Field Crop News

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

September 23, 2008    Vol. 08:29

IN THIS ISSUE:

• Weather Outlook
• Timing Fall Alfalfa Harvest
• Hessian Fly and Fly—free Planting Dates for Wheat
• Corn Stalk Quality
• Thinking about Winter Annual Grass Control in Small Grains
• Controlling Weeds Prior to Cover Crop Establishment
• Importing Manure from Regulated Farms
• National Farm Safety and Health Week
• Upcoming Events

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

Dry and mild weather will continue into Thursday, though morning clouds and fog will be more persistent in the eastern counties. The 10 day dry spell will end Thursday afternoon as moisture from a developing sub—tropical storm along the Carolina coast is directed into the Middle Atlantic region. Clouds and rain will progress from southeast to northwest (that is opposite the normal progression) later Thursday and Friday. Rain will be heavy at times in the eastern third of the state with more than an inch likely and some places expected to receive more than 3 inches. Less than a quarter of an inch of rain is likely in western sections of the state. Tropical air may reach into the eastern parts of the Commonwealth later Friday or Saturday with muggy conditions. An unknown at this writing is whether a new tropical storm (Kyle) will develop near Hispaniola late on Tuesday and what role it may play in the wet weather. There is about a 40% risk that it will rapidly develop and become a category 1 hurricane and then move north—northwest making landfall between Virginia and Long Island early Saturday. This scenario could bring high winds and flooding rains to the Delaware Valley and Poconos during the first half of the weekend. A push of cooler, drier air is expected by Sunday night or Monday. However, the cool air will be shallow and a disturbance is expected to form over the Southeast next week and threaten this region with more showers at mid—week.

Odds still favor a warmer than average October followed by a chilly November and this may translate into a later than usual frost in the southern half of the state plus an early and vigorous start to the lake effect snow season in the northwest and Laurel highlands. Latest indications point to a rather cold and snowy December.

Check out the predicted Growing Degree Days (base 55) for Pennsylvania for the next two weeks at: http://climate.met.psu.edu/data/regional_gdd.php

Timing Fall Alfalfa Harvest — Marvin Hall, PSU Forage Specialist

Traditionally, the recommendation has been NOT to harvest alfalfa 4–6 weeks (critical period) before the 1st killing frost. And that is still very safe advice! However, the dry weather we had in August combined with the current price of hay and more disease and winter hardy alfalfa varieties may cause some producers to rethink this old advice. Perhaps the risk of a cutting during that “critical period” is outweighed by potential increased profits.

Below are some things to consider when deciding to take an alfalfa harvest during the “critical period”. Assessing the risks can be helpful in making the “best” decision.

Age of stand: Older alfalfa stands are more likely to winter kill or suffer winter injury following a fall harvest than younger alfalfa stands.
Variety: Alfalfa varieties with moderate resistance to several diseases and sufficient winter hardiness have greater tolerance to stress from fall harvesting than less disease resistant or winter hardy varieties.
Soil pH and fertility: Adequate soil pH and fertility minimizes the risk of fall harvesting by allowing alfalfa plants to develop properly and be healthier.
Soil drainage: Alfalfa on well—drained soils is less likely to suffer winter injury than alfalfa on poorly—drained soils.
Harvest frequency: Alfalfa harvest schedules which do not allow the alfalfa plant to flower once during the season, predisposes the plant to winter injury.
Dry conditions in August: Dry weather, especially in August, causes alfalfa to store excess root energy reserves making it more winter hardy.
Fall cutting height: Leaving six to eight inches of stubble when taking a fall harvest will reduce the risk of winter injury.

If the decision is to take a harvest during the critical period, then the predicted dry weather makes this week look like an idea time to “get after it”.

Hessian Fly and Fly—free Planting Dates for Wheat — John Tooker, PSU Entomology Specialist

In the past few years there have been an increasing number of Hessian fly outbreaks in eastern states, including Delaware, Virginia, and North and South Carolina. This pest is not usually a problem because most farmers plant their wheat after “fly—free dates”——dates after which egg—laying adult Hessian flies are unlikely to be active. In PA these dates range from 22 Sept – 1 October depending on the county (for a list of dates for each county and some images of Hessian fly see: http://www.ento.psu.edu/Extension/factsheets/hessian_fly_wheat.htm). Insecticides are generally not effective for control of Hessian fly so the best options for farmers are to adhere to the fly—free dates and plant Hessian fly—resistant lines of wheat.

Hessian fly can become a problem if farmers ignore these fly—free dates and start planting wheat earlier in the year. Repeated early plantings are an invitation for a problem because Hessian flies occur in low numbers in most places, surviving on other grass species. These small, sustaining populations can jump to early planted wheat fields and quickly develop into economic problems.

For many, Hessian fly is an unfamiliar pest because they have not encountered this species themselves, but this small gall midge is the most damaging pest of wheat worldwide and the lifecycle is the key to its control. The flies have two broods each year. Flies of the fall brood appear in late September and live for only about one week, laying their eggs on leaves of young wheat plants. Maggots hatch from eggs in a few days and travel to the base of plants where they feed on plant juices. Maggots complete their growth before cold weather and pass the winter as puparia (singular: puparium), which is also called the “flaxseed” seed stage for its apparent similar to real flax seeds. When warm weather arrives in spring, adults emerge from their puparia, mate and lay eggs again. These maggots develop through the spring, spend the summer in the flaxseed stage, and emerge again in late September. If there are no wheat plants available, the flies will deposit eggs on barley or rye, which resist Hessian fly feeding better than wheat, or other grass species. This is why planting after the fly—free date is an effective control for wheat; if the flies emerge and die off before the new wheat plants are up the crop cannot be infested.

Corn Stalk Quality — Del Voight, Interim Grain Crop Specialist

Yield reports are beginning to trickle in with some interesting results.

In some areas soybeans are in the 60–80bu/acre range and corn is running from 120–278bu/acre. Although the drought took away some top yields growers are finding yields are not as poor as they would have expected given the situation. I would like to focus on the corn situation. The concern now for standing corn is harvest loss due to ear drop and stalk rot. There are a host of reasons why corn lodges and depending on the reason may impact not only the quality but the health of the crop and impact a ration as mycotoxins may result. Many dairy farms experience the call from the nutritionist that mycotoxin levels are high either in high moisture corn or from silage. Few producers track back the infected crop to where it originated in the field. In many cases it can be traced to a severely infected stalk or ear rot section of a field.

In a recent NCGA combine harvest of 237 bu/acre dry corn yield was limited due to stalk rot and premature death. The producer made the decision to harvest early when the moisture was 28% due to the stalk quality. One may consider this a bumper crop but yields under the same management a mile down the road were in the 270’s that did not show signs of stalk quality problems. The field in question also was beginning to drop its ears. Conducting a population test some ears fell easily when bumped and in the absence of pests such as corn borer this indicates a stalk issue. This field was subjected to several weeks without rain and the plant stress caused the plant to move nutrients from the stalk into the ear to preserve its reproduction and thereby weakening the plant to the point that pathogens infect and pre mature plant death results, including dropped ears. Keep in mind too that these hybrids are standing now with between 32 and 35,000 plants per acre which also adds to the stress level on the crop. These types of fields need to be identified now and early harvest despite drying costs must be considered. Further in some areas where hail occurred ear molds are also prevalent and again early harvest is the best route to prevent feed out issues.

This is not enough, however, the area in the field needs to be identified and a plan must be put into place and followed up on. The first step in successful management of stalk rot is to recognize that it can and is manageable. Second, growers need to plan in winter to combat stalk rot. Finally, growers need to follow the plan of attack.

Stalks may lodge due to insect, genetics of the hybrid, and more likely disease brought on by many factors of importance including soil potassium levels. A trained eye will determine which is responsible. In all cases where stalks lodge and problems occur a soil test from the area in question and coupled with an area that shows no sign may prove fruitful in diagnosis. If growers have a problem, in diagnosing these fields, coordinate a visit with an Extension Educator or one of the many Certified Crop Advisors. This is usually done after the fact and is useless for this year’s crop but will allow you to change things for next year. Let’s plan the attack now.

1. The first attack will be hybrid selection. An old Extension proverb is to never plant the same hybrid in the same field next year. Sounds simple? Follow it. I have been in many fields where this simple message is ignored and disaster occurred in the field.
2. Second choose hybrids that not only maintain yield but have high resistance to stalk rot. I am looking at seed catalog now and can pick three for my farm that have very high resistance to stalk rot pathogens. At winter meetings ask the dealers for their top picks then ensure to select with stalk rot resistance (anthracnose is the major one rated) in mind. One final note is some cooperative research I am involved in suggests Bt corn can reduce the incidence of disease invasion through keeping European corn borer from eating into the stalk. Be sure that is in the balance of your hybrid decision.
3. With soil test in hand get to the plant food dealer and correct any deficiencies in nutrients putting the highest priority on potassium. Expensive? Yes but you cannot afford the consequences of potassium deficiency. I have several personal experiences where very low potassium levels caused stalk rot in the field and this was compared to areas of the field with no stalk rot with adequate potassium. It is also well documented in the literature.
4. Plan to avoid the “sins” of soil management. If the soil is wet stay off it especially with the planter! It is easy for me to say that and I am aware of the farmer’s plight. But when soils are wet sidewall compaction at planting time can cause deficiencies in nutrients and eventually stress the plant and allow it to become susceptible to stalk rot pathogens as well as many other problems. If you do decide to “sin” be sure your planter is retrofitted with finger type closing wheels to break up the smearing action of the double disc openers. It makes no sense to correct a potassium deficiency and then not allow the roots to absorb it due to compaction. I could talk more about compaction at a later date for we are finding some interesting results on dairy farms.
5. Plant early to allow the plants time to generate roots that will reach water deep in the soil profile, avoid drought stress and subsequent invasion by stalk rot pathogens. This year is a great example of that. Strive to have ninety percent of corn planted on the early side of the ideal planting date.

Now that you have properly selected a hybrid, planted the hybrid early, corrected potassium deficiencies (within fields) and alleviated compaction it’s time to begin harvesting disease free corn silage and grain that will avoid that call from the nutritionist.

Other References:
Scouting for Stalk Rots

Thinking about Winter Annual Grass Control in Small Grains — Bill Curran, PSU Weed Science Specialist

Several weedy grasses have become more problematic in the Northeast in small grains over the last several years. Annual or Italian ryegrass (Lolium multiflorum) is more common to the south in Maryland and Virginia, but can also be found in some fields in Pennsylvania. ACCase or Hoelon resistant ryegrass is a problem in some fields. The annual brome species have also become problematic in our fall seeded small grains. These weedy bromes include at least four closely related species; downy brome (Bromus tectorum), Japanese brome (Bromus japonicus), hairy chess (Bromus commutatus), and cheat (Bromus secalinus). Downy brome is generally considered the most common of these different winter annual grassy weeds, and although herbicide susceptibility can differ, the biology, ecology and control are similar for the four species. Other names for these grassy bromes include cheatgrass, cheat, downy chess, wild oats (not to be confused with the real wild oats — Avena fatua), and others.

Managing these weedy grasses in small grains includes: 1. Prevent successful seed production. Many weedy grass seeds do not persist long in the soil (1 to 2 years), so preventing seed production can quickly reduce the soil seedbank and the problem. 2. Rotate to summer annual crops to prevent their success. These grasses are generally not a problem in spring planted crops and can easily be controlled in no—till. 3. Delay fall planting of winter grains to allow early flushes and kill with tillage or herbicides. This may require waiting until mid October before small grain seeding which may not be practical for barley but can help in winter wheat. 4. Use herbicides in small grains to control or suppress.

The effectiveness of herbicides varies by product and control/suppression can be limited. For grass control, Axial XL and Hoelon can be used on barley and wheat, while Osprey, Finesse Grass & Broadleaf, Maverick, and Prowl H2O are only labeled for wheat. Prowl H2O received a supplemental label for weed control in wheat last year. On medium textured soils, apply 1.5–2.5 pt/acre after wheat emergence and prior to weed emergence. Emerged weeds will not be controlled with this treatment. For Italian ryegrass, Axial, Hoelon, and Osprey have been effective treatments, especially when applied in the fall to emerged grasses. Hoelon will not control ACCase resistant biotypes and Axial performance has varied with the resistant biotype. For Bromus species, Maverick has been the most consistent product in our tests. In a trial this last year at Landisville, 2/3 oz Maverick applied on either November 8 or March 25 provided about 80% control of downy brome the following spring (June 4). Fall application is generally better than spring. In the same trial, fall-applied Osprey provided equivalent control to Maverick (81%), while the spring application was less effective. For Maverick, soybeans can be planted within 5 months of application on soils with a pH < 6.5 and a minimum of 30 inches of cumulative precipitation; with higher soil pH and less rainfall, the soybean recrop restriction is 12 months. Soybeans can be planted after 90 days of application with Osprey.

Controlling Weeds Prior to Cover Crop Establishment — Bill Curran, PSU Weed Science

September and October are the time to sow winter cover crops. Consider your weed management needs before you plant the seed. Two things to consider: 1.) Are there sufficient weeds in the field that will compete with a young struggling cover crop that could reduce the stand going into the winter? If the field is green with summer annual weeds that are or have already gone to seed, you may still want to burndown the residue (Gramoxone) to quickly stop weed competition. If summer annual weeds are scattered throughout the field and are at the end of their lifecycle, then an herbicide is generally not necessary. 2.) If winter annual weeds have emerged (henbit, chickweed, etc.) or more importantly, perennials (pokeweed, Canada thistle, etc.) are still active, then a timely herbicide application prior to seeding the cover crop can pay off. Not only can you potentially better control the perennials with the fall application, but you will also help the cover crop succeed. Of course glyphosate can be safely used prior to the emergence of any crop, while the PGR herbicides such as 2,4–D will persist for a week or two and dicamba up to several weeks depending on the rate and both can cause injury to cereal grains (and certainly legumes) as the seedlings attempt to emerge and establish. So, scout your target fields and plan ahead. With the cost of everything going up, a little planning can save you time and money in the long run.

Importing Manure from Regulated Farms — Douglas Beegle, PSU Soil Fertility Specialist

As we are getting into the fall manure spreading season, many farmers who import manure are suddenly realizing that importing manure may not be as simple as it used to be. The PA Nutrient Management Act (Act 38) and federal Concentrated Animal Feeding Operations (CAFO) regulations include specific requirements when manure is exported from regulated operations. If manure is being imported from a regulated farm under Act 38 or CAFO, there must be signed agreements between the exporter and the importer or the exporter and a broker. Manure brokering, applying, or hauling manure from a regulated farm must be by a certified manure hauler and/or broker under the PA Manure Hauler and Broker Act (Act 49). Also, Nutrient Balance Sheets (NBS), which are simplified nutrient management plans must be prepared for where the manure will be applied, unless the importer has his own nutrient management plan that includes the imported manure. The main impact on importing farms will be the necessity of having NBSs for the imported manure application. An NBS is a one page calculation of a balanced manure application rate and manure management. An important issue for the importing farm is how the planned manure rate is determined. An NBS provides 3 options which vary depending on the complexity of the NBS and the level of manure application restriction. Option 1 is very simple but also very restrictive and option 3 is more complex but much less restrictive. The details of the options are provided below:

Option 1: P Removal based manure rate
Application rates based on phosphorus removal of the planned crop with a 150’ manure application setback from streams, lakes and ponds. This is the simplest option which requires minimum inputs from the importer, but the planned manure rates will be the lowest with this option. No soil tests are required for this option.

Option 2: N Requirement based manure rate
Application rates based on the annual nitrogen requirements of the planned crop with a 150’ manure application setback from streams, lakes and ponds. This option is only available for crop management unit that have soil test levels less than 200 ppm phosphorus. This option allows higher N based rates but also requires soil tests.

Option 3: Phosphorus Index based manure rate
Application rates based on the annual nitrogen requirements of the planned crop or on the P removal of the planned crop depending on the outcome of the P Index evaluation. This option is similar to a full nutrient management plan rate determination. Depending on the outcome of the P Index evaluation, this option could allow N or P based rates and it could allow manure application within the 150’ manure application setback and/or on fields with soil tests greater than 200 ppm. The standard manure setback of 100’ from streams, lakes and ponds or a 35’ vegetated buffer would still apply within this 150’.

Typically, an NBS will be required for each crop group on the farm. For example, a farm that wants to apply imported manure to corn grain, corn silage, and grass hay would only need 3 NBSs, not one for each field. Not all fields have to be planned under the same option. For example, a farmer may use Option 2 for fields with soil tests less than 200 ppm P but use option 3 for fields that have soil tests greater than 200 ppm P or are within 150’ of water. This would require 2 NBSs for these two groups of fields.

Responsibility for preparing NBSs is with the exporting farm planner in the case of direct export to known importers and with a certified broker where manure is exported through a broker. In signing an importing agreement the importer is agreeing to apply the manure based on the NBS. Thus it is important that the importer communicate to the exporter or broker which option is desired. In most cases, if the importer does not specify the option, the planner will use Option 1 because it is the simplest to prepare. This could severely limit the application rates of the imported manure. It is also important to review the NBS to make sure it reflects the planned management of the imported manure before signing an agreement.

Detailed information on these requirements including the agreement forms and NBS worksheets are available on the Pennsylvania Nutrient Management Website at: http://panutrientmgmt.cas.psu.edu. Direct links to the documents referenced above are listed below:

• Exporter-Importer Agreements (http://panutrientmgmt.cas.psu.edu/pdf/Technical_Manual/Supplement%2011%20-%20Exporter%20Agreements%202008-09.pdf)
• Nutrient Balance sheets (http://panutrientmgmt.cas.psu.edu/pdf/pr_NBSPacket070501.pdf)
• Information on certified manure brokers and haulers (http://www.agriculture.state.pa.us/agriculture/cwp/view.asp?a=3&Q=138120)

National Farm Safety and Health Week — Dennis Murphy, PSU Farm Safety Specialist

There are many reasons why Farm Safety & Health Week is celebrated in late September each year, with the Fall harvesting season being one reason. Fall harvest activities often include increased exposure to machinery entanglements, traffic hazards, and respiratory hazards. Charlotte Halverson’s article that leads off this issue reminds us that farmers are likely to pay much more attention to the details of getting their crop out of the field than to the details of keeping themselves from being harmed while completing their harvesting tasks. Many farmers think that keeping themselves safe gets in the way of completing harvesting tasks quickly and efficiently because being safe might mean taking a break to minimize fatigue, shutting off a machine to clean or unplug it, using an escort vehicle on public roads, or waiting for fresh air to be blown into a silo. In other words, being safe often seems like a poor investment because time is money during harvesting season. Most farmers also think that the “accident won’t happen to me” because they are always “careful”, but that it might happen to “that guy down the road”. But remember—you are your neighbor’s neighbor!

Check out the full version of the latest issue of the Agricultural Safety and Health News: http://www.agsafety.psu.edu/newsletters/sepoct08.pdf

Upcoming Events — use the link to Calendar of Events (below) for contact information

October 21–22, 2008: Keystone Crop and Soils Conference, Location: Holiday Inn, Grantville, PA
October 22–23, 2008: PA Project Grass Statewide Grazing Conference, Location: Pantal Hotel, Punxsutawney, PA

Contributors: Extension Educators: Paul Craig (Dauphin), Kevin Fry (Armstrong), Del Voight (Lebanon), Mena Hautau (Berks), John Rowehl (York), H. Grant Troop (Lebanon), Susan Alexander (Jefferson), Craig Williams (Tioga), Jeff Graybill (Lancaster); Dept. Crop & Soil Science: Marvin Hall, Sjoerd Duiker, Doug Beegle, Bill Curran, Dwight Lingenfelter, John Tooker

Editor: Susan Alexander, Jefferson County

Upcoming Events

Real time pest and heat unit activity: http://psu.zedxinc.com/cgi-bin/site.cgi?location=2&user=psu#

Calendar of Events: http://www.events.psu.edu/cgi-bin/cal/webevent.cgi?cmd=opencal&cal=cal209&

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