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October 8, 1999 Vol. 99.11

IN THIS ISSUE:

Mark Your Calendar

Production

Pest Management

Agents Corner

Mark Your Calendar:

AGRONOMY AG-SERVICE SCHOOLS SET

Ever wonder what the long-term outlook and problems are for Genetically Modified Organisms (GMO's)? Need a little refresher on Fertility Management for maximum yields and drought conditions? Want to avoid bill collection problems? The Agronomy Ag-Service Schools for 1999 will address these issues and more. Make plans now to attend. Register with your local county Cooperative Extension office.

Date Location
Nov. 9 Meadville
Nov. 10 Somerset area
Dec. 7 Williamsport
Dec. 8 Reading
Dec. 9 Lancaster
Dec. 10 Carlisle

Marvin Hall, Agronomy, Forages

SUSTAINABLE CROP MANAGEMENT: I. SOIL MANAGEMENT WORKSHOP - DECEMBER 14 (HARRISBURG, PA) AND DECEMBER 15 (ANNAPOLIS, MD)

A lot of interest and discussion has developed recently about the importance of soil health factors related to sustainable and profitable crop production. This workshop will focus on the use of cover crops, crop rotations and tillage practices, and their relationship to developing and maintaining soil health properties that contribute to sustainable crop production. The program consists of two workshops for Certified Crop Advisers (CCAs) in the mid-Atlantic region; one in Pennsylvania and one in Maryland. Nationally know researchers and educators from Iowa, Indiana, Pennsylvania, and Maryland will lead the workshop.

The workshop will be in Harrisburg, PA on December 14 and Annapolis, MD on December 15, 1999. Mark these dates on your calendar. You will be receiving registration information shortly.

Application has been made for the following CCA CEU's: 4.0 Soil/Water and 1.0 Crop Management.

If you have questions relating to the program contact either John Ayers at 814-865-7776 or Elwood Hatley at 814-863-1013.

Elwood Hatley, Agronomy

Production:

CORN MANAGEMENT UPDATE

Despite the drought, 1999 was a relatively good year for our research program. Although the season is far from over, I thought it might be interesting to share a few of our observations from the year.

In a project we conducted with Advanced Agronomics and Skyview Laboratories, we analyzed drought stunted 6 to 7 foot tall corn for moisture and quality in late August. Whole plant moistures (72 to 74%) were higher than expected based on visual appearance. Crude protein, Potassium, Calcium, and DCAD were all higher than normal. Energy (NEL) averaged 0.64 compared to 0.70 in a normal year.

In silage trials we conducted in Lebanon and Lancaster this year, we found similar trends as well except we also measured lower lignin levels and lower lignin/NDF ratios. Thus, while the drought reduced the overall energy content of the silage because of reduced grain, the quality of the fiber produced should be increased.

Our hybrid by population trials have not been harvested, but it is apparent that both hybrid and populations seemed to have an effect. Some hybrids tolerated the drought better than others and the high (32,000 and 36,000 per acre) populations significantly reduced ear size.

At our Hershey location, the non Bt hybrids encountered severe late season corn borer pressure (4 to 5 cavities/plant) that affected lodging and ear mold incidence.

We conducted two liquid starter fertilizer trials this year on high P and K testing soils. We saw little visual difference among the treatments, which included various N/P ratios, K and S analyses. In another starter trial conducted by extension agent, John Rowehl, in York County, we observed patches of K deficiency where no starter was used, but this problem was eliminated where we used 140 lb/A of 10-20-20. This soil tested about 2.0% K saturation over-all, but in the deficient areas tested about 1.5% K.

We also continued our corn grazing program. We grazed corn with dairy heifers at the milk or dough stage. About 30% of the corn, mostly the lower stalks, was not utilized. The animals consume virtually all of the ears and most of the leaves. While this wastage is frustrating, it's not really that much different than harvesting hi moisture ear corn or "hi-chop" silage - without the machinery. This practice seems to be best suited for smaller farms that can effectively utilize a late season, high-energy grazing crop.

We have several other trials that are still being evaluated. We'll pass along the results, as they are available.

Gregory Roth/Mark Antle
Agronomy

POLLINATION PROBLEMS COMMON THIS YEAR

Now that many folks are getting out and inspecting their corn fields during harvest, the effects of the past season on the corn pollination are becoming evident. The biggest cause of poor pollination this year was the effect of drought on the timing of pollen shed and silk emergence. When stressed, the corn plant will often go ahead and shed pollen before the silks emerge. This happens because silk development is usually delayed more under water stress than tassel emergence. I visited one of my research trials on July 15 and the tassels had shed half of their pollen and virtually none of the silks were emerged yet.

Often the last silks from the ear tip emerge when pollen production is over, resulting in poorly pollinated ear tips. This year pollination is more widespread than just the ear tip, though. This was probably due to a very wide gap between pollen shed and silk emergence, which created a real shortage of pollen. In addition, very high populations (10 beetles/plant) of rootworm beetles in many fields kept silks clipped and further reduced the potential for pollination. Late emerging plants were especially hard hit since the beetles were attracted to the green silks on these late plants. Similarly, late hybrids in a strip test could also be unusually affected by the beetles. Pollen viability could also be affected by high temperatures over 90°F degrees.

Factors that help contribute to especially poor pollination would be those that exacerbate drought stress- lack of weed control, shallow soils, and high plant populations. Also, there are some differences among hybrids and their ability to tolerate stress. Fortunately, in many years pollination problems like this are somewhat of a rarity, given the good drought tolerance of many modern hybrids.

Greg Roth, Agronomy

Pest Management:

CONTROL OF PERENNIAL WEED SEEDLINGS WITH SOIL-APPLIED HERBICIDES

I have been asked a number of times over the years, about the effectiveness of some soil-applied herbicides for control of perennial weeds that emerge from seed. Fortunately, my colleague to the South decided to do more than simply guesstimate. Dr. Mark VanGessel from the University of Delaware, Georgetown, did an experiment where he examined the performance of several soil applied corn and soybean herbicides for the control of several herbaceous perennials from seed. The results of his study were published recently in Weed Technology 13:425-428. Here is a summary of his findings.

Dr. VanGessel evaluated eleven herbicides from several different families on the control of seven different perennials from seed, including bermudagrass, johnsongrass, hemp dogbane, common milkweed, Canada thistle, common pokeweed, and horsenettle. He sowed seed from each of these weed species in flats and sprayed them immediately following planting. The flats were placed in the greenhouse, provided with ample water and sunlight, and evaluated for percent control five weeks after treatment. The experiment was repeated two to three times, depending on the weed species. Dr. VanGessel conducted his study using a sandy loam soil typical of Delaware and herbicide rates typically lower than we would use on our silt loam soils of Pennsylvania. However, I would expect the same general trends to hold true here in Pennsylvania.

The following table provides the research results in detail, but here's a quick summary. Hemp dogbane and common pokeweed were controlled by eight of the eleven herbicides in the study, indicating they may be the two most susceptible species in the trial. Dual and Prowl provided control of only bermudagrass, and Lorox controlled only Canada thistle. FirstRate controlled all species except bermudagrass. Command provided greater than 80% control of all species except horsenettle and Scepter provided at least 80% control of all species except common milkweed. Sencor alone or in combination with Classic (Canopy), provided the broadest spectrum and highest level of control. Sencor provided greater than 85% control of all species except johnsongrass. The results of this experiment certainly prove that soil applied herbicides can indeed help limit the establishment of certain perennials species from seed.

Herbicide Product/acre Bermuda-grass Johnson-grass Hemp dogbane Common milkweed Canada thistle Common pokeweed Horse-nettle
Atrazine 90DF 13.3 oz 87 22 100 85 99 84 96
Authority 75DF 4.2 oz 41 41 100 64 73 90 65
Canopy 75DF 4 oz 88 80 100 97 99 96 89
Command 3ME 2 pt 99 97 98 91 99 86 38
Dual 8E 1.25 pt 100 33 69 75 30 16 28
FirstRate 84WDG 0.51 oz 32 85 92 86 98 95 91
Lorox 50DF 10.6 oz 56 27 58 32 88 36 48
Prowl 3.3E 1.2 pt 94 38 44 56 34 28 26
Python 80WDG 0.71 oz 65 76 81 80 98 92 81
Scepter 70DG 2.8 oz 84 86 81 77 91 86 80
Sencor 75DF 5.33 oz 94 76 100 99 100 88 96
LSD (0.05)   13 18 10 10 15 17 13

Bill Curran, Agronomy

HARVEST AIDS FOR CORN, SOYBEANS, AND ALFALFA

Soybean and corn grain is beginning, but there may still be the need to desiccate weeds prior to harvest in some fields. In addition, some opportunities for control of weeds in alfalfa or for control of an old alfalfa sod also exist. One or two changes have occurred within the last year that may help some producers harvest more grain or forage, or do a better job in managing their weed problems.

Corn

Certain formulations of 2,4-D are registered for pre-harvest use in corn. Check the 2,4-D label for specific use. Corn must be in the hard dough to dent stage and weeds must still be alive. Application may be made by high clearance equipment, by aerial application, or by hand. The rate range is 1 to 2.5 pints per acre depending on formulation and manufacturer. Do not forage or feed fodder for 7 days after treatment.

Sodium chlorate, a quick acting desiccant used widely in cotton, has a federal label as a harvest aid in both corn and soybeans. Agro Distributors (formerly Riverside/Terra Corporation), as well as several other companies, sell at least two different formulations of sodium chlorate. Check with your local dealer/distributor for more information about sodium chlorate use and availability. This product may have limited use in corn in our area since it must be applied by air.

Roundup Ultra 4S may be applied up to 3 quarts per acre 7 days or more prior to harvest. Application is made at 35% grain moisture or less and after the maximum kernel fill is complete and black layer has occurred. Application prior to this stage may reduce yield. It should not be applied to corn grown for seed. Although the harvest aid application may reduce corn grain moisture and improve drydown, results may vary. Roundup may be applied as a harvest aid in corn using either aerial or ground spray equipment.

Soybeans

Clarity 4S has been labeled for use as a preharvest application to control broadleaf weeds prior to soybean harvest. Apply 8-64 fluid ounces per acre Clarity as a broadcast or spot treatment to emerged or actively growing weeds after soybean pods have reached mature brown color and at least 75% leaf drop has occurred. A waiting interval or 14 days is required before harvest. Do not feed soybean fodder or hay following a preharvest treatment of Clarity.

Gramoxone Extra 2.5S may be used for drying weeds just before harvest in soybeans. Gramoxone will not desiccate black nightshade berries, but Penn State research showed that it will quicken berry drop. For indeterminate soybean varieties, plants must be mature (65% of the seed pods have reached a mature brown color or seed moisture is 30 percent or less). The rate is 12.8 ounces of Gramoxone Extra per acre and 1 quart of nonionic surfactant per 100 gallons of spray should be added. Do not pasture livestock within 15 days of treatment and remove livestock from treated fields at least 30 days before slaughter.

Roundup Ultra 4S may be used up to 6 quarts per acre prior to soybean harvest. This may be a good opportunity to attempt control of perennials such as quackgrass or Canada thistle. For perennial control, be sure that the plants have healthy green leaves at application time. Apply Roundup to soybeans after pods have set and lost all green color (80-90% drop of leaves has occurred). Allow a minimum of 7 days between application and harvest. Do not graze or harvest the treated crop for livestock feed within 25 days of application. The application rate is similar to other Roundup uses ranging from 1 to 3 quarts per acre. Do not use on soybeans grown for seed.

Touchdown 5L was recently labeled for preharvest application in soybeans. Apply up to 1.6 pints per acre Touchdown to mature soybeans when pods have lost their color to control weeds that may interfere with harvest or to control perennials. Including ammonium sulfate at 8.5 to 17 lb per 100 gallons of spray solution may improve control. Do not apply more than 12.8 pints per acre per year. Make preharvest applications at least 7 days before harvest. Do not graze or harvest for hay following harvest aid application.

Alfalfa

Roundup Ultra 4S preharvest application in alfalfa is aimed at the control of certain perennials such as quackgrass prior to rotation away from alfalfa. Apply Roundup at 1 quart per acre (maximum rate allowed). Treated alfalfa may be harvested 36 hours to 7 days after application (5 to 7 days will provide better weed control). The alfalfa stand should be actively growing (8-12 inches or more and as close to early bud to bloom stage as possible). Late summer or fall applications are more effective on perennial weeds as well as on alfalfa or perennial forage grasses. Follow-up tillage improves the control of some weeds such as dandelion as well as alfalfa. Plowing the treated forage following harvest or an additional herbicide application may be necessary for complete control of the alfalfa. In addition, adequate spray coverage of the target species within the alfalfa forage may be a concern.

Where this label may have some utility for Pennsylvania forage producers is in the control of certain cool-season perennial grasses such as quackgrass and orchardgrass prior to rotation. Application in the fall is most effective on these grasses. Although application in late spring has traditionally been less effective in controlling most perennial species including alfalfa, this strategy could help those producers that frequently try to capture both that first cutting hay and timely no-till corn planting.

Bill Curran and Dwight Lingenfelter,
Agronomy, Weed Science

Agents Corner:

BERKS COUNTY

Crop producers are focused on harvesting whatever crop is salvageable, here in Berks County. My estimate of 60-70% loss, just in our corn crop back in early August, is looking conservative. Corn yields that I have heard through producers and custom harvesters are 0-40 BU/A. Many silage fields are at 3-10T/A yield. Soybean yields are estimated to be at a high of 15-30 bu/A, but I know there are fields with less than that. Some soybean fields were taken for forage back in August. For the first time in my extension career of 19 years, I have seen soybeans die in the field!

Hurricane Floyd brought 6-9 inches of rain. I have seen horrible gullying in open fields. The 40-50 MPH wind blew over what corn crop was in the field. Although a lot of corn has been taken off, especially on shale ground where the most damage is, corn grain is starting to mold.

And how are clients coping? The group of producers most affected are grain farmers and independent livestock producers (yes, some of them are hanging on for dear life). Most dairy producers have forage available, but all say they will have to buy grain, not hay.

The positive aspect of the fall rain is that pastures have rebound and that a final cutting of hay will be taken. Producers have experimented with planting sorghum sudan grass and small grains as supplemental forage. For the past month, wheat also has been planted.

Mena Hautau
Berks County

CENTRE/CLINTON COUNTIES

Corn silage harvest has been completed and grain harvests have not yet begun, except for some high moisture corn. Recent rains have delayed some small grain plantings, but a lot of the wheat and barley have been planted.

Corn silage yields varied across the counties, depending on the amount of rain received this summer. I've heard of yields from 11 to 22 tons/acre. There were probably some lower yields than that, but nobody wants to talk about them.

We received a light frost on October 6, but the soybeans had long since stopped growing and many have lost their leaves. Bean yields will likely be lower than average, as many plants have pods very close to the ground and the beans themselves are rather small.

Fall plowing continues and cover crops are being sown in some cornfields that were harvested for silage. I've seen rye sprouting in several fields.

Some farmers are still harvesting alfalfa and hay crops. One farmer told me that his fourth cutting was the highest yielding cutting he had this year.

Gary Dauberman
Centre/Clinton Counties

MIFFLIN/JUNIATA/PERRY COUNTIES

After 5+ inches of rain, agriculture in Central PA is back in the business of growing. Fourth cutting alfalfa as well as grass, hay, and pastures have shown tremendous growth over the last three weeks. The challenge now will be to get these fields harvested. Haylage and wrapped round bales seems to be the preferred harvest methods for most farmers.

The recent moisture has allowed some of the later planted corn to grow quite a lot over the last two weeks. Some fields that I thought were never going to grow over two feet tall are now over 6 feet. Unfortunately these fields will not be able to make much in the way of ears. Also, some cornfields that still are extremely short have managed to put on a fairly nice ear. These situations are going to be good for the folks who have cattle that will be able to utilize the corn as silage. Grain producers are definitely going to be harvesting lower yields of poorer quality grain this year. In fact, I have had some reports of corn being disked down because it had no ears and the farmer could not find a buyer for the crop as silage.

The jury is still out on the soybean crop. In general the soybean plants are much shorter than normal. This will definitely result in fewer pods and less beans. We will need to wait until harvest to see if the beans actually are any larger or heavier than normal. Most of the leaves on the soybean plants are yellow or have fallen at this time. In most fields there are areas with green plants due to uneven emergence this past spring.

Postemergent weed control seemed to do very well in our area this year. The dry conditions kept later weed flushes to a minimum so that early as well as late postemergent applications resulted in very clean fields. Single application programs performed well and looked extremely economical under this year's growing conditions. I doubt that these single-pass, "post" programs would do quite so well in years with more rainfall.

The general economic condition of agriculture in Central PA is fair. Dairy producers will be able to use the crops this year to the greatest financial advantage. Farmers who primarily grow and sell grain crops will be hit with lower yields and poor prices. Most farmers should be able to weather these problems in 1999, but if 2000 is not a profitable year I suspect some will be forced to leave the farming business.

Greg Hostetter
Juniata County

William S. Curran
Associate Professor Weed Science
email: wsc2@psu.edu

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