Category Archives: Trees
Last week I heard several mention close calls on gravel roads. Please, slow down/stop before crossing unmarked intersections, fully stop at marked ones, and please remind young people of this too.
Crop Update: Keep watching silk clipping on corn that’s pollinating; rootworm and Japanese beetles clipping silks to ½” long triggers treatment thresholds. Southern rust was found in Nemaha and Greeley Counties last week from two samples at low incidence and severity. You can view updates at: https://corn.ipmpipe.org/southerncornrust/. Consultants and farmers with suspect samples are welcome to get them to me as in the past, or send to the Plant and Pest Diagnostic clinic in Lincoln. I’ve only seen gray leaf spot on the lowest leaves of fields last week so far, so disease is currently very low.
South Central Ag Lab Field Day: Reminder of this field day near Clay Center this week on July 28th which will cover nutrient, insect, disease, and weed management topics in addition to irrigation, cover crops, and biomass ones. There was a press release from UNL that had the wrong date, so just want to make sure those in the area interested in attending are clear that this will be held on July 28th from 8:45 a.m.-4 p.m. (Registration at 8:30). More details and registration at: https://enrec.unl.edu/2021scalfieldday. Walk-ins are also welcome; we just ask for pre-registration to aid in meal planning purposes.
Workshops on ag land management, leasing, carbon credits: Nebraska Extension and the University of Nebraska-Lincoln’s Center for Agricultural Profitability will host a land management workshop. It will offer updated leasing information relevant to landlords and tenants, including the latest financial trends in Nebraska agriculture, updated land values and cash rental rates for the state, strategies for equitable leasing and farm succession considerations. The latest information on carbon credit contracts for ag producers and landlords will also be discussed. The presentations will be led by Jim Jansen, an extension educator and agricultural economist, and Allan Vyhnalek, an extension educator specializing in farm and ranch transition and succession. The meeting is free to attend with meal sponsored by People’s Company, but registration is required. Locations include:
- July 28, 10:30-1:30 p.m., Extension Office, Columbus, Reg. 402-563-4901.
- Aug. 2, 10:30-1:30 p.m., Fairgrounds, Auburn. Reg. 402-274-4755.
- Aug. 3, 10:30-1:30 p.m., College Park, Grand Island. Reg. 308-385-5088.
- Aug. 17, 10:30-1:30 p.m., Extension Office, Lincoln. Reg. 402-441-7180
- Aug. 18, 9-Noon, Extension Office, Wilbur, Reg. 402-821-2151
Leaf Drop in Trees: Still receiving questions on this. For leaves such as Linden and Birch trees that have a lacy appearance of feeding on them, this is due to Japanese beetles. We hopefully are on our last week of them. For crabapple, flowering pear, ash, maples whose leaves are turning yellow/brown and dropping, this is due to fungal diseases and we wouldn’t recommend you do anything for this either. Next week I’ll talk about iron chlorosis and treatments for trees.
Brown Leaves on Oak Trees: Browning on leaf margins of individual leaves is anthracnose, which is a common fungus of shade trees. We don’t recommend that you do anything for this.
The past few years around fair time, we’ve seen oak trees (but sometimes others such as hackberry, honeylocust, elm, linden) that get a cluster of brown leaves towards the ends of branches. This damage is caused by twig girdlers or twig pruners, different types of beetles. Basically, the adult beetles chew a circle in the bark between where the old and new wood occurs on a twig. This girdles the twig, cutting off the water and nutrient supply causing its death. Eggs are then deposited and larvae hatch, tunnel, and survive in the dead twigs. Twigs girdled by any of these insects may stay attached to the main branch for several weeks or be broken out of the tree by wind. Tunneling in the twigs may not be evident in the fall if twigs fall out of the trees before the insect eggs have hatched. Mature trees with heavy infestations can look bad, but the damage isn’t a serious health problem to the tree and no chemical control is recommended. You can burn or discard infected twigs in the fall and spring that contain developing larvae to minimize the impacts for the future.
Warmer conditions have arrived for planting season this week! Quick reminder to check planting depths across your planter for the different fields as conditions may vary from field to field. Also a reminder to everyone to be extra aware on the roads with farm equipment moving much slower than regular traffic. Here’s wishing you a safe planting season!
Lawn Care: If your lawn is in need of fertilizer, the first round of fertilizer can go on sometime between now and May 10. Many crabgrass preventer products also contain fertilizer, so that can be used as your first application instead. A reminder to read and follow the instructions on the fertilizer package regarding rate, need to water in, and use the settings provided for lawn spreaders. Also be sure to remove granules from sidewalks and driveways as these get moved into stormwater systems and streams if one doesn’t. If you hired a lawn care company, make sure they’re removing granules from sidewalks and driveways as well.
If you have new seedings, weed control products such as crabgrass preventer, can damage new grass seedlings, depending on how much growth is present. If this is your situation, there actually is a product you can use that will prevent crabgrass without damaging your new seedlings. Scott’s Turf Builder Starter Food for New Grass contains mesotrione which provides PRE and POST control of weeds without affecting the new bluegrass or fescue seeding. Tenacity is also a product containing mesotrione that works as a POST for emerged crabgrass, foxtail, and for those dealing with nimblewill (best to apply on troublesome grassy weeds up to 1” tall).
Preventing Evergreen Tree Diseases: The wet springs the past several years have led to an increase of needle blights. Spring is the time to be spraying trees with preventive fungicides with timing depending on the disease. None of the options I list are exhaustive and not meant as endorsement. For windbreak situations of cedars and pines, some ag retailers have carried Tenn-Cop 5E or Camelot. Another professional product called 3336-F is labeled for various turf, horticultural, and tree diseases (such as tip blight and dothistroma needle blight of pines). For home-owner use for trees in landscapes, I will share what I’ve seen sold in our local stores. It’s important to read the product label to ensure it’s safe to use on the specific plant/tree you wish to treat as some copper products can harm plants. In Austrian and Ponderosa pines, tip blight (where tips die) and dothistroma needle blight (where needles turn brown and die) can be prevented with fungicide applications. Tip blight is best prevented in late April-early May with active ingredients of Propiconazole (found in Fertiloam liquid systemic fungicide), Copper Salts of Fatty & Rosin Acids (sometimes listed as copper soap such as Bonide liquid copper fungicide and other liquid copper formulations), or Bordeaux mixture. Dothistroma needle blight can be prevented in mid-May and a second application in mid-June with Copper salts of fatty and rosin acids and Bordeaux mixture. In spruces, needle cast can cause the yellow to reddish brown color of needles in the fall that remain that way in the spring. Fungicide should be applied when the new growth is half grown with a second application 3-4 weeks later. If your tree is severely infected, it may take applications like this for 2-3 years in a row. Chlorothalonil (found in Daconil and Fung-onil) is commonly recommended. Fungicides containing azoxystrobin, mancozeb, propiconazole, copper salts of fatty acids, and copper hydroxide are also effective at controlling this disease if the product is labeled for use on spruce. You can learn more about evergreen diseases, how to identify them, and more products for management at: https://go.unl.edu/rbcc.
Prevent Wild/Bur Cucumber in Shelterbelts: The past few years we’ve seen wild and bur cucumber overtaking windbreaks. These are fast growing, warm season annual vines. They die each fall and come back from seed which germinate and begin growth typically in May. Vines can be cut at the base or pulled if there’s only a few of them this spring. Many asked about chemical treatments last year. A pre-emergent control option for large shelterbelts is Simazine (Princep 4L) to kill weed seeds as they germinate. Don’t apply more than 4 qt. Princep 4L per acre (4 lb. a.i./A) per calendar year. Don’t apply more than twice per calendar year.
Pollinator Garden Webinar Series will be held May 4, 11 and 18th from 6:30-7:30 p.m. If interested, you can learn more and register here: https://go.unl.edu/bmnw.
Crop Update: This has been an interesting harvest season and yet, overall good one. To be at October 11th with so much of the area crop harvested is a blessing! I’ve heard growers thankful for the good harvest conditions and ability to go anywhere in fields without fear of getting stuck. Many were grateful for good soybean yields.
As we get further into corn harvest, there’s perhaps disappointment experienced on corn yields and moisture variance. Honestly, I’m struggling to explain some of it. Part of it is the difference in rainfall that we received in various parts of counties this year. There’s non-irrigated fields receiving 180-220 bu/ac which is a blessing! Another part is the impact of the July 8th wind event in which some fields had greater greensnap while others had more leaned plants. Depending on severity, was estimating and now seeing/hearing a lot of 180-240 bu/ac irrigated corn in those fields. The UNL Hybrid Maize model was predicting average yields for irrigated in this area of the State based on weather conditions. I just thought we may see actual yields go a little higher with how long it took to reach black layer. Have seen a couple really high yields with longer season numbers harvested wet.
Corn also greatly varies in moisture. Non-irrigated fields are quickly reaching 15.5% and lower. Irrigated fields range from 15-23%; what I can’t explain is that for hybrids planted in the same time-period, some short season ones are staying wet while some longer season ones are dryer. Everyone who has shared this situation with me had applied fungicide to their fields for southern rust control. Some also fertigated. Ultimately, just sharing what I’ve seen and heard thus far.
Received some questions this week on sampling for Soybean Cyst Nematode (SCN). It continues to be Nebraska’s top yield-limiting soybean disease with research showing it can cause up to 40% loss. The Nebraska Soybean Board is again sponsoring free sampling courtesy of soybean checkoff dollars. You don’t need a special bag to submit samples as a quart-sized plastic zip-top bag will suffice. If you had areas of a soybean field that yielded less than expected, particularly any areas that also showed sudden death syndrome or brown stem rot, consider taking a soil sample for SCN this fall. The female nematodes live in the top 8” of soil, thus sampling is as easy as taking your fertilizer sample for the following year’s corn crop and sending part of it in for an SCN analysis.
To collect a soil sample, use a soil probe to collect soil cores from a zig-zag pattern representing the lower yielding area of the field. For comparison, it’s wise to also take another sample from a better yielding area of a field. I’ve found that around 12 cores per sample is enough to provide around a 2 cup sample of soil that will fit in a ziplock type bag (and not have excess that needs to be dumped out). Be sure to label the bag with your contact info, field name, or other ID to report the results back to you. Also be sure to fill out a completed sample submission form requesting SCN analysis and mail the samples to the UNL Plant & Pest Diagnostic Clinic (1875 North 38th Street, 448 Plant Science Hall, Lincoln, NE 68583-0722). For those who submitted samples during the summer, campus mail is better now that the University campus is open again.
Caring for Drought-stressed trees/shrubs: With the continuing dry conditions, this is a critical time to prepare woody plants for winter and prevent winter injury, especially to evergreens. Dry fall conditions can reduce the number of leaves, blooms and fruits trees produce the next season. Trees often delay the appearance of drought-stress-sometimes months or years after the stress occurs. Even after the drought has ended, trees that experience drought stress are more susceptible to secondary attack by insect pests and disease problems, such as borers and canker diseases, which can cause tree death. When watering, moisten the soil around trees and shrubs, up to just beyond the dripline (outside edge of tree leaf/needle canopy), to a depth of 8 to 12”. Avoid overwatering; but continue to water until the ground freezes as long as dry conditions persist.
The Nebraska Department of Agriculture (NDA) confirmed Emerald Ash Borer (EAB) was found in a trap at the Blue Valley Campground in Seward, NE in early August 2020. This article will share information from Elizabeth Killinger, Extension Horticulture Educator, about what this means for your ash trees and what you should be doing now.
“Finding borer holes in ash trees doesn’t necessarily mean you have EAB. There are several different types of borers that attack ash trees, so correct identification is key. There are several different native borers that are normally found on ash trees. The ash/lilac borer, banded ash clearwing and carpenter worm can attack healthy ash trees. The redheaded ash borer, banded ash borer, flatheaded apple tree borer and eastern ash bark beetle attack stressed or dying ash trees. Knowing exactly which insect is in your tree will let you know if you should start looking for a replacement or if you need to treat.
EAB is an invasive beetle that attacks and kills all species of ash. It is a small, metallic-green beetle that is about 1/2 inch long. The larvae of this wood-boring insect tunnel under the bark of ash trees, disrupting the flow of water and nutrients, ultimately causing the tree to die. EAB infested ash trees will exhibit thinning or dying branches in the top of the tree, S-shaped larval galleries under bark, D-shaped exit holes and suckers or advantageous growth along the trunk and main branches.
Proper tree identification is key to knowing if you should be concerned about EAB or not. The bark of ash trees have diamond shapes or capital “A’s”. Ash trees have an opposite leaf pattern, or the buds are across from one another on the stem. They also have leaves of 5 to 7 leaflets. If you are lucky enough to get the seeded variety, the seeds look like paddle-shaped helicopters and are held in clusters on the tree. Ash trees, those in the Fraxinus genus, can include the green, white, Patmore, Marshall’s Seedless, and Autumn Purple Ash. Mountain Ash is not affected because it isn’t a true ash.
If your tree has EAB-like symptoms, like canopy thinning, branch dieback, sprouting growth from the base of the tree, or D-shaped exit holes, it should be examined by a professional. Leave your ash trees in as long as they are healthy, in good condition, and in a good location. If your tree is dying or diseased, it may be best to hire a certified arborist to look at your trees and determine the cause of the decline.
Because of the cost, treatments are only recommended for high value and/or already healthy trees. Once EAB has been confirmed within the 15 mile radius of your location, then you can begin the proper treatment applications on healthy trees. Depending on the size of the tree, a soil drench is one option for homeowners. The drench can be applied to trees with under a 20” diameter trunk yearly throughout the lifespan of that tree. Tree care professionals are able to use additional products like trunk injections on larger trees. Contact a certified arborist for these treatments. Some products are best applied in the spring, while others can be done throughout the summer. We don’t recommend treatments this fall.
Ash has been a popular landscape and conservation tree for a long time due to its fast growing nature and overall appearance. Diversity in the landscape is important to the overall health of the community forest. Aim to have diversity and try not to have any one species make up more than 10% of the landscape. A diverse landscape isn’t as affected by single outbreak. Now is an excellent time to start thinking about replacement trees for ash. For a list of replacement trees visit The Nebraska Forest Service list of replacement trees or Trees for Western Nebraska (PDF). More information about the emerald ash borer, finding an arborist, and recommendations can be found at https://nfs.unl.edu/nebraska-eab.”
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.
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.
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.
This Memorial Day will be different not gathering to honor those who have gone before us. Grateful for those who paid the ultimate sacrifice for our freedom! May we still take time to honor them.
Crop Update: Several weeks ago we were seeing large numbers of seed corn maggot flies. This past week have seen and heard reports of seed corn maggots attacking soybean seed/seedlings. Typically insecticide seed treatments provide protection; the exception is with high densities such as what we’re experiencing this year. They’re attracted to cover crop fields, fields with manure application, and tillage. There’s several generations but we shouldn’t have to worry about it again unless we experience replant situations. Fly emergence for the first three generations occurs when 354, 1080, and 1800 growing degree days have accumulated, respectively since January 1. There’s an updated article in CropWatch this week sharing more. They can reduce stands, but soybeans can withstand a great deal of stand loss. We recommend to leave a stand of at least 50,000 plants per acre with fair uniformity. That goes for anything that can reduce a soybean stand such as crusting, hail, herbicide damage, insects, disease, etc. We have research showing that the early planting will out-yield a replant. I realize there’s other considerations such as weed control and Dr. Shawn Conley at Wisconsin suggested putting the dollars into weed control instead of replant. They only found 2 bu/ac yield difference in stands of 50,000 plants/ac vs. optimal stands of 100,000-135,000 plants/ac. If you do consider replanting for any reason, we’d recommend going in next to the old stand with a similar maturity and proving it to yourself. Here’s a protocol if you’d like to test it yourself: https://go.unl.edu/wq24.
Post-Herbicide Applications: At pesticide training, I talk about the importance of overlapping residual. Ag industry partners talk about this too. It means aiming to apply the post-herbicide before the residual from the pre wears out. Many of us have seen fields that are clean one week with a flush of weeds the next. Sometimes it then rains, delaying post-applications. Dry conditions created difficulty getting pre-herbicides activated, allowing some weed escapes. Depending on the product, soil conditions, weather conditions, Dr. Stevan Knezevic shared that pre-products can last anywhere from 4-8 weeks. Page 24 of the 2020 Weed Guide also provides guidance on potential residual (also known as persistence in the soil) of herbicides if you’d like to check that out.
Bagworms: I haven’t spent time looking at evergreen trees to see if bagworm larvae
have emerged yet or not. If you have last year’s bags on your trees that are sealed (don’t have an open hole at the top), you can pick off some bags, place them in a ziplock bag, and place it outdoors on the south side of your house. When you see larvae emerge, it’s a good indication to start checking your trees in the next weeks. Each bag can hold 500-1000 eggs. The larvae are really small and hard to see. Stand still and watch the tree. If bagworm larvae are present, you will see very tiny movements as they begin the process of building new bags. I have pictures and a video at: https://jenreesources.com/2015/06/27/bagworms-in-evergreens/. Egg hatch is from mid-May to early June, depending on the year. Some caterpillar larvae remain on the same trees containing the bags from which they hatched. Others are blown by the wind to area trees allowing for new infestations to occur. For homeowners with small trees or only a few trees, bags can be picked from trees now and drown in soapy water or burned. In the summer, they can be squished, drowned, or burned. I have a great memory of visiting Grandma in the care center with my family. Grandma was concerned about the spruce in the courtyard. Seeing bagworms, I turned it into a science lesson for my nieces/nephews. They had a blast making quick work of picking off bags and squishing them to the delight/disgust of the residents watching (and their parents) 🙂 That’s not feasible for most situations though. We recommend waiting to treat trees until bags reach around 1/2” in size to ensure egg hatch is complete. Good coverage is needed when treating trees. With ground sprayers, we say to spray to the point of runoff. Bt products are effective early on. Most often I recommend a permethrin or bifenthrin product. Aerial application may also be an option for windbreaks. For more info., please see: https://go.unl.edu/rgju.
Planting season has rolled on this year with large planting progress made in short time! I’m grateful for the general warming trend with no cold snaps unlike so many recent years. Like many of you, am also praying for rain. For pre- herbicides, it is important to have 0.5-0.75” of moisture within a week of applying them for activation. That was a topic of concern I was hearing from both growers and ag industry last week, thus why it was recommended that some start pivots. I’m starting to see grass and broadleaf weeds coming through on ground that didn’t receive moisture to get the herbicide activated. Corn and soybean are also emerging fairly quickly with these warmer temps. The latest in pheromone trapping cutworm counts across the State can be found at: https://go.unl.edu/jdd3.
Some have asked about interseeding covers into early vegetative corn or soybean. Perhaps the three biggest things we’ve learned are to make sure the seed is in the ground vs. broadcast, plan to seed between V2-V5, and think about your herbicide program before trying this. An easy to understand site for herbicide impacts to covers is at: http://interseedingcovers.com/herbicide-options/. That whole website holds good information. There’s an Upper Big Blue NRD soil health project with partners of The Nature Conservancy, NRCS, and Extension where we will have 6 on-farm research studies and several other demos of interseeding this year. Growers are looking at impacts of different mixes, corn populations, row direction, and number of rows interseeded (1 vs. 3) between the corn rows. Looking forward to these additional studies to add to the research base which we talked about in this CropWatch article last year: https://go.unl.edu/4nh7.
My prayers go out to livestock and poultry producers; I just can’t imagine. There are a number of resources at https://animalscience.unl.edu/swine for emergency depopulation of livestock facilities. Such a hard time all around in ag. Free farm finance and legal clinics for May can be found at: https://go.unl.edu/joos. Nebraska Farm Hotline/Rural Response Hotline: 800-464-0258.
Evergreen Tree Diseases: The wet springs the past several years have led to an increase of needle blights. Spring is the time to be spraying trees with preventive fungicides with timing depending on the disease. None of the options I list are exhaustive and not meant as endorsement. For windbreak situations of cedars and pines, some ag retailers have carried Tenn-Cop 5E or Camelot. For home-owner use for trees in landscapes, I will share what I’ve seen sold in our local stores. It’s important to read the product label to ensure it’s safe to use on the specific plant/tree you wish to treat as some copper products can harm plants. In Austrian and Ponderosa pines, tip blight (where tips die) and dothistroma needle blight (where needles turn brown and die) can be prevented with fungicide applications. Tip blight is best prevented in late April-early May with active ingredients of Propiconazole (found in Fertiloam liquid systemic fungicide), Copper Salts of Fatty & Rosin Acids (sometimes listed as copper soap such as Bonide liquid copper fungicide and other liquid copper formulations), or Bordeaux mixture. Dothistroma needle blight can be prevented in mid-May and a second application in mid-June with Copper salts of fatty and rosin acids and Bordeaux mixture. In spruces, needle cast can cause the yellow to reddish brown color of needles in the fall that remain that way in the spring. Fungicide should be applied when the new growth is half grown with a second application 3-4 weeks later. If your tree is severely infected, it may take applications like this for 2-3 years in a row. Chlorothalonil (found in Daconil and Fung-onil) is commonly recommended. Fungicides containing azoxystrobin, mancozeb, propiconazole, copper salts of fatty acids, and copper hydroxide are also effective at controlling this disease if the product is labeled for use on spruce. You can learn more about evergreen diseases, how to identify them, and more products for management at: https://go.unl.edu/rbcc.
It’s too early for bagworm control. I’ll share more on what to look for next week.