Field Crop News at Penn State

Field Crop News

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

April 30, 2004    Vol. 04:02

IN THIS ISSUE:

Mark Your Calendar

Weather Outlook

Production

Pest Management

Agents Corner

WEATHER OUTLOOK

April 2004 has ended as a mild, moist month in Pennsylvania. The heaviest precipitation fell in northwestern sections (which had turned rather dry during the latter half of the winter).

Temperatures have averaged about 1-2F above normal. Snowfall was limited to the northern and mountainous sections and mainly during the first week of the month

The frequent ups and downs in temperature will continue and each swing will bring a risk of showers. Overall, May should average a bit below normal temperatures and above normal rainfall in eastern Pennsylvania, but near or below normal in the western half. After a balmy start (May 1), a slow-moving cold front will bring cooler and wet conditions from May 2-3.

Very cool weather is likely on May 4 with another risk of frost in the central valleys. Warmer air will return with some showers on May 5 and be followed by several very mild days (May 6-8). Another cold front will bring statewide showers either later May 8 or May 9. The cool air will return on May 10-12 and it will be mainly dry on May 11-12. A bout of thundery weather is likely at mid-month.

The early outlook for the summer points to near normal temperatures and somewhat above normal rainfall.

Paul Knight, WeatherWorld@psu.edu
Pennsylvania State Climatologist

PRODUCTION

EARLY PLANTED CORN MOVING ALONG

Our producers continue to push the envelope with early corn planting- mostly with great success. Our extension educators are tracking fields in several counties planted in late March and early April with the Intellicoat seed and most seem to be doing quite well. Many fields were planted with conventional seed in mid April in the capital region and even here in central Pennsylvania, due to the good soil conditions and good soil temperatures. Corn planted this early has done well during the past few years and is a testament to very good seed quality. Late April and early May can bring some cold temperature and delayed emergence, so a review of some issues that might appear on this corn are listed below:

  1. Expect corn to emerge in the 100 to 150 GDD range, with slightly longer for these early plantings.
  2. Check stands that are slow in emerging uniformly for common problems: lack of seed, seed viability, insect injury to seeds, variation in planting depth, unfurling underground etc. to make an early season assessment
  3. Purple corn may be common with this early corn due to cool temperatures, and usually recovers nicely when temperatures warm up. Be sure to rule out root damage from insects or herbicide injury.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

BARLEY SILAGE OPTIONS

One option for the use of barley is for silage. Last year, many dairy and livestock producers took advantage of conditions to make some excellent direct cut barely silage. Direct cut is harvested at the soft dough stage by running a small grain head on a forage chopper. The entire plant is cut and run through the chopper. Harvesting at soft dough results in much higher yields, slightly higher fiber and lower protein than at the boot stage as shown in this data from Virginia Tech in Table 1.

Table 1. Yield and quality of barley silage harvested at boot or two cutting heights at soft dough stage.
Boot Soft dough
6 inches		 Soft dough
10 inches
Source: Acosta et al., 1991. Journal of Dairy Science. 74:167-176.
Yield (lb DM/acre) 3,295 7,813 5,614
ADF, % DM 31.1 33.9 29.3
NDF, % DM 49.1 52.6 53.8
CP, % DM 16.6 9.1 8.9
Lignin (% DM) 5.7 6.9 6.0

Direct cut silage is a great option for custom harvesters, but it requires careful attention to the dry matter of the crop since it changes rapidly. Close monitoring of crop development and whole plant moistures is critical. Optimum plant moistures are similar to corn silage for harvest and silo management is important, as always.

There can be no delay in harvest as plant moistures will drop quickly. Harvesting at the boot stage and wilting the forage is an option to widen the harvest window. Chopping high can increase quality but will reduce yields. In the study cited below, medium producing cows did not benefit from the improved forage quality of the higher chopped forage. Scab infested barley can result in mycotoxins if harvested for silage and should be tested and managed accordingly. If barley silage is blended with other silage in the ration, the effects of small quality changes and mycotoxins will be reduced.

Agronomically, chopping barley for silage can provide earlier opportunities for corn silage and soybean double cropping, which can result in higher yields for these crops, especially corn.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

Paul Craig, phc8@psu.edu
Capital Region: Forages

THE PERILS OF SUBSOILING LONG-TERM NO-TILL

On Tax Day we compacted fields in a conservation tillage study. In this study we are interested in the effects of soil compaction in long-term no-till, and the possibilities of alleviation of compaction effects with strip-till (subsoiling with minimal surface residue disturbance). The field we used had been in no-till for more than 10 years. Since the beginning of our trial in 2002, we subsoiled some fields with an Unverferth Zone-Builder to a depth of 17". Therefore, we have fields that have been no-tilled for more than a decade, fields that have been subsoiled in 2002, 2003, and earlier this month. We did our compaction with a 30 ton total weight loaded manure truck with truck tires (axle load approximately 10 ton, moisture conditions suboptimal for traffic). We observed that when fields had been strip-tilled there was a lot more rutting, and less support for traffic, as can be seen in Figures 1-4. We also observed that the longer we were removed from our last subsoiling operation, the less rutting was caused. In our recently tilled soil, on the other hand, we sank probably one foot deep and got stuck several times.

The message is that you make a major decision when you subsoil your long-term no-till fields. It means you will have less support for traffic after that for at least 2 years, and greater potential for rutting. And if you cause ruts, there is a greater likelihood that you will have to revert back to some general tillage to smoothen them out. So subsoiling in no-till should only be done when absolutely necessary, and afterwards you will have to be even more careful with staying off wet fields. It would be much better if you could avoid compaction of long-term no-till fields by respecting soil moisture conditions for traffic, by using reduced axle loads to less than 10 tons (preferably less than 6 tons) and by using flotation tires. Then you would not have to use subsoiling at all.

As I look out of my window it is a gorgeous day, and the forecast looks great too. So it seems we may have a great start to the season, and hopefully we will be able to respect the soil better than we were able to last year! Have a great season!

Sjoerd Duiker, swd10@psu.edu
Soil Physics, Crop and Soil Sciences

figure 1

TENTATIVE SCHEDULE OF ON-FARM FIELD CROP RESEARCH FOR 2004

The On-Farm Research program continues to compile projects to be continued or initiated during 2004. Although the season for planting this year's crop is now upon us, the window of opportunity to discuss future projects is never closed. Please feel free to contact me throughout the year when you would like assistance in developing your ideas. Also, keep in mind that extra lead time may be necessary to secure funding for labor or resource-intensive projects.

Projects

Mechanical weed control in oats. (Berks) The certified organic grain and livestock Bock farm near Kutztown is hosting a three treatment trial planted in mid-April to investigate the frequency of flexible tine weeding on summer annual weed control. The treatments consist of single, double, or triple operations with the weeder. Weed density and weed and oat biomass prior to oat heading will be measured. Grain yields at harvest will also be measured. NOTE: A field day will take place on June 2, 2004 (see calendar). It will highlight this trial, organic grain production, and other production and marketing activities associated with the Bock farm.

Evaluation of Bt corn rootworm hybrids. (Lancaster, Adams, Montgomery, Lycoming, Centre, and Westmoreland) Seven trials to evaluate the effectiveness of several corn rootworm controls will complement the seven trials conducted during 2003. A complete summary of the 2003 results can be found on the PSU Corn and Soybean Management website at: http://cornandsoybeans.psu.edu/CMRR/cmrr04_02.html . Treatments will include the Bt event, its associated isoline with and without a soil applied insecticide. A fourth treatment, the isoline treated with Poncho 1250 seed treatment, will be included at three locations. Observations will include plant populations, root injury from corn rootworm, and grain moisture and yield at harvest.

Effect of corn row spacing and plant populations. (Perry) Four treatments will be compared. They will consist of the combinations of 15 or 30 inch row spacings and 27,000 or 34,000 seed drop population. Measurements will include forage quality and yield when plots are harvested for silage.

Evaluations of potato leafhopper resistant alfalfa. (Centre and Mercer) Plantings of one of the newest PLH-resistant alfalfa varieties will be compared with a comparable non-resistant variety. Yield and economics associated with production of the two varieties when grown on three farms in each county will be summarized. Plantings occurred during April 2004. Data will be collected thru 2005.

Pasture improvement by no-till interseeding new grasses and legume using banded or broadcast applications of glyphosate. (Tioga, Sullivan, Bradford, Columbia, and Union) Eight dairymen and livestock producers will participate in a comparison of forages with the expectation that pasture forage production can be increased. A side study will evaluate the opportunity to establish no-till interseedings with a banded application of glyphosate in place of broadcast applications. Planting will take place during late summer and plots will be monitored during the following two seasons

Comparison of corn production in no-till, conventional tillage, and surface aeration systems. (Fayette, Armstrong, Westmoreland, and Beaver) Three tillage systems for corn production will be initiated during 2004 and continued for three seasons. Plant populations and corn grain harvest yields will be the primary measurements.

Verification of web-based weed and insect predictive models for Northeast IPM programs. (Westmoreland, Armstrong, Wyoming, and Wayne) Corn fields are being monitored for the emergence and development of common annual weeds, European corn borer, and corn rootworms. Alfalfa is being monitored for emergence and development of alfalfa weevil. These observations will be compared to predictions of the same events by web-based development and emergence models.

Ron Hoover, rjh7@psu.edu
On-Farm Research Coordinator, Crop and Soil Sciences

SOYBEANS FOR FORAGE

As many of you already know we have been doing on-farm trials on soybean varieties harvested as forage. Of course this year with soybeans hitting $10.00 per bushel, harvesting them for grain was probably the right decision.

In any case, the reason we are looking at soybeans harvested for forage is because some of our local farmers are interested in evaluating possible options to their current forage and grain crop management. Soybeans is one of those options which can provide a high-quality feeding source with less fertility input costs and less times over the field than you might have with alfalfa. While still incorporating a legume into the crop rotation which is needed to break the life cycle of various pests and diseases common to corn, grains, and grasses.

In 2003, we were involved in a feeding trial comparing soybean forage to alfalfa forage in the low milking group of a local dairy herd. The feeding trial lasted six months and was a switch back design where alfalfa forage that was comparable to the soybean forage in quality was fed to the herd for two months and then replaced in the ration by soybean forage for two months. After that period the soybean forage was replaced in the ration by alfalfa forage for another two months. The results showed a 4 lb. per cow per day increase in milk production with the soybean forage treatment versus the alfalfa forage treatment. There was little difference in the butterfat and protein in the milk between treatments. We are continuing in 2004 to monitor the feeding of soybean forage harvested in 2003 on that same farm.

We also looked at two different soybean varieties (a maturity group 5 forage variety and a mid group 3 grain variety) double cropped after barley and harvested as a forage crop on a farm near Mill Hall. The Barley came off late and the soybeans did not get planted until July 15, 2003. The results, however, were surprising. The yields on both varieties showed an average dry matter yield per acre of 2 ton with 2.5 months of growth. The varieties were harvested in early October at a maturity stage of R4 (pods are green with 2 to 3 small beans inside). The Relative Feed Value was 148 or greater for both varieties with the grain variety showing a little better forage quality.

Local acres producing soybean forage increased by 58% to 190 acres in 2003. This year we will be looking at a new variety called TARA, a group V forage/grain variety developed by Tom Devine at USDA Labs in Beltsville, Maryland. It is supposed carry more pods than Donegal and get six feet tall. In Virginia, it is being harvested for grain and I am told yields well. We will have it on a farm here and will measure yields and quality for forage and grain (if it matures).

We continue to work with producers who want to harvest soybeans for forage and feel that it is important for folks equipped to handle and store forage to understand what the proper management techniques are for soybeans so that they can make the decision of whether to harvest them for forage or grain. With that understanding, a producer has some options available to him when trying to figure out what markets and weather are going to do.

Craig Altemose, cea10@psu.edu
Centre County

PEST MANAGEMENT

WHEAT HEAD SCAB PREDICTION MODELS AVAILABLE

Wheat head scab (Fusarium head blight) was a serious problem for many wheat and barley producers in PA this past season. In fact, the disease was severe throughout most of the mid-Atlantic region in 2003. The economic impact of this epidemic is still being felt in many sectors of the agriculture community as we struggle to deal with mycotoxin contaminated grain.

In 2004, growers can access a web site to help them evaluate the risk of head scab for their fields. The disease, caused by Fusarium graminearum, is most severe when conditions prior to and during the flowering of the crop favor the reproduction and infection by the fungus. In recent years researchers at North Dakota, South Dakota, Indiana, Ohio and Pennsylvania have developed a weather-driven model that predicts outbreaks for head scab. The accuracy of the models has been 80% based on validation research, and the risk forecasting system can be used as an early warning system from Pennsylvania wheat growers. The forecasting model predicts the risk of an epidemic with a greater than 10% severity based on weather conditions observed 7-days prior to flowering. At this level of disease head scab is considered to cause significant economic losses.

The forecasting models are available via the web at http://www.wheatscab.psu.edu/. This webpage provides links to information about the prediction model, biology of the disease and instructions how to use the 'Risk Map Tool'. When you first enter the site take a few minutes to read through the supporting materials as this will potentially answer many of your questions before you start. When you are ready to start using models you can select the 'Risk Map Tool' to initiate the model. Upon start-up the tool will ask you answer a few simple questions that will help customize the predictions for your production practices including the flowering date of your fields, the type of wheat you are growing (spring vs. winter wheat) and whether the wheat was planted into ground with more than 10% corn residue cover. The models use only observed weather variables so you will not be able to select future dates from the "Flowering Date Calendar'.

Once you have provided the information needed by the model select OK and then select a state on the map of the USA to begin. The map produced has three colors representing different levels of disease risk. The blue dots within the map represent weather stations that will allow you to view different variables that go into the model calculations. The information used to produce the maps is separate from the individual weather stations, and the map is still valid even if the tool does not pickup the station report for the date you selected. For now, we suggest that you select a range of dates to become familiar with how the system works. Watch the system as your wheat approaches flowering as these forecasts will be most relevant to your fields.

Please note this is an experimental system and the web site managers will be working with it throughout the season to 'fix' any bugs. If you do not get a prediction for a location, try again in a few hours.

I think it is also important to note that the model has some practical limitations. Specifically these models use only weather conditions prior to flowering of the crop. Research has shown that wet conditions during and after flowering and during seed fill have a great impact on the development of head scab and deoxynivalenol contamination in grain. These time periods are not evaluated by the pre-flowering model. We will continue to provide updates on the risk of head scab this year.

Erick De Wolf, edd10@psu.edu
Plant Pathology

MONITORING AND PREDICTING WEED EMERGENCE

An integral part of estimating competition between crops and weeds is identifying the emergence period for specific weed species. Knowing when particular weed species are likely to emerge can be important for planning tillage and postemergence weed management programs. From it's most basic stand point, early emerging species may be avoided by planting later, late emerging species may be better attacked by planting a competitive crop early, and species that have a prolonged emergence cycle may be the most difficult to manage in a summer annual crop.

Temperature-based emergence models have become popular because soil temperature serves as a fairly good predictor for weed seedling emergence as well as for the development of other pests. Rainfall, surface residue, and tillage can also influence weed emergence, but temperature has the greatest influence during spring and early summer.

Monitoring daily soil or air temperatures and tracking degree days (DD) is one of the easiest methods for predicting when weeds begin to emerge and for how long into the season. The most common method is to track cumulative DD during the period of interest. For weeds, this means monitoring daily high (Tmax) and low (Tmin) temperatures starting in early spring and continuing until mid July. A base temperature (Tbase) is also required which is the minimum temperature necessary for growth and development or in the case of weeds, germination and emergence. Several methods are used to calculate DD with the most common being: DD = (Tmax +Tmin )/ 2 - Tbase

figure 5

We conducted research over the last three years looking at the reliability of soil DD as a means of predicting weed species emergence. In our research, we monitored weed emergence across four locations in the Mid-Atlantic region over a two-year period. The project was funded by the USDA Northeast IPM Program and included scientists from Penn State, the University of Delaware and Rutgers University. We used 48 F as our base temperature and developed emergence models for 8 weed species. Our results were positive and temperature proved to be a good predictor for weed emergence. As an example, cumulative emergence for common ragweed is shown in Figure 5. Ragweed has a relatively short emergence cycle and is one of the earliest emerging species. Taking it a step further, the estimated calendar date for 10, 50 and 95% cumulative emergence for the eight weed species is shown in Table 2 for the four locations. Bridgeton and Georgetown are the most southern and Rock Springs in the most northern location. We are continuing to collect additional field data this and next summer with the hope of improving our prediction capabilities.

table 2

In the mean time, we have also launched with the help of ZedX Inc., a real time prediction tool that provides the estimated development for the eight weeds plus a number of insect pests. An example map for common ragweed emergence is shown in Figure 6. You can access the real time prediction website through the PSU Entomology website (http://www.ento.psu.edu/extension/field_crops/default.htm). We encourage you to check out the website and let us know how close or how far off from reality you think it is. Have fun scouting.

figure 6

Bill Curran, wcurran@psu.edu
Weed Science, Crop and Soil Sciences

Dennis Calvin, dcalvin@psu.edu
Entomology

WHAT CAN BE DONE IF THE CORN IS UP AND A PRE HERBICIDE WASN'T APPLIED?

If the corn is already coming up and you didn't get a chance to apply a pre herbicide, have no fear, because there is still an opportunity to apply certain soil residual products. A number of residual herbicides can be applied after planting up until corn and weeds reach a certain size or growth stage. The greatest risk of failure comes with trying to control annual grasses such as foxtail and panicum after they emerge. However, several products are available to control emerged grasses (e.g., Accent, Basis, Basis Gold, Celebrity Plus, Option, Steadfast (ATZ), glyphosate on Roundup Ready corn only, Lightning on CL/IMI-corn only, and Liberty on LibertyLink/GR corn.) In most cases, these post-grass herbicides can be tank-mixed with the residual products if some annual grasses have already emerged. (See the herbicide label for additional information on tank-mixing- WWW.CDMS.NET or WWW.GREENBOOK.NET ). For most products, do not apply in liquid fertilizer if corn has emerged or injury may occur. Some early postemergence considerations are listed in Table 3.

Table 3. Maximum corn and weed size for delayed preemergence herbicide applications.
Herbicides Maximum corn size Maximum weed size
a May be tank-mixed with a number of different products including Accent, Banvel or Clarity, Prowl, Pursuit (IMI-corn), etc. See a herbicide label for specific information.
b May be tank-mixed with Accent, Atrazine (Harness), Banvel or Clarity, Marksman, Permit, Pursuit (IMI-corn), or Roundup (Roundup Ready corn).
c Accent rate of 1/3 to 2/3 oz/acre and Beacon rate of 3/8 to 3/4 oz/acre; when tank-mixing all three herbicides-Accent rate is 0.33 oz/acre and Beacon is 0.38 oz/acre.
Atrazine 12 inches 1.5 inches
Axiom before emergence before emergence
Balance Pro before emergence before emergence
Bicep II Magnum, Bicep Lite II Magnum, Cinch ATZ/Lite, Dual II Magnum, Stalwart Xtra, Trizmet II 5 inches 2-leaf
Bicep II Magnum or Cinch ATZ + Prowl 4-leaf or 2 collars 1 to 2-leaf
Bullet or Micro-Tech + atrazine 5 inches 2-leaf
Clarity or Marksman + Dual or Lasso 3 inches 2-leaf grass
Clarity or Marksman + Outlook 8 inches 1-inch grass
Dual or Micro-Tech + atrazine, Bullet 5 inches 2-leaf
Dual II Magnum, Cinch + Clarity 5 inches 3-inch pigweed
Dual II Magnum + Marksman 3 inches 2-leaf grass
FulTime, Keystone, Surpass, TopNotcha ,Volley Atz 11 inches or by tank-mix partner before emergence or by tank-mix partner
Guardsman, G-Max Lite 12 inches 1.5-inch broadleaves; before grass emergence
Harness, Harness Xtrab, Degree, or Degree Xtra, Confidence Xtra 11 inches or by tank-mix partner before emergence or by tank-mix partner
Lumax, Camix 5 inches 3-inch broadleaves; inconsistent on emerged grasses
Outlook 12 inches before emergence or by tank-mix partner
Princep before emergence before emergence
Prowl H2O 30 inches before weed emergence
Prowl + Accent or Prowl + Accent + Beaconc 6-leaf see herbicide labels
Prowl + Atrazine, Prowl + Banvel 4-leaf 1 inch
Prowl + Marksman 2-leaf 1 inch grass
Prowl + Beaconc 6-leaf depends on weed (see Beacon label
Python WDG 20 inches before weed emergence

Dwight Lingenfelter, dxl18@psu.edu
Bill Curran, wcurran@psu.edu
Weed Science, Crop and Soil Sciences

Agents Corner

CAPITAL

Corn and soybean planting has begun this past weekend but has been held up by more than one and one half inches of rain Tuesday. Quite a few producers have tried the new Intellicoat seedings to great approval. Based on GDD predictions, germination has occurred as hoped for. Now if only we would get some heat and sun to help these emerging plants.

Rye for forage is ready to harvest across the southern region and will be region wide within days. Producers are looking for a window of harvest opportunities.

Alfalfa weevil reports are extremely scattered. There does not appear to be any widespread injury this season compared to recent years. However spring laid eggs will be hatching at this time and there could be localized problems.

Timothy mites and cereal rust mites, have seemed to exploded in most fields. Droughty looking stands are a sure sign of injury. Del Voight reported the occurance of fields with high numbers of adults in late March followed by a significant drop off in numbers in early April. Now those fields have a large population of adults again. Del's theory is that the earlier generation of adults laid the eggs of mites now appearing. Seems like we keep learning more and knowing less about this bugger.

Winter grain stands are variable. Late establishment and nitrogen applications are most likely the major reason but these is also injury from too much water.

Paul Craig, phc8@psu.edu
Dauphin County

CENTRAL

Field activities here in Central Pa have gotten off to a slow start this spring. There have been a few days of dry weather in between rains. The first and most important field activity was to empty manure storage structures that were full from the winter. Most oats and new forage seedings have been done, but there are still fields that have been too wet to plant. I have talked to a few farmers who planted some of the polymer coated seed corn. Some of this stayed in the ground 2 weeks before it emerged. Temperatures were below 30 degrees one night this week but I have not seen any crop damage.

The alfalfa has come through the winter in very good condition and is off to a good start. Wheat and barley fields did not all survive the winter. Some fields look very good while others apparently had heavy winter kill and will not be worth keeping for grain.

Greg Hostetter, gjh10@psu.edu
Mifflin/Juniata/Perry

SOUTHWEST

2004 is starting where 2003 left off, soils are saturated, field work is behind, and spirits are a bit low because of it.

However, during the week of April 19, there were several warm days when farmers were able to get on fields to perform spring activity, manure spreading, lime spreading, plowing, disking, spraying and the planting of oats and/or hay crop seedings. But beginning on April 25, the rain clouds returned and again fields are saturated.

Crops are a bit behind normal due to the cool damp weather, but alfalfa fields are perking up, winter grain crops are looking good on fields with suitable drainage and pasture meadows are now springing forth to provide forage for grazing livestock.

So all in all, spring is finally here despite the 40 degree temperature this day, April 27, but warmer temperatures usually are soon to follow and farmers are anxious to get planting so they can get to hay crop harvesting.

Don Fretts, dcf3@psu.edu
Fayette County


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Douglas Beegle, editor,
Professor, Agronomy, dbb@psu.edu

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