October 3, 1997 Vol. 97.12
IN THIS ISSUE:
Mark Your Calendar:
November 4, 1997 - Days Inn, Meadville
November 7, 1997 - Oakhurst Tea Room, Somerset
December 9, 1997 - Holiday Inn-TGIF Restaurant, Williamsport
December 10, 1997 - Quality Inn (Embers), Carlisle
December 11, 1997 - Lancaster County Farm and Home Center, Lancaster
December 12, 1997 - Berks County Agricultural Center, Reading
8:30 am. Registration: Registration fee is $15 plus meal cost.
| 9:00 am. | Soil Factors Influencing Crop Stress | Douglas Beegle Department of Agronomy |
| 9:30 am. | Plant Response to Environmental Stress | Marvin Hall Department of Agronomy |
| 10:15 am. | BREAK | |
| 10:30 am. | Insect Response to Environmental Stress | Dennis Calvin Department of Entomology |
| 11:30 am. | Planning A Cropping System To Reduce Plant Stress | Greg Roth/Elwood Hatley Department of Agronomy |
| Noon | LUNCH | |
| Technology Update: | ||
| 1:00 pm. | Technology For Managing Information And Its Potential Application | David Wagner Department of Agricultural and Biological Engineering |
| 1:40 pm. | Non-Target Herbicide Issues (tank residues, drift, nozzles, etc.) | Bill Hoffman Pesticide Education Program |
| 2:15 pm. | Managing Transgenic Crops To Control Insects and Resistance | Dennis Calvin Department of Entomology |
| 3:00 pm. | ADJOURN | |
Certified Crop Adviser Continuing Education Units:
Plans are nearly complete for the 1998 Pennsylvania Corn and Soybean Conference slated to be held on February 13, 1998, at the Holiday Inn at Grantville, just north of Harrisburg on I-81. Mark your calendar and plan to attend.
Leading off this years program will be Dr. Robert Steele, the new Dean of the Penn State College of Agricultural Sciences. Our keynote speaker this year will be Paul Knight, the Pennsylvania State Climatologist who regularly appears on Weather World. Paul will discuss the weather in the past season and trends in Pennsylvania's climate, including the potential for global warming.
Mark Mattingly, agronomist with Hoffman Seeds, will provide an overview of the last growing season for corn and soybeans. Other speakers will address soybean breeding issues and soybean market development. Dr. Lou Moore, from Penn State's Ag Economics and Rural Sociology Department will also be on hand to give his perspective on market conditions for 1998.
The conference will also include ag industry exhibitors, 5 Acre Corn Club and Soybean Yield Contest awards, and reports from the Pennsylvania Master Corn Growers and the Pennsylvania Soybean Board. A new feature this year will be several poster presentations about on-going corn and soybean research. Certified crop advisor credits will be available for the conference in pest management and crop production. Pesticide applicator credits will be available as well.
Greg Roth
Assoc. Prof. Agronomy
Production:
During September and early October, weather conditions are usually favorable for alfalfa growth. Increased emphasis on production coupled with high hay prices are causing alfalfa producers to consider harvesting during this period. When making the decision to take a fall harvest or not, it is important to understand the risks and possible economic benefit of harvesting during this period.
During the fall, winterhardy alfalfa plants develop cold resistance in response to shortening day lengths and cool temperatures. This process, known as hardening, involves reduced herbage production and increased carbohydrate storage in the roots. Carbohydrates are produced in green alfalfa herbage. In the spring and after cutting, carbohydrates are removed from the root until 6 to 8 inches of herbage is present, then carbohydrates begin to accumulate again. Winter survival of the alfalfa plant and spring regrowth are dependent on adequate carbohydrate storage before cold temperatures kill the herbage in the fall. About 50% of the stored carbohydrates are used during the winter for plant survival. The remaining carbohydrates are available in the spring for initial herbage growth. Cutting alfalfa in the fall may cause plants to regrow and expend some carbohydrates in the process. Subsequent regrowth often is insufficient to restore root carbohydrate levels by the first killing frost, which increases the risk of alfalfa winter kill.
Alfalfa stubble left in the field has the potential to catch and hold snow which insulates the crown and roots from extremely low air temperatures. Stubble may also serve to reduce the incidence of freezing and thawing, and disrupt ice sheets which may smother alfalfa plants.
Since harvesting during the hardening period disrupts carbohydrate accumulation in the roots there is increased risk of stand loss associated with fall harvesting. This leads to the traditional recommendation not to harvest alfalfa 4 to 6 weeks before the first killing frost. However, advances in alfalfa breeding and overall alfalfa management allow greater flexibility in fall harvest management than traditionally recommended. The real question is a economic gamble. Is the forage in the field worth the risk of reducing stand persistence? Alfalfa that has been drought stressed this summer has had extended periods between harvests and has had an opportunity to build up root carbohydrate reserves over a year with normal rainfall. It is still acknowledged that fall harvesting can stress the alfalfa plant and increase the potential for winter injury, but management practices and planning (as outlined below) can minimize this potential.
Although fall harvesting increases the risk to long-term stand persistence compared to not fall harvesting, it should be considered a management alternative to allow flexibility in alfalfa harvest scheduling. Fall harvesting of alfalfa that has been drought stressed will cause less stand thinning than fall harvesting alfalfa that has not been drought stressed. Risks to stand persistence can be reduced through management, use of alfalfa varieties with sufficient levels of disease resistance and winterhardiness, and high levels of soil fertility (especially potassium). Practices such as leaving 6 inches of stubble in the fall or leaving unharvested strips in the field will also help by increasing the potential for snow cover.
Marvin H. Hall
Assoc. Prof. Forage Mgmt.
Careful late season observations of hybrids and crop conditions are an important part of crop management. For me, this is always a very educational part of the season. Here's a sample of some issues that have come across my desk during the past two weeks:
How are silage yields comparing with last year? It is difficult to generalize, but in many areas a 25% reduction from last years yields is common. We have harvested some corn in Lebanon County that will rival last years yields in the 25 T/A range. There are other areas that have severe yield reductions, however.
What does mite damage on corn look like? George Myers, agronomist with Webbs Super Gro in Mill Hall, identified a field that had a sandblasted appearance, with some red and yellow streaking in the leaves and was senescing earlier than other fields in the area. We consulted with the Plant Diagnostic Clinic and Dennis Calvin and confirmed that this was a case of spider mite damage on corn. The spider mites apparently migrated from a roadside grass strip when the weather was hot and dry.
Why are the tops of my corn dying prematurely? John Yocum and I asked this question as have some farmers. We carefully examined some plants on the research farm and found tan to black lesions on the upper nodes. These were identified by the Plant Diagnostic Clinic as anthracnose. These top-dieback symptoms are due to disintegration of the pith at the nodes of the corn plant. More severe cases can result in shiny black lesions on stalks and stalk lodging.
How many nutrients will I remove by baling corn stalks? Lots of corn stalks get baled with little consideration for the nutrient removal. According to NRC, corn stover contains 5.9% protein, 0.10% P and 1.45% K. Based on these values a three ton per acre yield of corn stalks removes 56 pounds of N, 14 pounds of P2O5 and 104 pounds of K20. If the corn stalks are allowed to weather and are harvested during the winter, the nutrient removal for K will be reduced since the K is soluble and leaches from the stalks.
Greg Roth
Assoc. Prof. Agronomy
Pest Management:
Some of you have heard about the problems that have occurred recently in Maryland due to Pfiesteria and have been asking questions about it. Following are a few facts about Pfiesteria that my help answer questions about this issue.
This problem has gotten a lot of press and quite a bit of political attention because there have been major fish kills and also some human health problems related to this organism. The organism is Pfiesteria piscicida which is a dinoflagellate that produces toxins under certain conditions. This organism has apparently been present in estuaries like the Chesapeake Bay and the Delaware Bay for thousands of years, as a non-toxic predator. What has gotten everyone's attention is that it can and has become very toxic, with dramatic consequences. A problem, however, is that it has a very complex life cycle that is not well understood. Pfiesteria has at least 24 stages or forms in it's life cycle, and it can change between active and dormant forms very rapidly in response to the environment. It can be transported in the water and as an aerosol by the wind. Unfortunately, it is still unclear what causes it to become toxic.
Outbreaks of Pfiesteria seem to be related to certain conditions including: warm water temperatures, high levels of N, P and sediment, moderate to low salinity levels, increased rainfall and runoff, and the presence of fish in very large numbers. While the actual cause of the outbreaks is not known, nutrient enrichment from agriculture has been blamed by some people.
The effects on fish are dramatic. The organism excretes a toxin that causes the fish to become lethargic, so they tend to stay in the area where they are subject to further attack. It causes open, bleeding sores and eventually death of the fish. In humans who are directly exposed to the toxins it causes similar symptoms such as loss of memory and cognitive impairment and it causes sores on exposed skin. In addition, it can result in eye irritation and blurring, nausea and vomiting, respiratory distress, kidney and liver disfunction.
Where these outbreaks have occurred, this is a very serious problem, and it has raised major concerns. Unfortunately, because so little is known about pfiesteria it has also become a very controversial issue. Some people have dubbed it 'Pfiesteria Hysteria.' There are major arguments about the cause of the problem and therefore who to blame. There are questions about when and where outbreaks may occur and how widespread the problem might be. There is a strong push for immediate action to do something about the problem, but it is unclear what to do.
Hopefully, this gives you a little background on this issue that might help to answer some of the basic questions about Pfiesteria.
Douglas B. Beegle
Prof. Agronomy
AGENT'S CORNER
On the morning of October 2, scattered frost was severe enough to kill pepper plants in areas of northern Dauphin County. At this time it does not appear to have been hard enough to kill corn or beans, but the affects are widely scattered based on topography. Corn is rapidly maturing. Lots of leaf diseases and widespread injury from earlier corn borer infestations are apparent. Corn silage harvest is continuing, and grain harvest is beginning on short season crops planted in late April, as moistures fall to low 20%'s. Producers are attempting to harvest the grain and quickly replant to wheat and then wait for more mature corn grains. These fields are yielding close to 100 bu/ac where in 1996, comparable yields would have been closer to 150 bu/ac. Soybeans are turning yellow and beginning to drop leaves. Some shorter maturing beans are beginning to dry down nicely. As stated previously, yields are hard to guestimate. Barley plantings are rapidly developing and winter wheat planting has been progressing.
New seeding of forages look especially good. Light weed pressure for August seedings and just enough moisture to assist development is the norm. Many producers are continuing to harvest alfalfa at this time.
You may recall an early note from Dauphin County regarding an over-planting of corn this spring with populations approaching 44 to 46,000 ppa. Field observations of these fields reveal adequate pollination, but less than ideal weed control in most fields. The ears are small and display classical phosphorous deficiency symptoms. No soil tests to evaluate, but perhaps droughty soil conditions also affected P uptake.
Paul H. Craig
Dauphin County
Soybeans are maturing earlier than usual, presumably due to stress in the later part of the season here. I think we will be harvesting a crop quite a bit below average yield. The number of beans per pod is just not there. Effects of earlier spider mite damage can be seen in earlier leaf drop in the more severely affected areas.
Corn grain yields are down as expected, but also very variable (40-90 bushels/ac reported by some farmers on their early maturing varieties). Hopes are for better yields as we continue the harvest. The bulk of corn silage is in the silo, again with low yields and variability depending on location. As one farmer said, "they're running the tractor on the chopper in a much higher gear this year."
We have been very dry in the last couple of weeks and a gentle rain of about 1/2" on 9/29 has prompted more sowing of small grain. I don't know whether or not we'll see overall increases in small grain planting this fall or not. I have suspicions that some growers have been reminded of how keeping some acreage in a crop like wheat, in a year like this, can be a good asset to protect themselves from having a total failure.
John Rowehl
York County
Corn silage harvest is well under way in the our area. In general, moisture levels seem to be slightly lower than would be expected, considering the milkline of the corn kernels. As a result of our limited moisture this season, corn is much shorter than normal and many of the ears are not filled. The lack of ear fill is not uniform across all fields. I have had reports of ears not filled at the ends, at the base and also some ears missing kernels on one side. John Flanders, our local CMA technician, reports that his silage yield checks are averaging 12 tons per acre.
A few fields have been harvested for high moisture shelled corn, but I think we will need at least a week of good drying weather before the combines start taking many acres off.
Most soybean fields have yellow leaves. Shorter season varieties have actually lost their leaves and have brown pods. Yields look fairly good, some plants I checked have over 60 pods per plant with an average of 2.8 beans per pod. Most of the full season beans should mature before frost, while double-crop beans will be pushed hard to mature.
Pastures continue to produce well, recent rains and cool temperatures have pushed the grasses to heavy fall growth. Soil conditions are excellent for small grain planting to continue into the early part of October.
Greg Hostetter
Mifflin/Juniata/Perry Counties
William S. Curran
Assoc. Prof. Weed Science
William S. Curran
Associate Professor Weed Science
email: wsc2@psu.edu
Website Address: http://fcn.agronomy.psu.edu/