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Corn Newsletter : 2017-24
Precision Ag Field Day August 23Author(s): Mark Badertscher
Mark your calendar now for the Hardin County Precision Ag Field Day to be held August 23 at Kellogg Farms, 17392 Township Road 50 near Forest. Bill and Shane Kellogg have committed 305 acres to the Blanchard River Demonstration Farms Network in cooperation with Ohio Farm Bureau and USDA. Existing edge of field research shows that placing nutrients below ground dramatically decreases potential for nutrient losses. This farm utilizes subsurface placement of nutrients using strip tillage techniques. Cost savings and yield benefits that can be achieved by improving nutrient efficiencies by subsurface nutrient placement are being measured. In addition, various crop rotations are being compared while testing how to best implement cover crops and reduce tillage in those rotations. This farm is testing technologies that will help improve crop input efficiency, lower cost of production, while protecting our water quality.
The Hardin County Precision Ag Field Day will start with registration at 8:00 am. Presenters from Ohio State University Extension, USDA, ODA, Farm Bureau, and private industry will be on the program which will offer 3 Hours of Fertilizer Applicator Certification Training credit. Certified Crop Adviser credits are also planned. This field day will be one of the last opportunities to gain Ohio fertilizer certification before the September 30, 2017 deadline for all operators who apply fertilizer to 50 or more acres of crops for sale. Topics planned include Blanchard River Demonstration Farms overview, Edge of Field monitoring nutrients for water quality, variable rate fertilizer technology, managing big data on the farm, outfitting sprayer tanks with precision ag technology, nitrogen management, and use of UAVs (unmanned aerial vehicles) on the farm. Field demonstrations from precision agriculture equipment vendors are being planned for the afternoon as well as other topics and information that you won’t want to miss.
Managing Corn Rust with FungicidesAuthor(s): Pierce Paul
Both southern and common rust have been confirmed in multiple corn fields across the state, but as is usually the case in Ohio, the latter is much more wide-spread than the former, and most of the affected fields are in the southern half of the state. Southern rust is characterized by the presence of small, circular, light orangish pustules predominantly on the upper surface of the leaves, whereas common rust produces larger, more elongated, and darker (cinnamon-brown) pustules on both leaf surfaces.
Common Rust Southern Rust
Most of the fields that were planted early are now between R1 (silk emergence) and late-R2 (brown silk), and as such, are less likely to be heavily impacted by rust. Common rust in particular tends to become less severe as the season progresses as it prefers cooler conditions. By contrast, late-planted fields, most of which are still between V10 and V18, are at greater risk for yield reduction due to rust. Southern rust can be very damaging if the hybrid is susceptible, symptoms develop early (before tassel), and the weather stays warm and wet during pollination and grain fill.
Under favorable conditions rust can spread very quickly on a leaf, from one leaf to another, and from one plant to the next. The rate at which it spreads is heavily dependent on the amount of spores available (blowing in from the south or from a nearby affected field) and how long it takes for each set of new pustules to produce new spores. If it stays wet and warm over the next week or so as late-planted fields approach R1, several new crops of spores will be produced, new infections will occur, and more leaves will become damaged before grain fill is complete.
Several of the commonly used foliar fungicides will provide good to excellent control of both rust diseases. However, timing is extremely important. The best results are often seen when applications are made as soon as the first few pustules are observed. This helps to reduce the rate of disease development and spread by preventing new pustules from developing and reducing the number of spores available to infect healthy leaves. Give priority to protecting the latest-planted fields as they are at the greatest risk for damage and yield loss.
Stink Bugs in Soybean
As our beans start to put on pods, it’s time to start scouting for stink bugs. In 2016 a number of farmers had significant stink bug damage but didn’t realize it until harvest, when they discovered shriveled, blasted seeds. Seed damage can be prevented by scouting and treatment at appropriate threshold levels.
There are several species of stink bugs that can be found in soybean, even beneficials. These include the green, the brown, the red shouldered and the brown marmorated stink bug. The spined soldier bug looks similar to the brown stink bug, but has sharper points on its shoulders, and is more brown on the underside (the brown stink bug is actually more green underneath). Both nymphs (immatures) and adults feed on the developing seed by using their piercing/sucking mouthparts to poke through the pod. Seed that is fed upon will take a flat or shriveled appearance.
Often this damage is not seen until harvest time, because the pod usually retains its shape, despite the smaller seed. Therefore it is important to scout early and control if necessary. Most insecticides labeled for soybean include stink bugs on the label, and most are adequately effective. Keep in mind it is easier to kill immatures than adults. To sample for stink bugs, take multiple 10-sweep samples with a sweep net in multiple locations throughout the field. Average the number of stink bugs in the 10-sweep samples. The threshold to treat is 4 or more stink bugs (adults and nymphs combined). If soybeans are being grown for seed, the threshold can be dropped to 2 or more stink bugs.
August Establishment of Perennial Forages
Our wet weather conditions throughout much of 2017 prevented spring establishment of perennial forages for many producers. Additionally, the wet weather has caused stand loss in alfalfa fields due to compaction and crown damage from harvest on wet soils, and from root rot in poorly drained field areas. As a result, replacement of some of those acres is necessary. August provides growers with another window of opportunity to establish a perennial forage stand. Typically, the main risk with a late summer August planting is having sufficient moisture for seed germination and plant growth but this year that risk may be low.
There are some advantages to late summer forage planting as compared to a spring planting. Late summer planting means forage seedlings are not competing with the flush of annual spring and summer weed emergence/growth. The soil borne root rot and damping off disease organisms that thrive in cool, wet soils are not an issue. However, growers need to be aware of planting dates and the potential for late summer diseases in some situations.
According to the newly revised, 15th edition of the Ohio Agronomy guide, planting of alfalfa and other legumes should be completed by mid-August in Northern Ohio and by the end of August in Southern Ohio. These timelines take into consideration average frost dates and the time needed for forage plants to develop a root system capable of overwintering. For example, at about 8 to 10 weeks after emergence alfalfa plants pull the growing point below the soil surface, a process termed ‘contractile growth’. Once contractile growth occurs the alfalfa plant is considered a true perennial. The alfalfa plant needs to reach this growth stage to overwinter. Clover plants also need to have a crown formed, and grasses should be at least in the tillering stage of development before the onset of winter.
If the fall is warm and extended, similar to what we have experienced the past few years, it might be possible for successful establishment with later planting dates. Some alfalfa growers believe that the late summer planting deadline dates can be moved back by several weeks. It is a question of risk management. How lucky do you feel? Late summer and early fall planting dates of forages were tested in Pennsylvania in the mid-1990’s at two locations that historically are a little milder than most of Ohio’s winters. The year after seeding legumes, forage yield declined as planting dates were delayed after early August in the previous year. For each day planting was delayed after August 1, total forage dry matter yields the next year were reduced by an average of 158, 105, and 76 lbs./acre for alfalfa, red clover, and birdsfoot trefoil. Later planting dates usually affected grasses to a lesser degree. For example, orchardgrass yields only decreased significantly when planting was delayed past late-August and perennial ryegrass yields were actually greater in late-August than in early August plantings. However, for each day planting was delayed after August 30, yields declined 100 lb. /acre for orchardgrass and 153 lb. /acre for perennial ryegrass. Reed canarygrass, a slow establisher, was more sensitive to planting dates. Reed canarygrass yields the year after seeding declined 120 lbs. /acre for each day planting was delayed after August 1. The best policy is usually to plant most perennial forages as soon in August as possible, when soils conditions allow and when soil moisture is present.
Sclerotinia crown and stem rot is a concern with no-till seedings of alfalfa in late summer and especially where clover has been present in the past. This pathogen causes white mold on alfalfa seedlings. They become infected during cooler rainy spells in late October and November, the disease develops during the winter, and seedlings literally "melt away" in winter and early spring. It can be devastating where the pathogen is present. No-till is especially risky where clover has been present because the sclerotia germinate from a shallow depth. Early August plantings dramatically improve the alfalfa's ability to resist the infection. Late August seedings are very susceptible, with mid-August plantings being intermediate.
In a no-till situation, minimize competition from existing weeds by applying a burndown application of glyphosate before planting. Using no-till when herbicide-resistant weeds are present creates a very difficult situation with no effective control options, so tillage is probably a better choice in those situations. Post-emergence herbicide options exist for alfalfa. After the alfalfa is up and growing, control late summer and fall emerging winter annual broadleaf weeds. A mid- to late fall application of Butyrac, Buctril Pursuit or Raptor are the primary herbicide options. Fall application is much more effective than a spring application for control of these weeds especially if wild radish/wild turnip are in the weed mix. Pursuit and Raptor can control winter annual grasses in the fall in pure legume stands but not with a mixed alfalfa/grass planting. Consult the 2017 Ohio and Indiana Weed Control Guide and always read the specific product label for guidelines on timing and rates before applying any product.
For conventional tillage seeding prepare a firm seedbed to ensure good seed-to-soil contact. Be aware that too much tillage depletes soil moisture and increases the risk of soil crusting. Follow the "footprint guide" that soil should be firm enough for a footprint to sink no deeper than one-half inch. Tilled seedbeds do not need a pre-plant herbicide. Finally, keep in mind the following factors to increase establishment success.
- Soil fertility and pH: The recommended soil pH for alfalfa is 6.8. Forage grasses and clovers should have a pH of 6.0 or above. The minimum or critical soil phosphorus level for forage legumes is 25 ppm and the critical soil potassium level is somewhere between 100 and 125 ppm for many of our soils.
- Seed selection: Be sure to use high quality seed of adapted, tested varieties and use fresh inoculum of the proper Rhizobium bacteria. “Common” seed (variety not stated) is usually lower yielding and not as persistent, and from our trials the savings in seed cost is lost within the first year or two by lower forage yields.
- Planter calibration: If coated seed is used, be aware that coatings can account for up to one-third of the weight of the seed. This affects the number of seeds planted in planters set to plant seed on a weight basis. Seed coatings can also dramatically alter how the seed flows through the drill, so calibrate the drill or planter with the seed going into the field.
- Seed placement: The recommended seeding depth for forages is one-quarter to one-half inch deep. It is better to err on the side of planting shallow rather than too deep.
- Do not harvest a new perennial forage stand this fall. The ONLY exception to this rule is perennial and Italian ryegrass plantings. Mow or harvest these grasses to a two and a half to three-inch stubble in late November to improve winter survival. Do not cut any other species, especially legumes.
Does Tillering Impact Corn Yield?Author(s): Peter Thomison
This year I've seen more tillering in corn than normal, and there have been enquiries about the impact of tillers on crop growth. When farmers see extensive tillering in their corn hybrids they often express concern that the tillering will have a detrimental effect of crop performance (tillers will "suck" nutrients from the main plant and thereby reduce yields). As a result, tillers are often referred to a "suckers". However, research has shown that tillers usually have little influence on grain yields and what effects they do have are generally beneficial.
Tillers are lateral branches that form at below ground nodes. Although tiller buds form at each below ground node, the number of tillers that develop is determined by plant population and spacing, soil fertility, early season growing conditions, and the genetic background of the hybrid. Many hybrids will take advantage of available soil nutrients and moisture by forming one or more tillers where stands are thin in the row or at the ends of rows. Tillers are most likely to develop when soil fertility and moisture supplies are ample during the first few weeks of the growing season. They are usually visible by the 6-leaf stage of development. Hybrids with a strong tillering trait may form one or more tillers on every plant even at relatively high populations if the environment is favorable early in the growing season.
A number of studies have been conducted to determine relationships between tillers and the main plant. Defoliation experiments in the 1930's revealed that defoliated plants that had tillers yielded nearly twice as much grain as defoliated plants that had no tillers. These results suggested that there was a connection between the tiller and the main plant that allowed sugars produced in the tiller leaves to be moved to the ears of the main plants.
More recent studies have found that there is little movement of plant sugars between the main plant and tillers before tasselling. However, after silking and during grain fill, substantial amounts of plant sugars may move from earless tillers to ears on the main plant. When there are ears on both the tiller and the main plant, little movement of plant sugars occurs. The main plant and tillers act independently, each receiving sugars from their own leaves. The nubbin ears, that tillers may produce, therefore have no impact on the ear development of the main plant as was once thought.
If a particular hybrid shows excellent yield potential and also produces extensive tillering under some growing conditions, it should not be avoided. However, excessive tillering may indicate problems with stand density and distribution. If tillering is associated with row gaps and less than optimal plant populations, these are the conditions which need to be corrected to ensure optimal yields rather than selection of the hybrid.
Tillering can also be caused by diseases such as "crazy top" and Stewart's bacterial wilt (which are also associated with other symptoms). Such tillering is a disease symptom and not beneficial to plant performance. Severe weather conditions ( i.e. hail, frost, and flooding injury) that destroy or damage the growing point can also result in tiller development and non-productive plants.
Recent Rainfall: A Historical Perspective
To say that many parts of the state have experienced a wet stretch of weather would be an understatement. Heavy rainfall has left a wide variety of negative crop conditions, from yellowing in soybean fields where ponding has been persistent to highly variable heights on corn stands, delayed wheat harvest and hay cutting. With all of this rain, streams and rivers have been running much above normal as well. But how historic is our recent rainfall?
Table 1 shows accumulated precipitation for May through July 2017 for selected stations* around the state, one from each of Ohio’s 10 climate divisions where the greatest precipitation occurred, along with their departures from normal conditions (based on the 1981-2010 period), single 1-day maximum precipitation events, and their dates of occurrence. Totals range from 14.41” at Cleveland-Hopkins International Airport in the Northeast division to as much as 23.01” in Lima (Northwest division). This small sample of results shows just how heterogeneous precipitation can be, especially during summer when localized heavy rainfall occurs in thunderstorms that move over particular regions.
TABLE 1. May-July 2017 Precipitation+
+ Precipitation values through July 30, 2017. No precipitation expected on July 31.
The departures from normal vary widely as well, with areas from central Ohio to the north and west picking up between 5-11” of above normal rainfall. Climatologically, northern Ohio experiences slightly less rainfall than southern Ohio for the period. It is not surprising then that with 23” of rain, Lima reported a whopping 10.85” of surplus rainfall while South Point in southern Lawrence County (17.01” of rainfall) was only 2.45” above normal. Many of these stations reported single-day totals over 3” as well. According to CoCoRaHS reports (a community-based network of volunteers; https://cocorahs.org/), three sites in Ohio experienced events of more than 5” during the period (in Brown, Fayette, and Scioto Counties).
Figure 1 shows the rankings for each climate division (average of all the stations within each division) for May-July 2017 compared to the last 123 years (1895-2017). Seven of Ohio’s ten climate divisions experienced one of their top ten wettest May-July periods on record, with the Central, West Central, and Northwest divisions cracking the top 5. For the West Central division, only 1958 and 2003 had greater precipitation totals while for the Central division, this year beat out all years except 1990 and 1958.
One final note, while most of the state has experienced wet conditions, a few locations have managed to escape the worst of it. Portions of Summit, Portage, and northern Stark Counties are running about 75% of normal precipitation over the last 60 days. However, even these areas are not likely to develop drought conditions in the near-term.
Figure 1: Climate division ranks for precipitation for the period May-July 2017 compared to the 123 year record (1895-2017).
Data for this analysis originates from NOAA’s National Centers for Environmental Information (NCEI) Climate Division dataset (https://www.ncdc.noaa.gov/monitoring-references/maps/us-climate-divisions.php) and was obtained from the Midwest Regional Climate Center (http://mrcc.isws.illinois.edu/).
*Stations used had more than 98% of the data reported for this period and long-term means for historical perspective. Additional stations not included may have received greater precipitation totals for this period.
For more information on the weekly hydrologic conditions and climate outlook from the State Climate Office of Ohio, visit http://climate.osu.edu.
The Dicamba Situation – Assessment and Some Action ItemsAuthor(s): Mark Loux
We have had the opportunity to walk additional Ohio fields where soybeans were damaged by off-target movement of dicamba since our last C.O.R.N. newsletter article on this subject (see link below), and we continue to hear about even more affected fields. This situation continues to develop across the Midwest and South, and everyone involved is trying to assess causes and what these mean for future use. A couple of action items here for anyone associated with an off-target dicamba movement and injury situation:
- Take the time to report the problem to Monsanto (XtendiMax), BASF (Engenia), or DuPont FeXapan) so that they create a record of it. The compilation of these records has to be reported by companies back to regulatory agencies, which provides the agencies with information on how extensive the issues are. Reporting to the companies does not result in specific information being provided to ODA, or any further regulatory action or investigation by ODA. This also allows the three companies to investigate and get an assessment of causes of off-target movement. While affected growers may not receive the desired resolution or satisfaction from company investigations, there is still value in reporting with regard to broader resolution of the issue.
- Where possible, we would encourage reporting off-target dicamba situations to ODA also. This provides ODA with needed information on how extensive any problems are and what possible causes are. This is the basis for an official record specific to Ohio, that allows ODA to follow up with companies and/or EPA to determine whether revisions to labels, registrations, etc are needed here. Our experience is that affected parties do not necessarily want to subject their neighbors to investigation, especially given that problems may have occurred even where labels were followed. But this would be helpful in the end. Legally, applicators are required to notify ODA if anyone informs them that their application caused damage in excess of $500.00.
What follows is a rough assessment of dicamba issues here in Ohio, based on a limited number of farm visits and reports from people around the state, and a few things to think about as seed orders are placed and weed control programs for next year are planned.
1. No one wants a repeat of this year’s problems next year, and we have to assume that there will be some modifications of dicamba product labels and restrictions prior to the 2018 growing season. Purchasing Xtend seed with an assumption that the approved dicamba products can be applied in 2018 per the 2017 labels may be an erroneous conclusion. We have no idea what will happen here – just be aware of this. In our recent field investigations of dicamba problems, one message we received from the affected parties was along these lines – “while we realize that there can be hiccups with new technology, please pass on to the appropriate regulatory agencies that this is not an acceptable situation (and also implied I think was – “we expect it to be resolved before next year”)”. Message received and sent on. Monsanto, BASF, and DuPont – consider yourselves notified also.
2. As far as we know, off-target issues in Ohio have occurred only for postemergence applications of dicamba, in spite of a fair amount of preplant/preemergence use. We have to assume also that the lower number of official complaints in Ohio compared with states to the west and south of us is due at least in part to less frequent postemergence use here. Among other reasons for less risk when used preplant vs postemergence, including possibly lower temperatures and less frequent inversions, there is simply not as much emerged sensitive vegetation early in the season to damage should dicamba move off-target. While off-target movement this year seems to be causing injury only to non Xtend soybeans so far, there is certainly potential for damage to any other sensitive vegetation that is close enough – gardens, vineyards, orchards, etc. The apparent unpredictability of off-target movement this year for postemergence applications indicates to us the probability of damage in the future to something with way more value per acre than soybeans. We state this really just to reiterate that there is less risk to using dicamba early in the season, where it does have substantial value still for burndown of glyphosate-resistant marestail and ragweeds.
3. The “elephant in the room” for this entire situation has to do with the causes of off-target movement and injury, and the role of volatility. Causes of injury can include contaminated spray equipment from a previous application, addition of the wrong product during mixing, spray particle drift from an adjacent field due to wind during application, movement from a nearby treated field due to application during an inversion, or volatilization of dicamba from a nearby treated field sometime following application. Differences in patterns between particle drift and volatility were covered in the previous C.O.R.N. article linked below. It’s likely that there are examples of every one of these somewhere across the region. Based on the distances of dicamba movement and patterns of injury, weed scientists are concluding that post-application volatilization of approved dicamba products is likely one of the major causes, and our experience here in Ohio would support this conclusion (and some of this volatility could be due to use of unapproved dicamba of course). Applicators should be aware that current label guidelines address only controllable application parameters, and weather conditions the day of application, but do not address conditions that could affect the risk of volatility following application. Volatility is much less predictable and less controllable than the other causes listed here anyway. We should also mention that so far there is apparently no recognition of the probable role of volatility by the companies selling approved dicamba products – something good to know in the event you report a problem and have a conversation with them.
4. During farm visits in northwest Ohio last week, it appeared that dicamba seems to be moving from treated fields with runoff water also, and causing injury to sensitive soybeans at the destination of that runoff. We observed this on a small scale – water moving/ponding between two adjacent fields (one Xtend soybeans and one not). We also observed it on a larger scale, where a field next to a drainage ditch that drained several miles of cropland was flooded from that ditch and then developed dicamba injury. In the latter case one could probably conclude that there were multiple dicamba-treated fields upstream, which contributed runoff water to the ditch. It may be a wetter than average year in northwest Ohio, but the nature of the soils and drainage there would lead one to predict future occurrences.
Some links that may be of interest:
http://ocj.com/2017/07/ohio-ag-net-podcast-episode-18-in-the-barn-and-out-of-trouble/ (last 15 minutes or so of the podcast)
Western Bean Cutworm Monitoring Update for Week ending July 28, 2017
assisted by Mark Badertscher, Lee Beers, JD Bethel, Bruce Clevenger, Sam Custer, Thomas Dehaas, Allen Gahler, Jason Hartschuh, Ed Lentz, Rory Lewandowski, David Marrison, Sarah Noggle, Les Ober, Adrian Pekarcik, Eric Richer, Garth Ruff, John Schoenhals, Jeff Stachler, Alan Sundermeier, Curtis Young, Chris Zoller.
Western bean cutworm (WBCW) populations continue to decrease for the majority of monitoring counties in Ohio; with the exception of Ashtabula, Trumbull and Tuscarawas counties, where numbers are still increasing. A total of 79 traps were monitored in 20 counties. Overall, 1654 WBCW adults were captured for week ending July 28. The state average per trap decreased from 50 WBCW (week ending July 21) to 21 WBCW (week ending July 28).
Figure 1. Average western bean cutworm (WBCW) trap counts within participating counties for week ending July 28, 2017. Number represents the average WBCW per trap in each county.
Figure 2. Overall average number of western bean cutworm adults captured in traps in Ohio.
2017 Ohio Wheat Performance Test Data Available
The purpose of the Ohio Wheat Performance Test is to evaluate wheat varieties, blends, brands, and breeding lines for yield, grain quality, and other important performance characteristics. This information gives wheat producers comparative information for selecting the varieties best suited for their production system and market. Varieties differ in yield potential, winter hardiness, maturity, standability, disease and insect resistance, and other agronomic characteristics. Selection should be based on performance from multiple test sites and years.
In fall 2016, wheat was planted at three out of the five locations within two weeks of the fly-free date. Wheat was planted 17 and 15 days after the fly-free date at the Wood County and Wayne County locations, respectively, due to 1.3-1.4 inch of rainfall between September 26 and October 3. Slightly above average temperatures through December promoted early growth, and wheat entered dormancy in good to excellent condition. Wheat growth and development were a week to ten days earlier than normal due to above average temperatures in March and April. Generally, harvest conditions were favorable and earlier than normal. Overall, grain test weight averaged 56.0 lb/bu (compared to an average test weight of 58.4 lb/bu in 2016). Grain yield averaged between 87.1 and 109.1 bu/acre at the five locations.
About the C.O.R.N. Newsletter
C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.
The information presented here, along with any trade names used, is supplied with the understanding that no discrimination is intended and no endorsement is made by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.
CFAES provides research and related educational programs to clientele on a nondiscriminatory basis. For more information, visit cfaesdiversity.osu.edu. For an accessible format of this publication, visit cfaes.osu.edu/accessibility.