Category Archives: Trees
Crop Update and Hail Damage: While I don’t remember numbers as well, calendar dates are something I tend to remember. And, in agriculture, there’s numerous dates that accumulate over one’s life from hail, tornado, blizzard, flood, and wind events. I was reflecting on the Aug. 6th hail storm that occurred in Merrick, York, and Seward counties in 2018. This past week on August 7th, some woke up to hail/wind damage in Adams, Clay, and Nuckolls counties. The tree damage was incredible. Michael Sindelar, Clay Co. Educator, and I surveyed damage a day later. My estimation of the worst hit crops: corn around 80% defoliation with varying percentages of greensnap above/below ear and soybeans around 50% defoliated/broken off/with at least 50% pods on the ground. Where hail stones hit the ears, the kernels are mushy and mold is already setting in on corn at milk stage. There’s also mold setting in on soybean pods hit with hail stones. It’s hard to receive crop damage any time. The good news is that nothing appears to be a total loss; the majority of what we looked at was less than 40% defoliated and in general, the hail did not seem to penetrate the stalks, thus early stalk rot doesn’t appear to be setting in. Pictures at https://jenreesources.com.
Tree Problems: The majority of my questions the past 10 days were regarding tree leaves turning yellow and dropping from trees. They look stark against green grass. In general, what’s happening is the fact that we’ve had high humidity for a period of time now and we’ve had rain throughout spring and summer. Fungal pathogens thrive in these conditions. So, ornamental/flowering pears have pear rust; crabapples and apples have scab and also cedar-apple rust (depending on varieties); maples, ash, sycamores are showing anthracnose; and a number of other fungal leaf spots are observable on shade trees in general. Evergreen trees show various fungal needle spots. Ultimately, we don’t recommend doing anything for these diseases this time of year. We typically don’t recommend to spray shade trees in general, but fruit and evergreen trees should be sprayed in the spring if fungal diseases have occurred in the past. So, fungal diseased leaves may drop early and you may or may not observe a new flush of leaves yet this year. These fungal diseases won’t kill deciduous trees. They can kill evergreen trees over a period of years.
Oak leaves turning brown in clusters was also observed this past week. Sometimes
browning of leaves can be due to a fungal disease called anthracnose. Most of what I’m seeing, I believe, is environmental. It could be due to changes in hot/cool and periods of heavy moisture followed by lack of moisture on trees that had a huge flush of leaves due to moisture this spring. I really don’t know the cause for sure, but it doesn’t appear to be disease related from what I can tell. We wouldn’t recommend doing anything for the trees at this time.
UBBNRD Public Hearing: The Upper Big Blue NRD will hold a public hearing and informational open house on Aug. 19 at 7:00 p.m. at the Holthus Convention Center. The purpose is to receive comments on proposed changes to District Rule 5 – Ground Water Management Area Rules and Regulations. A complete copy of Rule 5 and the proposed changes are available at the district office and at www.upperbigblue.org/publichearing. The public will have the opportunity to learn more about these proposed changes and their effects, and address NRD board members about their concerns or support.
The proposed changes would stipulate that an approved nitrification inhibitor must be applied at the manufacturer’s recommended rate with pre-plant nitrogen fertilizer in the following situations: The application of anhydrous ammonia prior to March 1; The application of all nitrogen fertilizers other than anhydrous ammonia after February 29. In addition to these requirements, in Phase II and Phase III areas pre-plant application of nitrogen fertilizer shall not exceed 120 lbs. per acre. The remaining nitrogen fertilizer may be applied post plant. Prior to applying nitrogen fertilizer, but no later than April 1 of each year, each operator in the management area will be required to report information regarding the use of best management practices. For more information, visit www.upperbigblue.org or call (402)362-6601.
York County Corn Grower Plot Tour will be held Aug. 20th from 5-7 p.m. at 1611 Rd. 14 east of York. Pizza and refreshments will be provided and check out the latest hybrids. Guess the winning yield without going over and win a $50 gas card. All are welcome!
*End of News Column. Hail damage photos below.
Heat and Pollination: With last week’s heat and anticipated heat later this week, we were receiving questions regarding the impacts of heat and humidity on pollination. You can view the entire article in this week’s CropWatch at https://cropwatch.unl.edu. Key points include: Heat over 95°F depresses pollen production and prolonged periods of heat can reduce pollen production and viability. When soil moisture is sufficient, one day of 95-98°F has little or no impact on yields. After four consecutive days, there can be a 1% loss in yield for each day above that temperature. Greater yield loss potential occurs after the fifth or sixth day. High humidity, without a drop in humidity during the day, can delay pollination or prevent pollen from leaving anther sacs. We’ve been blessed we only had days of extended high heat around pollination, received a break in the heat in addition to weekend moisture.
Insect Pests: From light trap reports, peak western bean cutworm (WBC) flight appears
to have occurred last week, so scout for egg masses and live larvae with a 5-8% treatment threshold. Thistle caterpillars grew rapidly last week. Others are with me in considering spraying closer to 15% (instead of 20% threshold) with stressed fields from flash drought and/or off-target dicamba injury that don’t have canopy cover yet. In CropWatch, check out the articles regarding scouting for grasshoppers in field borders and what to expect for insects depending on crop growth stages yet this year.
Cattle Losses from High Heat: If the recent heat/humidity conditions are determined to be an extreme weather disaster event, then livestock losses would be covered by the Livestock Indemnity Program (LIP). Livestock producers who lost livestock should document losses in the expectation that they may be covered by LIP and contact your local Farm Service Agency (FSA) to report those losses.
South Central Ag Lab Field Day Aug. 1: View current field trials on improving crop production and profitability at UNL’s South Central Ag Lab (SCAL) on August 1 near Harvard. Guests can customize their day to select the tours they’re most interested in. Presentation topics include: Cover crops, pollinators and weed management; European corn borer, corn rootworm, and cover crop insect control; Herbicide-resistant weed management; Assessing injury and management decisions in corn and soybeans; Corn and soybean disease updates; Sensor-based nitrogen management in irrigated corn; Corn stover harvest management and impacts; mobile beef lab and hail machine demonstrations. Registration is at 8:30 a.m. followed by tours through 4 p.m. Lunch and refreshments are included. CCA credits have been applied for. For more info. see the program brochure and register at: https://go.unl.edu/2019scalfieldday.
Silage Webinar Aug. 2: With this year’s challenging weather and the need for forage, there may be more opportunities for harvesting corn for silage. Aimed at feedlot, cow-calf, and dairy producers, a silage webinar on August 2 at Noon CST will focus on moisture at chopping, chop length, inoculants, proper packing, silage covers and more. Pre-registration for the webinar is necessary and can be done at: https://go.unl.edu/vau7.
Trees Losing Leaves: The wet spring and humidity allowed for fungal diseases on leaves of shade trees with flowering pears and crabapples in particular dropping leaves early. I’ve also had a number of questions regarding red maple leaves (Autumn Blaze and Sunset) suddenly turning brown on trees. These symptoms may also be experienced on ash, tuliptree, and other maples. We think it’s environmental stress from having so much cool and wet early to almost a ‘flash drought’ situation in eastern Nebraska prior to this weekend’s rains. Sarah Browning has been recommending watering and mulch as the best ways to reduce stress and to prevent additional root death and tree decline. I’ve been seeing new growth starting to occur on trees so my hope is if your tree is experiencing this, that 10-14 days from now you will also see new growth occurring on your trees.
Crop Updates: It was nice to see corn greening up and getting some growth this past week! Also on people’s minds is the 45 day post-planting application deadline for RUP dicamba herbicides. The announcement that Risk Management Agency (RMA) adjusted the 2019 final haying and grazing date from Nov. 1 to Sept. 1 for prevented planting this year opened up additional options for our farmers affected by flooding and/or excess rain. An additional option was that “silage, haylage, and bailage should be treated in the same manner as haying and grazing this year. Producers can hay, graze or cut cover crops for silage, haylage or baleage on prevented plant acres on or after September 1 and still maintain eligibility for their full 2019 prevented planting indemnity.”
So how did this change things? Many I talked with, including my family, were originally planning on going with cool season covers like oats planted the first week of August. However, with the ability to harvest a cover crop for forage on Sept. 1, interest increased in utilizing warm season cover crops. For those planning on haying, our forage specialists recommend using millets. The regrowth after haying could then be used for grazing in the late fall/winter. They also said if you’re planning on a mix, don’t add brassicas into whatever you decide to hay as they don’t dry down and tend to create a moldy spot within hay. If you’re looking at grazing only, sudangrass, sorghum sudan, millets, and/or mix with other species are great options. Forage sorghum is a great option for silage.
The other consideration is that some of this ground going into prevent plant already had PRE herbicides applied, making legal options for cover crops that could be grazed or hayed difficult. So Friday was kind of a crazy day for me walking people through options. Honestly, sometimes corn or milo for silage ended up being the most feasible option based on labels. There are also acres of corn and bean fields that were drowned out due to recent flooding and are now considered a “failed crop” by FSA. Herbicides that were applied can make planting covers in those fields difficult too. Some farmers had contracts with seed companies providing free seed for replant. Thus, once again, corn for silage seemed like a feasible and economical option. So, I called Jeff Peterson at Seward Co. FSA to see if this could be an option. He said that it would be a feasible option in 2019 if it was also approved by the person’s crop insurance agent. The first step is to contact your crop insurance agent to discuss your options for prevent plant and/or failed crop. Then go to your FSA office and fill out their form for failed crop and/or prevent plant. Your crop insurance company may require a letter from Extension stating that corn can be used as a forage crop for silage. Again, it will be important to talk with your crop insurance agent and your FSA office about your options for the fields in your counties as I can’t guarantee these are options for every situation.
Tree Problems: The rain and humidity have allowed for numerous fungal diseases on our evergreen and deciduous trees. On deciduous trees, leaves with black/brown spots may be found. We don’t typically recommend fungicides for them and if the diseases get bad enough, the leaves may eventually fall off the trees early. A new flush of leaves typically follows 10-14 days later. On evergreen trees, we’re seeing a number of needle blights and shoot tip blights. We do recommend fungicide applications for them (typically in April or May). However, it is recommended to repeat them every 3-4 weeks when frequent rains occur. Product options for most evergreen diseases include chlorothalonil or a product containing Copper that is labeled for evergreen tree diseases. Bordeaux mixture is often recommended, but I have a hard time finding anyone that carries that.
Also, be checking trees for bagworms. They’re later this year and just forming new bags. In order to see them, what I do is walk up to the trees (especially cedars or spruces) and just watch the branches for any movement occurring on them. If you’ve had a bagworm problem in the past, what you’ll see is tiny, new brown bags moving as the larvae is building a new bag. I have more info and a video to help visualize what to look for: https://jenreesources.com/2015/06/27/bagworms-in-evergreens/. The best time to spray them is when the bags are less than ½ inch in size. More info and products can be found here: https://go.unl.edu/rgju.
What a blessing last week was for many to be in the fields to either finish or start planting! And, while some may not want it, we could also use some rain to help with the crusting issues that have been developing in various fields due to the warm temperatures and wind. As you assess stands, the following article provides some guidelines on what to look for and any replant considerations for corn: https://go.unl.edu/j727.
For those who planted soybean earlier into cooler soil conditions, Dr. Jim Specht also did so on different dates this year and monitored air/soil temperatures at the former ARDC near Mead. Air temperature daily lows were less than 36°F on eight days (five of which were 32°F or lower), were less than 40°F on 17 days, were less than 44°F on 23 days; and notably, were less than 48°F on 31 of the 37 days. I’ve talked about desiring a 24 hour window of near 50F temps for avoiding potential seed chilling of soybean. It’s based off some Canadian research that showed soybean completing the imbibitional (water uptake) phase in as little as 8-24 hours. Jim had a demo study this year in which he placed water into furrows and planted soybean seed 1.25” deep into the furrows on various days in April at 2:30 p.m. Adding water to the furrow was to hasten the imbibitional phase. There’s a slideshow with the full article in this week’s CropWatch at: https://go.unl.edu/yu2m. The article shows the seeds in this demonstration did not appear to be impacted by chilling injury in spite of low air/soil temperatures on some of the days including within a 24 hour period. The hypothesis is that planting in a warmer part of the day with good soil moisture allowed the imbibitional phase to complete more rapidly before the cold snaps occurred in the evening/following day. While this was only a demo, it spurs many questions. Further research to better document chilling injury and imbibitional period for different soil temps/moisture contents would hopefully help growers planting soybean in April.
Silver and Red Maple Trees: While back home helping with planting, I was also receiving numerous tree questions. For those with malformed leaves or various leaf coloration, I’m thinking that’s mostly due to the cool temperatures we’ve experienced. Malformed leaves can also be due to growth regulator herbicides such as 2,4-D (from weed and feed products or sprays) being applied to lawns when trees are beginning to leaf out.
For the past few weeks, I was observing the slow leaf-out of silver maples in town…even where portions of trees were leafing out and other portions seeming bare. Now, if your maples look like mine, they look brown and bare with huge seed production and minimal leaves. This can also be seen in red maple varieties such as the popular ‘Autumn Blaze’ maples from my observation. For everyone who called or texted, I told you I was assuming it was due to the cold snaps and frosts affecting trees leafing out. It also could be a result of the hard winter. Trees are interesting as stresses from previous years can also affect them several years down the road. While all that’s true, what I didn’t realize is that based on information from Ohio and Michigan State, frost at specific times trigger whether a tree goes into seed or leaf production. Maple trees produce very small flowers that turn into seeds every spring. Frost will kill some of the blossoms if received at the right time which leads to less seeds and more leaves. Even though it was a cold spring, perhaps fewer blossoms were killed than normal at the right time? It could also just be the natural cycle of heavy seed production this year? Regardless, the trees can’t support both massive seed production and leaf production, so many opted for seed production. The good news is that shade trees in general have an ability to shoot new leaves after being stressed. I see this every year after trees lose leaves due to herbicide damage, insects, diseases, or environmental conditions. So, give the trees a couple of weeks and you should begin to see new leaves developing. Don’t add fertilizer or other products to them as it’s not necessary and can actually stress trees that are stressed even more. By summer, the trees should look fairly normal. If they don’t, perhaps there’s another stressor occurring with your tree? The biggest culprits I see are roots that girdle (choke) the tree by wrapping themselves around the trunk or damage to the trunk from weed whackers.
What about those seeds in lawns and gardens? Some pre-emergent lawn herbicides will keep them from sprouting. Pulling them is time consuming, yet a valid option that’s best done as soon as seedlings emerge. Mowing may help keep some of them at bay. Weed and feed products for lawns often contain 2,4-D so using that or lawn care products with 2,4-D can be an option (just be sure to read the pesticide labels). Products like Preen can be pre-emergent options for flower beds/gardens.
Crop Update: Every year provides ample opportunities to learn and this year will be no different. We’ll learn a lot in the next few weeks with corn/soybean germination and emergence and the cold tolerance of seed. Grateful for the planting that’s been accomplished thus far! Some rainfall hopefully is providing a much needed break for some and could also help with the dry seed bed and crusting concerns with some fields.
I’ve seen information going around regarding delayed planting and changing to early relative maturities for corn. The concern is regarding frost occurring before the crop reaches black layer. We’re honestly too early for that conversation until we hit early June, but that may be a reality in portions of the State. When looking at the number of GDDs to Black Layer, it’s important to ask your seed company if that number is based on ‘from planting’ or ‘from emergence’. Bob Nielsen, Extension Specialist at Purdue, found from research conducted in the early 2000’s that when hybrids were planted late, they matured in fewer growing degree days (GDDs) than predicted. In their research, Bob and his team found that hybrids matured around 6.8 fewer GDDs for every day planted after May 1. This continued through the second week of June and they didn’t evaluate planting dates beyond then. He gives the example, “a hybrid rated at 2700 GDDs from planting to physiological maturity (kernel black layer) and planted on May 31 reaches physiological maturity in less than 2500 GDDs after planting (e.g., 2700 – (30 days x 6.8)).” Roger Elmore, Nebraska Extension Cropping System Specialist, put this in perspective in an older CropWatch article, “A 115 CRM hybrid (2782 GDD) planted on May 15 would behave like a 111 CRM hybrid and when planted on May 30 it would behave like a 107 CRM (2578 GDD) hybrid. If planted on May 30 this hybrid should mature around September 14 in southeast and southern Nebraska and around September 27 in central and northeast Nebraska.” So hopefully this is helpful with the upcoming weather forecast potentially delaying getting back into the fields. Bob does have a calculator at the following site which provides an estimated GDD adjustment when you plug in the GDDs of your current hybrids and your expected planting date: https://www.agry.purdue.edu/ext/corn/news/timeless/HybridMaturityDelayedPlant.html.
Renovating Flooded Pastures Workshop: After spring flooding, many river frontage pastures and crop fields were left with sand and silt deposits ranging from a few inches to up to three feet. Recovering that land for production will be the focus of a May 13 on-site workshop near Ravenna at 1:30 p.m. Jerry Volesky, Extension range and forage specialist, will discuss treatments and practices to aid land recovery. Participants are invited to park at McAuliff Farms at 41465 325th Road south of Ravenna. A tractor and trailer will transport attendees to the workshop location, where there are heavy deposits of sand and silt from flooding of the nearby South Loup River. For more information, contact Volesky at 308-696-6710 or email@example.com or the program sponsor, Town and County Bank at 308-452-3225.
Tree and Lawn Care Programs for York and Seward Counties: Two upcoming tree/lawn care will be held in York and Seward Counties. Sarah Browning, Nebraska Extension Educator, will be presenting the programs. There is no charge but please RSVP to (402) 441-7180 to attend either or both programs.
- “Made in the Shade: Trees for Nebraska’s Landscapes” will be held on May 30th from 6-7:30 p.m. at the 4-H Building at the Fairgrounds in York. Trees are the backbone of our landscapes, providing beauty, shade, noise reduction, wildlife habitat, and reduce home heating and cooling costs. In this program, learn how to keep your trees healthy and vigorous. We’ll also discuss tree species well-adapted to Nebraska’s challenging growing environment.
- “Troubleshooting the Landscape” will be held on June 5th from 6-7:30 p.m. at the Civic Center in Seward. Learn how to better manage these common problems in your landscape: Emerald Ash Borer, Weed control in lawns and landscapes, Summer and fall lawn care, and Pruning trees and shrubs.
Perhaps it was the hard winter, but I’m finding the flowering trees to be exceptionally pretty this year! Corn and even some soybean went into the ground this past week too. In last week’s column I shared regarding planting considerations yet would still encourage growers to keep considering your local field conditions before planting. You’re hearing some of these same things from both Extension and Industry partners and we realize field situations differ. We keep repeating these things to provide reassurance when you’re questioning decisions. We’ve already seen problems with anhydrous application in too wet of conditions in some fields. We’ve already seen some situations that were too wet when corn was planted leading to problems with compaction, depth issues, and not closing seed vee’s. With the cold snap, it’s important to consider soil temperatures (preferably around 50F or warmer for next 48 hours), soil moisture conditions, air temperatures for the next 48 hours, potential for cold rain, and cold tolerance of seed. Soil temperatures are listed at http://go.unl.edu/soiltemp and I would also encourage you to check your own particular field conditions. Last week, I was finding soil temperatures in local field conditions to be cooler than what was being reported from high plains regional climate center. If you don’t have a soil temperature thermometer, you can do this with a meat thermometer (and just dedicate it for field use).
I can appreciate the added concern and stress with this week’s forecast. There’s several planting-related articles in this week’s CropWatch at http://cropwatch.unl.edu. Two really helpful articles from Roger Elmore share on corn planting windows where he used USDA NASS data to show Nebraska data and also shared how other states throughout the Corn Belt have found similar results regarding planting windows. The key point is there’s a planting window between mid-April to mid-May within which optimum yields are usually obtained. After this period, yields decrease rapidly. So there’s still time and the planting conditions play a role in determining final yield by getting that seed off to a good start. You also keep hearing me talk about planting soybean early. Even as early as you can in May is better than mid to late May for higher yields if that works for your situation.
Browning Evergreen Trees and Shrubs: This past winter was hard on many things. When it comes to evergreen trees, the deep frost line and extreme cold led to the inability for transpiring trees to uptake moisture. This resulted in needles appearing brown and looking dead, particularly on the north and sometimes west sides of trees. I’m seeing this particularly on junipers, cedars, arborvitae, white pines, and some spruce. We’d recommend waiting till June before pruning any dead portions out or removing any trees/shrubs to see what happens with new growth.
Rhizosphaera Needle Cast in Spruce has been really bad the past few years. If you’re seeing spruce needles on lower parts of the tree turning yellow/reddish-purple/brown, then this disease may be the problem. The fungus continues moving upward on the tree. Affected needles are prematurely cast from the tree. Above average moisture during the growing season in parts of the State led to an increasing number of spruces affected by the Rhizosphaera fungus. What’s interesting is that the fungus infects the needles in spring but the symptoms often don’t appear till the following spring. One way to double check is to look for tiny black specks on the needles and on the twigs. The good news is that fungicide applications of chlorothalonil (Fungonil, Daconil, Bravo) or Bordeaux mixture in May can help when shoots are ½ to 2” in length! If we get frequent rains this growing season, applications can be repeated every 3-4 weeks.
Vegetable Planting Guide: Gary Zoubek had put together an excellent vegetable planting guide for the area which can be obtained at the Extension Office or at: https://go.unl.edu/d7qk.
Spring Lawn Seedings: With the difficulty of this past year, many didn’t get dormant seedings on because of all the snow and typically lawn renovation in the spring is difficult because of the inability for applying crabgrass preventer to newly seeded areas. However, a new product has changed this! 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. We’d still recommending seeding as soon as possible or else wait till August. 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).
Rhubarb and Frost: For those impacted by frost/freeze this past weekend, if rhubarb leaves are not damaged too much and the stalks remain firm, it is still safe to eat. If the leaves are severely damaged or the stalks become soft or mushy, do not eat these stalks. Remove and discard them. New stalks can be harvested and eaten. Rhubarb often develops seedheads following cold temperatures, but this also does not affect eating quality of the stalks. Remove rhubarb seedheads and discard.
Grateful for beautiful weather and harvest progressing again! We got the York County Corn Grower Plot out on Friday and special thank you to Ron and Brad Makovicka for their work and dedication to that effort! I will share the official plot results next week. The York County Corn Grower Banquet will be held on Thursday, November 15 at Chances ‘R in York with social time at 6:30 p.m. and meal at 7:00 p.m. Tickets are only $10 per person for a wonderful meal! Tickets can be obtained from any of the local directors or from the York County Extension Office at (402) 362-5508.Nate Blum from Nebraska LEAD Class 36 will give a presentation on his international tour and there will also be updates from Local, State, and National Corn Directors. For those who estimated yields during the plot tour, you need to be present in order to win the Yeti cooler.
Corn Yields: There’s an interesting article in this week’s CropWatch at http://cropwatch.unl.edu regarding final yield forecasts. Interesting to me are the box plots showing the range of ’30 year average’ vegetative and reproductive stages vs. 2018. The high heat in June shortened the vegetative time-frame. However, the silking through grain fill period was relatively typical for most locations and the long grain fill period with lower temperatures allowed for the better yields we’re experiencing (where drought and late-season hail wasn’t a factor).
Soybean Harvest Losses: Four soybeans in one square foot equals 1 bu/ac harvest loss. Various publications show how to determine harvest losses in areas of 10 to 25 sq. feet. For those with the SoyCorn Pocket Field Guide, page 78 shows estimating loss based on combine header width: http://nebraskasoybeans.org/wp-content/uploads/2017/02/SoyCorn-Field-Guide.pdf.
Evergreen Trees: Some evergreen needles are also changing color right now. It is good to look at your trees to determine the cause of the needle color changes. Evergreen trees actually go through a natural needle drop process with some years resulting in more thinning than others. I think this year may be one of those years as stress events can make needle drop heavier. Needle drop appears as needles turning yellow and falling from the tree. Pine trees may keep their needles for 2-3 or more years while spruce keep theirs for 5-7 years before needle drop occurs. Natural needle drop tends to appear along the main trunk and inside needles of the tree.
I also check for the presence of fungal disease. If the pine tree needles have dark spots/bands on them, it may be a fungal disease like dothistroma needle blight (on Ponderosa and Austrian pines) or brown spot (on scotch pines). The fungi actually kill the needles both directions from the location of the infection. With our heavy rains and high periods of humidity, I’m seeing increased fungal disease in evergreen trees this year. Fungicides applied in mid-May and again in mid to late June can help prevent this.
Pine wilt disease occurs in Scotch and Austrian pines. It’s caused by a bark beetle that has nematodes in its gut. The nematodes are native to Nebraska but Scotch and Austrian pines are not. Ponderosa pines aren’t affected because they’re native to Nebraska. The beetle ‘vomits’ the nematodes into the xylem (water-carrying vessels of the tree). The tree senses the presence of the nematodes and shuts down water to various branches as a way to prevent the nematodes from attacking. Thus why one sees a major branch then side of a tree turning gray-green then yellow-brown. Unfortunately, the entire tree will die typically within 3-9 months. Some farmers have tried trunk injections and drenches around their trees in hopes of saving them, to no avail.
On spruce trees, I’m seeing yellow/purple/browning of needles. This often is due to a fungal disease called rhizosphaera needle cast. One way to determine if this is the culprit is to look for tiny black dots on the gray twigs next to affected needles. The black dots are actually fungal structures that allow for infection to occur. Fungicide applied in May and after heavy rains can help. I always intend to spray my spruce tree each May but have failed to get it done the past several years. With recent rains, I’m trying it this fall to see if it can help; will let you know!
There have been several calls about arborvitae rapidly turning brown and I’m seeing evidence of heavy spidermite pressure at one time. Spruce spidermites affect spruce, juniper, arborvitae, etc. The rains and snow washed them off, which is one way to manage them. Evidence can be stippling (tiny yellow-green dots on needles) and also using a magnifying glass, one may see some webbing on undersides of needles. One can also just bang the needles on a white piece of paper to see if any mites are still active. Mites are most active in the cooler times of the season…so August through October in this case. Great resources for additional information include: Diseases of Evergreen Trees and Insect Pests of Evergreen Trees which can be obtained here: https://nfs.unl.edu/publications.
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/.