Monthly Archives: September 2021
There’s times after I write this column on Sunday nights that I could turn around and write another one after Monday hits! Last week was one of those weeks, so here’s considerations for this week. Also, reminder to remove ET gages and irrigation scheduling equipment from fields before harvest.
Woolly Bear Caterpillars have been around since fair time at lower levels in landscapes and fields. However, they are showing up fairly heavy in later season soybeans right now, so it’s wise to be scouting for them. They’re doing a lot of leaf defoliation, yet also watch the pods for clipping or feeding on them. The economic threshold for defoliation is 20% in reproductive stages. I have been seeing them dying in fields from beneficial fungi as well, so look for dead/dying caterpillars and consider this as well. Decisions to treat are very field dependent. Organic options include various Bt products which impact caterpillars but don’t hurt other beneficial insects. Be aware of pre-harvest intervals (PHI) listed on the label (also pages 338-344 of 2021 Weed/Disease/Insect Guide); most products list 18+ days.
(Photo captions below): 3 woolly bears on this plant (left), lots of defoliation (top, right), and what dead woolly bears due to beneficial fungal pathogens look like (notice the duller color-they start almost looking a gray/white with age and don’t move).
Fall Armyworms: My phone went crazy again last week about them. Feel badly for all who had to reseed new alfalfa seedings, reseed cover crops, reseed small grains, and for all reseeding lawns. Their feeding happens so quickly. Even those who cut older stands of alfalfa were finding the armyworms weren’t killed after cutting. I was most commonly asked if cover crops or small grains should even be planted/replanted until the fall armyworms disappeared. Yes, they should as these small grains and covers obtain better establishment and growth the sooner they’re planted. The fall armyworms will eventually move south; however, entomologists don’t know the exact trigger for that. With the moths still flying, we may continue seeing larval feeding for a few weeks. What I told people who called or texted was to plant (being prepared with a product in mind should you need it), scout once the new seedlings start coming and be ready to apply a product if necessary. I listed a number of products in last week’s column, including organic options for consideration. Not every field nor lawn is impacted; it’s all dependent upon where the moths lay their eggs. A field or lawn that was impacted once may not be impacted again.
Harvest: Beans have dried down fast in spite of some green stems and leaves attached. Hearing moistures ranging from 10-14% on 2.0-2.5 maturity beans with yields depending on rain and disease. Even the corn is drier than what it appears inside some of these fields as I’m taking on-farm research notes. With harvest most likely ramping up this week, please be safe! It’s really dry which makes for dangerous road conditions and greater fire potential.
Harvesting soybeans as close to 13% is a goal for which to aim, in spite of the challenge. It’s perhaps a combination of art and luck depending on environmental conditions. Consider beginning harvest at 14% moisture making combine adjustments and operating at slower speeds as necessary. While there’s a dock of around 2.5% for the first 2 points delivering wet beans, delivering soybeans much below 13% moisture reduces profits because there’s fewer bushels to sell (load weight divided by 60 lbs/bu assuming 13% moisture). Selling soybeans at 8% moisture, you’re losing about 5.43% 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. Only 4-5 beans on the ground can add up to a bushel/acre loss due to shatter. The following are profit examples:
Example 1. If the grower was to sell beans at 13.8% moisture, he/she would be docked 2.5% of the selling price of $12.30/bu, reducing the actual price to $11.99 per bushel. Total income per acre would be: 75 bu/ac yield x $11.99/bu = $899.25 per acre gross
Example 2. If the soybeans were harvested at 9% moisture, there would be 3.3 fewer bushels per acre to sell (4.4% of 75 bu/ac yield due to water loss): 75 bu/ac – 3.3 bu/ac =71.7 bu/ac yield x $12.30 = $881.91 per acre gross. In this example it’s better to take a dockage for selling beans at 13.8% moisture than sell them at 9%. The difference is a positive gain of $17.34 per acre or around $2341 on a 135 acre field.
Example 3. If the soybeans were harvested at 12% moisture, there would be 0.86 fewer bushels per acre to sell (1.14% of 75 bu/ac due to water loss): 75 bu/ac – 0.86 = 74.14 bu/ac yield X $12.30 = $911.92 per acre gross. If you can’t hit 13%, it’s still pretty profitable to sell them for 12% moisture compared to the other examples. Here’s wishing you a safe and profitable harvest!
Fall Armyworms: Received numerous reports of fall armyworm damage this past week from Kansas-Nebraska state line north to York. Damage was occurring in new alfalfa seedings in addition to established alfalfa, a new triticale seeding, and several lawns. With moths still being observed, we may see fall armyworms around for a few weeks yet, so it would be wise to be watching any alfalfa, wheat, rye, triticale and lawns for them. There’s no good way of knowing where they’ll appear; it’s all based on where the moth chooses to lay her eggs. Several reports of one field affected while the field next to it is fine. Same with lawns. Egg masses are fuzzy white masses that can include up to 200 caterpillars and the eggs can hatch in 2-5 days. Newly hatched larvae will be thin and often black/gray in color. I have some pictures from my colleague Jody Green at jenreesources.com.
In town, if you find the egg masses on lawn furniture, siding, or garden features, simply wipe them up with paper towel and discard in the garbage. They’re far easier to control when the larvae are ¾ inch or less. When they get larger than this, insecticides aren’t as effective, and usually, by that time, so much damage has occurred that the area will need reseeded. Products with active ingredients such as bifenthrin or permethrin are effective and are options for both farmers for fields and also homeowners with lawns. Sevin is also an option for both. Kentucky bluegrass lawns may be able to recover from rhizomes regrowing in the spring. However, fescue and ryegrass will need intervention this fall for reseeding. An organic insecticide option is Dipel which will take a little longer to work, but is still effective on smaller larvae. For lawn situations, it’s important to water the insecticide product in the ground to get the granules off the leaf blades and into the soil.
(Photo caption: Fall armyworm moth, egg mass, and larvae. Photos via Jody Green and UNL Entomology).
Large grubs on concrete: Had several reports last week of large white grubs on concrete stairs, sidewalks, and driveways. They are really large, up to 1.5 inches. What’s interesting about them is they crawl on their backs! These are grub larvae of the green June beetle which is a large beetle that often sounds like it’s ‘buzzing’ during June and July. The adult beetle can cause damage to ripening fruits such as stone fruits and berries. However, the grub larvae are not a major turf pest, unlike other grub species. They feed on thatch layers and organic matter, but don’t really attack lawn roots. They make holes in the soil, so rain and irrigation will drive them out onto concrete.
Small Grains and Weed Control: Last week I mentioned considerations for wheat planting. Even if small grains aren’t taken for seed, they do a tremendous job for weed and erosion control, provide an option for grazing, and uptake excess moisture and nutrients (helpful in seed corn field situations). Small grains, particularly oats and rye, have been proven to help with reducing soybean pathogens such as fungi and nematodes causing SDS and SCN. I’ve been watching a couple side-by-side soybean fields in which one was planted green into rye and the other didn’t have rye. Even the farmer commented on it to me this week how the quarter without rye has senesced earlier and has problems with anthracnose and Diaporthe complex (including pod and stem blight) while the other is essentially disease free.
Wheat provides an option for both grazing and grain. Rye provides the best option for earliest green-up/growth in the spring and longest seeding time as it can be seeded into December. Triticale provides the most biomass, including for haying and small grain silage, but produces the latest into late May/early June. It’s too late to plant oats for the fall, but they are an option for the spring. All keep the ground covered from light interception penetrating the soil surface which allows weed seeds to germinate.
Researchers from K-State looked at marestail (horseweed) and palmer amaranth control from 2014-2015 in no-till soybeans at six locations in eastern Kansas. They also found the majority of marestail emerged in the fall (research from UNL showed up to 95% does). They compared five cover crop treatments including: no cover; fall-sown winter wheat; spring-sown oat; pea; and mixture of oat and pea. Cover crops were terminated in May with glyphosate and 2,4-D alone compared to a control of no herbicide use. Ten weeks post-termination, palmer amaranth biomass was 98% less in winter wheat and 91% less in spring oat compared to no cover crop and no herbicide control. The same cover crops were also compared to a no cover crop treatment where all received a May herbicide application of 2,4-D and glyphosate with residual herbicides of flumioxazin + pyroxasulfone (Fierce). With the addition of residual, there was no difference in palmer amaranth biomass in the no cover crop with residual herbicide and all the cover crop species where a residual herbicide was added. I share the Research Figure on my blog site which is incredibly visual and have shared it in pesticide trainings as well. To me, it so visually shares how well residual herbicides can work, which we’re aware of. However, what strikes me the most is how much work that residual had to do on its own to achieve the same control as a cover crop + residual herbicide. Adding the cover crop reduced the load of the herbicide alone and is another tool in the toolbox. It also shows how effective cover crops for weed control can be for organic systems if there’s a solid way for terminating them. I realize cover crops don’t fit every field or every situation. Just some considerations as we especially think of situations where planting a small grain this fall could be used for weed and erosion control and/or grazing.
Crop Update: The cooler weather and rains have been welcome here even though other parts of the State have had excess and flooding. I think grain fill has slowed down some in the corn, which will hopefully help. The rains will help the beans, milo, and pastures. If we can escape storms, early planted beans look pretty powerful this year! In a recent conversation with Dr. Jim Specht, he was sharing how he was anticipating really high bean yields. Upon asking him about that and also about the smoke/haze, he shared that he didn’t think it would have much impact on soybeans compared to corn. This is because soybeans are C3 crops where the photosystem saturates out at lower solar radiation levels; C4 crops like corn don’t, thus cloudy/hazy days have more impact on corn. The high humidity we’ve experienced has reduced transpiration of crops, allowing many non-irrigated soybeans to hang on till these August rains. As I’ve looked at crops in several counties, for the most part, it’s taken awhile for beans to start turning, even in the non-irrigated corners compared to what we typically see in dry years. Here’s hoping for some nice bean yields!
York Co. Corn Grower Plot Tour will be held this Thursday, September 9th from 5:30-7:00 p.m. at 1416 Road I, York, NE. Pizza and beverages will be provided. Attendees can guess the highest yield without going over for a chance to win a $50 gas card. We’re grateful to Ron and Brad Makovicka for hosting the plot and to all the companies represented in providing entries! We hope to see you there!
Wheat: I realize planting wheat is most likely not on many people’s radar in this part of the State. Yet, after attending the wheat and alfalfa expo today, just wanted to share a few thoughts and resources for those considering it. For those seeking resources, my colleague Nathan Mueller in Saline County has dedicated a section of his web page (http://croptechcafe.org/winterwheat/) to growing wheat in Eastern NE including an email listserv that shares new information. The website has a virtual variety tour where you can view varieties and their characteristics. A new tool on the website I learned about is a seeding rate calculator that helps in ensuring correct seeding rate based on the seed weight of the lot you receive. CropWatch also has its yearly ‘wheat edition’ in September, so be on the lookout for that this month at https://cropwatch.unl.edu and you can also check out https://cropwatch.unl.edu/wheat. Key points I emphasize for wheat include: killing out volunteer wheat in a mile radius at least 2 weeks prior to planting new wheat, treating wheat with fungicide seed treatment, and ensuring proper seeding depth by ensuring enough weight on the seeder particularly when no-till planting into residue.
I realize the economics for one year don’t look great for wheat. However, looking at the bigger picture, what is the value of that wheat crop in allowing additional time for a forage or cover crop, breaking pest cycles, and giving you an additional 2-3 months-time before needing to apply herbicides for weeds like palmer amaranth? What value does the residue provide for the following year to help reduce the number of weeds and/or in conserving soil moisture for the successive corn crop?
There’s also different ways of adding wheat into an operation. There’s some who have tried double cropping with both short season corn or soybeans after harvesting wheat. There’s also been interest regarding relay-cropping wheat and soybeans on Twitter. This past year, I had the opportunity to watch a few growers in the Archer/Chapman area try relay cropping wheat with soybeans on acres that were in seed corn the previous year. Their goals included using the small grain in wheat to aid in reducing palmer amaranth pressure and to obtain greater economic benefit from harvesting both a wheat and soybean crop. The Panhandle Research and Extension Center in Scottsbluff was doing the same with wheat and dry beans. There’s a lot we’re all learning in this arena and it’s just another way, with a lot more management challenges, to consider adding wheat in a crop rotation. Perhaps the biggest thing we learned was to have a high wheat seeding rate and proper fertility to allow the heads to be more uniform with less tillers that are short (similar to if one is raising a small grain for seed).
For those not desirous of planting wheat for grain, it can be used as a small grain cover crop for weed control as well. At two field days near Clay Center this summer, some individuals from Kansas and southern portions of Nebraska talked about how they recommend wheat or barley before a corn crop and rye before a soybean crop when considering a small grain cover crop for weed control. Their reasoning made a lot of sense. Wheat and barley don’t take off growing/greening up as fast as rye does. They also don’t obtain as much biomass (which also allows for faster nutrient cycling). They found farmers felt more comfortable planting corn green into wheat compared to rye for those reasons. I have no research or experience on that, but it makes sense and wanted to share if it’s something any of you would be interested in trying next year. In a soybean situation, I still recommend rye before the soybeans for weed control because of the increased biomass, and we’ll have data from Dr. Amit Jhala and his team this winter on that.