CMEG Crop Management Extension Group

Field Crop News

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

June 13, 2006    Vol. 06:08

IN THIS ISSUE:

Weather Outlook — Paul Knight

Enjoy the cool weather since there is another hot, humid episode coming. The cool conditions will persist until Friday with an opportunity for some showers on Wednesday, mainly in the afternoon as a fresh surge of chilly air aloft reaches Pennsylvania. Rainfall will be generally less than a quarter of an inch, though the remnants of Alberto will brush the Northeast Coast with gusty winds and some showers, perhaps even in eastern Pennsylvania. A few readings below 40F are possible in northern sections early Friday before a steady warming trend commences. The weekend will see temperatures rise above seasonal levels (into the 80’s and low 90’s by Sunday) and the humidity should reach uncomfortable values too. A scattering of afternoon and evening thundershowers are expected later Sunday, though more likely later Monday and Tuesday. The heat should persist until mid-week.

Harvest Timeliness and Wheat Quality — Greg Roth

Wheat harvest is rapidly approaching with a crop that is in generally good condition with reasonable prices. Planning now for a timely harvest can capitalize on this situation and maximize returns from this years crop. A recent article by Farrer et al. in Agronomy Journal from North Carolina State University described some of the yield and quality losses that can occur if harvest is delayed.

The researchers found that delaying harvest by 8 to 19 days can result in lower yields, lower test weights, higher DON levels, lower test weights and lower falling numbers. Yields decreased up to nearly 20% in one case where harvest was delayed by 8 days. Harvest losses were greatest in environments when precipitation was low between the first and second harvest and shattering was increased. Test weights decreased by 1% to 14%, with the largest test weight decreases occurring in environments where precipitation was above average following the first harvest date and were probably associated with rewetting and drying of the grain.

At three of the five trials in this study where DON data was collected, delaying harvest caused the DON levels to increase. In two of the trials, delaying caused the DON level to increase above 2 ppm, a standard for many mills. These differences were not related to weather conditions at the study sites.

At one of the locations, delaying harvest caused a significant decline in the falling number. The falling number is an indication of the α amylase activity, which is usually associated with sprouting. Falling number is a measure of the viscosity of a flour/water suspension and is measured in the number of seconds it take for a ball on a stirrer to sink through this standard suspension. A lower number is an indication of a less viscous fluid and more starch breakdown into sugars. At one location in this study, delaying harvest 15 days reduced the falling number from 318 to 170 seconds. At the other locations, delaying harvest had no effect. Reduced falling numbers are common when the wheat sprouts, but in this case no sprouting was visible but the crop was exposed to a combination of high temperatures and precipitation which may have caused the sprouting process to start and the falling number to decline. Increasingly, mills and grain brokers are looking at the falling number.

Conditions in North Carolina could be more severe than what we encounter in Pennsylvania, but I suspect some of the test weight, DON and falling number issues that occur in our wheat result from delayed harvests. Consider doing what you can to start and finish wheat harvest this year as rapidly as possible to maintain the quality of the grain. Some producers have been opting to harvest the wheat early and dry it to maintain grain quality. This North Carolina study suggests that this may pay in some environments.

Check Moisture before Baling Hay — Marvin Hall

Baling hay at the optimum moisture content can be a tricky business, which often involves some guesswork and cooperation from the weather. Baling at moisture levels above the optimum will cause heating and spoilage of the hay. Conversely, baling at moisture levels below the optimum causes excessive leaf loss which translates into lower quality hay. The optimum moisture for baling is not a constant and depends on the bale size being used.

Moisture for small rectangular bales should be no higher than 20%, unless a preservative is used. The upper moisture limit in large bales, both round and rectangular, is about 16% to avoid excessive heating during storage. If large round bales are stored outside and uncovered, moisture content at baling can be up to 20%.

Determining moisture content can be done with a microwave oven or Koster moisture tester before baling, or an electronic moisture meter at baling. When using an electronic moisture meter, probe from the end of rectangular bales and through the rounded diameter of round bales. At least five probes of each bale should be taken and the readings should be averaged. If readings vary more than three percentage points, more probes should be taken and the average re-calculated.

Many factors can affect a meter's accuracy such as bale density. Tightly packed bales will give the most accurate readings. The use of chemical preservatives is another factor that may affect the accuracy of electronic moisture meters. Some chemicals such as propionic acid can increase readings as much as four percentage points. If preservatives are used and the instruction manual for the moisture meter does not provide information about effects of chemicals on meter performance, contact the manufacturer for additional information.

Monitoring Baled Hay — Marvin Hall

With the rains Pennsylvania has been getting, there has been some hay put up a little on the wet side without preservatives. Combine that with high humidity weather for the past week and you've got a situation that can lead to a couple of different problems.

First, the excess moisture creates an environment inside the bale for fungi and bacteria to grow. These microbes produce excessive heat which causes the hay to get very hot. This heating process leads to the breakdown of protein and thus reduces the quality of the hay. Molds and fungus that are produced are in fact sometimes harmful to the animals that are being fed this heat damaged hay and sometimes they can be fatal especially if fed to equine.

Another problem arising from the baling of high moisture hay is barn fires. If hay with too high of moisture is stored inside, a fire could ensue within a week to six weeks of storage. If you are the least bit concerned that you baled your hay with too high a moisture (20% or greater for small rectangular bales and 16% for large rectangular or round bales), it is a good idea to monitor the temperatures inside the storage facility.

Good ventilation is extremely important in any hay storage structure no matter what the condition of your hay is when storing.

Frequency of temperature monitoring in hay
Keep monitoring temperatures until the hay is below 120 degrees Fahrenheit.
120 degrees or below no concern
130 to 140 monitor daily
140 to 150 monitor twice daily
150 to 160 monitor every two hours (begin moving hay out of structure)
160 to 175 call fire department, have them onsite before moving hay

Hay preservatives are an option to reduce risk of mold and fire when baling hay slightly above the recommended moisture level. The most commonly used hay preservatives are organic acids, 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.

Potato Leafhoppers Are Back in the State — Kevin Fry

Potato Leafhoppers have begun to reach threshold numbers throughout Pennsylvania. It is time to start sweeping for leafhoppers on a routine basis. If a cutting has been recently made, wait until regrowth reaches a height of 2–3 inches. It will also be very important to keep an eye on new seedings as second cuttings are being made. Leafhoppers can migrate from harvested fields to the new seedings and reach threshold numbers quickly and cause significant damage. Early harvest of these fields may be desirable to limit further reduction of quality. One warning for early harvested new seedings, if herbicides were used, you will need to check for harvest and feeding restrictions. For example, Butyrac (2,4–DB) has a 60 day grazing and feeding restriction for new seedings. In situations like this where a herbicide was used, spraying an insecticide to control leafhoppers may be necessary. Daily scouting to monitor leafhopper pressure will be very important.

To scout your fields, using a sweep net, make 20 pendulum sweeps, 3 to 4 inches below the tops of the plants while walking in a zigzag pattern. Count the number of leafhopper adults and nymphs caught. Repeat this procedure 4 more times throughout the field so that you complete 100 sweeps in the field. Divide total number of leafhoppers by 100, this gives you the number of leafhoppers per sweep and can be compared with established thresholds. Thresholds are based upon height and value of alfalfa, cost to spray, and leafhopper numbers. For example, if the alfalfa had a value of $150/ton and the insecticide application was $12/acre the threshold values would be as follows.

0-4 inches alfalfa - 0.3 leafhoppers/sweep
4-8 inches alfalfa - 0.4 leafhoppers/sweep
8-12 inches alfalfa - 1.1 leafhoppers/sweep

For complete thresholds levels, scouting instructions, and how to make a sweep net see http://www.ento.psu.edu/extension/factsheets/potatoLeafhopperAlfalfa.htm The Agronomy Guide lists several insecticides available for control of potato leafhoppers. http://agguide.agronomy.psu.edu/

Multiflora Rose Management in Pastures — Dwight Lingenfelter and Dave Messersmith

Multiflora rose is in full bloom across much of Pennsylvania, marking one of the best seasons for control. Several herbicides can provide good control of multiflora rose, especially when applied during flowering. Three foliar applied herbicides suggested for late-spring/summer are Cimarron or Ally, Crossbow, and glyphosate.

Cimarron (Ally) can be used as a broadcast or spot treatment. Apply Cimarron at a rate of 0.5 to 1 oz/A plus a surfactant for broadcast treatments or 1.0 oz/100 gallons water plus surfactant for spot treatments. (Ally can only be applied at a rate of 0.3 oz/A) There is no application to grazing interval for Cimarron or Ally.

Foliar applications of Crossbow can be effective on multiflora rose. For spot treatments, use 4 to 6 oz/3 gallons water and spray until foliage is uniformly wet. For broadcast applications, use 1.5 to 4 gallons of Crossbow in enough water to deliver 10 to 30 gallons of spray per acre. Mid June, when multiflora rose is flowering, is an excellent time to make these applications. Follow-up treatments may be necessary. An interval of 14 days is required for lactating dairy if using 2 gallons/A or less.

Glyphosate can be used as spot treatments on isolated patches of multiflora rose. Apply a 1 percent solution (about 1 qt/25 gallons water) of glyphosate with a hand-held sprayer. Uniformly wet leaves and green stems, but avoid runoff. In PSU research, Glyphosate has been more effective at controlling multiflora rose at fall application time. So application should be made in late summer or early fall when plants are actively growing (after fruit formation). A 14 day interval is required for grazing animals.

To achieve the best control of multiflora rose, a combination of several tactics should be used. For example, mowing established plants now (during flowering) followed by an application of glyphosate to the regrowth in early fall would provide better control than either mowing or herbicide alone.

No matter which control tactic is used, follow-up maintenance practices are a must for long-term control. Removal of dead brush, annual mowing and adequate soil fertility are examples of practices that should be used to encourage pasture growth and maintain control of multiflora rose.

For more information on multiflora rose and its management refer to the publication Agronomy Facts 46: Multiflora Rose Management in Grass Pastures. http://cropsoil.psu.edu/extension/facts/agfact46.pdf

The Weather and Nitrogen Testing — Doug Beegle

Some areas of the state have had some very cool, wet conditions lately which has resulted in some pretty serious stress on corn. A lot of this corn is yellow which has raised concerns about N deficiency. Probably some of this is due to N deficiency but the big question is whether this is just a temporary deficiency due to the extreme conditions or if the field is really N deficient. Heavy rains can quickly reduce available N by leaching and denitrification and the cool weather can slow microbial release of soil N. However, once it quits raining and warms up the microbes get back in action and the available N levels will often recover within a few days. If the corn does not recover with a few days of nice weather this could indicate a significant loss of N and a long term N deficiency in the field.

There have been a number of questions about using the Pre-sidedress Soil Nitrate Test (PSNT) or Chlorophyll meter test to check the N status of these fields that are showing the potential N stress. These tests can be used in this situation. However, they are not a direct measure of the amount of available N in the soil but rather they are estimating the ability of the soil to continuously supply N to meet the ongoing crop demand. For this reason, it is very important that you wait a few days following the stress to let the system recover to more normal operating conditions before you test. Also, if the plants are still showing obvious signs of stress do not use the chlorophyll meter test because there are a number of things, other than N deficiency, that can cause the plants to yellow under these conditions. This could give you a false N deficiency reading.

The PSNT is the better way to go in these situations. Remember to sample when the corn is about 12” tall (later is better than earlier) but wait at least 2 days after heavy rains and it is better if you can wait longer especially when it is also cold, sample to 12” depth, dry the sample quickly and thoroughly (same day) before sending it to the lab. Most labs will provide 1 day turnaround on the PSNT nitrate analysis so that you can get the results back in time to make a sidedress decision.

Details on the PSNT can be found in Penn State Agronomy Facts #17 “Presidedress Soil Nitrate Test for Corn.” (http://cropsoil.psu.edu/extension/facts/agfact17.pdf

Glyphosate: Reality of Resistance and Use Rates — Dwight Lingenfelter

Glyphosate resistance is a real issue here in the Northeast. As I talk with some producers and dealers about herbicide resistance problem, sometimes, I get the impression that they think we in the Northeast are isolated from this problem and this is only something that happens out in the Midwest or the southern US. Yes, it is likely true that due to our diverse cropping systems and rotations, we can prevent or delay the potential onset of herbicide resistance. However, we do have some weed species which have developed resistance to commonly used herbicides in our crops. Since glyphosate is used widely in our crops, we need to protect its usefulness. There is always the potential for glyphosate resistance to occur in weeds such as horseweed, pigweed, lambsquarters, ragweed, and others. Every so often there are reports of one of these species not being controlled by an application of glyphosate, not only in other parts of the US, but also in our area as well. Just because a weed is not controlled by glyphosate (or another herbicide) does not mean it is automatically resistant. There are many factors that must be met for resistance to be confirmed. Therefore, we ask that as you are scouting your fields after herbicides have been applied (esp. post applications), take note of any suspect populations or certain species that are not being effectively controlled and report them to us or your local county extension agent so we can determine if it is a potential problem.

Glyphosate rates: As a reminder, be sure to increase glyphosate rates as required by larger weed sizes. As a rule of thumb and as listed in the glyphosate label: for weeds up to 6” tall use 0.75 lb ae glyphosate; if weeds are 6 to 12” tall, use 1.13 lb ae; and for weeds taller than 12”, use 1.5 lb ae.

PA Five Acre Corn Club — Tom Murphy and Greg Roth

Now is the time to get signed up for the Pennsylvania Five Acre Corn Club if you haven't already. The purpose of the program is two-fold. First to increase management skills of corn producers in the state by looking at the details of what it costs to grow an acre of corn at maximum production. And second, to recognize top PA growers in the state and highlight the methods they used to achieve the yields they harvested. If you want to participate in the program this season, you need to complete the application form and return it prior to the July 1st deadline. Enrollment forms can be found online at http://cornandsoybeans.psu.edu. The entry fee of $20.00 needs to be submitted with the registration form by the deadline. If you plan to enter, you might want to ask your seed company representative to sponsor the fee since many of them will.

Also, if you plan to enter the similar contest sponsored by the National Corn Growers Association, you can use the same field that you use for the State test as long as the National harvest method is used. And while we are talking about contests, don't overlook the PA Soybean Contest. The top winner in PA receives a trip to the commodity classic, all expenses paid! All three of these programs give you the chance to see the management techniques and crop inputs used for maximum production. They don't involve a lot of your time and the outcome is very interesting when you're shooting for top yields.

Dates to Remember:

SARE Soil Quality Workshop, Rodale Institute — July 5, 6, and 7. Contact Bill Curran wcurran@psu.edu for additional information.

Eco Weed Day for Ag Teachers, PSU Agronomy Farm — July 17. Contact Bill Curran wcurran@psu.edu for additional information.

2006 Penn State Agronomic Field Diagnostic Clinic — July 18 and 20. Visit our website at http://cropsoil.psu.edu/extension/clinic.htm for more information.

For Additional Related Activities CMEG, Please Visit the Calendar of Events: http://www.events.psu.edu/cgi-bin/cal/webevent.cgi?cmd=opencal&cal=cal209&

Contributors: State Specialists: Marvin Hall, Doug Beegle, Erick DeWolf, Sjoerd Duiker, Greg Roth, Bill Curran, and Dwight Lingenfelter. Extension Educators: Paul Craig (Dauphin), Del Voight (Lebanon) Kevin Fry (Armstrong), Andrew Frankenfield (Montgomery), Jere Wingert (Franklin), Mena Hautau (Berks), Joel Hunter (Crawford), Jeff Graybill (Lancaster), and Dave Messersmith (Wayne).

Editor: Tom Murphy

Real time pest and heat unit activity: http://psu.zedxinc.com/cgi-bin/site.cgi?location=2&user=psu#

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

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