CMEG Crop Management Extension Group

Field Crop News

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

July 7, 2009    Vol. 09:18

IN THIS ISSUE:

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

Finally, a spell of warm and very humid conditions is likely on Friday and Saturday (and perhaps part of Sunday in the southeast counties). Leading up to the sultry weather, Wednesday should dawn clear and it will be quite cool in the northern counties (readings in the 40’s, perhaps some upper 30’s). As more humid air begins its return, clouds will increase and skies will turn overcast with a few showers possible late in the western and central mountains. A moist flow from the east on Thursday will contribute to widespread clouds and lower temperatures. Patches of drizzle and a few showers are expected, mainly in the mountains east of the crest of the Appalachians. As hotter air approaches on Friday, thunderstorms will erupt in many sections during the afternoon and evening which will keep temperatures down, though it will become quite sticky. Saturday is expected to be sultry until a cool front triggers late day thunderstorms. Drier and cooler air should arrive from northwest to southeast on Sunday, though it may still be sultry in the southeast. Dry and seasonably cool weather will return for the first few days of the next work—week.

A notable wet period is still possible in the latter half of July or August. Odds favor the first named storm in the Atlantic (Ana) to form near the Southeast coast between July 20–31. The hurricane season should have most of the storms develop after August 20. A very cool spell is likely during mid—September, with perhaps an unusually early end to the growing season in the northern counties. However, the latest indications point to a warmer than average September and October. The development of a weak El Nino conditions in the Pacific portend a wetter winter (and probably snowier) in the state.

Managing Scab in Wheat — Greg Roth, PSU Grain Crop Specialist

We have known that some of our wheat has shown symptoms of fusarium head blight or scab based on scouting during past several weeks. Del Voight reviewed this in a previous newsletter article (http://fcn.agronomy.psu.edu/2009/fcn0916.cfm)

Some of the wheat varieties in our trials at Rock Springs have shown up to 30% incidence. One consequence of head blight is the presence of the the mycotoxin deoxynivalenol or DON in the grain. Reports are coming in around the state that DON levels in wheat are variable with some reaching as high as 10 ppm DON. While the FDA standard for DON in finished food products is 1 ppm DON, elevators have been accepting wheat with levels up to 3–4 ppm. Above these levels, wheat is rejected or channeled into the feed wheat market. Some farmers have been reserving wheat for their own feed use. Livestock vary in their tolerance to DON with hogs being the most sensitive, beef cattle and poultry the least sensitive. Check with a nutritionist before feeding DON contaminated wheat.

Key issues now are to try to segregate fields that appear to have the lowest incidence and market those separately. Fields with good air drainage, less susceptible varieties or those treated with a fungicide for scab might warrant separation if possible. There is some evidence that field edges, along fence rows or where wheat was double planted may also have higher fusarium head blight and DON levels. Setting combines to remove the lighter kernels, using a grain cleaner to clean grain before storage, and trying to make sure grain is distributed evenly throughout the bin are potential techniques to minimize DON and avoid hot spots in the bin. Good management is not bulletproof: we have reports that even some wheat that had good test weight with a low incidence of scab has tested high for DON.

Unfortunately, quantitative testing procedures are expensive and only available at grain handling facilities. Even with these quantitative tests, there is some variation due to sampling. This factsheet provides some guidance and links on grain sampling techniques. http://www.scabusa.org/pdfs/ptt/grain-sampling_don-analysis.pdf Qualitative tests are available such as this one from Neogen (http://www.neogen.com/FoodSafety/AS_Index.asp). These can provide some guidance on whether loads of wheat are above 1.0ppm DON. At our field day last week in Landisville, we demonstrated the use of one of these kits.

If the crop is insured, it is critical to review testing procedures with your agent now if you have not already done so. With the lower price of wheat and now potential for lower quality and dockages, there could be justification for claims. This will likely require the submission of a sample to a certified USDA GIPSA laboratory in Maumee, OH (419–893–3076) to substantiate the quality issue.

Crop Considerations after Small Grain Harvest, Too late for Soybeans? — Del Voight, Interim PSU Grain Crop Specialist

This year has changed the game when it comes to double cropping soybeans. Typically as July progresses after small grain harvest, producers will not double crop soybeans. However, the late timing this year might not be an issue with continued rains and ideal planting conditions, many producers will continue to plant. I have seen fields planted directly after barley that did not emerge for two weeks due to lack of rain. We have plenty of moisture in the soil right now and it appears that some is in the forecast. Here are some considerations.

  1. Plan to establish at least 180,000 plants per acre. In order to achieve this, a minimum planting population of 200,000 is recommended at this time.
  2. Plant narrow row less than 15 and 7 inch or narrower preferred. There is less time for the soybeans to gain height to pod so the narrow rows allows for more beans to grow at higher populations.
  3. A full season bean maturity is still recommended to allow for some vegetative growth prior to flowering.
  4. If the field has visible weeds, be sure to burn down to ensure weed competition is kept to a minimum.
  5. Set a realistic economic target. Traditional double crop yields of 30bu/acre is not out of the question (we typically see about a 50% response the first week of July)and at 12 dollar soybeans there is some but not a lot of room to spend input costs over and above that which needs to be spent to make the crop.
  6. Be aware that the potential for an early frost is always possible. If forage is needed, consider management for a forage use of the soybean. If the goal is forage supply then perhaps sorghum sudan or other annual crop may be a better selection.

Nitrogen Losses: What to do now? — Douglas Beegle, PSU Soil Fertility Specialist

Many areas of the state have experienced heavy precipitation this year which has resulted in significant loss of N by leaching in our well drained soils and denitrification in our less well drained soils and in any soil that stands saturated for any amount of time. Some corn is yellow and stunted simply from trying to grow in wet soil. To distinguish nitrogen deficiency, the symptoms will show up on the lower leaves first with yellowing starting at the tip of the leaf and going down the midrib. This has been a year when sidedressing N will probably really pay, because with sidedressing, at least the losses due to the early wet weather were avoided. In some areas the rain and consequently the losses have continued even after sidedressing.

The question now is that since we are generally well past the normal sidedressing time and we are faced with stunted yellow corn, is it still worth sidedressing and how much should be applied? If the corn is N deficient and it is still small enough to get through the field to sidedress it will probably pay to make a sidedress N application even this late assuming we will get some reasonable growing conditions from here on out. The main N uptake period is during the rapid growth period from knee high to tasseling. So if N can be applied before that occurs it should benefit the crop. The question of how much is more difficult because it is hard to accurately estimate how much N is lost in a given situation because of the complex interactions with N between the weather, the soil, and the crop. Also, if the crop is stunted and severely N deficient this late in the season, the yield potential has also obviously been reduced which must be considered in making an N management decision. In some cases where manure is the main source of N the losses may have been relatively smaller but the wet conditions are slowing mineralization of manure N resulting in deficiencies that may be disappearing as the soil dries out and the microbes kick in and start mineralizing organic N.

The Pre—Sidedress Soil Nitrate Test (PSNT) is still valid later in the season and could still be used in these situations to help determine the magnitude of the losses and provide some guidance for a sidedress recommendation. (See Agronomy Facts #17 Pre—Sidedress Soil Nitrate Test for Corn at: http://cropsoil.psu.edu/extension/facts/agfact17.pdf ) The PSNT is valid even when N has been applied earlier in the season. It is important to remember that the chlorophyll meter N test is not valid if more than 15 lbs of nitrogen fertilizer has been applied per acre early in the season. As a fall—back recommendation, a late sidedressing of 50 to 75 lb N/A on these stunted, N deficient fields will generally be worth doing. Go toward the lower end if the yield potential has been significantly reduced or if there was a significant manure application and/or a heavy manure history on the field. If the yield potential is still reasonable and there is no manure history, use a higher rate.

Soybean Pests: Aphids and Japanese Beetles — John Tooker, PSU Entomology Specialist

As we reported last week, soybean aphids are colonizing Pennsylvania soybean fields. On top of aphids, Japanese beetles are starting to emerge and feed on soybean leaves. Because of this pest pressure, growers may be inclined to spray their fields in the coming weeks. I would encourage growers to wait and employ economic thresholds in making their decisions when to spray. Research has shown that timing is the most important factor in efficiently and economically managing soybean aphid populations. The right time to treat is when the economic threshold of 250 aphids per plant is exceeded. Treating earlier or later might prove to be ineffective, wasting money and time. Counting aphids on plants can be a time consuming effort, but researchers at the University of Minnesota have streamlined the process by developing a sampling scheme called Speed Scouting, limiting the number of aphids one needs to count. It is a true time saver. See this website for more details: http://www.soybeans.umn.edu/crop/insects/aphid/aphid_sampling.htm

Control of Japanese beetle and other defoliators should also be driven by threshold—based decisions. Reasonable thresholds for leaf—feeding pests are: 30% defoliation during vegetative stages; 15% defoliation for bloom to pod-fill; and 25% pod—fill to maturity. Assess defoliation on the canopy as a whole. One sampling tactic is to randomly sample 10 plants and pick one trifoliate leaf from the top one—third of the canopy, one from the middle third, and one from the bottom third. From each trifoliate, discard the least and most heavily damaged leaflets, then with the remaining 30 leaflets, estimate the percent defoliation. The image below can be used as a gauge.

PA-PIPE map

Fig. 1. Representative levels of percent defoliation of
soybean leaves.

Another point to address is the inclination to tank mix insecticides aimed at aphids or other soybean pests with herbicides and/or fungicides. It turns out that this tactic is often an inefficient way to attempt to control insect pests because the residual in these insecticide applications is often insufficient to offer good control. Also, the lower pressure used to apply the herbicide/fungicide does not provide the coverage needed for good insect control. Lastly, broadcast applications of insecticides will decrease populations of beneficial insects that can contribute large amounts of unrecognized control to soybean aphids, spider mites, thrips, and similar pest species. Similarly, growers might also be inclined to apply a prophylactic application of fungicides to their soybeans, but it should be recognized that these sprays will eliminate beneficial fungi that often play substantial roles in controlling pest species, particularly when the weather has been wet as it has been this year.

Tillage Survey Shows No—Till Dominant, Increasing — Sjoerd Duiker, Soil Management

USDA’s National Agricultural Statistics Service released results of its 2009 Tillage Survey in Pennsylvania this month. The farmer survey shows no—tillage is the dominant practice, being used on 58% of the acreage of annual field crops, an increase of 8 points over 2008. Other conservation tillage practices held steady at 21%, whereas the proportion of conventional tillage decreased from 30% in 2008 to 21% in 2009, a decrease of 9 points. No—tillage is most common for soybean production (70% no—till), whereas it is used on about 55% of the acreage of corn, barley and wheat. 23% of the oats are no—tilled. New alfalfa seedings are established with no—till on 35% of the acreage, a decrease of 5 points compared with 2008. The results of the survey can be accessed at http://www.nass.usda.gov/Statistics_by_State/Pennsylvania/Publications/Survey_Results/tillage_practices09.pdf.

Upcoming Events

5—Acre Corn Club

Now is the time to consider entering fields in the Pennsylvania Five Acre Corn Club. As part of this program we have been monitoring corn yields throughout the state in conjunction with the Pennsylvania Corn Growers Association and corn growers around the state. Last year was a phenomenal year and it will be very interesting to see how this year unfolds. Yields have been increasing steadily in the program. In 1998, for example, 93 club members averaged 165 bushels per acre. Ten years later in 2008, yields from 65 members averaged 219 bushels per acre, or 54 bushels per acre higher than in 1998. I’ll provide more detailed analysis of club results later in the year. In the meantime, consider enrolling a field you’re working with in the club. Early registration deadline is July 1. This year a late registration deadline of August 1 was added. Enrollment forms and rules can be found at: http://cornandsoybeans.psu.edu/corncl.cfm

Register Now: Penn State Agronomic Diagnostic Clinic, July 28–29 — Dwight Lingenfelter, PSU Weed Science

We are less than a month away from the annual field Clinic. Below, please find information about the upcoming Penn State Agronomic Field Diagnostic Clinic held on July 28 and 29, 2009, 9am – 4:30pm at the Penn State Agronomy Research Farm near Rock Springs, PA.

This year’s Clinic will include sessions on:

(CCA, NM, and pesticide credits will be available.)
Visit http://cropsoil.psu.edu/extension/clinic.cfm for more information about each topic.

The cost is $60/person. ($80 after July 21)

To register, please visit: http://cropsoil.psu.edu/extension/clinic.cfm and use the “on—line” registration system or complete the hard—copy form and fax or mail it. Credit card payments will be accepted. Phone—in and email registrations are discouraged. (Note: when using the registration system, please make sure to complete all the necessary steps.) If you have questions about the Clinic please contact Dwight Lingenfelter (dwight@psu.edu). We look forward to seeing you at this year’s Clinic!

Contributors: Contributors: Extension Educators: John Rowehl (York), Paul Craig (Dauphin), Kevin Fry (Armstrong), Mark Madden (Sullivan), Jeff Graybill (Lancaster), Grant Troop (Lebanon), Tianna DuPont (Northampton), Susan Alexander (Jefferson), Joel Hunter (Crawford), Mena Hautau (Berks), and Craig Williams (Tioga). State Specialists: Ron Hoover, John Tooker, Sjoerd Duiker, Charlie White, Greg Roth, Doug Beegle, and Del Voight.

Editor: Kevin Fry, Armstrong County

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&

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