Zinc Deficiency in Corn

Kitty O’Neil, Field Crops & Soils Specialist and Team Leader – North Country Regional Ag Team, Cornell University Cooperative Extension

Corn can exhibit interveinal chlorosis (striped leaves) as a result of several factors – nutrient deficiencies or other causes.  Many times, these stripes appear during a cold, wet spring and later disappear.

Nutrient deficiencies that can cause striped leaves include sulfur, manganese, magnesium and zinc.

  • Sulfur deficiency can occur on low organic matter, coarse soils receiving little or no manure or other organic inputs.
  • Manganese deficiency can occur when soils are dry for extended periods or in high pH soils.
  • Magnesium deficiency can occur in low pH, coarse soils or when soil K is especially high.
  • Zinc deficiency can occur in high pH, coarse, low OM soils – especially in a cold, wet spring.
  • Lastly, herbicide or nematode damage can cause striped leaves sometimes too.

On a typical NYS dairy farm where fields are have a reasonable pH and plenty of manure applied, early season striping in corn is usually caused by Zn deficiency caused by the cool, wet spring.  Striping often goes away as the season warms up and plants grow.  Tissue testing can help to diagnose a nutrient deficiency if the symptoms persist or are severe.

For a deeper dive into zinc deficiency, see the Nutrient Management Spear Program’s Fact Sheet #32.

Print Friendly, PDF & Email

NNYADP-Funded Field Crop Survey Provides Real-Time Alert, Data Trend Tracking

 Growers hear from Cornell faculty and Extension educators at this NNY corn and soybean field day in Henderson, N.Y.
Growers hear from Cornell faculty and Extension educators at this NNY corn and soybean field day in Henderson, N.Y. Photo: NNYADP

To help Northern New York farmers be alert to newly emerging field crop diseases and trends, the farmer-driven Northern New York Agricultural Development Program funds an annual field crop diagnosis and assessment project. The data produced by the survey is critical to farmers locally and statewide.

The annual evaluations, revived in 2013, provide farmers with real-time alerts in the current growing season, and add to multi-year data tracking that identifies trends and indicates emerging and re-emerging challenges.

“Northern New York farmers are increasingly faced with important management decisions that require real-time knowledge of plant diseases. The regional survey provides data to help them select crop varieties with disease-resistance and plan management practices to most cost-effectively and efficiently respond to the current-day threats and year-to-year variability,” says project leader Michael E. Hunter, a Cornell University Cooperative Extension Regional Field Crops Specialist.

Hunter and Cornell University Cooperative Extension Regional Field Crops and Soils Specialist Kitty O’Neil collaborate with Cornell University Plant Pathologist Gary Bergstrom, Ph.D. to respectively detect potential issues and collect crop samples in the fields, and analyze them at the Bergstrom Lab at Cornell University in Ithaca, N.Y.

Thirty-two farms located across the six-county Northern New York region that includes Clinton, Essex, Franklin, Jefferson, Lewis and St. Lawrence counties participated in the most recently-completed survey.

The NNYADP-funded survey also includes 19 sentinel cornfields and 18 sentinel fields of soybean, chosen to maximize the diversity of environments and cropping practices that can impact disease potential. In 2018, across the NNY survey area, seven corn diseases and six soybean diseases in total were identified and diagnosed.

“We are seeing an increasing number of growers using an integrated approach to managing field crop diseases on their farms. There are growers that are now paying closer attention to disease-resistant crop varieties, crop rotations, tillage practices, soil fertility management and fungicide selection based on the crop diseases identified in this regional survey,” Hunter notes.

The results of the 2019 field crops disease diagnosis and assessment survey will be posted on the Northern New York Agricultural Development Program website at www.nnyagdev.org and disseminated to growers, crop consultants, agribusiness and extension field crops educators at crop meetings and field days locally and statewide.

Funding for the Northern New York Agricultural Development Program is supported by the New York State Legislature and administered by the New York State Department of Agriculture and Markets.

Print Friendly, PDF & Email

Waterhemp Herbicide Resistance Tests: Preliminary results

Bryan Brown, New York State Integrated Pest Management
Collaborators: Antonio DiTommaso, Kathleen Howard, Mike Hunter, Jeff Miller, Scott Morris, Jodi Putman, Peter Sikkema, Mike Stanyard

Waterhemp seedlings in greenhouse
Bryan Brown is coordinating a project testing waterhemp for resistance to herbicides.

Last summer, several populations of waterhemp (Amaranthus tuberculatus) survived herbicide applications in western NY corn and soybeans.

Growers asked if these weeds are actually resistant to certain herbicides. If so, which ones? And are all populations of western NY waterhemp resistant to the same herbicides, or do they differ?

To answer these questions, we collected seed from these surviving weeds at three locations in NY, grew them in a Cornell University greenhouse alongside a population of waterhemp that we know is susceptible to herbicides, and then used a spray chamber to apply a range of herbicides and rates.

The herbicides we used were glyphosate (i.e. Roundup, WSSA Group 9), atrazine (i.e. Aatrex, WSSA Group 5), lactofen (i.e. Cobra, WSSA Group 14), and imazethapyr (i.e. Pursuit, WSSA Group 2). The WSSA groups represented here are the ones waterhemp has developed the most resistance to in other states. For each herbicide, we used five different rates. Each rate was applied to five waterhemp plants from each population. Following the methods of other studies, plants were sprayed when they were around 5” tall. BASF Agricultural Solutions and Valent USA LLC supplied some of the materials for this study.

We’ll be doing a final analysis three weeks after spraying. But here’s how the NY populations look after only one week. At the full labelled rates, glyphosate resulted in 50% control and lactofen resulted in 99% control. Atrazine and imazethapyr resulted in poor control, but waterhemp plants were larger than the maximum size stated on the label.

But it’s the comparison of our three NY populations to the susceptible population that determines resistance. Final control ratings will be done in two weeks, but initial results indicate that two NY populations are potentially resistant to glyphosate, three are potentially resistant to atrazine, none are likely resistant to lactofen, and two are potentially resistant to imazethapyr. So herbicides in WSSA Groups 2, 9, and 5 shouldn’t be solely relied upon to control this weed.

Since there were some differences between NY populations, we’ve shared each farm’s results with the participating growers so they can make the necessary changes to their management plans.

So if you haven’t seen it already, keep an eye out for waterhemp this year. It looks similar to other NY pigweeds, except that it’s completely hairless and it has separate male (pollen-producing) and female (seed-producing) flowering heads. (A video comparison may be found from American Agriculturalist.) Since it can travel in seed, feed, and equipment ­– make sure they’re clean. And think about trying out some new weed control options.

Print Friendly, PDF & Email

Resources for dealing with Spring Weather Delays

Cornell Cooperative Extension and PRO-DAIRY

The following article was written in 2011. With the wet weather much of New York State has been seeing this spring, we thought it would be helpful to re-visit the article again this year.

 

 

 

While the forecast still seems unsettled we are all hopeful that we are past the worst of the rain and can begin catch up on spring’s work.  Here we have attempted to summarize a variety of relevant topics as you consider how to best tackle all the work that needs to take place is a condensed time-frame.  As always contact your local Extension office for more information on any of these topics.

Safety First!

Harvest is a busy time for most farm operations. Time means money when it comes to yields, production schedules, and operating costs. However, time also ensures safety at harvest. The extra time it takes to perform a task properly can determine whether the job is completed at all. Harvest season comes with many stresses. Exposure to dangerous situations can increase the mental pressure, and your risk of injury. Follow safe practices around harvest equipment to make the most of your work time.  The most important goal this spring is to send all family members and employees home to their families SAFE … EVERYDAY!!

Planning and Team Work

With your condensed time window for key field activities this spring, the solution to accomplishing everything on time might come from a different way of thinking.  Consider the 5,000-foot view of the land that you and your neighbors work and think of the inventory of people and equipment potentially available to apply manure, fit fields, plant, harvest, haul, pack bunk, etc. for the collective land base.  Are there opportunities to share equipment and time even where you haven’t done so before?  Can you bring in equipment or a custom operator to take care of one activity while you focus on another? Does it make sense to use the 4-row planter when a 6-row is sitting idle a mile away?  Can you bring in extra help for milking?  Do you have any retired neighbors who could lend a hand with field work?

Consider gathering with your neighbors to strategize and to make sure that the most efficient equipment is fully utilized this year.  Remember: you and your neighbors are in the same boat, so you might as well paddle together!

Tillage and Impact on Wet Soil

While driving on and tilling wet soil may be somewhat unavoidable this spring, there is still an opportunity to reduce the amount of damage that is done.  Here is a summary of pointers from Tom Kilcer, Advanced Ag Systems, Kinderhook, NY:

  • Keep tillage shallow, in friable top soil not wet soil underneath.
  • Utilize vertical tillage, avoid equipment such as disks that simply smear and ruin the structure of wet soils.
  • Minimize weight whenever possible (fertilizer hoppers, etc.).
  • Make sure wheels on planter tractor are offset and not compacting the corn rows.
  • Check the seed furrow when planting: if planter is smearing sidewalls, it is too wet to plant.
  • Pay extra attention to seed placement and row cover by planter.

Park the Corn Planter when 1st Cutting is Ready!

The window of opportunity for high quality hay forage is 1-3 days. Window of opportunity to plant corn is April 25 to June 1 = 36 days.  The harvest opportunity for corn is corn silage or snaplage or HMSC or dry shell or ear corn.

First cut is 40% of yield in 3 cut system. Delaying cutting alfalfa past optimum first-crop harvest timing reduces the quality. Subsequent crops are then also delayed, making timely harvest of the last crop before fall more difficult. It is important to get that first cut off somehow. If forage inventory is good, consider alternative storage options to feed to heifers or just chop poor quality forage back onto the field. Do you really need all of it? Re-growth is critical for a 3 cut system.

To go from ideal alfalfa of 20% CP, 30% ADF, and 40% NDF, to 17 – 34 – 45, takes only 5 or 6 days! Obviously, poor quality forage does not have the same milk producing potential.

What nutrient changes can you expect in alfalfa due to advancing maturity?

  • Decreased intake – due to higher NDF, which increases about 0.9% per day.
  • Decreased digestibility and energy value – due to higher ADF, which increases about 0.7% per day and a larger amount of lignin, which is indigestible.
  • Decreased protein – decreases about 0.5% per day.

How much does it cost me to delay harvest? A lot! For each unit of NDF increase past 40% NDF for will:

  • Need: increased energy and protein supplements.
  • Have: lost production from the effect of lower NDF digestibility on dry matter intake.

Filling rates by total tractor weights chartTips for haylage harvest:

  • DO NOT ensile haylage wetter than 30% (target 32-40% DM). You all will be in a hurry to get haylage in the silos. Haylage wetter than 30% will have a greater chance of clostridia fermentation and butyric acid production.
  • Do NOT chop alfalfa WET!
  • Do INOCULATE at the forage harvester!
  • DO ADD another PACK tractor or weight to existing tractors.
  • Consider harvest strategies such as HAY IN A DAY to lower weather risk and improve forage quality. Hay in a Day YouTube video: http://www.youtube.com/watch?v=oSsQvVga6tw
  • Keep windrows up off the ground to minimize soil contamination at harvest.

Alfalfa height at optimum mixed stand NDF graphIssues with wet haylage:

  • Reduced intake
  • Potential health problems -ketosis
  • And for problems to get worse with time
  • Dispose of silage with very high (>2%) butyric acid content
  • Bad silage can be good fertilizer.

Don’t fill your storage with poor first cutting.  You’ll feel duty-bound to feed out even as it depresses production, cash flow and you.

1st Cutting is just around the Corner

Despite the wet start to the season, we have had more heat than many think.  So even though other aspects of springs work are behind the hay is not, with reports from around NYS showing that it is on track for this time of May.  So take the time to check those hayfields starting now!

Inoculants to Minimize Risk with Haylage Made Under Adverse Conditions?

The probability you may be forced into putting up at least some of 1st crop wetter than you would like has gone up with near-normal relative maturity for the date (5/5/11) and saturated soils. Having an effective forage inoculant on hand with a track record of pushing fermentation towards “normal” and away from “clostridial” is good risk management.

Manufacturers and suppliers of inoculants practice supply and demand risk management. They cannot afford to be hung out to dry with pallets full of unsold/unused product. There is only so much product available beyond the pre-orders taken during the winter. If you act fast you may have a shot at some supply.

Effective inoculant? Not much controlled research is done testing inoculants under these known (wet) adverse conditions. Yet we seem to face them more often than we’d like. Check the literature that was dropped off by the representative. Look for actual forage analyses of wet haylage put up under actual farm conditions within the past 5 years with their inoculant.           Make sure it was truly “wet”, in the 28 – 34% dry matter range (or worse).  A slow, cold clostridial fermentation consumes energy, creates intake-depressing butyric acid and breaks down the nitrogen in protein to ammonia.  If use of the inoculant was a financial “win” for the farm, these key measures will serve as gauges.  pH < 4.5, Lactic Acid > 2 (alfalfa) – 3 (grass), Acetic Acid < 2 (alfalfa) – 3 (grass), Butyric Acid < 0.1 and Ammonia as % of N < 15.

Is It Too Late for Spring Forage Seedings?

Wet soil conditions and delayed field work have prompted questions on how late alfalfa or clover/grass seedings can be made.  The typical spring planting window is April through early May for NNY.  Early June is not an ideal time to establish new seedings.  The warm soil temperatures and hot weather will bring on large flushes of annual weeds, putting the new forage seedlings at a disadvantage. Consider shifting seedings to early August.  In the meantime if you need tonnage you can put in an annual crop after hay is harvested.

If oats are used as a companion crop, their rate of seeding should be reduced to half of normal (or even eliminated) with May seedings.

When is it Time to Stop Planting Corn Altogether?

Effect on yeild of delayed planting of corn by hybrid maturityHere is a graph showing the effect on yield of delayed planting according to hybrid maturity.  Unfortunately I don’t think there is enough seed available for many farms to be able to switch out their longer season hybrids for short ones at this point.  While it is important to keep hybrid maturity in mind, there are a number of other factors you need to consider for your farm.  Here are a few of the considerations that may apply:

  • Hybrid Maturity you ordered/have on hand
  • Forage Inventories
  • Ability to store and segregate different forages
  • Capacity/ability of your landbase

Excerpt from: 2011 Cornell Guide For Integrated Field Crop Management
To achieve the full yield potential of an early planting date, full-season hybrids (hybrids that match the growing degree days in a region) are necessary. After the first or second week of May, however, the yield potential of full-season hybrids decreases appreciably. Furthermore, full-season hybrids may not mature in the fall if planted after the second week of May. Therefore, for grain production, full-season hybrids should be planted only in late April or the first 10 days of May. For silage production, full-season hybrids can be planted until mid-May. The majority of corn acreage should be planted to medium-season hybrids (200 growing degree days less than the growing degree days in a region). If planting must be delayed until late May or early June, early-season hybrids are recommended.

Corn planted after late June will be sloppy wet and hard to deal with at harvest and feedout.

Warm Season Annual Forage Crops

Warm season annual forage crops provide additional forage when perennial forages are in short supply.  While some farmers include them as part of their regular cropping system, many plant them for emergency forage crops.  Delayed spring planting and following winterkilled alfalfa are situations where these crops fit on the farm.

Most warm season annual forage crops can be planted anytime between early June and mid July.  There are many warm season annual forage crops that can be successfully grown in Northern New York.  Teff and brown midrib (BMR) sorghum sudangrass are two warm season annual grasses that are well suited to our region.

Teff is a warm season annual grass that can be grown for hay, silage or pasture.  Despite the fact that there has been very little teff grown in NNY, local research has demonstrated that it has the potential to produce high quality forage under proper management.  See Agronomy Factsheets “Teff as an Emergency Forage” http://nmsp.cals.cornell.edu/guidelines/factsheets.html

In a one cut system, 1.5 to 2 tons DM per acre are expected, while in a 2 to 3 cut system, dry matter yields range from 3.3 to 4.9 tons per acre.  When harvested at the proper time and sufficient nitrogen applied, crude protein will generally be between 15 and 16% of dry matter.

Brown Midrib Sorghum Sudangrass (BMR SxS) is a low lignin, highly digestible, warm-season, annual grass.  It can be high yielding but harvest management can be an issue given its high moisture content. See Agronomy Factsheet “Brown Midrib Sorghum Sudangrass, Part 1” http://nmsp.cals.cornell.edu/guidelines/factsheets.html

Dry matter yields of 3 to 5.5 tons per acre are expected and when harvested at the proper time with sufficient nitrogen applied, crude protein will generally be between 15 and 16% of dry matter.

Warm season annual forages can provide needed forage at key times during the year and have been used successfully by producers for many years.  In addition to Teff and BMR SxS, other options include Spring Grains, Buckwheat and Japanese Millet. Several factors should be considered before planting any crop.  If you have any questions about growing summer annuals contact your local Extension office.

 

Contributors:

John Conway and Janice Degni, South Central NY Dairy & Field Crops Team

Mike Hunter and Ron Kuck, Cornell Cooperative Extension of Jefferson County

Frans Vokey and Joe Lawrence, Cornell Cooperative Extension of Lewis County

Print Friendly, PDF & Email

Corn and Alfalfa Growers: Plan to Apply NNY Nematode Biocontrol Now

A young farmer applies biocontrol nematodes to his alfalfa field using a farm-made applicator unit in Lewis County. Photo: Joe Lawrence

Northern N.Y., March 20, 2019.  New York corn growers can now reap the benefits of the long-term commitment made by the farmer-driven Northern New York Agricultural Development Program (NNYADP) to the research needed for managing the most destructive alfalfa crop pest. Not only does the science-built biocontrol nematode protocol significantly reduce alfalfa snout beetle populations, it also has shown management capacity for dealing with corn rootworm, wireworm, and white grubs.

“We are confident that dairy farmers who inoculate their fields with these biocontrol nematodes for management of alfalfa snout beetle or corn rootworm are also benefitting from reduced populations of wireworms and white grub insects,” Cornell University entomologist Elson Shields, Ph.D., Ithaca, N.Y., said.

The successful biocontrol nematode protocol developed by Shields and research technical Antonio Testa is now being applied to multiple crops in New York State and in multiple states.

More than 500,000 acres in New York State are known to have alfalfa snout beetle infestation. Shields’ research team estimates the total cost of alfalfa snout beetle left untreated on a farm  ranges from $300 to $600 per cow. The one-time cost of applying the biocontrol nematodes is approximately $30 per acre, plus any application costs.

Farmers interested in applying the biocontrol nematodes through the Shields Lab rearing program at Cornell have only a three-year window to do so. It requires three to five years to totally inoculate a farm to significantly reduce the alfalfa snout beetle populations. The Shields Lab will stop rearing the nematodes as part of its research program in 2021.

For more information on purchasing the biocontrol nematodes and information on proper application methods, growers should contact the Shields Lab at least 45 days prior to a planned application. Contact Tony Testa at 607-591-1493 or at28@cornell.edu. Farmers can also work through Cornell Cooperative Extension Field Crops Specialists Kitty O’Neil and Mike Hunter, and Doug Zehr with the Lowville Farmers Co-Op.

Farmers interested in applying the biocontrol nematodes for corn rootworm management may be eligible to participate in a Northeast Sustainable Agriculture and Research Education grant for the next three years to receive reduced biocontrol nematode pricing on a limited basis. For more information, contact Mike Hunter at 315-788-8450 or Tony Testa at 607-591-1493 for details.

Research has shown that a single application of the biocontrol nematodes can persist for 10 years across an alfalfa-corn rotation and that the nematode population was higher after four years of corn than in alfalfa before the corn planting.

Since 2010, more than 20,000 acres of alfalfa in Northern New York have received a biocontrol nematode application.  At least one new nematode-rearing business enterprise was started as a result of the NNYADP-funded research and technical training on the biocontrol nematodes. Custom applicators in the region have also provided nematode application services.

The Shields Lab is available to work with anyone who would like to develop a business enterprise to supply nematodes to custom applicators or to farmers who wish to apply them on their own.

The NNYADP website at www.nnyagdev.org includes Shields’ research reports on development of the alfalfa snout beetle biocontrol solution, the results of NNYADP-funded field and laboratory trials developing alfalfa snout beetle-resistant alfalfa varieties, and more recent studies of the impact of the biocontrol nematodes on corn rootworm and on applying the biocontrol nematodes in liquid manure.

Funding for the Northern New York Agricultural Development Program is supported by the New York State Senate and administered by the New York State Department of Agriculture and Markets.

Print Friendly, PDF & Email

Fall is the Time to Test for Soybean Cyst Nematode

Jaime Cummings, NYS IPM Program

Since its first confirmation in Cayuga County in 2016, New York soybean farmers have a new pest to be leery of, the Soybean Cyst Nematode (SCN).  SCN is considered the number one pest of soybeans globally, causing yield losses of approximately 100 million bushels annually across the U.S. alone.  These high yield losses are due to the rapid and highly productive life cycle of SCN (Fig. 1).  It’s true that those yield loss estimates don’t relate directly to our current situation in NY at the moment, but the best way to avoid these potential losses is to gain a better understanding of SCN populations statewide.

Figure 1. How SCN populations increase exponentially in a field. (Image courtesy of SCN Coalition website)

Fortunately, a network of pathologists and nematologists across the US who have been dealing with this potentially devastating pest for years have come together to fight as a unified front as an organization called the SCN Coalition.  Their website is full of useful information, resources, recommendations and much more, including proper sampling techniques, which labs you can send soil samples to for testing, and best management practices.

We highly recommend that NY soybean growers take a proactive approach at identifying and managing SCN while populations are low.  And, now is the best time to get out and take your soil samples for SCN testing.  Just because it’s only been officially confirmed in one county doesn’t mean it isn’t more widespread, or possibly even in your own fields.  And, once established in a field, management can be tricky because this pest has been developing races that have been overcoming the most widely deployed sources of genetic resistance incorporated into the majority of the commercial soybean varieties.  Check out this short video for more information on the SCN resistance issue.

Since SCN populations are likely low in fields across NY at this time, it’s important to focus your soil sampling for testing on fields with a long history of soybean production, and in areas of those fields that are most likely to harbor populations.  The most high risk areas for finding SCN in your fields include compacted areas such as entryways, areas that are frequently flooded, areas where you have found sudden death syndrome, sections with high pH, or areas of fields that you notice are consistently low-yielding (Fig. 2).  Despite your focused soil sampling efforts, you may get zeros as your test results.  This doesn’t necessarily mean that your fields are SCN-free though, because it can be challenging to detect SCN at low population levels due to the way cysts are distributed in the soil (Fig. 3).  Zeros are good, but it doesn’t mean you shouldn’t continue to sample annually.

Figure 2. High-risk areas in fields where soil sampling should be focused when attempting to confirm presence of SCN. (Image courtesy of SCN Coalition website)
Figure 3. Detecting low population levels of SCN can be challenging. (Image courtesy of SCN Coalition website)

Although SCN management is getting more challenging as resistance is breaking down, we recommend an integrated management approach.  This would involve annual testing of your fields to know your numbers (and eventually your races of SCN), rotating SCN resistance sources in your soybean varieties, crop rotation with non-host crops (corn, wheat), and utilization of nematicidal seed treatments (Fig. 4).

Figure 4. Take an integrated approach to managing SCN once detected. (Image courtesy of SCN Coalition website)

Now is the ideal time for you to collect soil samples for SCN testing.  Focus on high-risk areas outlined above, and collect 15-20 1-inch-diameter core samples, 8 inches deep from within soybean rows near the roots.  Mix the cores well and send to an SCN testing lab, following specific packaging instructions from individual facilities.  Many options are available for SCN testing facilities, including public and private labs.  Testing prices on average are around $25-$28 per sample at most SCN testing labs.  The Cornell plant disease diagnostic clinic offers this service, or you may consider one of the most highly recommended facilities which focus entirely on SCN, such as Midwest Laboratories, SCN Diagnostics, or University of Illinois Plant Clinic.  Most private and public testing facilities accept out of state samples.

For anyone interested in further, in-depth information on SCN, please check out this hour-long training webinar on the biology and management of SCN from Iowa State Nematologist Greg Tylka.

Print Friendly, PDF & Email

NYS IPM Weekly Field Crops Pest Report – August 24, 2018

Corn Silage Harvest Quickly Approaching

by Joe Lawrence – PRO-DAIRY

As always this crop season has brought unique opportunities and challenges for corn silage.  It may be helpful to compare and contrast 2018 with the last two years as we look at the potential timing of this year’s harvest.

For much of the state, 2016 was excessively dry to drought conditions through mid-August. However, where the crop survived to see the rains in late August it bounced back a bit, though some yield was already lost. Late summer saw some more normal rain events and a continuation of above average growing degree day (GDD) accumulation. Typically, we would expect the heat to lead to earlier maturity of the corn crop. However, with each shot of rain, the stressed crop seemed to re-hydrate as it attempted to finish ear development, which resulted in an extended dry down period and later than expected harvest.

We don’t need a reminder that the 2017 season was wet and cool from beginning to end. Late planting and below average GDD accumulation delayed harvest well into the fall and some of the crop received a killing frost prior to maturity. Also of note is that GDD accumulation slows down considerably in mid-September, so as the crop neared maturity last year it did so at a much slower pace than it is likely to this year, when it will be at this stage in mid-August to early September.

This season brought excessively dry and drought conditions for much of the state. However, relief from the drought came three to four weeks earlier than it did in 2016, aiding in pollination and more normal late season development of the crop.  Therefore, we should not expect the extended dry down period that was observed in many areas in 2016.

In terms of GDD accumulation, 2018 was above average in May, below average in June and above average in July and August (to date). While the slight deficit in June may have led to a slower start for corn planted in late May, that deficit was erased by the end of July as we continue to accumulate above average heat units.

GDD accumulation for corn planted in early May is even further above average and current forecasts suggest that most areas of the state will end August with GDD accumulation (since May 1) between 125 and 150 GDD’s above average. To translate that into calendar days, based on average GDD accumulation in late August and early September, this puts use seven to 10 calendars ahead of average since May 1.

Past research by Bill Cox at the Cornell Aurora Research Farm provides approximate GDD accumulation needed from silking to the crop reaching 32 percent dry matter (DM) for 96 to 115 day relative maturity (RM) corn (Table 1).  Based on this we would expect that corn below 96 day RM will take 750 GDD or slightly less.

Currently 32 percent DM is considered on the low end of desired harvest DM, target DM ranges are found in Table 2. Therefore, the accumulation of 750 GDD’s after silking represents a good time to start measuring whole plant dry matters.

Using our Corn Silage Hybrid Evaluation program projected crop progress is shown in Table 3a and 3b.

The dry down rate of corn in the field as it nears silage harvest is largely dependent on the weather and health of the crop. A general range is 0.4 to 0.7 percentage points per day.  Using 35 percent DM as a target for harvest, you could expect the crop to reach this four to seven days after it reaches 32 percent DM.

Also, consider that while the crop looks like it will finish fairly strong and produce a good ear, it is not likely to recover the lost yield from early season stressors. This combined with depressed hay crop yields in many areas should be taken into consideration when projecting forage needs for the coming year.

References
Cox, William. 2008. Timing Corn Silage Harvest. Cornell University What’s Cropping Up? Newsletter. Vol. 18, No. 4.

For More Information

Print Friendly, PDF & Email

Fusarium head blight commentary on winter barley and wheat

Gary Bergstrom, Extension Plant Pathologist, Cornell University
This is a critical week for management of Fusarium head blight (FHB) in winter malting barley.  Some winter barley fields in New York are fully headed now and many more will head out this later week.  Even though we have had frequent rains, the Fusarium Risk Assessment Map (http://www.wheatscab.psu.edu/riskTool.html) shows mostly low risk of Fusarium infection in New York because temperatures have been considered too low for spore production in many areas. A moderate to high risk of FHB is indicated for areas of the Southern Tier, southern Hudson Valley, and Long Island.  Maximal suppression of FHB and grain contamination by deoxynivalenol (DON) mycotoxin results when fully emerged heads of winter malting barley are sprayed with full label rates of Caramba or Prosaro fungicides. A heads emerged spray with these triazole fungicides also helps protect upper leaves against fungal leaf blotches, powdery mildew, and rust.  Foliar sprays of Caramba or Prosaro up to seven days after head emergence may still result in significant FHB and DON suppression.   Fungicide products containing strobilurins should not be applied to headed wheat or barley as they may result in increased levels of DON in grain.
Winter wheat is generally a week or more behind in development from winter barley planted on the same fall date.  Winter wheat in New York varies from stem elongation to flag leaf visible stages.  We should reach the critical fungicide application window for winter wheat over the next two weeks.  The triazole products Caramba and Prosaro are the most effective fungicides for suppression of FHB and DON contamination when applied at flowering (emergence of anthers on heads).  A flowering application of triazole fungicide should be based on Fusarium head blight (FHB) risk as well as the risks of powdery mildew, rusts, and fungal leaf blotches in the upper canopy based on scouting of individual fields.  There is an application window of approximately 7 days from the beginning of flowering in which reasonable FHB suppression can be expected.   Check the Fusarium Risk Assessment Tool (http://www.wheatscab.psu.edu/) and your local weather forecast frequently as your winter wheat crop approaches heading and flowering.
Print Friendly, PDF & Email