Field Crop News

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

October 14, 2005    Vol. 05:13

IN THIS ISSUE:

Mark Your Calendar

Weather Outlook

Production

Pest Management

Agents Corner

MARK YOUR CALENDAR

CERTIFIED CROP ADVISOR WORKSHOP PLANNED FOR NOVEMBER 2, 2005

The Certified Crop Advisor (CCA) program certifies crop advisors who demonstrate crop management experience and pass comprehensive state and national exams covering nutrient management, soil and water management, integrated pest management and crop management. On November 2, Penn State faculty and staff from the departments of Crop & Soil Sciences, Entomology, and Plant Pathology will hold a one-day workshop at University Park to prepare individuals planning to take the CCA exams in Harrisburg on February 3. The workshop will be held in Room 504 Agricultural Sciences and Industries Building. It will start at 8:30 a.m. and end at 5 p.m. There is no charge for attending the workshop. To register, call or e-mail Lisa Crytser (814-865-2543, lac8@psu.edu. Everyone serving or planning to serve the crop production industry should take this opportunity to become certified.

The registration period for the February 3 exams is October 3 to December 16. Registrations received after December 16, 2005 will not be processed. The fees to take the state and national exams are $100 and $125, respectively. For more information about the CCA program visit the ASA website www.agronomy.org or contact Amy Bradford abradford@pennag.com. Because the average passing percentage over all testing opportunities is only 60%, the one-day workshop may provide the advantage you need for certification success.

Jan Pruss, jap5@psu.edu
Crop Management, Crop and Soil Sciences

WEATHER OUTLOOK

The statewide rainfall from May-September in 2004 (last year) tallied the highest ever at 31.06". During the same period this year, a mere 14.52" fell on average, making this growing season the 11th driest in the past 110 years. It was also the largest change ever from one warm season to the next in Pennsylvania climate records. Of course, the phenomenal rainfall of last weekend brought more than 10 inches (nearly 80% of the rain that fell from May-September) in a swath from Berks to Northampton to Monroe counties. The rest of the state received between 2 and 6 inches east of the Allegheny plateau. In years past when a rather wet growing season was followed by a much drier one (about 8–10 occasions), the winter following the dry year was noticeably colder than normal. Since there is no signal from the tropical Pacific (neutral phase of El Nino), the possibility of a bitter cold period during December-February is higher than average. Precipitation during those winters has been near to slightly above average. In the short range, sunshine finally returns during the weekend along with gusty winds and chillier air. A changeable weather pattern is expected during the last two weeks of October with showers becoming sparse again.

Paul Knight, pgk2@psu.edu
Pennsylvania State Climatologist

PRODUCTION

FALL CLEAN TILLAGE

Figure 1. Severe rill erosion in clean-tilled fields after 11 inch rainfall event.

After a dry summer we suddenly got hit with large quantities of rainfall at the beginning of October. Here in State College we got 3 inches in about a day, whereas parts of Lancaster County received as much as 11 inches. Fortunately, the soil was very dry and the rain came as a constant curtain instead of very hard in a short period of time. So despite the unusually high rainfall event, runoff and erosion were limited. With some exceptions that is, in freshly tilled fields. I happened to be in Gap (Lancaster County) yesterday (10/11/05) and took the above picture of a recently seeded field. The evidence of sheet and rill erosion was clear in this field. To avoid conditions like this, it is recommended to use no-till to establish forages. A good place to no-till alfalfa or grass this fall would have been after early corn silage harvest or into small grain stubble. If you are considering no-tilling forages in the spring of 2006, select fields with a limited amount of crop residue cover for greater success. Some good scenarios are: after corn silage, soybeans, or small grains. In the case of corn silage, I recommend to use an oat cover crop that should have been established immediately after corn silage harvest. The oats winter kill and provide a nice mulch for the alfalfa to be planted into. No-tilling forages after corn grain harvest is challenging because of the difficulty to get good seed-to-soil contact without planting seeds too deep. I include a picture of no-tilled rye about 1 mile away from the following picture. It is evident that no soil moved in this field!

Figure 2. No-till established rye into corn silage stalks after packed manure application.

Sjoerd Duiker, swd10@psu.edu
Soil Management, Crop and Soil Sciences

MANURE SLURRY-ENRICHED COVER CROP SEEDING

Figure 3. Low-disturbance aeration tillage combined with slurry application.

A new method of cover crop seeding with manure application is under investigation by the Department of Biosystems and Agricultural Engineering at Michigan State University. A commercial variety of winter wheat (Sisson) and a common variety of cereal rye were established in late September in corn silage stubble. The wheat was sown with a Great Plains no-till drill, and both wheat and cereal rye were sown with a new manure slurry-enriched seeding process.

The slurry seeding was done with a slurry tanker (3000 gal) equipped with a rear-mounted rolling-tine aerator (12 ft; Aer-Way) and SSD (sub-surface deposition) slurry distribution system. The seed was placed in the spreader tank where bypass flow provided tank agitation and seed mixing. The seed-laden dairy slurry was applied at 5000 gal/ac. Specific comparisons were:

  1. surface manure, no tillage, no seed,
  2. wheat, 2 bu/ac, no-till drill, 50 lb/ac N as urea in April 2005,
  3. wheat, 2 bu/ac, slurry seed, 5° gang angle on aerator,
  4. wheat, 2 bu/ac, slurry seed, 10° gang angle,
  5. wheat, 4 bu/ac, slurry seed, 5° gang angle,
  6. wheat, 4 bu/ac, slurry seed, 10° gang angle,
  7. cereal rye, 2 bu/ac, 5° gang angle, and
  8. cereal rye, 2 bu/ac, 10° gang angle.

The dairy slurry (9.5% solids, sawdust bedding) provided 125 lb/ac total N (65 lb/ac as NH4-N; 60 lb/ac as organic N), 43 lb/ac P as P2O5, and 140 lb/ac K as K2O. Drop tubes placed the seed-laden slurry in the fractured and loosened soil behind each set of rolling tines. No additional tillage or soil firming was done.

Biomass and Grain Yield
Figure 4. Wheat and rye yields.

Each of the slurry-seeded treatments provided a uniform cover that suppressed weed growth. Although primary interest was in cover crop establishment, plots were maintained for grain yield measurements to see how the slurry-seeding method would compare with conventional drilling. Grain was harvested on July 25, 2005. Wheat yields ranged from 75 to 81 bu/ac and the rye yields ranged from 67 to 71 bu/ac. There were no statistically significant differences between treatments (Figure 4). Additional work is in progress on farms throughout the Great Lakes region to evaluate the agronomic and environmental benefits of this new cover crop establishment method.

This method provides some interesting options for combining cover crop establishment with manure application on our Pennsylvania diary and hog farms. Being able to combine cover crop establishment and manure injection could make manure injection more cost and time effective. The aerator manure injection system is currently under investigation in a collaborative project between USDA-ARS and the Dept. of Crop and Soil Sciences. We will keep you abreast of new developments.

Adapted from http://www.egr.msu.edu/age/aenewsletter/1_sept_oct_05/harrigan9_05.htm.

Sjoerd Duiker, swd10@psu.edu
Soil Management, Crop and Soil Sciences

BIOTECH BACKGROUNDER

According to USDA figures, corn producers planted 52 percent of their acres to biotech crops this year, up from 47 percent last year. That marks the first time over half of the US crop has been biotech. This winter and probably in many more to come, corn producers will face the question of whether biotech traits pay in corn production. The answer varies depending on the situation.

One corn trait that seems to be growing in adoption in corn is the Roundup Ready trait. The advantages of the Roundup Ready trait are greater flexibility for in-season weed control, less potential for postemergent herbicide injury, and an opportunity to reduce herbicide cost. This trait seem especially useful when no-tilling in a hay sod and in situations where postemergent applications are frequently needed and are often difficult to get on in a timely basis. Penn State studies have shown similar agronomic performance between Roundup Ready hybrids and their conventional isolines. Most consistent weed control has occurred with a pre-emergent herbicide followed by a post emergent glyphosate application. An early post emergent (V2-V4 corn) tank mix of a reduced rate pre-emerge herbicide plus glyphosate is also an option. Planting glyphosate tolerant corn in a rotation with glyphosate tolerant soybeans can result in some volunteer corn in soybeans that will result in some necessary adjustments to the soybean herbicide program. Overuse of glyphosate alone can lead to weed shifts and weed resistance.

Many of our producers now have considerable experience with the European corn borer Bt trait. The benefit to Bt corn is dependent on the presence of corn borer pressure. Over a three year period we measured a 5.8% increase in yield with Bt hybrids compared to their isolines at sites in southcentral PA and Maryland. We’ve seen larger responses where corn planting has been delayed past mid to late May, with longer season hybrids and in high yielding fields. This year we encountered heavy ECB pressure in a mid-May test planted in Lancaster, with about 4 corn borers/plant. We expect about a 2.5% yield loss for each corn borer tunnel in a corn plant at maturity. In midseason and northern PA locations, corn borer response usually decreases. An online program has been developed to estimate the potential response to different maturity Bt varieties across our region and is located at http://www.cei.psu.edu/bt/. The Herculex version of the Bt trait adds black cutworm control. All of these Bt varieties require a refuge of non Bt corn planted within a half mile as part of the resistance management plan.

The rootworm Bt trait was introduced in 2003 and the number of hybrids available with that trait has increased dramatically since then. Our studies have shown very good control of the rootworm larva with these products and similar or better performance than soil insecticides. The benefit of rootworm Bt is dependent upon having the pest. In our trials in 2003 and 2004 six of twelve trials had minimal root worm pressure. The rootworm Bt seems to sometimes show a yield and height advantage in stress environments. Over all twelve tests that we conducted with the rootworm Bt, we found a 5.0 bushel/acre advantage over the isoline treated with insecticides, mostly due to the yield advantage in several stressful environments. The rootworm Bt trait available this year has been the Yieldgard Rootworm trait, but next year another trait, the Herculex Rootworm trait will enter the market. Initial studies conducted at other universities indicates the Herculex Rootworm trait provides excellent rootworm control as well. Both traits require a 20% refuge in an adjacent field.

Before making a biotech choice, producers should consider other pest management alternatives that might reduce the need for some of these options. Early hybrids and early planting are options for the corn borer. Crop rotation, seed treatments in low to medium pressure fields and scouting for rootworm beetles are tactics related to the rootworm trait. Many fields don’t have significant rootworm pressure. Also consider the economics of switching to biotech hybrids, considering the yield and the effects on pest management costs. And finally, be sure to consider the performance of the background genetics of the hybrid and the other important traits, like disease resistance. These are especially important when a biotech trait is just being introduced and hybrid availability is limited.

Another consideration is the use of stacked traits. Stacked trait hybrids offer flexibility for use of several traits, but often come at a significantly higher price. It is common now for one of the included traits to be discounted. When considering the cost effectiveness of stacked traits, be sure to consider the benefits from each of the traits in relation to the added cost of the seed. Stacked trait hybrids will likely become more prevalent in the future.

Managing biotech corn will likely be a part of corn production for the foreseeable future. Improving your skills at understanding and using biotechnology effectively will help to make sure you maximize the benefits from this technology.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

Pest Management

GLYPHOSATE RESISTANCE MANAGEMENT — IS IT WORTH THE EFFORT?

I recently attended a glyphosate stewardship discussion in St. Louis hosted by Monsanto. At this meeting, we heard about several new glyphosate resistant weeds including palmer amaranth in North Carolina and Tennessee and waterhemp in Missouri as well as "tolerant" lambsquarters appearing in several states. The Northeastern Weed Science Society continues to discuss the adoption of a herbicide stewardship resolution that initially focused on glyphosate, but has been broadened to be more inclusive of herbicides in general. The need for some hard data on the impact of changing management practices to preclude or delay resistance is imperative, but that information seems to be slow in coming forward. The following article written by Bob Hartzler at Iowa State University does a nice job discussing the issue and describes a recently published paper from Australia. Thanks Bob for putting this out there.

In recent weeks several states have reported glyphosate resistance in Palmer amaranth (Amaranthus palmeri) or common waterhemp (Amaranthus tuberculatus). Of particular concern is that glyphosate has significant advantages over other available control practices for these weeds, thus their spread could have serious repercussions on cropping systems highly reliant on Roundup Ready crops and glyphosate. The continued reports of glyphosate resistance in new weed species might lead some to conclude that resistance is inevitable, and thus there is little value to incorporating practices intended to slow the evolution of resistance.

A recent paper (http://www.weeds.iastate.edu/reference/preemptive.pdf) out of the weed science group in Western Australia discusses the economics of utilizing weed management strategies for the purpose of delaying the onset of glyphosate resistance. Although the management strategy discussed in the paper is not appropriate for the cropping systems utilized in the Midwest, I believe the authors provide some valuable insights regarding glyphosate resistance management. In a summary of resistance strategies for most selective herbicides, they stated the two alternatives are either 'just say no' or 'accept the inevitable'. These tactics are based on the assumption that abstinence is the only effective way to prevent resistance. They cite previous economic analyses which concluded there was no economic advantage to taking preemptive action to delay the onset of herbicide resistance. However, they concluded that for glyphosate a third option, 'short term pain for long-term gain', could be the optimal approach for managing weeds.

So why is glyphosate resistance different? Why not simply 'use it till we lose it'? According to the Australian researchers, the difference is that the frequency of glyphosate resistance genes is much lower than that of resistance genes for other herbicides. Due to the low frequency of glyphosate resistance, it may be possible to significantly prolong the time required for the resistance gene to increase to problematic levels (control failures). While we don't have a resistance avoidance tactic as effective as the double knockdown (1) described in the paper, I believe the relative rarity of glyphosate resistance in weed populations and the availability of effective herbicide alternatives to glyphosate make resistance management a worthwhile endeavor in our corn-soybean production system.

There are numerous approaches to managing glyphosate resistance, therefore creating a continuum of risk levels. The 'just say no' approach would be one extreme, where a farmer decides simply not to use glyphosate. The other end of the spectrum, 'accept the inevitable', would be continuous planting of Roundup Ready crops with sole reliance on glyphosate to control weeds. The two primary resistance management strategies applicable to most Midwest farms are: 1) incorporate other herbicides into the system, and 2) rotate between Roundup Ready and non-Roundup Ready crops. Avoiding continuous planting of Roundup Ready crops is the simplest approach to managing resistance since it completely eliminates selection pressure from glyphosate in the 'off' years. The benefit of using alternative herbicides during years when Roundup Ready crops are planted is more difficult to measure since their impact on glyphosate selection pressure varies with the alternative herbicides' effectiveness on the weeds present in the field (http://www.weeds.iastate.edu/mgmt/2004/combination.shtml). Farmers should evaluate where their weed management system falls on this risk continuum, and hopefully adopt systems that place them somewhere in the middle of the two extremes in order to preserve the integrity of glyphosate.

(1) Knockdown is 'Australian' for a burndown herbicide treatment. Double knockdown is the application of a second knockdown treatment one to two weeks after the first to control any weeds that survived the first application. The first knockdown herbicide would be glyphosate, the second treatment would be with paraquat.

Ref quoted: Weersink, A., R.S. Llewellyn and D.J. Pannell. 2005. Economics of preemptive management to avoid weed resistance to glyphosate in Australia. Crop Protect. 25:659-665

WEED CONTROL IN SMALL GRAINS

Last fall, we wrote an article summarizing the major herbicide options for small grains (FCN Vol:04:12). Several new products had been labeled over the years including an added option for grass control. Here a brief summary of the most common grass and broadleaf options:

Osprey is an ALS-inhibitor herbicide from Bayer CropScience. It is labeled for wheat and in our region primarily targets control of annual ryegrass, including Hoelon (ACCase) resistant biotypes. It does have activity on annual bluegrass and will suppress common chickweed, henbit, and pigweed. The Osprey label was recently revised and includes some additional language such as concern for crop injury when frost occurs shortly after application to the actively growing wheat. Some additional changes include simplifying adjuvant recommendations and stating to always include a non ionic surfactant (NIS) plus an ammonium nitrogen fertilizer or MSO (methylated seed oil) or a "basic blend" type adjuvant. The application in fluid fertilizer section was also clarified and states that Osprey may be applied using liquid nitrogen solution as the carrier. The fertilizer spray solution should not exceed 15% liquid nitrogen and NIS should be added at no more than 0.25% v/v. Osprey may be tank-mixed with other herbicides including, Harmony Extra, Harmony GT, MCPA, Buctril, and Stinger. Soybeans can be planted 90 days after application, corn after 12 months and alfalfa after 10 months. Refer to the most current label for other use restrictions.

Harmony Extra and Peak are effective on wild garlic and wild onion as well as chickweed and several other winter annual broadleaves. Peak is weak on henbit and deadnettle. In addition, Peak recrop restrictions include 10 mo. for soybean and 15 mo. for alfalfa. Harmony GT contains only one of the active ingredients (thifensulfuron) in Harmony Extra and thus does not have the same weed control spectrum. (In most cases, Harmony Extra remains the herbicide standard in small grains.) Clarity, Banvel, 2,4-D, or MCPA can improve the control of some winter annuals and perennials and Stinger is the most effective small grain herbicide for thistles. Again, see a current herbicide label for specific weed species, rates, and restrictions.

NEW PRODUCT UPDATE

Gramoxone Inteon — Syngenta is introducing a new formation of Gramoxone (paraquat) that includes the new "Inteon Technology". According to Syngenta, this new technology provides a 10X reduction in oral toxicity by including a special safening agent that is derived from a seaweed extract called "alginate". The pesticide forms a gel when it comes in contact with acid pH (1 to 3) typically found in the stomach. This slows dispersion of the pesticide into the small intestine allowing the emetic to act. Gramoxone Inteon is a slightly thicker consistency than Gramoxone Max, the odor is less offensive, and it is a 2 lb/gal formulation. So, 2 pt/acre of Gramoxone Max is equivalent to 3 pt/acre of the new Gramoxone Inteon formulation. We tested this product last season in a no-till corn trial and observed good performance indicative of Gramoxone.

Milestone — Dow AgroSciences is introducing a pasture herbicide containing a new active ingredient called aminopyralid. Milestone is the single active ingredient and a second premixed product also containing 2,4-D will also be marketed for pasture. Aminopyralid is a plant growth regulator and specifically a pyridine related to clopyralid (Stinger) and triclopyr (Garlon). Aminopyralid is a new generation active ingredient that is effective at low rates compared to similar herbicides. Typical pasture use rates for aminopyralid is 1 to 1.75 oz active ingredient per acre (4 to 7 oz Milestone). Some of the other benefits include very low toxicity to birds, fish, mammals and aquatic invertebrates, non volatile, no grazing restrictions, and it is NOT a restricted use pesticide. Milestone a broadleaf herbicide that provides systemic control of several problem weeds including most thistles, dock species, and solanaceous weeds (e.g. horsenettle) to name just a few. We have tested the herbicide for two seasons in pasture and would characterize it as a fairly broad spectrum product with some residual control with good forage grass safety. Additional products containing aminopyralid will also be available for wheat and barley. You will certainly hear more about this active ingredient as it becomes available.

Bill Curran, wcurran@psu.edu
Weed Management, Crop and Soil Sciences

Agents Corner

Central

On October 7th and 8th, we finally got the rain we waited all summer for! Too late for grain crops but will help some of the livestock producers with wells that were very low and were hauling water. Grain was coming off rapidly until the rain hit and has stalled waiting for fields to dry and sun to return mid-week. Shorter season corn is yielding surprising in the 200+ bushel range in some river bottom locations that received critical summer showers. Shaly side hills are yielding 160+ bushels. Moistures are in the mid to upper teens with some dry enough to go right into the bin bypassing the dryer. Reports of beans in the area in the 40 to 50 bushel range, but I fully expect we will see some in the region go 65+ bushels in spite of the drought. Winter small grain plantings looking fair to good but should gain ground with the additional moisture. I have seen some fabulous alfalfa plantings in the area and the rain should help there as well. Pasture recovering and with no frost yet, growers with sorghum-sudangrass fields are still getting growth for an increased fall yield.

Tom Murphy, tbm1@psu.edu
Lycoming County

SOUTHWEST

The summer like weather extending into October has really pushed crop progress along. Corn silage harvest is all but complete and high moisture corn isn’t far behind. Both of which ended up on the dry side for dairymen. Grain producers have been shelling corn for a few weeks now and yields have been respectable. Only a few fields of soybeans have been harvested at this time. Double crop beans have made it to maturity this year without being frosted, unlike the last couple of years. Yields look to be down due to the dry weather.

Most of 4th cutting is being finished up with lower tonnage again. The hot dry weather has been tough on forage supplies, most producers have been feeding hay for over two months now. I wonder what the hay market will be like this winter?

Pastures are just beginning to show a little life now with the cooler temperatures and the inch of rain on Oct 6–7, first we've had in weeks. Producers may still have a chance to boost forage grasses to extend the grazing season if they choose to buy some nitrogen.

Kevin Fry, ksf107@psu.edu
Armstrong County