March 14, 1997 Vol. 97.1
IN THIS ISSUE:Welcome to the first issue of the 1997 Field Crop News. As in the past, this newsletter will attempt to provide timely crop management information. New subscribers, address changes, or comments and suggestions should be sent to Lisa Crytser at 116 ASI Bldg., University Park, PA 16802, (814) 865-2543, CRYTSER@AGRONOMY.CAS.PSU.EDU. In addition, this newsletter will be available via the World Wide Web through the Department of Agronomy Homepage. You can access this information at: http://www.cas.psu.edu/docs/ casdept/agronomy/extension/fcn/fcnindex.html
Hopefully you have noticed the recent articles and advertisements in Lancaster Farming. These are supported by the CCA State Board to increase farm level recognition of the program. In order for the state office to answer inquiries about the availability of CCA's in particular areas, we ask that you notify the state office with (1) your address and phone, (2) your company name and phone, and (3) the counties you service. Mail this information to 1408 Mission Road, Lancaster PA, 17601.
The PA CCA board has agreed to accept CEU's from approved self study programs. The national board has instituted this program as another way for CCA's to obtain CEU's. A self study program must be approved by the national or state boards for CCA's to receive CEU's. I believe a self study article has been included in the last three editions of the Ag Consultant magazine.
Elwood Hatley, CCA
Weed Science Field Days, July 10 and 11
Now is the time to get corn planters ready for the busy spring season ahead. Time spent maintaining and evaluating planter parts for wear will translate into better stands this spring and ultimately higher yields next fall.
A three hour satellite transmitted corn planter clinic was held at Penn State's Ag Arena on February 18. This excellent clinic is available on tape for a nominal charge. Tapes may be ordered by calling 814-865-6309. Since one picture is worth a thousand words - this tape is more effective than "zillions" of words.
Lynn Hoffman
Much of our wheat acreage was seeded late and as a result went into the winter with limited growth. This, plus the environmental conditions encountered this winter could result in increased winter kill. Fields should be evaluated as the plants start growth and green-up this spring. Satisfactory yields depend on having approximately 40 heads per linear foot of row when planted in seven inch rows. To achieve this, we need a stand of 18 to 20 plants per foot of row. Winter grains plants have the ability to increase tiller production as the population is reduced. This reduces the effect of low populations on yield. However, populations can be reduced to the point that the land area should be replanted into another crop later in the spring. This occurs when we have about a 50% stand remaining or 9 to 10 plants per linear foot of row.
The rate, amount and timing of spring applied nitrogen depends on several factors:
There are several reasons we continually stress the importance of seeding spring oats early. Oats are a short day, cool season crop. It is sensitive to high temperature and moisture stress at flowering. Early planting reduces the probability of these stress factors occurring during this critical period. Oats are also very sensitive to soil temperatures at planting. Research has shown that yield starts declining as soil temperatures rise above 45 degrees at planting. Combining the effects of warm soils at planting with increased potential for environmental stress at flowering can greatly reduce the potential yield from spring planted oats.
Elwood Hatley, CCA
Recently, while I was reading through some farm magazines and research reports from New Zealand, something jumped out at me that left me shaking my head. I thought that you may find it equally as interesting.
For several years, farmers in the United States who are rotationally grazing their animals have looked to New Zealand for the "latest and best" technology in grazing. Forage species that have been developed in New Zealand (e.g. chicory, brassicas, plantain, and many perennial ryegrass varieties) have been purchased "like hot cakes" here the U.S. Several of these forage species have been advertised as crops that will continue to grow during our hot and dry "summer slump" period, and in deed several of them will.
However, New Zealand researchers and farmers are not convinced they have found the best solution to slow pasture growth during the summer. Consequently, they are evaluating some "new" forage species for their summer growth potential. The bulk of this work involves three species that we would be familiar with: orchardgrass, smooth bromegrass, and reed canarygrass! That's right, three grass species that we have all around Pennsylvania. There is a large on-farm research project in the biggest dairy region of New Zealand looking at these three grass species for continued forage production during the warm and dry summer months.
This is what has me shaking my head. While some Pennsylvania farmers are killing their orchardgrass pastures and planting new forage species from New Zealand, the New Zealand farmers are killing their pastures and planting orchardgrass! Isn't it amazing? What goes around, comes around.
Marvin Hall
Crownvetch and birdsfoot trefoil can be used as perennial living mulches in the production of corn, soybeans, small grains and forages. The primary benefit is the almost total reduction in soil erosion. Other benefits are enhanced productivity through soil conservation, increased soil organic matter and organic nitrogen, improved soil tilth, better footing during spring planting and fall harvesting seasons when it might otherwise be too wet to get into the field. Positive side effects include a reduction in environmental pollution from soil, nutrient and pesticide runoff, recycling of nutrients from deeper in the soil profile and more flexibility in meeting soil erosion criteria, including increasing the amount of corn and soybeans that can be grown on sloping cropland than otherwise would be allowed.
With the recent introduction of imidazolinone resistant (IMI) corn and a weed control program based on Pursuit, it is now possible to establish these legumes in corn without injuring the corn or the legume ground cover. Crownvetch is very slow to establish but once established, it will persist forever with the right management. Birdsfoot trefoil provides quick cover but gradually thins out over a period of years as a result of crownvetch competition and chemical suppression, leaving a predominately crownvetch cover. Corn of any kind can be planted into a one year old stand of birdsfoot trefoil and crownvetch using a recommended rate of Basis for weed control with little or no injury to the cover crop or corn. Examine a Basis label for complete use rate and application timing guidelines. Atrazine at a rate of 0.5 to 0.75 lb/A needs to be tank mixed with Basis to suppress the birdsfoot trefoil so it won't compete with the corn. Generally corn yields have not been suppressed when cover crop suppression is 95 to 98% for the first six weeks after planting. Fortunately crownvetch and most of the birdsfoot trefoil will recover and provide up to 80% ground cover by fall even after suppression of this magnitude early in the summer.
Birdsfoot trefoil that is one year old and crownvetch that is two or more years old will tolerate 0.5 lb/A of Roundup applied at about the time dandelion is in bloom. This makes it possible to plant Roundup Ready(r) soybeans and use low rates of Roundup for weed control and crownvetch or birdsfoot trefoil suppression. Roundup Ready(r) soybean yields up to 60 bu/A were obtained when planted into crownvetch in 1996, but yields up to 75 bu/A were obtained where there was no cover crop. It would appear that some refinement of this system may be necessary to prevent soybean yield suppression when planting into a crownvetch or birdsfoot trefoil living mulch.
Small grains and alfalfa have also been planted into crownvetch and grown without a loss in yield and without losing the cover crop. A blanket treatment of Roundup or Gramoxone is commonly necessary before planting small grains or alfalfa to suppress the cover crop for the first six weeks of crop growth. Additional treatments may be necessary for annual or winter annual weed control. Crownvetch will tolerate most small grain or alfalfa herbicides and still be there in sufficient amounts so reseeding is not necessary when rotating back to corn.
The whole program is explained on the web at: http://www.cas.psu.edu/docs/CASDEPT/AGRONOMY/Extension/LivingMulch/LivingMulch.html.
Anyone in the state or region interested in putting out a 10 acre farm demonstration field should contact Nate Hartwig (nlh@psu.edu) at 814-865-1906 sometime before April 1, 1997. There are already 25 farmers across Pennsylvania who have established 10 acre field demonstration plots in the last two years. We would like to double these numbers this year.
Nate Hartwig, Prof. of Weed Science
Label Changes and New Products:
New Products:
New Products:
Label Change:
New Product:
Bill Curran and Dwight Lingenfelter
As those alfalfa fields break dormancy and the chickweed, deadnettle, and yellow rocket take off, our attention may turn to alfalfa weed control. Although there is nothing new for broadleaf weed control in alfalfa, Select herbicide may be a new option for grass control in 1997 - see previous article. As for items to consider now or in the next few weeks, remember a few important guidelines.
Gramoxone Extra (paraquat) - May be applied at 1.5 to 2.5 pt/A to established "dormant" stands with 2 inches or less spring regrowth. The weeds must be actively growing at the time of application. Gramoxone is also labeled at 13 to 24 fl oz/A for dormant application on newly fall seeded stands. Gramoxone will desiccate any green tissue including actively growing alfalfa. Be especially cautious with new fall seedings. Gramoxone is effective on low to moderate infestations of winter annuals including chickweed, henbit, deadnettle, and mustard species. If winter annual weed infestations are severe, consider one of the soil active alternatives. Do not use on mixed stands.
Lexone/Sencor 75DF (metribuzin) - May be used on established alfalfa. Apply 0.5 to 1 lb/A before spring regrowth. Impregnation on dry fertilizer can improve crop safety and allow for slightly later applications (up to 3 inches spring regrowth). Lexone or Sencor controls winter annual broadleaves and grasses (higher rates for grass control). May be used on mixed alfalfa-grass.
Poast Plus 1E (sethoxydim) - Poast Plus controls annual grasses and suppresses perennial grasses in seedling and established alfalfa. Apply Poast Plus at 1.5 to 2.5 pt/A to actively growing grassy weeds. Poast Plus performance improves with warmer temperatures. However, Poast Plus should be applied to small grasses. Do not used on mixed stands.
Pursuit 70DG (imazethapyr) - Pursuit may be used for weed control in seedling or established alfalfa. Apply Pursuit to actively growing weeds 1 to 3 inches in height. Pursuit performance improves with warmer temperatures. Pursuit is effective on many winter annual broadleaves including small chickweed. Pursuit may be used on established alfalfa-grass mixtures.
Sinbar 80W (terbacil) - May be applied to established alfalfa at up to 1.5 lb/A or to a new fall seeding at 0.33 to 0.5 lb/A. The reduced rate seedling year application is specifically aimed at chickweed. Sinbar is effective on a number of annual broadleaves and some grasses at the higher rates. Apply to "dormant" alfalfa before 2 inches of spring regrowth. Do not use on mixed stands.
Velpar 2L (hexazinone) - Apply Velpar to established alfalfa at 2 to 6 pt/A during the dormant period before 2 inches of spring regrowth. Velpar is effective on annual broadleaves and grasses. Velpar is the most effective dormant season treatment for suppression of dandelion and dock species (higher rates for grasses and perennial suppression). Do not use on mixed stands.
Late march through mid-April is typically a good time to control weeds in small grains. Available small grain herbicides control annual broadleaf weeds and can suppress perennial broadleaves.
Harmony Extra and Peak are effective on wild garlic and wild onion. Harmony Extra and Peak both are effective on chickweed and several other winter annual broadleaves. Peak is weak on henbit and deadnettle. In addition, Peak recrop restrictions include 10 mo. for soybeans and 15 mo. for alfalfa. 2,4-D, Banvel, or MCPA can improve the control of some winter annuals and perennials and Stinger is the most effective herbicide on thistles. The following table summarizes the available small grain herbicides. See a current herbicide label for specific weed species, rates, and restrictions.
| Herbicide | Cereal | Max. growth stage | Rate/A | Legume Companion | Fertilizer Carrier |
| Banvel | wheat, barley, oats | jointing (stage 6) | 1/4 pint | no | yes |
| Buctril | wheat, barley, oats | boot (stage 9) | 1-2 pints | yes | yes |
| Harmony Extra | wheat, barley | before visible flag (stage 7) | 0.3 to 0.6 oz | no | yes |
| oats | before jointing (stage 5) | ||||
| 2,4-D ester | wheat, barley | before jointing (stage 5) | 1/2-1 pt | no | yes |
| 2,4-D amine | wheat, barley, oats | ||||
| MCPA | wheat, barley, oats | before jointing (stage 5) | 1/2-1 pt | yes | no |
| Peak | wheat, barley, oats | jointing (stage) | 0.25-0.5 oz | no | yes |
| Stinger | wheat, barley, oats | boot (stage 9) | 1/4-2/3 pt | no | no |
Bill Curran
Time is rapidly approaching for scouting winter wheat fields for disease pressure. The major diseases affecting the yield of wheat in Pennsylvania are caused by fungi (i.e. powdery mildew, septoria, leaf rust, take-all, head scab) and several virus diseases (barley yellow dwarf virus, soil borne mosaic virus). Of these only powdery mildew, septoria and leaf rust are controlled by applying foliar fungicides. Most years we consider powdery mildew to be the most prevalent disease. However, last year septoria was a major problem. This resulted from the frequent rains which favor septoria development. I believe we were looking for mildew and missed the opportunity to control septoria with the timely application of a fungicide. Remember, powdery mildew requires a period of relatively cool (60 to 70 F) temperatures with high humidity. Frequent rainfall actually reduces mildew severity because this tends to wash the fungus from the leaves. On the other hand, septoria pressures increase with increasing rainfall because this aids in moving the fungus up the plant.
One of the most difficult wheat production decisions is to apply or not to apply a foliar fungicide. This is because there are so many variables entering into the decision: the disease susceptibility of the variety; yield potential of the crop; stage of growth; disease identification; disease severity; past weather conditions and future weather predictions; cost of application and grain price. We have updated our suggestions for scouting fields and included suggested threshold values for powdery mildew, septoria and leaf rust in the 1997-98 Agronomy Guide (page 146).
Elwood Hatley, CCA
Planning an insect management program should be more than simply applying a soil insecticide at-planting as insurance. A sound insect management plan begins by keeping field by field records on history of insect problems, weed species, previous crop, manure applications, and other cultural practices in the field. This information can tell you a lot about the potential for various insect pests. The following information is designed to help you identify which insects are likely to be a problem in a field.
Black Cutworm
A very common insect pest attacking corn early in the season is the black cutworm. Although less than 1% of fields have economic problems in most years as much as 5% of the corn can be economic in a heavy year in PA. This insect is a migratory insect that moves into our state during late March through early June. It prefers winter annual weeds such as common chickweed, shepherds purse, and several mustard species. Therefore, fields with the highest risk of attack by this insect are fields with heavy populations of the above weeds during early spring. Adults of the black cutworm deposit their eggs and the young larvae feed on the weeds, eventually moving to corn once the weeds are killed by a herbicide or tillage. Because of this relationship, black cutworm can be eliminated as a pest by removing the weeds at least 10 days prior to planting, either through tillage or an herbicide application (plants must be dessicated or brown for this long). This eliminates the cutworms food and shelter for long enough to prevent survival and movement to young corn plants. If removal of the weeds attracting the pest is not a viable option, three options remain. The first is to apply a soil insecticide with activity against this pest at-planting. However, because this pest generally occurs in less than 1% of corn fields, use a soil insecticide only if corn rootworm or several other soil insects also are a threat. The second option is to apply a foliar insecticide at the time preemergence herbicides are applied (see the Agronomy Guide for a compatibility chart and products). This option should only be considered if time is limited and the field has a history of black cutworm problems. The last option is to scout the field at least once a week from crop emergence until the corn is 12 inches tall. In fields that are at high risk, a quick visit to the field every 2 to 3 days during this period could help reduce the risk of missing the problem.
True Armyworm
Corn fields at risk of attack by this pest are those planted into a rye mulch (to some degree other small grains) or old pasture. As with the black cutworm, only a small percentage of PA fields are attacked by this pest every year. Any field planted into rye is at high risk and should be scouted regularly or an effective insecticide should be included with the preemergence herbicide application. The only other high risk situation is an old pasture, where numerous other insects may also cause problems. When planting into an old pasture, it is usually a good idea to protect the crop with a broadspectrum soil insecticide with activity against white grub, wireworm, black cutworm, sod webworm, seed corn maggot, and stalk borer.
This is a fairly rare pest in Pennsylvania corn fields, since much of our hay is alfalfa or red clover. Stalk borer problems are associated with corn fields planted into old grass hay fields that contain clumps of orchardgrass and around field margins where forage grasses and large stemmed broadleaf weeds occur. In corn fields planted into old hay, problems can be avoided if the orchardgrass is killed (brown) at least 10 days prior to planting. Mowing weeds around the field margin can eliminate habitat and sources of stalk borer. When live orchardgrass remains in the field until after the corn has emerged, an foliar insecticide broadcast with the preemergence herbicide can provide some protection. However, for the highest level of control, an insecticide should be applied five days after the herbicide or at the time the orchardgrass is beginning to dry down. Note: larvae migrate out of the plants at this time.
Seed corn maggot
This is a pest of fields with decaying organic matter such as manure, plowed down pastures, rye, weeds, etc. The adult flies are attracted to these fields to deposit their eggs. Larvae that hatch from the eggs feed on the decaying organic matter and germinating seed. The presence of high numbers of seed corn maggot larvae does not necessary mean great stand reductions. The other requirement is cool wet growing conditions that delay emergence and development of the young plant. Under these conditions a high percentage of corn seeds can be consumed before they emerge. In fields with high organic residue, use a seed treatment containing diazinon or a soil insecticide at planting. A seed treatment is a much cheaper alternative if the field is not at risk of other common pests.
Insect Problems Associated with Old Sods
One of the worst situations for insect pests is when corn is planted into an old sod, particularly if the field is no-till. Because old pastures provide a stable environment over several years, they can harbor a number of insect pests. Black cutworm, true armyworm, sod webworm, stalk borer, white grub, wireworm, and seed corn maggot all are associated with these situations. Because of this wide array of potential pests, it is usually a good idea to use a broad spectrum soil insecticide at-planting to protect your crop. If you have information from previous scouting about wireworm and white grub population, then you may be able to prevent significant injury by scouting the field weekly and applying a foliar insecticide if needed. This should only be done if you have a reliable crop consultant or time to scout the field on a regular basis.
Dennis Calvin
The frost is out of the soil in Lebanon County indicating the coming of spring. Soil temperatures are pushing over 40 degrees Fahrenheit. Most winter wheat and barley are at stage 2 with early planted pushing stage 3-4. Many producers were able to topdress small grains especially late planted grains.
As mentioned in previous correspondence, winter annual weeds are abundant and may require control in both small grains and alfalfa. Alfalfa has broken dormancy and is continuing to grow. Most fields have 1 inch of regrowth. So far, heaving appears minimal. However, I have seen some fields of alfalfa in the southern parts of the county that definitely will be affected by heaving. Much of the next few weeks of weather will determine whether heaving will become a widespread problem.
As of March 10, 1997 Lebanon has 15 GDD. Aphids have started there lifecycle. I expect many other insects that overwinter here to become a threat as the season progresses, due to mild winter conditions, warm temperatures, and plenty of moisture. Specifically, the flea beetle who is responsible for the spread of stewarts wilt in sweet corn could become a problem. There has been three working days that most of the soils were fit to till. The soil moisture continues to be at field capacity.
Del Voight
Lebanon County
William S. Curran
Associate Professor Weed Science
email: wsc2@psu.edu
Website Address: http://fcn.agronomy.psu.edu/