CMEG Crop Management Extension Group

Field Crop News

Website Address: http://fcn.agronomy.psu.edu/

June 9, 2009    Vol. 09:14

IN THIS ISSUE:

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

So far this growing season (since April 1), the southern and eastern two—thirds of the state has received sufficient to above normal rainfall. The northwestern third of the Commonwealth are deficient, but most places are less than 2 inches below normal (or about 2 weeks behind in seasonal rainfall). However, across much of New York, there are the seeds of drought as most of the upstate region has had less than 50% of the expected moisture since early April. Wednesday will start as a more comfortable and drier day across Pennsylvania. More humid air will return in the western counties during the afternoon and across the region at night. The period from late afternoon Wednesday until mid-morning on Friday will be unsettled with sticky conditions along with clusters of thundershowers. Most sections will receive between 0.20–0.70" and some parts of southeastern Pennsylvania may measure up to 2 inches.

A relatively dry spell will start on Friday and likely continue into late Monday or Tuesday. About a third of the state may notice a brief shower on Saturday. Temperatures will be near or slightly below seasonal levels. A burgeoning heat wave in the southern Plains and lower Mississippi Valley later next week, may trigger some thunderstorms as sultry air approaches the Mid—Atlantic States.

There are still indications that a heat wave is likely (more than 3 days above 90°F) during the third or early in the fourth week of June and it is possible that this may be the hottest weather of the year in some places. Odds still favor a bit above average temperatures for June. A notable wet period is possible in the latter half of July or August. The hurricane season should have most of the storms develop after August 20. Very cool conditions are likely during September, with perhaps an unusually early end to the growing season in the northern counties.

Time to Monitor Diseases in Wheat and Barley — Greg Roth, Grain Crop Management and Delbert Voight, Interim Grain Crop Specialist

The recent wet weather appears to be increasing the level of foliar diseases on barley and wheat. Our barley trials are rapidly advancing in maturity and are currently in the soft dough stage in Lancaster. Leaf rust is widespread in the trial, probably due to spores deposited in recent showers. Leaf rust and Stagonospora leaf and glume blotch are our most common foliar diseases in wheat and are starting to appear in wheat, especially in crops that have not been treated with fungicides. Often the rust comes in late and its impact on yield is questionable. Stagonospora is favored by almost exactly the kind of conditions we have just experienced: wet weather from mid-May through June and temperatures ranging between 68 degrees and 80 degrees Fahrenheit. The disease is characterized by lens—shaped, chocolate-brown lesions with yellow borders. The glume blotch is characterized by brown to tan lesions on glumes and awns. For more details see this factsheet: http://ohioline.osu.edu/ac-fact/0002.html Severe infestations of Stagonospora on the upper two leaves of wheat can result in reduced test weight.

Evidence of head scab will be appearing soon. The first symptoms are a tan or brown discoloration of the base of florets on the wheat head, progressing to bleached florets and heads. http://www.wheatscab.psu.edu/PDF/Fusarium_Head_Blight_.pdf. Now is the time to start assessing the incidence in our fields and noting the effectiveness of fungicides or differences that exist among wheat varieties in scab resistance. Ohio State has done a good job of rating the scab resistance of wheat varieties and noting the variation possible in current genetics: http://oardc.osu.edu/wheattrials/regions.asp?year=2008#three. Scouting will also prepare us to explore harvesting and marketing options. We will be conducting a survey as well and will share that data in an upcoming newsletter.

Reports from other states like Virginia, North Carolina, Kentucky and the Eastern Shore of Maryland report significant scab incidence in their crops. These were summarized in a recent press release from the Wheat and Barley Scab initiative. http://www.scabusa.org/pdfs/uswbsi_fhb-update_06-09.pdf The risk potential for our crop is a bit uncertain…in many areas of the southeastern part of the state the online scab risk model indicated a low risk for wheat during the flowering period, but for many central counties, there were areas of moderate risk during flowering and some areas of high risk, especially for late planted wheat that has just flowered: http://www.wheatscab.psu.edu/riskTool_2009.html

Forage Update — Paul H. Craig, Dauphin County Extension

Challenges caused by weather patterns have forced hay producers to “multi-task” to maximum at the present. Stands of some excellent Timothy are primed for harvest. Second cuttings of alfalfa are getting close. New alfalfa stands are ready to go now also and there are still, more than a fair amount, of old and getting older, orchardgrass stands. In southern PA the weather has not cooperated except for those 2, week-long, harvest windows in May. In between and since then forage harvest has stopped.

Question 1? With limited harvest time should I get the old orchardgrass or turn focus on Timothy, and then go to alfalfa. Focus of forage harvest should be to maximize quality and value. The orchardgrass has lost its greatest value and while getting more mature daily it will not decrease in value as greatly as later maturing Timothy. Those old orchardgrass stands would be better used in an AgBag or some other type of wet, storage structure where separation can be managed. Watch moisture levels and adding a grass-based inoculant will be advantageous. Balage is also a consideration. The goal would be to get it harvested and into the fermentation process rapidly.

Question 2? What is the best way to manage a swath under these wet soil conditions, wide or narrow/ted? There are 2 schools of thought regarding swath management. One wants a narrow swath to allow sunlight and air to dry soil and then ted. Another school says to forget the soil condition and cut as wide as possible, get rapid dry down and then merge and chop or perhaps condition, then ted and rake for dry hay. I doubt there is one and only one way to skin a cat.

Timeliness becomes an issue when forage would be put in a narrow swath. The quicker plant material is distributed and exposed to sunlight the faster, drying will occur. Haylage producers will mow forage and not use conditioning rolls and lay forage in wide swaths—frequently called wide swathing. Within hours, for later cuts, this forage will drop to ideal levels for haylage harvest. If dry hay is targeted then conditioning is needed to improve whole plant moisture drops to hay harvest levels.

Question 3? This question relates to harvesting “tough” hay. With wet soils, extremely heavy, old first cutting stands may prove challenging to get dry in between the storms, is propionic acid an option? Marvin Hall, in an earlier Field Crop New, wrote that hay preservatives are an option to reduce risk of mold and fire when baling hay slightly above the recommended moisture level. The most common hay preservatives are organic acid and the most common and most effective of the organic acids has been propionic acid. Some commercial products also contain a small percentage of acetic acid. However, acetic acid is less effective as a hay preservative.

Not all organic acids or commercial organic acid products are created equal. Product effectiveness, cost per pound of acid, or concentration of active ingredient varies among the different products sold. Some products only contain 15% propionic acid. Typically, the most cost-effective products are those with the highest concentration of propionic acid.

Bale moisture is the primary factor determining effective application rates. An easy method to determine effective preservation rate (actual pounds of propionic acid per dry matter ton) is to take the moisture percentage of the hay and subtract 10. For example, hay baled at 25% moisture requires about 15 pounds of acid per ton of dry matter (25% moisture — 10 = 15 lbs acid required per ton).

Recommended application rates assume a hay product that is uniform in moisture. If some bales or parts of bales are significantly higher in moisture than the field average, application rates will need to be adjusted upward to insure effective preservation of the entire hay lot.

To be effective, preservative must be uniformly distributed on the hay crop as it enters the baling chamber. This often means that multiple application nozzles are needed on the baler. Some hay producers dilute the propionic acid product with water and then increase flow rates through the application equipment to improve coverage on the crop.

Unfortunately, the preservation effect initially gained from using organic acids is not long-term in nature. Acids lower pH of the forage and limit microbial growth. Acids do not dry out bales. With time, the acid will dissipate from the hay. This can result in mold formation after 4 to 6 months of storage if enough moisture is still present to support such growth. Using an organic acid preservative will not necessarily improve storage characteristics such as long-term dry matter loss or hay color.

Finally, Question 4? What about the risk of Hot Hay? Due to higher moisture levels bacteria, fungi and yeasts can continue to multiply on harvested forages. Until moistures drop to 15% or less significant development can occur. This growth leads to heat and in some hay mows “sweating”. If this heat is retained within a pile or hay mow it can reach spontaneous combustion temperatures. Any suspected, hay harvests should be monitored closely. A thermometer can be put on a string and dropped down a pipe driven into hay piles to monitor temperatures. Many fire companies have temperature reading monitors if concerns are raised. When temperatures approach 150 F degrees continuous 2 times/day monitoring is required. At 160 to 175 F degrees there is a high risk for ignition and a fire company should be on stand by and transfer of the hay is needed.

True Armyworm a Risk to Corn Fields — John Tooker, PSU Entomology Specialist

Reports indicate that true armyworm caterpillars are active and causing damage in corn in southeastern and western Pennsylvania. These first reports of activity are likely to be the leading edge of armyworm reports, so it would be wise to keep an eye on at-risk corn fields. True armyworm typically causes problems in reduced tillage or no-till systems, particularly when corn is planted after a small-grain cover crop or when corn is adjacent to recently harvested small grains. Adult moths fly into Pennsylvania after overwintering in the soil in states to our south. Females lay their eggs on weeds and/or grasses along field margins or on small grains and move to corn when weeds or grain cover crops are killed with herbicides.

Armyworm can occasionally cause problems feeding on small grains sowed for harvest, but tend to be problematic more often in corn when small grains are harvested for forage because armyworms move to young corn plants. Armyworms tend to feed at night along the margins of corn leaves, avoiding midribs. During the day, larvae hide in leaf sheaths or in the soil or leaf litter. Armyworms can warrant treatment should infestations reach 25% of plants in a field. See Penn State Agronomy Guide for treatment options.

Corn Sidedress Nitrogen Management Tips — Douglas Beegle, Soil Fertility Specialist

One of the most important principles of nitrogen (N) management is to apply N as close to the time of crop need as is practical. Nitrogen is very dynamic and the longer it is in the soil before the crop uses it, the more it will be lost. The greatest losses will occur in very well drained soils and in very poorly drained soils during times of high rainfall. Delaying most or all of the N application as long as practical, especially in these soil and weather situations will reduce N loss. Applying a majority or all of the N as a sidedressing is usually the most efficient method. Also, delaying N applications allows the grower to better assess the crop yield potential 4 to 6 weeks into the season and select a more appropriate N rate than is possible preseason.

In situations where there is no manure in the system, one-third to one-half of the N should have been applied around planting time and the balance sidedressed. In systems with manure, any additional N that is required beyond what the manure is supplying and a small amount in the starter, can be applied as a sidedressing. In these situations delaying the application also allows use of the Pre-sidedress Soil Nitrate Test (PSNT) (Agronomy Facts 17) or Chlorophyll Meter Tests (Agronomy Facts 53) to evaluate whether the manure is supplying adequate N to meet the needs of the crop and thus reduce the uncertainty that goes along with deciding if additional N is needed in manured systems. Both tests require testing around V6, when the corn is about 12” tall and if additional N is recommended, it must be sidedressed. It is very important to remember that the Chlorophyll Meter Test cannot be used if more than 15 lb fertilizer N/A was applied at or near planting.

There are a number of ways that corn can be sidedressed. The most common is to dribble UAN solution on the soil surface between the corn rows using drop tubes or hoses over the nozzles. Dribbling reduces plant injury and also reduces volatilization losses compared to broadcast applications. Dribbling between every row is preferred, but N can be dribbled between every other row if it is precisely placed in the middle between the rows. Sprayers with 20" nozzle spacing with drop tubes can also be used but expect a little more injury because sometimes the tube will be on the row. The other common method that can be effective is to broadcast urea over the top of the corn. There is a greater potential for injury with this method, however the injury that does occur rarely hurts yield. The best advice with this method is to do it and then don't look at the field for a week or so, after that it will look fine. Also, there is usually greater volatilization loss with broadcast urea. These problems are minimized if it rains soon after the application. It also helps to minimize volatilization if the urea is broadcast on a dry soil surface (hopefully just before it rains). Losses are greatest if the urea is broadcast on a moist soil surface after a rain when evaporation is high. A urease inhibitor can also help reduce volatilization losses from surface applied urea.

Cultivation or knifing the N between the rows minimizes the volatilization losses of N. However, the benefits compared to dribbling are often not enough to justify the extra expense of cultivation or injection based on the N alone. Obviously, there may be other benefits to cultivation in certain systems that may make this more economical. Thus, if you are cultivating anyway put the N on right before cultivation.

Finally, don’t wait too long. Make sure that you have time to apply the N before the corn is too tall. Start early enough to allow for wet weather that may limit the days that you or your custom applicator has to do the sidedressing.

Watch for K Deficiency — Doug Beegle, Soil Fertility Specialist

With high fertilizer K prices this year, many farmers did not apply the recommended potash or applied a reduced rate. Now as the crops are developing, potassium deficiency is showing up in some of these fields. Potassium deficiency symptoms occur on the edges of the lower leaves on most plants. In corn and soybeans, the symptoms start as yellowing on the edges of the lower leaves. Eventually the edges of the leaves will turn brown and the whole leaf may die. In alfalfa, the symptoms start as small spots on the edges of the leaves which eventually grow together and end up as yellow and finally brown leaf edges. As the deficiency becomes more severe, the symptoms will progress higher up the plant.

Potassium deficiency on corn, soybeans and alfalfa

Even with high fertilizer prices we need to make sure we are meeting the nutrient needs of our crops if we want optimum production. Plants take up about the same amount of K as they do N. Also note that removal of K depends on how the crop is harvested. In spite of the large uptake of K, relatively small amounts of K are removed in grain. However, when the whole plant is harvested a very large amount of K is removed. For example corn grain at 150 bu/A removes 45 lb K2O/A, but if the same corn crop is harvested for silage, the removal is 275 lb K2O/A. This can make a big difference in the K levels in different field on a farm. Many fields that get a lot of manure in the corn part of the rotation have good reserves of potassium. Fields receiving little manure or that are late in the forage rotation can have fairly low soil test levels and fields coming out of forages often are lowest in K.

As always, begin with a soil test. Even though it may be the last minute, the Ag Analytical Services Lab at Penn State normally has about 2 day turn—around with soil samples. So if you overnight your samples to the lab and have signed up for free web access to your results you can still have your results in time to make topdressing decisions. Other labs have similar service. For forage crops low in K, fertilize between cuttings. If you have a forage field with K deficiency, it is especially important to correct this before going into the winter. Potassium is very important for winter survival. For corn or soybeans, if the soil test is low or the crop is showing deficiency symptoms, topdressing with potash will be beneficial. Because K is not very mobile, this topdressing will not usually give as good a result as if the K was applied preplant but it will help.

Horseweed/Marestail Escaping Control — Bill Curran, PSU Weed Specialist

Glyphosate resistant horseweed is escaping some burndown programs in no—till soybean and can be quite difficult to control with post emergence herbicides. Horseweed is most easily controlled when small in the late fall or early spring. As this weed becomes larger, it becomes much more difficult to control. Many populations particularly in the Southeast are resistant to glyphosate and some populations are also resistant to the ALS inhibitors (Classic, FirstRate, etc.). The most effective and economical treatments include 2,4–D ester plus glyphosate prior to soybean planting. Application in the fall or early spring can be quite effective and the use of soil residual herbicides can reduce or prevent emergence of horseweed after crop planting. A primary goal in managing horseweed in no—till soybean should be effective control of emerged plants prior to planting. This strategy will reduce the need for post emergence herbicides which can be limited in effectiveness and exert further selection for herbicide resistance in the population.

The herbicide FirstRate (cloransulam) has become more widely used in our region both prior to soybean emergence (also found in the premixes Gangster, Sonic, and Valor XLT) and post emergence in combination with glyphosate. FirstRate should be applied at 0.3 oz/acre for control/suppression of small (less than 6 inches tall) horseweed and it will not control ALS resistant populations. I have heard from several sources that FirstRate is in short supply in the region and suitable alternatives are few. Classic has activity on horseweed (suppression), but again the weeds must be small and not ALS resistant. You can apply up to 0.75 oz Classic per acre alone or up to 0.33 oz/acre in combination with glyphosate. Include appropriate adjuvants in the spray tank. Synchrony XP is a mixture of Classic plus Harmony GT and also has activity on small horseweed (suppression). Classic is the primary active ingredient against horseweed in this mixture. Synchrony can be applied alone or tank mixed with glyphosate at 0.375 oz/acre in non STS soybeans to broaden the spectrum of control. The 0.375 oz rate is equivalent to 0.32 oz Classic plus 0.03 oz Harmony GT 75DF. Again, include appropriate adjuvants in the spray tank. Remember that both Classic and Harmony GT (and Synchrony) can cause stunting and chlorosis in soybeans. Application of greater than 0.375 oz/acre Synchrony to soybean varieties not designated as STS will result in severe crop injury and potential yield loss.

Other herbicides including Pursuit, Raptor, Basagran, 2,4–DB, Cobra, Reflex etc. are not effective for post emergence horseweed control. When in a pinch, Dr. Mark VanGessel at the University of Delaware found that the best option for rescue is glyphosate. His work has shown up to 60% stunting of glyphosate—resistant horseweed with a post glyphosate application which is sometimes enough to slow them down and give the soybeans a competitive advantage. He has not found any suitable alternatives that provide greater than 60% suppression in soybean when horseweed escaped earlier control attempts and is heading above the soybean canopy.

Late Planting of Corn and Soybeans — Delbert G. Voight, Jr., Interim Grain Crop Specialist

As we move out of another rainy spell there are some considerations for those that choose to plant corn or soybeans. There are also ramifications to crop insurance plans as well as we near the latest coverage by planting date. Be sure to check with your agent. Another note is to consider the recrop restrictions and make adjustments for products that may limit re-cropping next spring.

Table 1
Maturity Rating (Days) Estimated GDD requirement (Planting-Phys.Maturity)
75–80 1800–1900
80–85 1900–2000
85–90 2000–2100
90–95 2100–2200
95–100 2200–2300
100–105 2300–2400
105–110 2400–2500
110–115 2500–2600
115–120 2600–2700
Table 2
Date Full yield potential (percent)
Developed from Ohio, Indiana, Minnesota, and Pennsylvania data
May 10 100
May 20 98
May 30 95
June 10 88
June 20 76
Table 3
Row width (inches) Number of seeds planted/foot row¹ Number of plants/25 feet row
Full Season² Double Crop Full Season Double Crop
¹Based on 85% germination (full season = 176,000 seed/A, double crop = 235,000/A.
²Full season = 150,000 plants/A; double crop = 200,000 plants/A
* Double-crop beans should be planted in row widths of 15 inches or closer.
7 2.5 3.5 50 65
10 3.5 4.5 70 95
14 5.0 6.5 100 135
15 5.0 6.5 110 145
21 7.0 * 150  
24 8.0 * 170  
30 10.0 * 215  

Upcoming Events

Weed Suppression and Biodiversity through Cover Crops and Field Edge Plants Field Day—Register Today

Agronomy Research Farm, Russell E. Larson Agricultural Research Center—Pennsylvania Furnace, Centre County

Wednesday, June 17 - 9:00am–4:00pm

$15 PASA Members, $25 all others. Lunch will be provided.

Register On-Line through PASA.

This field day is a collaboration between PASA and Penn State. This field day will focus on managing cover crops and field edge plants for weed suppression and biodiversity gains. Starting promptly at 9:00 am, the morning session will focus on integrating cover crops, cultural controls, and shallow tillage for weed control in grain production systems. Farmers and ag professionals interested in reducing tillage and improving soil quality will learn about cover crops and tools for effective weed management. Come get a first hand look at a cover crop roller and cover crop mulches, a high residue rotary hoe, a high residue inter-row cultivator, and other tools for enhancing weed management in high residue situations.

Starting at 1 pm, farmers, gardeners, and ag professionals will evaluate and gain a better understanding of how crops and field edge vegetation influence pollinators and biological control of insect pests. Learn to assess the effects of different plants in agricultural landscapes, and how to tailor plantings to enhance beneficial ecosystem processes.

Come for the morning, afternoon, or both and join us for lunch at 12 noon. Contact PASA (814-349-9856) or Bill Curran at Penn State (wcurran@psu.edu or 814-863-1014) for additional information.

Register for the Agronomic Weed Control Twilight Tour at Landisville, June 29, 2009

The Second Annual Twilight Weed Tour, Southeast Research and Extension Center (Landisville). Will be held begin at 4:30 pm on June 29, 2009. This is the evening before the “Farming for Success” Field Day on June 30. We will tour the weed control plots from 5:00 to 7:00 pm. You will have an opportunity to examine corn and soybean weed control trials including some cover crop control studies. The format of the program will allow time to view the various treatments /studies and discuss the results with those in attendance. We will finish the evening socializing with one another and enjoying a hot meal.

This event costs $25 per person and includes dinner and educational materials. To register, fill out and send in the form before June 24. Pesticide and CCA credits will be offered. Please contact John Bray or Del Voight at 717-270-4391 in advance if you need additional information.

Register Now for the Rock Springs Agronomy Weed Tour — July 9, 2009

Attend the Annual Agronomic Weed Control Research Tour at Penn State — July 9, 2009 at the Penn State Agronomy Research Farm, Rock Springs, PA (Meet at the Agronomy Farm, Rock Springs, Rt. 45 west of State College, enter Gate D). A number of experiments will be showcased and available for viewing including new corn, soybean, sweet corn, and potato weed control trials. New herbicides include Balance Flexx, the Kixor products (Sharpen, Integrity, and Optill), Corvus, Capreno, Envive, Halex GT, Ignite, Authority Assist and First, Sonic, and Valor XLT to name a few. You will have the opportunity to see Dupont’s GAT corn and potential programs for that. In addition see how the roller/crimper is working on cereal rye and hairy vetch in reduced and no herbicide systems.

Pest Management CCA CEU’s and Pesticide Recertification Credits will be available.

Agenda:

8:30–9:00 am - Registration
9:00 am–12:00 noon - Tour
12:00 noon–1:00 pm - Catered lunch

PreRegistration for this event will be $20.00 and includes lunch and a tour book. Walk-in Registration the day of the event will be $25.00. To register by credit card, go to http://guest.cvent.com/i.aspx?5S,M3,ea617e7d-a373-4a32-8029-ff1a08fb0b49 or contact Lisa Crytser in the Dept. of Crop and Soil Sciences at lac8@psu.edu or 814-865-2543.

Contributors: State Specialists: Marvin Hall, Doug Beegle, Greg Roth, Bill Curran, John Tooker, Charles White,and Ron Hoover. Contributors: Extension Educators: Paul Craig (Dauphin), Kevin Fry (Armstrong), Del Voight (Lebanon), Tianna DuPont (Lehigh), H. Grant Troop (Lebanon), Mark Madden (Sullivan), Jeff Graybill (Lancaster), Joel Hunter (Crawford); Jonathon Rotz (Cumberland), Craig Williams (Tioga).

Editor:Paul H. Craig

Upcoming Events

Real time pest and heat unit activity: http://agsci.psu.edu/news/spotlight/pa-pipe

Calendar of Events: http://www.events.psu.edu/cgi-bin/cal/webevent.cgi?cmd=opencal&cal=cal209&

If you have any questions or would like to suggest a topic, please contact your local Extension Educator.

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If you have problems subscribing or wish to cancel your subscription, please contact Lisa Crytser by e-mail at lac8@psu.edu or by phone at 814-865-2543.

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