C.O.R.N. Newsletter 2007-35

Dates Covered: 
October 15, 2007 - October 21, 2007
Editor: 
Curtis E. Young

More on Soybean Green Stem

Authors: Jim Beuerlein

There are almost 200 different varieties in the 2007 Ohio Soybean Performance Trials. A few varieties have maintained green stems, and sometimes leaves, for up to three weeks after other varieties of the same maturity dropped their leaves and the stems dried in the normal fashion. As we harvest these green stem plots the grain is as dry as the normal looking varieties and they thresh just as easily. The green stem issue appears to be variety specific at this time, but we have not had a chance to look at their yield and agronomic characteristic to learn more about them. Other varieties have green branches with green leaves and no pods at the bottom of the plant.

We know from previous work that when the pods are removed from a plant node when they first form and start to expand, the leaf at that node will stay green after the rest of the plant matures. If we remove all the small pods from a branch on a plant, that branch will not mature either. Further, if we prevent the setting of pods on the main stem of a plant but allow pods to develop normally on the branches, those branches will mature normally while the main stem stays green and holds onto its leaves. Anatomical studies of the flow of carbohydrates within a plant show that each leaf fills the pods at its nod only, but if all its carbohydrates are not needed at that node, the extra will move to the next lower node. Therefore, soybean plants digest their leaves, petioles and stems to complete the pod filling process and add a few more bushels per acre. If the digestion of plant parts is not needed to complete pod fill, then these plant parts remain green as we have observed this fall. Some viruses can have a similar effect, but our green stem plants do not appear to have a virus.

We have made a list of the varieties in the trial with the green stems, and will attempt to find out more about the condition and provide more information later this year. We should not consider this condition negatively, as it may be a key in moving soybean to a new yield level. If these varieties are producing more carbohydrate than the plants need for a big yield, maybe the plant breeders will be able to hold onto that characteristic and delete the green stem part. In the meantime, the green stems are usually not a deterrent to a somewhat normal harvest. I hope to have more information on this topic later.

Wheat, Aphids, and Barley Yellow Dwarf Virus (BYDV)

Authors: Ron Hammond, Pierce Paul, Bruce Eisley

Having received reports of insecticide spraying on wheat for aphids, we thought it appropriate to discuss the various reasons and options for aphid management. Aphid infestations in wheat great enough to cause economic damage are rare in Ohio. However, aphids can, under certain conditions, build in numbers and damage wheat by feeding on the plant during seedling stages. At this time, the number of aphids being found in most fields is well below the treatment threshold of 50 aphids per linear foot of row.

Most concern is with virus transmission. Most insecticide applications appear to be towards lowering the incidence of BYDV next spring by reducing the number of aphids now, rather than stopping the injury from the aphids themselves. For aphids to successfully transmit the virus, they normally need between 12 and 30 hours feeding to acquire the virus, and then 4 or more hours of feeding to transmit it. However, aphids are capable of acquiring the virus after feeding on infected plants for only 30 minutes and once they acquire the virus, they can transmit it to healthy plants for the rest of their life. High incidences of BYDV had been reported last spring in some parts of Ohio. Some of those fields reportedly had as much as 20% of the plants showing symptoms typical of this disease: erect leaves with yellowish to reddish-purple tips. This disease is caused by several related viruses transmitted by more than 20 different species of aphids. Yield reduction due to BYDV is generally greater when infections occur in the fall than in the spring. BYDV tends to be most severe in fields planted before the fly-free date in which aphid populations reach high levels. However, some fields planted after the fly-free date last year had high levels of BYDV, most likely because of warm temperatures that kept aphids active for a longer time period. Because the past month has seen warmer than normal temperatures, growers are concerned with the potential for problems.

The recommended management tactic for BYWV are: 1) plant varieties less susceptible to BYDV; 2) delay planting until after the Hessian fly safe date to avoid early fall infections; 3) balanced fertility; and 4) controlling volunteer wheat, barley, and oats (for more on BYDV, visit the field crops disease website at http://www.oardc.ohio-state.edu/ohiofieldcropdisease/wheat/byd.htm). Spraying insecticide to control aphids in an attempt to manage BYDV is open to discussion, and usually not a recommend tactic. During active feeding, a few aphids will be enough to transmit the virus from one plant to another. Any aphids present prior to spraying may have already transmitted BYDV, while other aphids may continue to arrive in the field after the spraying. When spraying insecticides to control aphids early, growers should know that the residual effect of the insecticide may not last long enough to protect against later aphid population buildup nor virus transmission. Though insecticides applied after infection will reduce the aphid population, it will not prevent the disease from developing once the plants have been infected. Once infections occur, there is very little that can be done.

Are there situations where it is acceptable to spray for aphids, and where insecticide application might pay? Purdue recently published an article in their newsletter that addresses possible situations (http://extension.entm.purdue.edu/pestcrop/2007/issue25/index.html). These include: 1) wheat under drought stress with aphids present; 2) growing a variety known to be susceptible to BYD with aphids present; 3) wheat being grown for seed; 4) wheat that is highly intensively managed with a 100+ bu/A potential yield; and 5) wheat planted before the fly-free date. If a decision is made to spray an insecticide, see the following web site (http://bugs.osu.edu/ag/545/sgiap.pdf) for a list of labeled materials. However, for most growers, cost-effective control of BYDV may not be possible by aphid spraying.

Phosphorus and Potash Recommendations for Corn and Soybeans

Authors: Edwin Lentz, Robert Mullen

The high cost of phosphorus and potash fertilizer this Fall has many producers closely evaluating their nutrient management programs. In parts of the state where weather conditions may reduce crop yields, soil phosphorus or potassium not removed by the crop will generally accumulate (build-up) for future crops, but how much? A soil test is the key to this question and any questions associated with a nutrient management program. Understanding the relationship between soil levels and crop response should help determine whether your soils have more than adequate, adequate, or deficient levels of phosphorus and potash for next year's corn or soybean crop.

Generally corn or soybeans have more than adequate phosphorus when soil levels are above 40 ppm (80 lb). Additional applications at or above this level will accumulate in the soil but not benefit the crop, and may even cause environmental concerns. At adequate levels (15-30 ppm/30-60 lb), additional phosphorus should be applied to equal the amount removed by the crop. For corn, crop removal equals the yield goal multiplied by 0.35; for soybeans, crop removal equals the yield goal multiplied by 0.83. Between 30-40 ppm application amounts less than crop removal would be recommended. If soil levels were below 15 ppm, then applications would include crop removal and a program that raises the overall soil P level. For example, if soil P levels were 10 ppm (20 lb), then a 160 bu/A corn crop would require 85 lb/A P and a 50 bu/A soybean crop would require 65 lb/A.

Potash recommendations follow the same philosophy as phosphorus except consideration is given for soil cation exchange capacity (CEC). Since applied potash may be held more tightly by soils with high CEC, potash rates increase as the soil CEC increases. Regardless of CEC and yield goals, corn and soybean yields would not respond to additional potash at soil potash levels above 200 ppm (400 lb). Corn and soybeans grown on soils that have a CEC < 10 would not respond to additional potash when the soil test level > 150 ppm (300 lb). Tables on page 14 in the Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat & Alfalfa guide provide potash rates for corn and soybeans at various yield goals and soil CEC. Many private soil testing laboratories have the capability to make recommendations from this guide upon request.

In summary, by understanding your soil tests, phosphorus and potash rates may be reduced without lowering corn and soybean yields. This may be one way to lower input costs during a year of high fertilizer prices. More details on soil fertility may be obtained in Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat, and Alfalfa, Bulletin E-2567, available through you county Extension Office or at the following website: http://ohioline.osu.edu/e2567/index.html. Recommendations from this publication incorporate over 40 years of data from field calibration and correlation studies.

Fall Applied Nitrogen for Corn Production

Authors: Edwin Lentz, Robert Mullen

Each year after soybean harvest, producers may consider applying nitrogen in the Fall for next year's corn crop. There are two main advantages to this practice: 1) nitrogen prices may be lower in the fall than the spring; and 2) time and labor may be more available than spring. However, the big disadvantage is the greater potential for nitrogen loss. In some years this nitrogen loss may cause a yield reduction. In an 8-year study, Ohio State University scientists, Stehouwer and Johnson, showed that average corn yields were about 5% higher from spring applied anhydrous compared to fall applied at the 160 pounds of nitrogen per acre. Without a nitrification inhibitor, the difference was almost 10%. In 2006, Lentz and Mullen again compared fall and spring applied anhydrous ammonia with N-Serv and found no statistical differences between the application times. However, spring applied consistently had larger yields over the three N rates (100, 150, 200). The data would suggest that yields are larger for spring applications compared to fall but the percentage difference will depend upon the weather for a given year.

In summary, fall applied nitrogen is an option for Ohio corn producers, however, since fall applied nitrogen has to remain in the soil for about six to seven months there is a great potential for nitrogen loss. To minimize these losses consider the following management practices:

*Only use anhydrous ammonia. Besides often being the most economical source of nitrogen, it is the slowest of all nitrogen fertilizers to convert to nitrate-nitrogen.

*Use a nitrification inhibitor. These products delay the conversion of ammonium to nitrate-nitrogen. The duration of this delay is weather dependent. Warm weather will shorten the effectiveness of the inhibitor.

*Apply fall nitrogen when soil temperatures stay below 50 F and will remain below 50 F. Generally this occurs after October 20, however, as of Monday October 15, soil temperatures are still averaging around 55 F in the northwest part of the state and 60 F in the western part of the state, so we are still not quite to soil temperatures conducive to nitrogen application. Cooler temperatures will reduce the activity of the bacteria that converts ammonium to nitrate-nitrogen and will decrease the degradation of the nitrification inhibitor.

*Apply fall nitrogen only on well-drained soils. Do not fall apply on sandy ground.

Fall Cutting of Alfalfa

Authors: Mark Sulc

Many Ohio alfalfa producers will likely take another cutting this fall. The late spring freeze followed by dry weather reduced forage yields across Ohio, so producers are now very anxious to harvest any available forage. While fall regrowth is poor to nonexistent in southern Ohio, alfalfa regrowth in central and northern regions of Ohio is very good.

Unfortunately, cutting alfalfa in October can carry serious risk to the health of the stand, especially this year. Many stands were weakened by the late spring freeze earlier this year, and may not have fully recovered from that stress because of the poor growing conditions this past summer. Only now are those stands having the opportunity to recover energy reserves through the vigorous fall regrowth and favorable temperatures and sunshine we've been experiencing.

Cutting now will interrupt the process of storage of energy and proteins in alfalfa taproots. If cut now, regrowth during the remainder of the fall will utilize those taproot reserves, which will result in the plant having lower energy status going into the winter.

But many producers are in a critical situation with the short hay supplies. So how can we reduce the potential for damage from cutting alfalfa stands again this fall?

A LATE fall harvest is a safer alternative than cutting now in mid-October, BUT ONLY IF the soil is well drained. By LATE, I mean as close as possible to a killing frost of alfalfa, which happens when air temperatures reach 25 F for several hours. This often does not happen until sometime in November in Ohio.

I know that the weather is usually lousy in November for cutting forage, but waiting to get closer to the killing frost will prevent late fall regrowth that "burns up" energy reserves, and will reduce the risk of less vigorous stands next spring.

This spring I observed large variations among alfalfa stands in the damage caused by the late spring frost and the ability of those stands to recover. The stands that were healthy and strong suffered much less damage and recovered more quickly from the late freeze than the stands that were weak. Previous cutting during the critical period of fall growth and the resultant low energy status of the alfalfa in the spring was a factor in reducing its ability to recover from that late freeze.

A fall harvest after a killing frost is relatively safe IF the soil is well drained and there is no history or risk of heaving on that particular soil. Without residue cover, the temperature of the soil will fluctuate much more, so the potential for heaving injury is greater. This happened in a study at Wooster, when a November 1st cutting resulted in heaving of about 50% of the plants. Where no fall cutting was made, less than 10% of the plants heaved.

Producers often feel that cutting in October has not damaged their alfalfa stands in the past. But how many leave sections that were not cut in the fall to be able to objectively evaluate whether the fall cutting indeed did not reduce yield the following year?

I am often asked whether leaving a large amount of fall growth can harm the alfalfa stand in the winter. The fear is that the alfalfa will smother itself out. I have let pure stands of alfalfa go into the winter with a lot of growth, even more than we see this fall, and I have never experienced a problem or seen the crop "smother out."

Fall management of alfalfa is one of the few controllable factors that will potentially influence the health of your alfalfa stand next spring. It could play a determining role in how much yield you get next year, as it did this spring after the late freeze. If you don’t need the forage, walk away from it and let it insulate your stand this winter. It won’t smother out because of excessive alfalfa growth.

If you do need the forage now and to get through this winter, then taking a cutting in early November or after a killing frost will reduce the risk of injury to the stand. But try to limit late cutting of alfalfa to well-drained soils with good pH and fertility status. Also leave a 6-inch stubble.

Finally, if you do cut alfalfa this fall, leave some strips or areas that you do not cut within the same field. You might learn something interesting next spring about fall cutting on your farm by having those side-by-side comparisons.

Odds and Ends on Fall Herbicide Treatments

Authors: Mark Loux

This article contains reminders about fall herbicide treatments for several different situations. Fall treatments can be invaluable for control of a number of weeds, including dandelion, poison hemlock, wild carrot, wild turnip, and dense stands of winter annual weeds.

1) Fall herbicide treatments can be applied anytime between now and about Thanksgiving, and possibly later depending upon weather. Because weather can sometimes turn cold and wet in November, we suggest making sure that fields with problem winter weed infestations be treated in a timely manner. Where the harvest workload results in a lack of time to apply herbicides, consider having herbicides custom-applied.

2) In any wheat field that has not yet been planted or where the wheat has not yet emerged, an application of glyphosate is the most effective treatment for control of dandelions and winter annuals. This is a far more effective tool for management of dandelion than any of the herbicides that can be applied to emerged wheat. Application of glyphosate at this time will typically result in wheat that is free of winter weeds next spring. As a result, spring herbicide treatments, where needed, can be timed for best control of early-emerging summer annuals such as giant ragweed, marestail, and lambsquarters.

3) Where glyphosate was not applied prior to emergence of winter wheat, it is possible to apply other herbicides to emerged wheat yet this fall for control of winter annuals. Broadleaf herbicides labeled for application in the fall to emerged wheat include Harmony Extra, bromoxynil, dicamba, Peak, and Sencor. Of these herbicides, Harmony Extra provides the broadest spectrum of control of broadleaf winter annual weeds. There are also four herbicides labeled for fall application to emerged wheat for control of winter annual grasses: including Axial/Axial XL (annual ryegrass); Maverick (downy brome and cheat); Olympus (downy brome and cheat); and Osprey (annual bluegrass and annual ryegrass).

4) We spend a lot of time discussing fall treatments for corn and soybeans, but they can be an effective tool for control of certain weeds in pastures and hayfields. The biennial weeds that are common in pastures, such as bull thistle, burdock, and poison hemlock, can be effectively controlled at this time of the year. This is also the best time of the year to apply herbicides for control of Canada thistle. Unfortunately, all of the herbicides that control these weeds will also injure or kill any desirable legumes in the pasture. See the "Pasture" section of the "Weed Control Guide for Ohio and Indiana" for more information on herbicide effectiveness on specific weeds.

5) Late-summer seedings of alfalfa often become infested with winter annual weeds, such as chickweed, mustards, field pennycress, wild turnip, and wild radish. These weeds can compete with the alfalfa in the fall and early spring, reducing the health of the stand and the quality of the first cutting next spring. Wild radish and wild turnip can be extremely difficult to control in the spring, because overwintering plants already have a well-developed, large root by the time herbicides can be applied. Fall herbicide treatments provide the most effective control of these two weeds. We have somewhat limited research on the control of wild radish and wild turnip, but results so far show that Butyrac (2 qts/A) or Pursuit plus Butyrac plus COC (1.44 oz + 1 qt/A + 1%v/v) are among the most effective treatments. Pursuit will injure any grasses in the field, especially in new seedings. Pursuit will provide the greatest activity (suppression only) on common chickweed. Pursuit will provide the greatest residual control of all of the herbicides available to be applied to late-summer seedings of alfalfa. If the alfalfa was recently cut, allow enough regrowth of alfalfa and weeds to maximize control. If the alfalfa will still be harvested, either apply herbicides and wait for the harvest restrictions or harvest this week and allow for regrowth before applying herbicides.

Nutrient Value of Manure

Authors: Robert Mullen, Edwin Lentz

Manure is an excellent nutrient resource that many of our agronomic producers have at their disposal; the question is - what is its nutrient value? This, unfortunately, is not an easily answered question. The best way to determine the nutrient value of a manure resource is to have the material analyzed and determine its chemical characteristics (i.e. nitrogen, phosphorus, potassium, etc.). Based on manure analysis, we can determine how much of the manure should be supplied to meet a crop's nutrient demand.

Nitrogen (N) is typically the nutrient in the greatest demand, and it is also the most difficult to predict its availability. Nitrogen can be subject to several transformations, and some of these transformations result in nitrogen loss from the soil-plant system. Volatilization is the loss of ammonia-nitrogen from the soil surface typically from the surface application of manure. Once the ammonia is lost to the atmosphere it will not return (not in a given year anyway). Nitrification is the transformation of ammonium-N to nitrate-N, a soluble form of nitrogen that can move readily within the soil profile. Nitrate-N can be lost from the soil solution by leaching (downward movement within the soil profile) or by denitrification (biological conversion of nitrate-N to nitrous/nitric oxide that is lost to the atmosphere).

Manure nitrogen is present in two forms - organic-N and ammonium-N. Plants can not readily utilize organic-N (remember plants only use inorganic nutrients), so it must be mineralized into ammonium-N. Ohio State University assumes that for most animal manures 33% of the organic-N fraction will be mineralized within the first year. Ammonium-N availability from manure is dependent upon timing and method of application. Manure applied just prior to seeding that is incorporated would be considered readily available for plant uptake with little chance of loss prior to plant demand. Additional information on calculating N availability can be found in Ohio State University Bulletin 604 (http://ohioline.osu.edu/b604/pdfb604.pdf). Phosphorus and potassium from manure are assumed to be as available as commercial forms of fertilizer.

If manure analysis is not used to determine nutrient content, then book values must be used. This is not the recommended method of determining manure application rates, but in the absence of analysis it is the only alternative. Average manure nutrient values based on animal types, animal numbers, and storage type can be calculated in an Excel spreadsheet available for download at the following webpage (https://agcrops.osu.edu/fertility/documents/OSU_manure_balance_calculator_locked.xls). Nutrient values can also be found in Ohio State University Bulleting 604.

The difficulty in properly allocating manure nutrients is that manure is an unbalanced form of fertilizer. Manure application rates based on N availability usually result in over-application of phosphorus, and conversely, manure application rates based on phosphorus usually result in the under-application of nitrogen. Soil testing can reveal phosphorus need and can determine if application of manure is warranted from both an agronomic and environmental perspective.

There is much more to be said about manure nutrient management than contained in this short newsletter article. This is simply a starting point for manure nutrient management. Using a combination of manure analysis, soil testing, and simple calculations, you can better allocate manure nutrients.
 

Managing the value of Manure

Authors: Jon Rausch, Tami Combs

Animal manure is one of the most complete nutrient resources for agronomic crops. However, like other fertilizers it requires management to capitalize on its economic value. Manure has its complications. Air and water quality can become an issue when it is not properly managed.

Nutrient testing programs establish the foundation for developing sound manure management practices. Routine manure testing provides the farmers with a good estimate of the nutrients contained within the manure. In the same way, routine soil testing provides an estimate of the nutrients contained within the soil profile and determines if excess nutrients are accumulating in the soil. These results in conjunction with realistic crop yield goals will establish an agronomic application rate for manure, which is necessary to meet the nutrient requirements of a growing crop. However, agronomic application rates do not always match the environmental limitations of the field or soil.

Typically, liquid manure requires more management than more solid forms of manure. As the water content of manure increases manure can more easily move off-site. At times the agronomic rate may exceed the application rate needed to minimize the potential for manure to move off-site and cause an environmental problem. For liquid manure this environmental rate is closely related to the available water holding capacity of the soil on the day of application. It is recommended that liquid manure be applied at the rate limited by either crop nutrient needs or the available water holding capacity of the soil. This optimized manure application rate will minimize ponding and the downward movement of liquid manure on artificially drained soils. If the soil is approaching saturation, the total volume of manure applied will be limited by the available water holding capacity of the soil.

Dry soils present additional needs. Relatively dry soils can hold a large volume of water before becoming saturated. Those dry soils may also crack presenting a direct conduit to subsurface drain/tiles. Prior tillage may be necessary to disrupt the cracks and aid in liquid absorption. The appropriate application rate will balance the ability of the soil to absorb and hold the manure and the nutrients content of the manure. In some cases, multiple reduced rate application passes may be necessary to achieve the desired nutrients. The bottom line is manure must be managed in order to maximize its nutrient and biological benefits.

Furthermore, equipment calibration is critical component of a sound application program. Manure nutrients are not fully utilized unless they are applied in the correct place and at the correct time. If producers are not reasonably certain of the quantity of the manure applied, it is very difficult to estimate the quantity of nutrients supplied by the manure application. Equipment that is not properly calibrated could cause manure nutrients to be over applied or under applied, reducing crop yields.

The even distribution of manure over the land surface also affects the value of manure nutrients. Application equipment that concentrates the flow of liquid manure into a relatively narrow band will have an application rate significantly higher in that band than the rate achieved if manure had been evenly distribute between these narrow bands. If injection is desired consider using narrower spacing to reduce the volume from individual injection points (or a disk type implement with a distribution manifold for even distribution across the swath). If injection is used, it should only be deep enough to cover the manure with soil, keeping the nutrients in the root zone.

When entering a field for manure application observe where environmentally sensitive areas, for example, ditches, grassed waterway, surface drains, property boundaries, drinking water wells, residential boundaries public access areas, stand pipes or tile inlets, buffer strips, wet areas and tile blow-outs. Be aware of the field conditions for example, surface residue cover, field slope, soil moisture, wind direction and speed, temperature, humidity, time of day, and the weather forecast. All of these factors will determine when, where and how much, if any, manure should be applied on that day. Established setbacks from sensitive areas can be found in Natural Resources Conservation Service, Practice Standard 633, Waste Utilization and Ohio Livestock Manure Management Guide (Bulletin 604). A copy of the practice standard and/or Bulletin 604 is available through your local SWCD/NRCS or OSUE office.

To put it simply, the value of manure is directly related to the management of that manure before, during and after application. Manure nutrient management balances nutrient resources available from manure and soil with the needs of the crop and field limitation. Calibration of the application equipment, awareness of environmentally sensitive areas and available water holding capacity of the soils are good management practices to help minimize the potential unwanted environmental impacts. The value of manure is in its proper management.
 

Western Corn Rootworm Recommendations for 2008

Authors: Ron Hammond, Bruce Eisley

As we get into harvest, growers are already making plans for their 2008 planting season including ordering corn hybrids with or without seed treatments. Because we continued to see high levels of corn rootworm injury this past summer, both in corn following corn and in first year corn following soybean, a review of management recommendations are in order.

As in 2006, we saw rootworm root feeding injury ratings well over 1, at least one node missing, in many fields. And if you read the CORN article last week on the western corn rootworm variant, you know that this variant continued to be sampled from soybeans in numbers at or over the threshold in many fields in western and northwest Ohio. Thus, there are many management decisions that need to be considered.

If not in an area where the first year corn rootworm variant is considered a problem, rotation is still your first and best option. Rotation will break the rootworm cycle and prevent injury because the field will be in a non-host crop. If near one of these areas where the rootworm variant was at or above thresholds in the trap collections, you might want to consider treating your first year corn. If trapped fields in your area were not at threshold (still the majority of fields), you should consider not treating. See last week's CORN article for more information. If growing corn following corn, there is still a chance that treatment will not be needed, but unless the field was scouted for rootworm adults in August, it is not possible to predict if rootworm will be a problem or not. Thus, most growers will probably choose to take preventive action when growing corn following corn. If it is decided that a field needs to be treated for corn rootworm, there are a number of management options that can be used for control.

Granular Insecticides - There are a number of granular insecticides that are labeled for rootworm control. All do a good job against low to moderate populations (the typical level in Ohio) of rootworm and some do a good job against higher levels. The most important thing about using granules is to make sure the granular equipment is properly calibrated and the granules are applied properly at planting.

Liquid Insecticides - Several liquid insecticides are labeled for corn rootworm larvae. They do as good a job against rootworm larvae as some of the other options on the market. As with the granules, it is important the liquid application equipments be properly calibrated and the material delivered properly at planting.

Seed Treatments - Currently there are two seed treatments, Cruiser and Poncho, labeled at 1.25 mg ai/seed for rootworm larval control. They do a good job against low to moderate populations but may not do a good job against high populations. They will probably do a good job against most of the rootworm populations we encounter in Ohio but if in an area where the rootworm was a severe problem in 2007, we suggest NOT using them for rootworm management. If one of the seed treatments is used, it is important to follow company directions concerning hopper box additives to make sure the seed flows properly.

Bt-Rootworm hybrids - There are three Bt-rootworm proteins (YieldGard Rootworm, Plus, VT, VT Triple; Herculex RW or Extra; and Agrisure RW, CB/RW, or 3000GT) that can be used to control the rootworm. Hybrids with the Bt-rootworm proteins do a good job of controlling rootworm against all levels, even high ones. There are things to remember if using a transgenic hybrid containing the Bt-rootworm toxin. First, these hybrids will come treated with the low rate of an insecticide seed treatment to control secondary soil insect pests. Second, and foremost, you MUST plant a 20% refuge within or adjacent to your Bt-hybrid corn. This is not an option. Your seed dealer should provide you with detailed information on this refuge requirement; we will discuss some of these requirements in next week’s CORN newsletter. When considering how you might treat that 20% refuge for rootworm control, you can use granules, liquids, or seed treatments.

Comprehensive Nutrient Management Plan Provider Workshop

Authors: Greg LaBarge

A session which lays the ground work for Technical Service Providers, NRCS and SWCD to provide Comprehensive Nutrient Management Plans to farmer clientele is scheduled for November 13, 14 and 15. The program is approved for those who wish to do plans for farmers in Ohio, Michigan and Indiana. Sessions will highlight the information that goes into development of a CNMP and software that is available to do the work necessary to complete a plan.

A listing of the process to become certified can be found state at the following websites: Ohio (http://www.oh.nrcs.usda.gov/technical/cnmp.html), Michigan (http://www.maeap.org/modules.php?name=DocReader&op=showCat&cid=79&mt=2) and Indiana (http://www.in.nrcs.usda.gov/tsp.html).

Participants will need to do additional work beyond the course above and complete a approved plan to reach full certification status. By participation in this workshops potential plan providers can map out a individualized plan to reach full certification.

A complete copy of the agenda can be found and registration material can be found at: https://agcrops.osu.edu/calendar/. For more information contact Greg LaBarge, Extension Educator OSU Extension-Fulton County at 419-337-9210 or labarge.1@osu.edu.
 

The Agronomic Crops Team Remembers Steve Ruhl

OSU Extension lost a friend and a wonderful County Extension Educator when Steve Ruhl of Morrow County died unexpectedly on October 1, 2007. Steve was an Associate Professor for The Ohio State University and served as the Agriculture Extension Educator for Morrow County and part time for Marion County. For his efforts Steve won numerous awards, which include four team teaching awards from the Ohio Chapter of Epsilon Sigma Phi and the Distinguished Service Award which is the highest award granted to an Agricultural Extension Educator in 1997. Steve is survived by his wife, Deb and three sons: Kevin Ruhl, Jason (Christina) Ruhl both of Mount Gilead, and Brian (Chelsey Ault) Ruhl of Ontario. Memorial contributions may be made to the Steve Ruhl Agricultural Scholarship Fund, c/o First Federal Bank, 70 N. Main St., Mount Gilead, Ohio 43338. Steve was a true "County Agent" and will be missed by OSU Extension and all the farmers he served.

Archive Issue Contributors: 

State Specialists: Ann Dorrance, and Pierce Paul (Plant Pathology), Ron Hammond, Andy Michel and Bruce Eisley (Entomology), Mark Loux and Jeff Stachler (Weed Science), Robert Mullen (Soil Fertility), Mark Sulc (Forage Production), Jon Rausch and Tami Combs (Environmental Management Program), and Jim Beuerlein (Small Grains). Extension Educators: Harold Watters (Champaign), Howard Siegrist (Licking), Roger Bender (Shelby), Glen Arnold (Putnam), Ed Lentz (Seneca), Wes Haun (Logan), Mike Gastier (Huron), Steve Foster (Darke), Gary Wilson (Hancock), Alan Sundermeier (Wood), Todd Mangen (Mercer), Greg LaBarge (Fulton), Mark Koenig (Sandusky), and Curtis Young (Allen).

About the C.O.R.N. Newsletter

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.