Category Archives: Crop Updates
This post shares observations of what I’ve been seeing in fields pre-harvest and during harvest during this 2018 growing season. Some of these problems stemmed from hail/wind damage and others insect damage. This is a longer post with the desire to have many resources available to you in one place. Hopefully this will be helpful for diagnosing concerns as harvest continues.
(Photos above) Hail-damaged soybeans pre-harvest. The plants in this field weren’t pummeled into the ground, but from the road it was deceiving as to what the soybeans were actually like on these plants. The two smaller photos are all the soybeans found on 2 adjacent plants from the top soybean photo pre-harvest. There were a lot of aborted pods on stems and moldy beans in general. For those who combined hail damaged beans in the area, farmers shared they had everything from ‘lima’ beans to shriveled, moldy beans as you can see in these pics, which is also what we were anticipating may be found.
Cladosporium ear and kernel rot seen on kernels already affected by Fusarium, particularly in hail damaged fields. This is a lesser ear rot fungi and doesn’t produce a mycotoxin but can create increased damage to kernels. Was recommending taking grain damaged to this extent directly to the elevator.
Photos above shared by a Clay County farmer who observed kernel germination and Fusarium growth (mostly due to western bean cutworm damage) upon harvesting his field. Hormonal balance within the kernels shifts towards harvest. At full maturity, very little abscisic acid (ABA) is left in the kernel (in both corn and soybeans) which allows them to germinate in correct conditions after harvest. These conditions include moisture and temperatures above 50ºF. Presence of fungi such as Fusarium and Gibberella also increases gibberellins in the kernels allowing for kernel germination with presence of moisture as we’re seeing this harvest. Increasing air flow during harvest will hopefully blow most of these damaged kernels out the back of the combine.
- Corn Ear Rots, Storage Molds, Mycotoxins, and Animal Health, ISU, 1997. (Nice comprehensive resource available in PDF download via web search)
- UNL Corn Disease Profile III: Ear Rots
There’s over 25 species of fungi that can produce ear molds with the majority of them ceasing growth at 15% moisture within the kernel. Thus, we recommend drying grain to 15% moisture as quickly as possible to cease additional fungal growth within the grain bin. The table below shares the days required to dry corn to 15% moisture with 1.0 cfm/bu and various temperature and humidity conditions.
- Management of in-bin natural air grain drying systems to minimize energy cost
- Grain storage management to reduce mold and mycotoxins (ppt presentation)
- UNL CropWatch Grain Storage Resources
- Managing large grain bins for potential mycotoxin contamination
In 2018, we’re primarily seeing Fusarium and Gibberella species which have the potential to produce mycotoxins. Thus, the information below is directed at those fungal species and mycotoxin levels that can be associated with them. Again, the presence of fungi does not automatically mean a mycotoxin is present.
- Grain storage management to reduce mold and mycotoxins (ppt presentation)
- UNL CropWatch Grain Storage Resources
- Managing large grain bins for potential mycotoxin contamination
- Understanding Fungal Toxins UNL
- Sampling and Analyzing Feed for Toxins UNL
- Use of Feed Contaminated with Fungal Toxins UNL
- Feeding Storm Damaged Corn: A few thoughts from a Veterinarian
Also, there’s a new app called “Mycotoxins” and it’s another resource with ear rot pictures and mycotoxin information put out by several Universities produced for both Apple and Android devices.
Great to see many farm families at Husker Harvest Days last week and also great to see harvest getting started! Just a reminder for all of us to watch for equipment on the roads and allow for extra time to slow down, particularly with the speed limit changes. Dawn, dusk, and the evening can be the hardest times to see equipment and it can be difficult to see how wide or long the equipment extends. Harvest is hard work and a lot of hours yet is also a blessing to finish the growing season. Here’s wishing everyone a safe harvest season!
Harvest: As storm and drought-damaged corn is being harvested, just a reminder that grain should be tested for presence of ear molds and any potential mycotoxins now in addition to moisture/test weight. I’m hearing some differences in what’s all being tested when the harvest sample is taken, so be sure to talk to your insurance agent about this. It’s important to also test for mold and potential mycotoxins as that gives you an indication of what’s in the grain, particularly if any grain is going into the bin. We’d recommend not binning the worst damaged fields/areas of fields, particularly if you have a lot of diplodia in the field. Drying grain to 14% moisture as quickly as possible will stop most fungal growth and we recommend drying to 13% if diplodia is an issue in your corn ears. I’m also consistently hearing about light test weights in the storm damaged grain.
Rapid crop dry down has been a topic of conversation; I’ll share more next week. Briefly, grain moisture loss occurs when husks lose their color, when portions of the ear are exposed above the husk, with looser husks around the ears, when ears turn down, and when there’s fewer and thinner husk leaves. For those asking about dying patches in soybean fields (in which pods are not filling seeds), I’m consistently finding anthracnose in samples but am unsure it’s always been the cause. The concern with rapid dry down in corn is just how quickly these plants are cannibalizing stalks to keep filling ears, the amount of stalk rot in fields, and large ears (watch for potential weakened ear shanks due to various stresses). I test for stalk rot using a pinch test where I pinch the internode between the lower plant nodes for 20 plants and determine a percentage throughout portions of fields. Consider harvesting fields with higher amounts of stalk rot/weakened ear shanks first and also consider harvesting at higher moisture. I’m finding stalk quality quickly deteriorating, even in non-storm damaged fields.
For those with palmer amaranth on field edges, just a reminder that 99% of the seed is still viable going through that combine. Thus, the combine is one of the best ways of spreading palmer throughout your field and from field to field. My recommendation from observing palmer spread the past five years is to avoid combining field edges, strips, or patches where palmer is an issue. Instead, disk down the field edges to bury the seed and then plant an inexpensive small grain like bin-run wheat to reduce early germination next spring. Some have also planted rye. I don’t know if shredding vs. one-time disking is as effective this time of year (since palmer shoots seed heads at the soil line too but unsure if if produces viable seed past mid-September here). As I’ve spoken during pesticide trainings and other meetings, farmers have also shared their experiences. Some farmers shared they took this advice and reduced the problem the successive year and didn’t spread it through their fields (even if they were no-till farmers and had to till the field edges one time). I’ve had other farmers share they combined that field edge or patch and could tell the following year exactly where the combine went for the first few passes within the field as the palmer was a problem there. So, just another consideration as it takes a system’s approach for everything we do including weed management; palmer management begins right now with harvest.
Another management consideration is to harvest soybeans as close to 13% (the elevator standard) as possible. And, I realize this is easier for me to write about than to actually do depending on many factors! Soybeans delivered below or above 13% moisture lose potential profit. At greater than 13% moisture, there is a moisture dock on the scale ticket for delivering wet beans, resulting in a lower price per bushel. And with less than 13% moisture, profit is lost because there are fewer “bushels” to sell rather than a dockage on the ticket. There are fewer bushels because the load weight is divided by 60 pounds per bushel (assuming 13% moisture) rather than by the actual pounds per bushel for the moisture content of the beans at the time of delivery. If you sell soybeans at 8% moisture, you’re losing about 5.43% of your yield; at 9% moisture, it’s 4.4%; at 10% moisture, 3.3%; at 11% moisture, 2.25%; and at 12% moisture, it’s 1.14% yield loss. That doesn’t take into account additional risk for shatter losses during harvest. For a field that’s yielding 75 bu/ac, harvesting it at 9% results in selling 3.3 fewer bushels per acre based on weight because you’re not selling the water that you’re entitled to sell if the beans were at 13% moisture. With soybeans priced at $7/bushel, that’s a loss of about $23 per acre (with greater loss when soybean price increases).
By the time this is printed in newspapers, we’ll be remembering September 11th. Grateful for all the first responders and all who have served our Country to defend our freedom since that day. Grateful for the sacrifices their families have made as well. Thinking of and praying for the families of those who lost their lives in the attacks and in defense of our Country since. May we never forget!
Encouragement: The wet weather has created challenges with harvest, making silage, increasing ear/stalk rots, kernel germination, and dampening spirits. So seeking to encourage: grateful for the soil moisture profile recharge the rain has provided and how it’s allowing pastures to recover and cover crops to grow! It’s really special to live in a State where our State Fair is now so ag and family focused! It was wonderful seeing so many farm families during the fair and I look forward to seeing many during Husker Harvest Days too! Thankfully harvest will be here soon and we’ll appreciate the sunshine that much more when we see it again!
Sprouted Kernels: I’m seeing and hearing of kernel sprouting in hail damaged and drought stressed corn in addition to corn hybrids that have tighter husks and upright ears. Sprouting is also occurring in soybean. So why are we seeing this?
Prior to full maturity it comes down to a hormonal imbalance within the kernels between gibberellin and abscisic acid (ABA). According to a study by White, et. al (2000), Gibberellin production with the lack of ABA allowed for kernel germination while less Gibberellin and more ABA deterred kernel germination. At full maturity, very little ABA is left in the kernel (in both corn and soybeans) which allows them to germinate in correct conditions after harvest.
These conditions include temperatures above 50ºF and moisture. Thus the continuous drizzle and rain we’ve experienced can allow for sprouting within soybean pods. In corn, sprouting under those conditions typically occurs at the base of the ear first but we’re also seeing it in exposed ear tips. We’ve also seen Fusarium and Gibberella ear rot fungi occurring in ears that have been damaged by hail and/or insects in ears. These fungi also produce gibberellins which can aid in the hormonal imbalance and stimulate kernel germination.
If you’re seeing kernel sprouting in your field, make sure your crop insurance adjuster is aware of the situation and submit samples for kernel damage due to mold and sprouting. Also check for mycotoxins prior to harvest if ear molds are a problem in your field. The local co-op will decide whether to accept the load based on percent damage and the standards they need to follow. If the load is rejected, contact your crop insurance agent to determine your next step.
Sprouted kernels lead to higher kernel damage and more fines in a load. Keys for harvest will include
- harvesting early,
- drying it to 14%, potentially drying at a high temperature to kill the sprout,
- screening out fines, and
- monitoring stored grain closely for hot spots, mold, and additional sprouting grain.
With the moisture continuing to exacerbate corn ear molds,particularly in hail damaged fields, you may also decide to take the grain for silage instead. More information regarding correctly making silage can be found at: https://cropwatch.unl.edu/2018/silage-hailed-corn.
Husker Harvest Days Cornstalk Baling Workshop: Baling of cornstalk residue has been an increasing topic of interest among growers. Reasons are many including residue management when cattle don’t graze a field, use of residue as a feedstuff, and as was the case in 2017, to bale up much of the downed ears with the cornstalks. With this interest, we’ve had individuals contact us about custom baling residue as an additional income source. With the topic of residue baling comes many questions. These include:
- What is the nutrient value of the residue removed from the field?
- What are the impacts of residual removal on subsequent yields and field soil properties?
- What is the feed value of that residue?
- How do I best set my current equipment to bale corn residue?
- Is my current equipment the best to bale corn residue?
This year, Nebraska Extension, Farm Progress, and several forage equipment manufacturers are partnering in a Corn Residue Baling Workshop at Husker Harvest Days (September 11-13). The workshop will be from 1:30-2:00 p.m. daily in the fields adjacent to the haying demonstrations, which begin at 2 p.m. Equipment manufacturers who have committed to the demonstration include: CNH, AGCO, Rowse Rakes, Vermeer, and John Deere.
Some of the manufacturers will be showcasing the same equipment in this workshop and in the haying demos. Each manufacturer will talk briefly about their equipment and specific settings that might be needed to make their machinery work better on residue. Because of the high moisture content of the corn residue during the Husker Harvest Days Show, equipment demonstrations of baling residue are not a possibility; however, videos of the manufacturers’ equipment in action can be viewed in the University of Nebraska Institute of Ag and Natural Resources building.
Crop Update: I’m so sorry to all affected by Monday night’s hail/wind storms! For those reading this before Monday, a reminder of hail damage meetings we’re having Monday Morning, 10 a.m. at the Utica Auditorium and Monday Afternoon, 1:30 p.m. at the Fairgrounds in Central City. I will post key points of what’s discussed at http://jenreesources.com after the meetings. Please also check out our Hail Know Website at https://cropwatch.unl.edu/hailknow and take the survey on the page to help us better know how to serve you with that resource.
This week’s CropWatch at http://cropwatch.unl.edu shares two different dicamba-related articles. One is a case study to walk through the forensic analysis for off-target dicamba movement showing how it originated from a corn field. The other goes into more detail regarding soybean still producing a new node every 3.7 days upon off-target dicamba movement (as long as the apical meristem has not been killed). It’s truly a significant piece of information, because without it, the assumptions within the forensic analysis don’t work!
Also, you have an opportunity to share your voice and input. This past week we’ve heard that EPA is planning to make their decision by mid-August on whether or not to extend registrations of XtendiMax®, Engenia®, and FeXapan® in order to help inform the seed and chemical industry for next year’s purchases. Some of you have called or talked with me about this. A few have understandably been pretty upset that these products are getting so much blame when, in this part of the State, much off-target dicamba movement starts from corn applications. That doesn’t get as much press nationally. While I’ve tried hard to share the story here and am grateful to our media partners who have helped me, I’m one very small voice. I have no idea what will happen; my concern is the bigger picture-potentially losing dicamba period as a tool in our toolbox.
So you have an opportunity to share your voice in Nebraska Extension’s survey that will be shared with the EPA: https://www.surveymonkey.com/r/JWDCY3C. Share your opinion on Xtend technology. Share your opinion on where you’ve discovered off-target movement from in 2017 and 2018. Share your opinion on dicamba. The results will also be compiled and shared on CropWatch and winter meetings. Thank you for considering this!
Aphids and Frogeye: I’ve also received a handful of questions regarding corn leaf aphids in corn and frogeye leaf spot in soybean. Both have rapidly increased in some corn and soybean fields. At beginning dent and various stages of starch-fill corn, I just have a hard time putting anything else into this crop. So I haven’t been recommending insecticides and there’s no thresholds this late to support it. In fields I checked from last week to this week with corn leaf and bird cherry oat aphids, I’ve also seen an explosion of beneficial insects and mummification occurring of aphids, which is helpful. Regarding frogeye, it’s one where we recommend a product containing a high amount of strobilurin at R3 or R5. Many beans are at R6 or almost there, so again, I’m having a hard time putting any more money into this. High humidity and leaf wetness for 12 hours or more will rapidly increase frogeye, so the worst situations I’ve seen through the years are in gravity-irrigated fields. Also, seeing a number of soybean defoliators in fields. Please check out this CropWatch article at: https://cropwatch.unl.edu/2018/soybean-defoliators to better help understand how much defoliation can occur in soybean.
Lawn Renovation: For those seeking to improve your lawn or get one established, August is a great time to do so! I really like this resource for this purpose: https://go.unl.edu/rz9z. If you’d prefer to watch videos, Backyard Farmer has a series of Lawn Renovation videos, but this link gets you to the most recent one regarding fall renovation: https://youtu.be/Fxd1NUQ8ScQ.
Thank you to all who made the York County Fair go so smoothly! It’s always a joy to see the 4-H and FFA youth and families rewarded for the hard work they put into their projects!
Crop Update: I didn’t get out to the field much this week with fair but did spend a few
hours one afternoon. There are portions of the area I serve that have been blessed with rains and look really good. The main thing that I’m seeing a lot more of this week is aphids in corn fields. This can be common in fields where fungicide is applied as the fungicide kills a beneficial fungus that attacks aphids. Some aphid species are also attracted to moisture stressed crops. The heat has also pushed the crop along quickly. We have another yield forecasting article in this week’s CropWatch at http://cropwatch.unl.edu where we talk about the impact of the heat on yields. As of right now, based on comparing this year to 30 years of weather data, it’s appearing corn may reach maturity 1-3 weeks early. Irrigated yields are estimated to be near average and above to near average for non-irrigated corn (where drought is not a factor). These yield forecasts are based on simulations under ‘perfect conditions’ (with no nutrient loss, disease etc.) but they can give us an indication of what may happen if we continue with higher heat conditions.
Unfortunately, pockets in the area continue to miss rains. The drought monitor still is not
reflecting the drought in this part of the State; at this point, I’m unsure what else either Al Dutcher or I can do about this. One farmer reminded me drought occurred in the same area in 2006, 2012, and now 2018-six years apart each time. Driving the area, hardest drought-stressed crops really took a turn this past week with corn in hard dough to early dent with some kernel abortion and soybeans are beginning to abort pods and quit filling seeds. One question has been on weighing taking corn for silage or not. If you have at least an estimated 50 bu/ac grain in most of the field other than highly compacted areas, it may be more profitable to keep for grain (unless you’re looking for cattle feed). The following are some resources to consider further:
- July 2018 BeefWatch article on considerations for green chop/silage for cattle feed, include best management practices, etc.: https://go.unl.edu/e3y5
- July 2018 K-State article for considerations on taking corn for silage or grain: https://enewsletters.k-state.edu/beeftips/2018/07/02/considerations-for-use-of-drought-stressed-corn-for-cattle/
- All UNL Drought Resources: http://droughtresources.unl.edu
Dicamba: We’ve often mentioned the research showing a soybean plant producing a new node every 3.7 days upon reaching V1 stage. And, I’ve used that in the forensics assessment for determining a timing for off-target dicamba movement. One question I’ve had was “Do soybean plants continue to produce a new node every 3.7 days upon being affected by off-target dicamba?” My assumption in the forensic analysis I have used is that a new node continued to be produced every 3.7 days in spite of off-target dicamba. However, the only way to really test this would be to have the same soybean variety in both an Xtend and non-Xtend version. We will release a CropWatch article next week in which a situation like this occurred at the Eastern NE Research and Extension Center. Dr. Jim Specht counted nodes in both the non-Xtend variety with off-target dicamba and the Xtend variety that wasn’t affected. He found the same number of nodes in spite of the dicamba affected non-Xtend variety being shorter in height and having less canopy. So that in itself is good information for use in forensic assessments. However, he also found plants in which a higher off-target dicamba dose affected the top-most growing point. When that occurred, the number of nodes was affected.
Last year, a group of us released a dicamba survey during Soybean Management Field Days. Reminder those are upcoming this week (https://enre.unl.edu/soydays)! The survey helps us understand your perspectives about dicamba and this year we’ve added questions regarding using Xtend technology. Hopefully it will provide helpful information for all of us and the results will be shared via CropWatch and winter meetings. We’d encourage and be grateful for any soybean growers to participate at: https://www.surveymonkey.com/r/JWDCY3C.
South Central Ag Lab Field Day: Please hold August 29, 2018 for UNL’s South Central Ag Lab (SCAL) Field Day near Clay Center! Attendees can choose which sessions you would like to attend. Options include the latest SCAL research in the areas of Irrigation/Water Use; Nutrient Management; Weed, Disease, and Insect Management; Cover Crops; and Cropping Systems. CCA credits will be available and there’s no charge to attend. Will have more specifics for you next week but please hold the date for now!
Vine Crop Problems: The following resource explains options for diagnosing various problems with cucumbers, squash, and melons: https://hortnews.extension.iastate.edu/2011/8-24/cucurbitwilt.html.
Crop Update: This past week was fairly interesting with southern rust being confirmed in a few Fillmore, Thayer, and Saunders County fields. We would recommend to continue scouting fields as the disease was low incidence at all these sites. There also were a number of questions regarding fungicide applications.
For those asking about chemigating fungicides, it’s important to ensure the fungicide
product label allows for chemigation and to follow the recommended irrigation amount if specified on the label. If an irrigation amount isn’t specified, Tamra Jackson-Ziems and I were talking about trying to apply with as small amount as possible (perhaps like 0.25″). She has chemigation data at 0.25″ vs. 0.50″ vs. ground application from 2005-2007, but not vs. aerial application. The data had a high degree of variability numerically in the yield data in spite of non-statistical differences. The only other info I could find was the University of Georgia recommends only 0.10″ on chemigation using fungicides, but they didn’t show any data. I encourage those who can to please consider doing this as an on-farm research study where chemigation occurs in pies throughout the field with other pies left untreated. I realize it’s not popular to leave areas untreated, but it may be of interest to you. For those asking about comparing aerial vs. chemigation for corn, that would be very difficult with one pivot with true research involving replication. Perhaps it could be done if a producer had a couple of quarters side by side, planted the same day with same hybrid and crop rotation where we could truly compare via research. If you do and that’s of interest to you, please contact either Tamra or myself. A couple have also discussed maybe applying half a pivot aerially and the other half via chemigation and just taking observations, which may also be beneficial to you.
We also released a few CropWatch articles this week on differentiating growth regulator herbicide injury in soybean and using a forensic method to diagnose off-target dicamba
injury in soybean. Please check them out at http://cropwatch.unl.edu. I hadn’t heard anyone really explain the difference between 2,4-D and dicamba in how they work in plants so felt that information was important in addition to the fact dicamba is highly translocateable and 2,4-D isn’t. That also has been important in home-owner discussions regarding off-target movement to garden produce. And, a reminder to all home-owners that weed control products used in lawns and empty lots often contain dicamba and/or 2,4-D…so it’s important to read those labels regarding environmental conditions in applying them and also when you can/can’t use grass clippings as mulch.
Buzzing Beetles: This past week, several people came to the office or called
regarding large green beetles flying around that sounded like bumble bees. These are called Green June beetles. They only fly during the day. There are also smaller green beetles with white spots (tufts of hair) around the abdomen; those are Japanese beetles. Japanese beetles feed on crops in addition to favorites such as Linden trees and knockout roses. Both have larval forms that are white grubs and both have a one year life cycle. In the beetle form, both adult beetles are fond of ripe fruit such as grapes, berries, plums, and peaches. As larvae, the grubs feed on decaying organic matter and grass roots in the soil. However, the June beetle larvae can reach 2″ long creating larger tunnels in lawns and pastures as they move in the soil.
Some have said, “I thought June beetles were golden/tan!” And you would be correct! There’s several types of “June” beetles. The most common and perhaps most damaging is known as the June beetle or masked chafer which is golden/tan in color and has a one year life cycle. There’s also a May/June beetle (also known as the 3 year grub) which tends to do more damage in range/pasture ground. Those beetles are tan to brown/near black in color.
When it comes to damage, start looking for browning areas of turf occurring late July, throughout August, and early September. The turf may look like drought stress or fungal disease; however, if you can gently roll the turf back like a carpet, it’s most likely grubs (and you should also find the presence of grubs). Other signs of grubs can include birds, skunks, etc. tearing up your lawn. White grubs in general feed on decaying organic matter, lawn and ornamental roots in the soil. Grubs don’t tend to be an issue in fescue lawns or lawns that are low maintenance or newly established. They tend to prefer Kentucky bluegrass lawns that are highly maintained with fertilizer and irrigation. They also may be spotty in their feeding such as under yard lights or on irrigated slopes. The threshold level for turfgrass damage by masked chafer larvae is 8-10 white grubs per square foot of lawn…so I would assume that to be the case for all grub species. One or two grubs per square foot is normal and does not require control. If grub control is needed, products like Sevin or Dylox provide the best control for mature grubs and should be watered in after application.
Crop Updates: A great deal of timely information was provided in this week’s CropWatch at http://cropwatch.unl.edu including information about high heat and pollination, applying fertilizer during pollination, western bean cutworm scouting, forecasted yields, etc. Please check it out!
Several called me asking about applying fertilizer during pollination. I shared that while
I wasn’t aware of research, I personally was concerned about anything potentially interfering with pollination and that I do recommend 30 lbs of N at brown silk if needed or if you were originally planning split nitrogen apps. This is based on research from Purdue sharing today’s hybrids use 30-40% of their total Nitrogen from flowering through maturity. After discussing with Dr. Tom Hoegemeyer, Adjunct UNL Professor of Practice, he offered the following insights: “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.
Last week also brought questions regarding thresholds and difficulty in finding Western Bean Cutworm egg masses with moth flights at their peak. You can view light trap data from UNL’s South Central Ag Lab thanks to Terry Devries at: https://scal.unl.edu/ltr2018.pdf. There’s also a great article in this week’s CropWatch on how to scout for them, insecticide options, and additional recommendations. Thresholds for western bean cutworm are 5-8% of corn plants in the field containing egg masses or larvae. Egg masses can be difficult to find during pollination with pollen hiding them. ‘Typically’ egg masses are found in the top third of the plant on the upper sides of leaves and near midribs or leaf axils. However, with higher heat, I tend to find them closer to the ears and have even seen masses laid on the ear husks and on the backsides of leaves (not common). While larvae are generally known to move up the plant to feed at the tassels, I’ve seen high heat force larvae into ears earlier. It typically takes 5-7 days for larvae to hatch and the egg masses turn purple just prior to hatching. A number of insecticide options are available for both aerial application and via chemigation; these products are listed in the CropWatch article.
With insecticide applications occurring in corn for both western bean cutworm and also corn rootworm beetles, many have also called or talked with me about the recommendation of fungicide applications. Right now, I haven’t found gray leaf spot above 3 leaves below the ear leaf in several counties. There’s been some mis-diagnosing bacterial leaf streak as gray leaf spot. Southern rust was just confirmed in a Kansas county this week, but we still have yet to confirm it in Nebraska. Even the longest residual products won’t get us through August if a fungicide application occurs now. I can appreciate that economics are tight so the thought is to save an additional application cost by applying a fungicide now with the insecticide. And, I can appreciate economics are tight regarding why apply a fungicide right now when disease pressure doesn’t warrant it? Perhaps, at least those of you with the ability to chemigate could consider waiting till disease pressure warrants it for your field, if it does. Always in the back of my mind is the need for late-season protection with southern rust eventually showing up and gray leaf spot often worse then.
My perspective is from a resistance management and research-based one. We have 5 total modes of action for fungicides with 2 of them being in nearly every fungicide product we use in corn, soybean, and wheat because they work against foliar fungal pathogens. At some point, our pathogens will also adapt, as we’ve seen our weeds and insects do…it would be like losing our ability to control gray leaf spot and southern rust similar to palmer amaranth on the weed side. In Nebraska, Dr. Tamra Jackson-Ziem’s research has not shown an automatic yield increase to fungicide application in the absence of disease. And, it has also not shown an automatic yield increase when applied at tassel. In a high heat and low disease year like 2012, there were no statistical yield differences with fungicide application vs. the untreated control. Even in years with some disease pressure such as 2008-2010, she found no statistical yield differences between when various products were applied from Tassel through Dough stages. In high disease years, her research shows the benefit of fungicide application for reduced disease pressure and increased stalk strength. Fungicides are great tools to help us with disease pressure and stalk strength. Just would encourage all of us to consider when we really need to apply them and to understand that research in Nebraska does not automatically show increased yields with the use of them or with the timing of Tassel/Silking vs. later in the year. Also, hybrids may vary in their response due to disease susceptibility and other factors. Not all her data is listed at this site, but you can view it for yourself at: https://go.unl.edu/ni3y.
Bagworms: I’ve been seeing shelter belts and various trees turning brown from heavy
bagworm infestations. Please be checking your trees if you are noticing them turning brown. Additional information can be found at: https://go.unl.edu/rgju.
Crop Update: A few diseases started showing up the past few weeks in various portions of eastern and south central Nebraska. Phytophthora root rot in soybean is perhaps the
most common in both areas. We normally think of this disease as seedling damping off and death; however, it can also affect plants later in the season. What surprised me was how much we are seeing it this year in higher ground and sidehills instead of the typical lower ground we often see it on. Dr. Loren Giesler, Extension Soybean Pathologist said that in situations where we’ve had dry conditions followed by heavy rains (as we have this year), especially on clayey or soils prone to compaction, Phytophthora can also affect plants. He has a few videos along with additional information at the following website: https://go.unl.edu/tdfh. Symptoms characteristic at these growth stages include wilting of plants during the day with leaves eventually turning yellow-brown-gray and remaining on the plants. Also, look for a brown stem lesion that goes from the soil line upward about 4-6″. Some of these plants are also snapping off at the soil line. For those experiencing Phytophthora this year, future management includes:
- Using resistant varieties including a combination of good partial resistance and an Rps gene. Partial resistance alone will not be as effective during early growth stages or under high disease pressure.
- Cultural practices include anything that can improve soil drainage and compaction.
- Seed treatment fungicides containing mefenoxam or metalaxyl should be used and you may need to consider a higher rate of them.
Regarding corn diseases, bacterial leaf streak (BLS) has greatly increased on more
susceptible hybrids since rain events. Early lesions can look very similar to gray leaf spot, so it’s important to correctly identify the two. The margins of BLS are wavy vs. those of gray leaf spot are more blunt. Both can have yellow margins when backlit by the sun. Fungicides are not effective against BLS and hybrids do vary in their tolerance to this disease. It’s important to scout fields as we may see an increase in fungal diseases due to the humidity, leaf wetness, and recent rain events. Southern rust has taken awhile to develop in the southern U.S., which is somewhat unusual, yet many states have been in drought this year too. As of July 5th, southern rust has been confirmed in Georgia with one suspected sample in a Missouri county. You can watch the map at: http://ext.ipipe.org/ and follow @corndisease on Twitter for the latest on corn disease findings in the U.S.
Trees: With numerous wind storms, the following resource has a lot of great information regarding pruning storm damaged trees correctly and questions to ask tree care services regarding tree pruning: https://go.unl.edu/94fm.
Agronomy Youth Field Day: All youth ages 9-18 years old are invited to the 3rd Annual Agronomy Youth Field Day. Youth will have exciting educational experiences while discovering Science & Agronomy/ Irrigation / Mechanized Agricultural careers for producing Nebraska crops! The field day will be held Wednesday, August 8 from 9 a.m.-3 p.m. at Nebraska College of Technical Agriculture Educational Center in Curtis, NE.
Hands-on activities (for all age levels) will focus on pest management, equipment technology, crop growth, soil management, precision farming & center-pivot irrigation technology. Several Nebraska Extension Cropping & Water Systems and 4-H Youth Development Educators along with Nebraska College of Technical Agriculture in Curtis Agronomy / Ag Mechanics Department professors will be sharing the researched based information with the students.
Participants will gain important life skills while discovering the science behind producing Nebraska crops. The six-hour field day is a great opportunity for ALL the youth to learn more about the agronomy industry and increase their basic understanding of science, ag literacy, a technology & STEM while exploring careers. Parents/Adults are welcome and lunch will be provided.
Reserve your spot today by registering online at: https://go.unl.edu/agronomyyouthfieldday by August 3, 2018. For more information (or if trouble with registration) contact Nebraska Extension Frontier County at 308-367-4424 or email 4-H Educator Kathy Burr at firstname.lastname@example.org.
Crop Update: What a blessing to have rain this past week! Grateful for how it provided much needed moisture into the top two feet in many cases. Updated soil moisture status will be at http://jenreesources.com. Some in our area and in other parts of the State received wind, hail damage, and flooding to crops. This week’s CropWatch at http://cropwatch.unl.edu shares information for those situations. A few summarizing points: for those with greensnap or with severe hail damage, you may wonder what potential yield may be based on your planting date and current plant stand. The following chart from Iowa State University and explanation of how to understand it may be helpful: https://crops.extension.iastate.edu/cropnews/2009/05/assessing-corn-stands-replanting.
For those with flooding, corn in the V7-10 leaf stage can survive for about 7-10 days in flooded water. Temperatures above 86F can result in greater stress on those plants than if the temps remain cooler than that during that time. Another consideration for the future, it’s not uncommon to find a disease called ‘crazy top’ of corn when the tassels begin to emerge. We’ve seen this the past several years where creeks or areas along waterways or field edges were ponded. There’s nothing you can do to prevent this.
For those with hail damage, damage from V7-10 leaf corn can result in a number of situations depending on the severity of hail. Minimal yield loss is assumed for leaf damage in crop insurance charts. Final plant stands will be important which will account for broken off plants that don’t recover. Stem bruising also isn’t factored in. For corn, bacterial diseases tend to be my larger concern at these growth stages. Bacterial top rot is one in which the plant dies from the top down and has a strong odor to it and creates a soft, slimy mess. Goss’ wilt is another concern-particularly systemic Goss’ wilt. You can check for this if you have a dying plant that doesn’t have a soft rot by taking a
cross section of the stem and looking for discoloration of the vascular bundles. You can also send plants like this to the Plant and Pest Diagnostic Lab in Lincoln for confirmation.
Regarding fungicide use on hail damaged corn, Iowa State and the University of Illinois did studies finding similar results. Both found no statistical difference in applying a fungicide vs. the untreated check in spite of small numerical differences. Regarding timing, the Iowa State study simulated hail damage at tassel and applied fungicide an average of 3 days and 8 days post-hail. There were no statistical differences on yield of the timing of the applications either. They did find statistically less fungal diseases in the hail-damaged plots vs. the non-hail damaged plots and speculated it was due to more air flow and less leaf area available for disease to occur. I have observed that fungicide can help with stalk strength and maintaining whatever green tissue remains when we had the 2013 hail storm in Clay County at brown-silk to blister corn. But this early, it’s hard to justify a fungicide application based on the data that’s available. If you’re interested in testing this for yourself, the following is an on-farm research Fungicide Protocol for Hailed Corn and Soybean.
For hail damage on soybean, many of the beans are at flowering or approaching flowering. Again, stem bruising isn’t counted in crop insurance assessments. I haven’t really observed bacterial or other disease issues necessarily from stem bruising in soybean. What tends to be more of an issue is those plants hardening off and becoming brittle to walk through. For soybeans, the blessing is that often new buds form and you will see increased branching which can help with canopy closure…it just can hurt right now when soybeans were already near canopy and we’re trying to reduce additional inputs for weed control. Things to consider are that pods may be closer to the ground from this increased branching and you may need to harvest earlier to help with getting beans that become brittle before snapping off in wind storms. I leave plant stands of near 60,000 plants/acre based on our soybean pop studies that received hail damage. If you want to prove any replanting differences to yourself, you may wish to consider the following Soybean Replant Protocol. We’d recommend waiting on herbicide apps till some new growth occurs, which is difficult when I’ve watched palmer essentially be not affected by hail and put on two new leaves within a few days in the past. Last year we started making herbicide apps 5-7 days post-hail. Additional hail resources are at a new resource called ‘Hail Know’ at: https://cropwatch.unl.edu/hailknow. There’s a lot of info I haven’t transferred to this site yet…but you can view photos and comments on hail recovery at numerous growth stages over time at my blog under the ‘Storm Damage’ category: https://jenreesources.com/category/storm-damage-2/.
Last week I shared the following video regarding determining timing of off-target dicamba movement to soybean: https://youtu.be/rQid7-vX-TU. Sharing again with an increase in the number of fields that were experiencing cupped symptoms last week.
This past week contained many off-target herbicide concern calls. Prior to Memorial Day I had made a note that post-herbicide applications to corn began in much of the area and anticipated phone calls to begin in about two weeks. Most of the conversations this week were more FYI to let me know they had soybean leaf cupping.
Here’s a few things to consider if you are having soybean leaf cupping.
- First, was a post-herbicide application made to your soybeans? If so, check for any potential tank contamination (Check out this CropWatch article: https://go.unl.edu/fnig). If not, check out this publication (http://ipcm.wisc.edu/download/pubsPM/dicamba2004.pdf) to determine if any of the criteria mentioned could possibly be contributing to the problem.
- Determine how old the plant is by asking when the soybean was planted and even better when it emerged. A soybean plant will produce a new node every 3.75 days.
- To determine the timing of damage, I count the total number of nodes on the plant to the last trifoliolate where leaf edges are not touching. The total number of nodes may differ in different parts of the field such as irrigated and non-irrigated especially after herbicide damage and drought-stress (Example 8 nodes irrigated and 6 non-irrigated). Take the number of nodes X 3.75 to get total approximation of plant age. Then count back on the calendar to determine approximate emergence date. If I use 8 nodes in this example X 3.75 = around 30 days ago the plant emerged.
- I then count the number of nodes to the very first damage I see on leaves (Example 3). Multiply this number of nodes times 3.75 and count forward on the calendar from emergence to that date. For instance, in this case, damage occurred around 11 days after emergence.
- I also like to count how many completely unfurled trifoliolates are affected (Example 6 trifoliolates). Take that number and multiply by 3.75 (Example 6 X 3.75= approximately 23 days ago the damage occurred).
- In this example, it worked to count either direction (from emergence and from current date) to determine approximate timing of off-target movement occurring. In all the situations I’ve looked at thus far, the timing goes back to around Memorial Day with post-dicamba herbicide applications applied to corn.
- Auxin-like herbicides affect only cell division. Thus, fully developed leaves (no longer expanding via cell division) are not affected even though they may be expanding by leaf cell enlargement. Only the tips of the newest exposed soybean leaves may experience damage to dicamba as they are still undergoing cell division. Otherwise, it can take 7-14 days for leaf damage from dicamba injury to appear on susceptible plants and damage will occur typically 4-6 nodes. This is because dicamba is also translocated once inside leaf cells. Thus it impacts cell division of the leaf primordia at the stem apex. We may not even see those leaves yet because they are still enclosed in the stem apex tissue.
- In a matter of weeks, affected fields can go from appearing to have minor damage, to looking really bad, to growing out of damage. It looks worst when those affected nodes push upward giving the field a grayish/white cast to it as the leaves become much reduced in size and are tightly cupped. Eventually the leaves will begin to look more normal again in time (as long as a second off-target movement doesn’t occur).
What can you do? Water via irrigation and/or rainfall is the best recovery tool for dicamba damage. Waiting is another. We’re blessed to grow indeterminate soybean in Nebraska which continues to produce nodes and leaves upon flowering which allows our soybean to grow out of damage.
- Wait till harvest to determine any yield impacts if there are areas impacted vs. those which aren’t. Otherwise, field-scale damage is difficult to discern yield impacts.
- You can talk with your neighbors/ag retailers regarding what they sprayed. In our area of the State, it’s often difficult to pinpoint the source of off-target movement with so many applying dicamba products to corn for palmer control often around the same time-frame. Now that post-apps to soybean are also occurring, that may also become a challenge. Of all the fields I visited last year, less than a handful of farmers sought any sort of compensation and those were more often due to tank contamination issues. If you wish to pursue that route, you need to file a complaint with the Nebraska Department of Ag.
- For future dicamba applications, check out these best management tips: https://go.unl.edu/97ok.
- For those of you reading this in a source outside of my blog, I created a video to hopefully be more visual and clear on understanding this method of diagnosing timing. You can check it out at my YouTube site: https://www.youtube.com/user/jenreesources.
Bagworms: It’s June and one of my top questions has been “Have I found bagworms yet?” Well, they’re now feeding and forming new bags on junipers and spruces. What you’re looking for are not the old bags at this point, but very small (fingernail size) new bags that move as the caterpillar is feeding and making the larger bag. This video from Backyard Farmer (https://youtu.be/05A2quj9nO4) does a great job of showing various stages of bagworms and sharing on control methods. Check it out!
Irrigation Scheduling Workshops: Steve Melvin, Extension Educator in Hamilton/Merrick Counties asked I share about upcoming irrigation workshops hosted by UNL and Upper Big Blue NRD. The program will focus on installing the equipment and making irrigation scheduling decisions using the data generated by Watermark sensors. The workshops will be held from Noon-1:30 p.m. on June 25th at the Corner Café, 221 Main St in Stromsburg and also at the same time June 28th at the Hordville Community Building, 110 Main St. The Upper Big Blue NRD will provide the lunch. The first presentation will be Installation of Watermark Sensors and Data Logger presented by Dan Leininger, Water Conservationist with the Upper Big Blue NRD. The second will be Deciding When and How Much Water to Apply Using Watermark Sensor Readings presented by Steve Melvin. The irrigation scheduling strategies presented in Steve’s presentation can be used with any soil water monitoring equipment data. More information is available by calling Steve Melvin at (308) 946-3843 or visiting https://extension.unl.edu/statewide/merrick/.