of what I’m seeing on my blog at jenreesources.com. There’s been some questions about ‘late season’ Nitrogen applications. I’ve had to ask how late is ‘late season’; brown silk has always been the latest I recommended. Most University research considered ‘late season’ as by tassel time. I haven’t found any University research that has said applications should be made later than brown silk or would be beneficial past this time.
In soybeans, there’s a disease called Phyllostichta leaf spot that I had never before seen.
It’s one caused by a fungus that begins often as brown lesions on leaf margins and can move between leaf veins. In learning more about it, it can be residue born or seed transmitted. It doesn’t sound like anything to be too concerned about, just something different that’s been seen in some fields this year.
Painted lady butterflies are the orange and brown butterflies that are flying now that are often confused for monarchs. A painted lady female can lay up to 500 pale green eggs on plants individually instead of in egg masses. The larvae (called thistle caterpillars) hatch in around a week and can feed from 2-6 weeks depending on weather conditions. They feed on around 100 different host species including thistles, soybeans, asters, zinnias, etc. These butterflies are often used in schools to teach students about complete metamorphosis using the life cycle of a butterfly.
Soybean Defoliators: In addition to thistle caterpillars, other defoliators including various worms, grasshoppers, Japanese beetles are also present. Thresholds for damage for all soybean defoliators is 20% defoliation of plants during the reproductive stages. If you’re unsure what 20% defoliation in soybean looks like, check out the graphic in CropWatch at: https://go.unl.edu/7qjg. It’s actually a good graphic to keep on one’s phone as it’s very easy to over-estimate 20% defoliation.
Unsolicited Seeds from China: I haven’t heard of anyone in this area officially receiving a packet yet. USDA is aware that people across the country have received suspicious, unsolicited packages of seed that appear to be coming from China. USDA’s Animal and Plant Health Inspection Service (APHIS) is working closely with the Department of Homeland Security’s Customs and Border Protection, other federal agencies, and State departments of agriculture to investigate the situation. Anyone in Nebraska who receives an unsolicited package of seeds should immediately contact Julie C. Van Meter at 402-471-6847) or Shayne Galford at 402-434-2346. Please hold onto the seeds and packaging, including the mailing label, until someone from your State department of agriculture or APHIS contacts you with further instructions. Do not plant seeds from unknown origins. At this time, there’s no evidence indicating this is something other than a “brushing scam” where people receive unsolicited items from a seller who then posts false customer reviews to boost sales.
Squash Vine Borers tend to be a problem at some point every year. If you’re seeing zuchinni, squash, or pumpkin plants looking wilted and suddenly dying, check the stems at the base of the plant. If you see insect frass (like sawdust), squash vine borers are most likely the culprit. You can remove the plants and discard if you’re done with them. Otherwise, you can also slit the stems and kill the larvae. Then cover the stem base with soil to encourage new root growth. There’s only one generation a year and it’s too late to apply insecticides (should be applied to plant base beginning in late June-mid-July). Some master gardeners also say wrapping the base of stems with aluminum foil discourages moths from laying eggs.
Physoderma brown spot on outer stalk tissue. It looks bad but not penetrating beyond the outer stalk tissue.
Crop Update: Grateful to see how corn ears in wind damaged fields were able to expand and expose silks to pollen! Noticing on the primary ear node one normal ear and another 1-2 small ears on the same node in some hybrids-more common this year than I’ve noticed before. Unsure what to think of it; just an observation. Southern rust has been confirmed in 19 Nebraska counties at low incidence and severity; levels not necessary for fungicide applications yet (in my opinion). Last week I shared UNL data that showed no yield differences between a check treatment vs. various growth development timings (through 100% dent) and various fungicides in two low and moderate disease years. For those dealing with spidermites, it’s important to determine whether the plants have two-spotted or banks grass mites as they differ in control. For more information, check out this information: https://go.unl.edu/idsm.
Virtual Field Days: As someone who enjoys field days and meetings to see and catch up with people, it’s been hard to not have field days this year! Thankfully we can share information via technology. The following are resources for weed management and wheat production/variety info:
- South Central Ag Lab Weed Science Field Day: https://go.unl.edu/2020weedfieldday
- Glyphosate Resistant Palmer Amaranth Field Day: https://go.unl.edu/palmer-amaranth2020
- Wheat Field Days (Part 1 Production background): https://mediahub.unl.edu/media/13563
- Wheat Field Days (Part 2 Varieties): https://mediahub.unl.edu/media/13564
Tree Problems: Trees are important to any landscape, whether in town or on the farm!
Often, there’s stories behind their planting and it’s always hard to see them decline/die. The #1 killer I’ve found of cedar windbreaks is landscape fabric used as a weed barrier when trees are planted. No matter what the product says or who tells you it will tear as the tree grows, it rarely does. It does a great job with weed control! And, 5-15 years down the road, it’s understandably forgotten. Once the tree trunk expands to where the original edge of the hole is, the trunk often can’t tear the fabric right at the soil line while the trunk above and below it tries to expand. Sometimes a tree can survive for awhile with the choking. However, if you ever see a tree that dies quickly with no other apparent reason, it usually
is due to something with the root system or choking somehow on the tree. I realize it’s a pain, but with as much work and money that goes into windbreaks, it’s a really good idea to take some time and pull weed barrier away from the tree trunks. A long-handled tool with tines can help but just make sure to carefully get all the way to the trunk to release any potential choking (I often have to get under the tree and cut the fabric next to the trunk to accomplish this). This goes for weed barrier used for any trees and shrubs. Weed barrier with rock is one of the biggest killers of plants I see in landscapes.
Bagworms are also impacting cedars, spruce, and various shrubs. Right now I recommend using Bifenthrin as it irritates the bagworms and makes them leave bags to be better exposed to the product. It has a two week residual and is used as an insecticide for many plant situations. Get really good coverage of the trees/plants when applying.
A number of fungal diseases are impacting evergreen trees. Many started the past few springs due to wet, humid weather. They are showing up worse now with recent humidity. The good news is trees can be treated with various fungicide products next spring that can be obtained from local hardware, farm, and landscape stores. PLEASE read and follow the label (can pull the label back in the store) regarding if the tree/plant is labeled for the product. I’ve been called out to disasters this year when the wrong products were applied to trees for which they weren’t labeled.
Japanese beetles continue to be a problem. Hopefully they’ll be finished in the next few weeks. Apply products at dusk to reduce harm to pollinators. Natural products include Neem and Pyola oil that can be applied every week. Conventional insecticides can provide 2 weeks of control: pyrethroid products like Tempo and Bayer Advanced Lawn & Garden Multi-Insect Killer (cyfluthrin) or Ortho Bug B Gone (bifenthrin).
York County Fair Open Class: Quick note for those exhibiting in York County Fair’s Open Class, we ask that you have entry tags completely filled out including mailing address PRIOR TO fair this year. Entry tags can be obtained from the York Co. Extension Office and Wagner Decorating. All rules same as last year except Needlework is limited to 3 entries per exhibitor. Exhibits can be dropped off on the WEST side of Ag Hall Tues. Aug. 4th from 6-8 p.m. and Wed. Aug. 5th from 8-11 a.m. Volunteers will take items into buildings as much as possible.
Crop Update: The smell of pollen is in the air! Did you know each tassel contains around 6000 pollen-producing anthers? Two good articles from Dr. Bob Nielsen, Purdue University at https://go.unl.edu/x5tv.
How does heat impact pollination? Dr. Tom Hoegemeyer, former UNL Professor of Practice, shared that high humidity, without a drop in humidity during the day, can delay pollination or prevent pollen from leaving anther sacs. While heat over 95°F depresses pollen production, one day of 95-98°F has no or little yield impact when soil moisture is sufficient. After 4 consecutive days, there can be a 1% loss in yield for each day above that temperature. Greater yield loss occurs after the fifth or sixth day. Thankfully we’re not in a high heat pattern during this critical time of pollination!
My concerns regarding pollination: bent ear leaves covering silks in wind-damaged fields. Seeing a great deal of this. Also seeing silks continuing to elongate and grow through broken mid-ribs to increase exposure to pollen. Will continue to observe impacts.
Preliminary storm prediction center weather data showed a total of 93 wind, 11 hail, and 13 tornado damage reports on July 8th in Nebraska. Univ. of Wisconsin found lodged plants had yield reductions of 2-6% (V10-12 stage), 5-15% (V13-15 stage), and 12-31% (V17 and after stages). For greensnapped plants (below ear), Iowa State found in the worst case situation, yield reduction may range up to a 1:1 percent broken:yield loss. It’s possible these losses will be as low as 1:0.73 or even 1:0.50. We have an article in this week’s CropWatch (https://go.unl.edu/cwy2) with more detailed information. Recovery pics also at https://jenreesources.com.
Southern Rust was confirmed at low incidence and severity in Fillmore, Nuckolls, and Jefferson county fields this past week (probable for Thayer). Received questions on fungicide applications. In conversations, it seems like there’s fear of making the wrong decision and ultimately pressure to apply them. I realize economically it’s easier to justify adding a fungicide with insecticide when insect thresholds are met to save application costs. Most fungicide studies focus on VT applications; however, yield increases with automatic VT applications aren’t consistently proven in Nebraska.
In fact, 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.
- 2008: No 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.
- 2009: No 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.
Thus I’ve recommended waiting till disease pressure warrants the application (have personally recommended apps as late as hard dough in previous years). Hybrids vary in disease susceptibility (thus response to fungicide application). The main ‘plant health’ benefit observed in Nebraska when disease pressure was low (ex. 2012) was stalk strength and that may be something to consider again in this lower disease year. Regarding any improved water use efficiency for drought-stressed plants, the peer-reviewed research published on this was in 2007. The researchers found slightly increased efficiency in well-watered plants, but it was reduced in water-stressed plants. They suggested fungicide use in water-stressed plants could potentially negatively influence water use efficiency and photosynthesis.
Same area of a York County Field taken morning of July 9th (left photo) and morning of July 13th (right photo). Grateful to see how plants are re-orienting themselves in many impacted lodged fields!
Seeing some new growth on some greensnapped plants. Dissecting the growth revealed baby corn ears (they won’t amount to anything). Just shows the resiliency in plants regarding how they’re created to survive and reproduce. I never cease to be amazed by their Creator!
Wind-damaged Corn: The evening/early morning hours of July 8-9 caused quite a bit of damage to corn fields for some of you reading this. It’s always hard to see crop damage. For field corn, it came at a critical time prior to pollination. The severity and amount of recovery for every field situation will vary depending on the soil moisture at time of the wind, root mass structure, hybrid planted, severity of leaning/bent/snapped plants, and growth stage of the plants. It will also depend on where the bending and snapping of those plants occurred. ‘Recovery’ encompasses the plants righting themselves, re-establishing roots, and re-orienting leaves as they have the ability to bend and grow up towards the sunlight in areas of the plant where plant tissues were not yet lignified (hardened). We know hybrids have been bred to better withstand greensnap. We know that plants that are leaning due to root lodging may have better ability to upright themselves (and have seen this in some fields since the storm). We also know that it is harder for plants near tasseling to upright themselves compared to plants at earlier vegetative stages.
What to expect? It really depends on the conditions outlined above. We all will learn a lot and I encourage us to share what we are observing. For fields very close to tassel with severe bending near ears, we may see pollination, possibly even ear formation issues. There may be fields that were leaning and will have minimal impacts after uprighting themselves. The main research I can find regarding corn lodging yield impacts comes from the University of Wisconsin in 1988. In the study, they manually lodged corn at various growth stages over 2 years to determine yield impacts. Corn lodged at V10-V12 resulted in a yield reduction of 2-6%. Corn lodged at V13-15 resulted in a yield reduction of 5-15%. Corn lodged after V17 resulted in a 12-31% yield reduction.
What to do? Recommend waiting, observing, call your crop insurance adjuster. Don’t apply products right now. Economically, we need to see how each field recovers before putting more into the crop. Plants are already stressed so give them time to try to recover. A respected agronomist shared another point with me-that adding heavy amounts of water right now can add weight onto the plants and keep them sticking together when they’re trying to separate. For those who were planning on fertigation, I’ve seen soil sample results and heard from several people that we’re seeing increased mineralization this year in fields due to the heat. It may be worth a tissue and/or soil test to see if you really need additional nitrogen (final application at brown silk). Regarding fungicides, my recommendation prior to the storm was to wait till at least brown silk (or after) due to low disease pressure, uneven growth stages in fields, waiting for southern rust, and economics; I stand by that after this storm. Fungicides can’t help much with the plant stress being experienced.
Spidermites have been found in low levels in corn, but in some cases, fairly high levels in soybean. Higher levels have been observed in stressed fields (due to off-target herbicide damage and/or beans stressed due to drought). If you’re noticing pockets in fields that appear to be yellow/brown/dying and spreading, check the top side of the leaf for stippling (yellow needle-like pin-pricks) and undersides for webbing and mites. Seeing them in non-stressed beans at low levels as well. Check out this information from Illinois for guidelines on when and how to control: http://bulletin.ipm.illinois.edu/?p=5080.
Gardening Resources: Nebraska Extension is hosting a series of 12 virtual learning sessions for home gardeners to discuss timely issues around vegetable gardening and trees. Each session will include a short (15-20 minute) presentation on the specified topic and opportunities for participants to chat about their issues and “ask the expert”. Sessions will be each Tuesday through September at 7 p.m. CST. Participants can register via go.unl.edu/grobigredvirtual – you can register for all the sessions you’re interested in at one time. You can also view the series via this Facebook post: https://www.facebook.com/events/1195072680839800.
Japanese Beetles: Areas of the State have seen Japanese beetles for a few weeks. They’ve shown up strong in the York/Seward county area this past week with the number of calls I’ve received.
Unfortunately they cause two problems. The larvae are grubs that can impact our lawns. The adult beetle is ½” in length with a metallic green head and white ‘tufts’ that look like spots on its abdomen. Adults emerge from grassy areas like lawns, ditches, and even fields; however, they don’t emerge at the same time. They emerge over a 4-6 week period beginning in late June and last for around 4-6 weeks. There’s one generation per year. Adult beetles feed, mate, and lay eggs in lawns and grassy areas. The eggs hatch 10-14 days later into grub larvae and feed on turf and grassy areas in the August time-frame. They also over-winter in turf and grassy areas.
Adults feed on 300 plant species, but their favorites are ones that are in many of our
landscapes (roses, cannas, marigolds, grapes, Virginia creeper, and trees such as lindens, birch, Japanese and Norway maples, cherry, plum, peach, American elm). They also feed on soybean and corn crops. They love hot weather and full sun and feed on leaf tissue during the day (leaf tissue will look skeletonized or lacy and turn brown). Trees may be severely impacted with browning occurring from the top to bottom. Thankfully healthy trees will re-leaf next year since the underlying twigs and branches aren’t damaged-even if the entire canopy is impacted this year. It’s not recommended to remove branches or trees.
DO NOT use Japanese beetle traps!!! Research shows they attract beetles to the landscape and many homeowners I’ve talked with will attest to this!
Beetle Control: Wait till dusk (7-9 p.m.) before trying to control beetles as they are less
active then and to reduce impact to pollinators. Organic means include hand-removing beetles by knocking them into soapy water. You can also spray trees with water to knock them down to the ground and then drown in soapy water. This takes diligence over many days. With heavy beetle infestations, it’s not uncommon to literally have scoop shovels full of the beetles when removing from trees. Neem and Pyola are two organic sprays that will protect for 3-7 days. Applying these products regularly (once per week) can also be effective as a repellent.
Japanese beetles often impact the same flowering plants that other pollinators visit. Use insecticide products correctly to avoid damage to pollinators. Avoid spraying insecticides on windy days or when pollinators are present (best to spray late in day near dusk) and be sure to read and follow all label instructions and harvest intervals (for cherries, plums, etc.). Conventional insecticides can provide 2 weeks of control: pyrethroid products like Tempo and Bayer Advanced Lawn & Garden Multi-Insect Killer (cyfluthrin) or Ortho Bug B Gone (bifenthrin). Sevin (carbaryl) is another option although more dangerous for bees.
Grub Control: Turf damage can be evident in Aug./Sept. Products that control common white grub can also provide control of Japanese beetle grubs and should be applied mid-to-late June. Dylox can be used as a rescue treatment if grub control is needed later on and no grub products were applied in the spring.
Next Year: Systemic products like imidacloprid can be used as a soil drench around plants (apply around Mother’s Day). These products can’t be used on Linden trees. You may also wish to swap out more susceptible plants for those less susceptible as you observe which plants they tend to impact most in your backyard.
Also seeing green June beetles and this shows the difference between them and Japanese beetles. Green June beetles don’t have the same impact on leaf damage. They do lay eggs in turf which become grubs as well.
Corn: Corn plants are rapidly growing and at or nearing tasseling soon. One sign of rapid
growth is to look at the new leaf edges. Sometimes there will be a white margin, more transparent look, wrinkles, or notches in them. All of those are signs of rapid growth which take place during cell division.
Fertigation and Irrigation: Some fertilizer is occurring now before tassel. I also recommend 30 lbs of N at brown silk if needed. This is based on research from Purdue University sharing today’s hybrids use 30-40% of their total Nitrogen from flowering through maturity. In the past, some have asked about applying fertilizer during pollination. The following information is from Dr. Tom Hoegemeyer, Plant Breeder and UNL Professor of Practice Emeritus, “Pollination mostly occurs between 8:30 a.m. and Noon. Thus, as a precaution, I would not run a pivot on pollinating corn from 6 a.m. to Noon. When the temperature is 90°F to 95°F, the pollen is killed by heat and is seldom viable past 2 p.m. That leaves lots of time to run pivots, apply N, etc. when it won’t harm pollination. Silks tend to be viable for three or four days at these temperatures, so if a plant isn’t pollinated one day, generally the next day will work just fine. (If nitrogen is needed), I’d recommend that nitrogen go on as soon as practical. Corn nitrogen use is very high during the pre-tassel growth phase and again at kernel growth, from one to three weeks post pollination. About seven to ten days post pollination (before brown silk) lower N will start causing kernel abortion and serious yield loss in corn.” The UNL recommendation for fertigation is to use 30 lb of N with 0.25″ of water or 50-60 lb of N with 0.50″ of water.
Insects and Diseases: Thus far, insects and diseases have been pretty minimal in corn. Seeing some spidermites in low numbers. Japanese beetles are showing up in areas where they’ve traditionally been more of a problem. In corn, the threshold is 3 or more beetles per plant, clipping silks to ½” or less, with pollination less than 50% complete. The hard thing about the beetles is they have a long emergence of 3-4 weeks where they don’t all emerge at the same time…and they live as an adult for 3-4 weeks. The threshold for corn rootworm beetles for silk clipping is similar. Light trap data for western bean cutworm is showing moths are beginning to appear in low numbers. They prefer laying eggs on upper leaf surfaces of corn in late whorl stage to early tassel (however, I’ve seen them lay eggs on the underside of leaves and on leaves closer to developing ears in high heat). The current UNL economic threshold for treatment is 5-8% corn plants with eggs or larvae.
And, often there’s discussion about fungicide applications at tassel time or throwing in a
fungicide with an insecticide (or vice versa) to save an application cost. I shared a great deal about this a few weeks ago; please be very careful with growth stages and what is applied in the tassel time. With uneven emergence, not all plants in the field will be tasseling at the same time, which allows for corn ear abnormalities when NIS in particular is added to the tank (or is in the product formulations) and applied just prior to tasseling. That’s why I prefer to see fungicide applications delayed to at least full brown silk and preferably later if there’s no disease pressure to warrant the application.
Research at UNL South Central Ag Lab showed we can still apply fungicide to dough stage with no yield difference, particularly in low disease pressure years. The research also didn’t show an automatic yield increase with tassel applications. This allows us to account for southern rust which has occurred at some point all but two years of my Extension career. With tight economics, it just makes more sense to me to delay fungicide applications to when disease warrants it vs. applying too early as some have had to repeat applications (when southern rust occurred after applying too early). It’s also just good resistance management to not apply when disease and insect pressure doesn’t warrant it. Also be aware that we can see corn leaf aphids flare after fungicide applications as the fungicide kills a natural fungus that keeps their numbers in check. Aphids also can interfere with pollination by covering tassels.
Soybeans: As soybeans approach R3 (beginning pod), that’s the critical time to avoid
water stress in soybean (similar to tassel for corn). We recommend avoiding irrigating during flowering whenever possible to reduce disease pressure (such as white mold and SDS). Don’t pull insecticide triggers too early for soybean defoliators. UNL recommends 20% defoliation at reproductive stages from all defoliators.
Independence Day: As we approach July 4th this year, I can’t help but think how
different it may be on many levels, particularly from all that’s occurring in our Country. Our flag is one of the most beautiful things to me because it represents so much…many willingly put their lives on the line for my freedom and freedom for all of us…many dying to do so. The flag and patriotism, gratitude for this Country, those who serve(d), and families left behind means much to me (most likely to many of you as well). My hope and prayer is that this Independence Day also provides an opportunity for families to talk about our independence, freedoms, patriotism, respect, and that freedom isn’t free. I hope that in spite of all the challenges and division occurring that we would pause, remember, and be grateful that we live in the greatest Nation in the world! We are so blessed!
July 4th Food: To ensure you’re staying safe from food-borne illness and for fun family recipes, check out this information from our Food experts: https://food.unl.edu/july-food-calendar#4th!
Crop Update: Corn and soybean have been rapidly growing in spite of having difficulty in closing canopies this year. Dr. Roger Elmore shared a paper with me on high winds altering corn leaf architecture (will share more next week). So it may be part of what we’re seeing in addition to hybrid differences? Many continue to contact me about bacterial leaf streak and there’s nothing outside of hybrid tolerance to do for it. Seems like hail occurs weekly in some part of the State. Resource: https://cropwatch.unl.edu/hail-know/assess-my-damage.
Chiggers: For whatever reason, chiggers, ticks, mosquitoes all find me. There’s all kinds of information/hypotheses available as to why some people tend to get bites more than others. Never have chiggers gotten me as bad as this year! As bites tend to peak around the 4th of July with more families outdoors, here’s some things to consider. Chiggers (also known as redbugs or jiggers) are the immature stages of red harvest mites. They tend to hang out in moist, tall grassy/weedy areas such as along streams, road-side ditches, forested areas, lawns. But they can also hang out in moist and dry lawns with a lot of trees too. They bite humans and other animals including pets. Eggs are laid on clusters on plants and the larvae hatch and wait for their host to come along. They latch onto clothing, shoes, and fur and can hang on while working their way to the skin (often to an area where clothing is tighter like around socks, undergarments, back of knees and under armpits). They actually don’t burrow into human flesh. They only survive on a warm-blooded host for around 3 days before falling off to molt for the next stage in life cycle which doesn’t feed on humans.
They have needle-like mouthparts that allow them to pierce the skin then inject saliva that dissolves body cells in the area to aid them in feeding. Thus, they don’t feed on blood but liquefied cells. The feeding creates an allergic reaction in which many see swelling, intense itching, and small, clustered, red bumps (which can become larger welts in some). To prevent chigger bites, avoid sitting or lying on the ground when picnicking or working outdoors. Wear loose-fitting clothing and apply a repellent like DEET to shoes, socks, and pants before going into areas more favorable for chiggers. It’s also wise to take a hot shower with plenty of soap as soon as possible after being outdoors and launder clothing with hot water before re-wearing. Also launder any blankets/sheets being used outdoors. If you receive bites, rubbing alcohol can be used then apply an anti-itch cream to help reduce itching. Thankfully chiggers can’t live in the home but they can become dislodged in bedding and on floors, so laundering bedding and vacuuming is also wise.
Keep lawns and shrubs well-manicured, particularly where adjacent to dwellings. If you tend to have problems with chiggers in your lawn, they can be reduced from 75-95% for several weeks with a liquid treatment of bifenthrin. Be sure to read and follow all label instructions.
Crop Update: The National Weather Service in Omaha shared that it’s been the 2nd hottest June on record (150 years) and the 2nd windiest June (72 years). It’s truly taken its toll on people, plants, and animals. It’s also resulted in increased stress levels with much to be done (spraying, hilling/cultivating, fertigating, changing herbicide plans, etc.) as crops rapidly grow.
Since the Memorial Day rains, I’ve observed bacterial leaf streak (BLS) on corn in fields.
BLS has long, narrow, red/brown colored lesions that follow leaf veins. The lesions also have a yellow halo when backlit. Upon close examination, the lesion edges are wavy, which differentiate it from gray leaf spot. It started fairly minor, but some more susceptible hybrids are showing higher levels of lesions right now. There’s also been a number of whitish colored lesions on leaves from wind damage/sand blasting (if they
weren’t due to herbicide situations). It’s from some of these wind damaged areas that BLS is also occurring. The bacterium causing BLS can infect directly through stomata; however, it can also infect through wounding. So the wind-driven rains and also high winds with sand blasting have also increased the incidence and severity of BLS in fields. Fungicides aren’t effective on it and it’s not known to result in yield loss.
Received a number of field calls/questions regarding herbicide application problems. Also recognize the challenge in figuring out a plan B, C, or D with some fields. Some practical things for those still needing to spray: know what traits are in what fields and double/triple check with whoever is spraying that the right product is going to the correct field. Double check the crop growth stage and the label as to what can be in the tank mix to avoid crop damage. Don’t go by plant height as there’s short beans that are flowering now and shorter corn in no-till and/or cover crop situations that is further along than one may realize. Proper tank/boom/nozzle cleanout is also always important to avoid crop damage to the next field being sprayed. And, spraying in high winds doesn’t help any of us.
For irrigation, UNL research shows we can wait till 35% depletion in the top 2 feet prior to tassel or top 3 feet once tasseling occurs. There’s a number of reasons why farmers have been irrigating: applying fertilizer, activating herbicide, small/replant crops with shallow roots, softening the topsoil for brace root establishment, and some may not be needing to water. There’s an article in this week’s CropWatch by Steve Melvin regarding irrigating considerations during the vegetative stages. We have a CropWatch poll to learn where people obtain their evapotranspiration (ET info.). Please help us by filling it out at: https://go.unl.edu/wxqv. There’s also ET and GDD info. available from CropWatch at: https://cropwatch.unl.edu/gdd-etdata and the NAWMN ETgage site (ET info. only) at: https://nawmn.unl.edu/ETdata/DataMap. The recent weather has helped with moving roots down. From digging plants and watching moisture sensors, many area fields from V7-10 have roots at least at 12” and below now.
Light Trap Reports: Light trap data can aid in scouting for various moth/butterfly pests. The closest light trap reports for the area are at UNL’s South Central Ag Lab near Clay Center and the Eastern NE Research and Extension Center near Mead. You can find all the reports online for the State at: https://entomology.unl.edu/fldcrops/lightrap.
Field Days: Weed Science (Clay Center) and Palmer Amaranth (Carleton) Field Days are cancelled for this year. Dr. Amit Jhala and his team are working on ways to present the data and information virtually. Nathan Mueller shared a self-guided tour is setup at the 2020 Jefferson County Winter Wheat Variety Trials in cooperation with Brian Maust (Variety Trial Technician) and Mark Knobel (hosting farmer). It’s located north of Fairbury on Hwy 15, then east 1 mile on 716th Rd, then 3/4 of a mile north on 569th Ave, east side of the road marked with a UNL sign. You can take a self-guided tour by grabbing a handout in the realtor box at the plots. It’s asked that you not walk/damage the wheat (i.e. pulling heads) and stay in the wide walking alleys. Please bring your own hand sanitizer so you can use it after touching the realtor box. Will keep you updated on additional information regarding these and other field days as details are released.
Storm damage resources: Have had a number of calls throughout the State this week
from those who have experienced hail, flooding, and/or wind damage. The warmer temperatures were helpful for regenerating plant growth after hail; however, they’re not helpful for those who had heavy rains and flooding that didn’t recede. I shared this last week too but here’s a Hail Damage Assessment resource with many videos: https://cropwatch.unl.edu/hail-know/assess-my-damage. For flooding, corn plants prior to V6 can survive under water for 2-4 days if temperatures do not exceed 77°F. From V7-V10, plants can survive 7-10 days if temperatures do not exceed 86°F. For soybeans, yield losses are minimal if flooding lasts less than 48 hours. If flooded for 4-5 days, fewer nodes develop and plants will be shorter. If flooded for 6+ days, possible stand and yield loss. The longer it takes a field to dry out, the more yield loss that may occur. For soybeans at flowering, there’s potential for yield loss, especially on poorly drained soils.
As we deal with corn leaf loss due to natural sloughing off, early frost, and recent hail
and wind damage, it can make corn development staging tricky for post- pesticide applications. The reason I keep emphasizing development stages is because I’ve been called out to many ear formation concerns the past several years. No one intends for these things to happen! These are opportunities for all of us to learn. In all cases, mis-diagnosis of development stage occurred prior to the pesticide application (whether herbicide, insecticide and/or fungicide). The use of non-ionic surfactant (NIS) in the tank from V10-VT resulted in the ear formation issues in addition to increased surfactant load from multiple products in the tank mix. My hope in emphasizing corn development staging this year is to hopefully reduce the incidence of ear abnormalities that occur from post- pesticide applications. I put together the following video to hopefully help: https://twitter.com/jenreesources/status/1272370173853470720?s=20.
Gardening 101 resources: A team within Extension pulled together all the vegetable gardening resources to create a one-stop place for vegetable gardening. This resource, housed on the backyard farmer website, is a place for beginning gardeners and experienced ones. Check it out at https://go.unl.edu/veggies101!
Sunscald/scorch on green beans: This past week I received a few pictures of green beans that had large brown ‘burnt looking’ areas. This is caused by sunscald. The sun and wind has been intense. Seek to evenly water and avoid watering the foliage.
Trees: Lots of tree questions past few weeks. If leaves are pre-maturely turning yellow and dropping, it’s most likely due to fungal disease. This is mostly happening since the 3” rain over Memorial Day. All the trees I’ve looked at are already starting to develop new leaves. Weed whackers cause more injury to trees that one realizes, so be very careful using them around trees, or put mulch around them to reduce weeds. Remove ‘mulch volcanoes’ around trees as the mulch against the trunk can cause rot. Mulch should not be piled against the trunk. Seek to make clean and proper pruning cuts for all the storm damage that has occurred to trees. For those who’ve experienced bark removal from lightning strikes or winter cracking, don’t paint anything over the wound and don’t fertilize or do anything to the tree. Allow the tree to seek to heal on its own. It’s amazing what trees can overcome! Winter and spring dessication injury may be causing evergreens (cedars, junipers, yews, and arborvitae) to suddenly turning brown. Kelly Feehan, Extension Educator shares, “During warmer than average temperatures in February and March, moisture was lost from green needles and could not be replaced from frozen or cold soils. This was followed by a dry spring; and then above average temperatures and extreme winds. These conditions increase the rate of transpiration and increased moisture loss from needles. If the moisture is not replaced quickly, tissues dessicate and eventually die. Evergreens growing in open exposed sites, near pavement or light colored houses, and those planted in the last three to five years are most susceptible. Other than using organic mulch and keeping soil moist, there is not much to do. Once an evergreen or a branch turns completely brown, it will not recover.” You can prune out dead branches/areas and see how the plants overall recover.
*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
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
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
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.