Field Crop News, Vol. 12:12, May 22, 2012

May 22, 2012    Vol. 12:12

IN THIS ISSUE:

• Weather Outlook
• A Variety of Insect and Slug Pests Attracting Attention this Spring
• Weed Control Odds and Ends for Hay and Pasture Weeds
• Adjuvant Selection Becoming More Complicated
• Buttercups in Bloom
• Upcoming Events

Weather Outlook — Paul Knight, Pennsylvania State Climatologist, College of Earth and Mineral Sciences

A large, sluggish, weak disturbance will keep its grip on the weather in the eastern half of Pennsylvania into Thursday with abundant clouds and episodes of showers and drizzle along with temperatures between 60-75°F. Little drying is expected in this part of the Commonwealth until sunshine returns at the end of the week. Meanwhile, the western half of the state will slowly improve with increasing intervals of sunshine each afternoon, though still a few thundershowers developing late each day. Readings will reach the lower 80’s by Thursday.

High pressure will take control of the weather during Friday setting up the region for a hazy, hot and humid Memorial Day weekend with many urban areas topping 90 degrees each afternoon from Saturday to Monday. A few thunderstorms are expected each day, with Monday expected to be the most active. Noticeably drier and somewhat cooler air should arrive on Tuesday or early Wednesday ending the brief heat wave. More seasonable weather is expected for the second half of next week with a showery time on either Friday and/or Saturday. The first week of June may average below normal temperatures.

Odds still favor a heat wave in June with a string of days in the 90’s. The remainder of the summer is expected to alternate between spells of rather warm, humid weather and occasional bouts of seasonable conditions, though August should turn noticeably cooler.

A Variety of Insect and Slug Pests Attracting Attention this Spring — John Tooker, PSU Entomology Specialist

In the past few weeks, I have provided updates on various insect and slug pests that have warranted attention this spring http://extension.psu.edu/field-crop-news/archives/2012. This week the list will reiterate much of these same points and expand slightly because crop scouts and growers around Pennsylvania are reporting many actively feeding pest species.

At our research farm in Centre County, we have found a few corn fields with substantial black cutworm damage. These caterpillars are active at night, but were easy to find with a trowel by digging up the cut seedling. Presence of the black, greasy looking caterpillars verifies the source of damage, which can be difficult to diagnose is some cases, particularly in slug infested fields. Some of the fields where we found damage were planted with seed protected by the high rate of a popular seed treatment; nevertheless, damage is evident. Similarly, some transgenic corn varieties claim activity against black cutworm, but this control is not always perfect and damage to these Bt hybrids can be surprising. To hedge against any surprises, growers and field personnel would be wise to scout fields, including transgenic and seed-treated fields, for this cutting damage, and apply rescue treatments if larvae are small and the economic threshold is exceeded. For details on black cutworm and thresholds, check here: http://www.ento.psu.edu/extensi on/factsheets/black_cutworm.htm.

 

True armyworms are also active. These caterpillars can cause damage to small grains and corn, but tend to be most problematic in corn planted before a small grain cover crop was completely dead. Be sure to scout for damage from this pest because, true to its name, populations can generate quickly and march through fields causing extensive damage - in corn characteristic defoliation leaves just the midrib remaining. For details see: http://ento.psu.edu/extension/factsheets/arm yworm

Slugs continue to be problematic with the regular bouts of rain experienced by much of the state. These slimy mollusks can quickly decimate newly sprouted fields, so be sure to scout low-lying fields or those with heavy residue. Corn seedlings often can grow out of seemingly serious damage. If the upper leaves are more or less free of damage, chances of the corn growing out of it are pretty good. If rescue treatments are warranted, act quickly. See our factsheet for details and control options for slugs: http://ento.psu.edu/extension/factsheets/slugs-as-pests-of-field-crops

We are getting an increasing number of reports of cereal leaf beetle activity around Pennsylvania. This time of year cereal leaf beetle infestations are often diagnosed from the cab of a vehicle as fields turn frosted and frosted fields are too late to save. This year substantial populations have been detected when growers inspect their sprayers after applying fungicides and finding larvae all over the sprayer. Once populations reach one or more larvae per stem, treatment is probably warranted, especially if larvae are feeding on the flag leaf prior to head emergence. Damage later in head filling does not appear to be significant and if adults are seen late in spring, it is likely too late to manage this pest. For details on this pest’s life cycle and management options, see our recently revised fact sheet: http://ento.psu.edu/extension/factsheets/cereal-leaf-beetle

Bean leaf beetle populations are abundant in many soybean fields this spring. Cold temperatures typically knock back populations of this native pest species, so the mild conditions we had this past winter have likely contributed to larger populations. Seed treatments are very effective against this early season pest, but soybean seedlings can still experience defoliation and damage to the cotyledons. Growers may be uncomfortable with damage they are seeing, but beans typically recover well and there is rarely a yield drag from this early season damage. So unless damage is extreme, be patient and trust your treated beans.

Lastly, we have gotten our first reports of potato leafhopper populations in alfalfa fields. Hot dry temperatures can really speed development of this pest, but populations this time of year can still increase, so keep those sweep nets handy and watch your alfalfa fields. Happy Souting!

Weed Control Odds and Ends for Hay and Pasture Weeds — Dwight Lingenfelter and Bill Curran, PSU Weed Science

Herbicides in new grass and legume seedings. Herbicide selection for new forage grass and/or legume seedings are limited. Most herbicide labels for grasses like orchardgrass, timothy, etc. state that the grasses should be well established with at least 4–5 inches of growth. Some labels are more restrictive than this. The metsulfuron label states that grasses should be established for at least 6 months prior to an application. This ensures that they are developing a solid root system that could tolerate potential stress from the herbicide. Herbicide selection, formulation (ester vs. amine) rate, and environmental conditions at application will all impact the potential for injury. Herbicide use in new legume seedings has similar concerns. In general, legumes should have several trifoliate leaves and be 2 to 3 inches tall before making an application. The Pursuit and Raptor labels state that alfalfa should have 2 trifoliates or larger at application; two of the most lenient products for new alfalfa seedings. Also, keep in mind that at the same time that we want our crop to have sufficient growth, our targets are generally “small” annual weeds which are easier to kill – a bit of a paradox. Finally, products are even more limited with mixed seedings. Pursuit is labeled for established alfalfa-grass mixtures as is metribuzin (Dimetric, TriCor, etc.); MCPA and Buctril are labeled on legume/small grain companion seedings, and several other products have labels for CREP mixtures http://pubs.cas.psu.edu/FreePubs/pdfs/uc198.pd f.

Established hay and pasture. The flowering stage is an excellent time to attempt some control of poisonous perennial plants. A number of common plants can be poisonous when eaten in sufficient quantity by livestock, so monitor those pasture and hay fields closely. Remember that perennial weeds are most sensitive to control with a systemic herbicide when they are in the bud to bloom stage and in late summer. Biennials including musk and plumless thistle, burdock, wild carrot, etc. should be treated before they begin to bolt (they are bolting now or very soon) and the smaller the better. Late fall or early spring is even a better time to treat them. And finally, control summer annual weeds as soon after they emerge as possible when they are most sensitive to chemical control. Below are some guidelines to provide a quick management summary for some common weeds of pasture.

Management guidelines for some problem weeds of pastures.

Annuals

Winter annuals (Mustard species, common chickweed, etc.)

• Mow after bolting to prevent seed production.
• Apply an effective herbicide in fall or spring prior to bolting.
• Most winter annuals emerge by late fall - a smaller percentage will emerge in early spring
• Prevent seed production to prevent spread.

Summer annuals (Pigweed species, common lambsquarters, common ragweed, etc.)

• Keep pasture full and competitive.
• Mow after bolting to prevent seed production.
• Apply an effective herbicide in early summer.
• Prevent seed production to prevent spread.

Biennials

Biennials (common burdock, bull and musk thistle, poison hemlock, etc.)

• Mow after plants have bolted but before seed set to prevent seed production.
• Remove or dig individual plants by hand.
• Apply an effective herbicide to rosettes in the spring or fall.
• Prevent seed production to prevent spread.
• Several insect biocontrol tools may help with thistles in the future.

Perennials

Creeping perennials (Canada thistle, horsenettle, etc.)

• Mow to suppress vegetative growth and prevent seed production.
• Spray with an effective systemic herbicide at bud to bloom stage or in early fall prior to frost.
• Most perennials spread by both seed and vegetative structures.

Woody perennials (multiflora rose, autumn olive, etc.)

• Mow to suppress and prevent seed production - remove roots by hand or with heavy equipment.
• Spray with an effective systemic herbicide at bud to bloom stage or in early fall.

Rose rosette disease has spread as far North as Central PA and may impact Multiflora rose in the future.

Adjuvant Selection Becoming More Complicated — Bill Curran and Dwight Lingenfelter, Penn State Weed Science

We have had several questions about appropriate adjuvants to include with post corn herbicide applications. Table 2.2–16 in the Penn State Agronomy Guide includes spray additives for burndown and post corn herbicides. Table 2.4–14 has the similar information for soybean herbicides. Recent questions have been about products tank-mixed with glyphosate and whether additional adjuvants are necessary particularly with fully-loaded glyphosate formulations. Questions mostly arise when the potential tank-mix partner recommends crop oil concentrate (COC) or methylated seed oil (MSO). Most of this issue seems related to the pigment inhibitor or Group 27 herbicides which often call for oil adjuvants. In general, our experience has been that ammonium sulfate (AMS) should almost always be included and no additional nonionic surfactant (NIS) is necessary for fully loaded glyphosate products. Additional NIS should be added for partial or unloaded glyphosate. Crop oil concentrate (COC) and MSO are generally not recommended for glyphosate tank- mixtures. A useful publication that is available for just $3.00 in hard copy or on-line for free is the Compendium of Herbicide Adjuvants, http://www.herbicide-adjuvants.com/ by Dr. Brian Young bgyoung@siu.edu, at Southern Illinois University. It is current and organizes adjuvant products by their use category as well as several other categories (manufacturer, crops, etc.). Below are several specific label guidelines that may require special consideration, however it is best to check a current label or with a manufacturer representative for the latest information.

Tank mixtures with glyphosate:
For Callisto or Callisto Xtra, add AMS and additional NIS if glyphosate is not fully loaded. Do not add UAN, COC or MSO type adjuvants.

For Impact, add MSO or COC + UAN or AMS. Use NIS in place of oils if tank-mixed with PGR herbicides (Clarity, 2,4–D, Distinct, Marksman) during periods of cold and wet or hot and/or humid weather.

For Capreno, with full use rates of a loaded glyphosate formulation, the addition of a glyphosate-compatible surfactant is recommended. The addition of a glyphosate compatible surfactant is required with low load or unloaded glyphosate products. Glyphosate- compatible oil-based surfactants such as the high surfactant oil concentrate (HSOC) will optimize the performance of Capreno herbicide in the combinations. Examples of HSOC adjuvants include Cide Winder, Destiny HC, FS COC Supreme, and Superb HC just to name a few.

Tank mixtures with Liberty or Ignite: Add AMS, no additional surfactant is needed with any labeled tank mix partner.

Buttercups in Bloom — Bill Curran and Dwight Lingenfelter, Penn State Weed Science

A number of buttercup species (Ranunculus sp.) are quite visible in many pastures this time of year (see accompanying image). This genus includes about 600 species with about 25 included in The Plants of Pennsylvania http://www.upenn.edu/pennpress/book/14335.html. They are mostly herbaceous perennials with bright yellow or white flowers, but some are annual or biennial. Buttercups are poisonous to livestock, but are generally left uneaten because of their acrid taste. People have commented that they seem more conspicuous than normal this year.

Buttercups in pasture are generally a symptom of overgrazing and in general not enough attention paid to pasture management. You can control or reduce the buttercups with several herbicides, but they will return the next season if additional management is not included (rotational grazing, fertility and pH, drainage, overseeding, etc.). If you are willing to use an herbicide, when is the best time is to control buttercups in pasture? For both annuals and perennials, trying to control or suppress them prior to seed production in early summer would be helpful. However, as it is for most perennials, a well timed late summer application may be most effective. We conducted a study back in 2008 in Lebanon County, PA on a farm infested with perennial bulbous buttercup (Ranunculus bulbosus). We tested a number of herbicides in a mixed-grass pasture examining two application times; July 8 and September 24, 2008. We evaluated the plots the year of application and the following summer. The year of application treatments only provided 50 to 77% control of buttercup and continued to decline. By the year after application, the September timing provided better control than the July timing. The aminopyralid containing products (Milestone and ForeFront) tended to be near the top with 83% or better control. Clarity + 2,4-D amine provided 67% control with Cimarron Plus and a metsulfuron + Clarity + 2,4–D amine treatment coming in at 77% control. As mentioned in last weeks' newsletter, aminopyralid, a component of ForeFront can only be used in permanent grass pasture settings in Pennsylvania, it cannot be used in hay production (supplemental label update: http://www.cdms.net/LDat/ldA6J003.pdf) and special manure handling is required. This is generally not a product suitable for horse pastures where manure may leave the farm.

Upcoming Events

2012 Farming for Success Field Day – June 21st, 2012

Penn State Extension is pleased to announce the “The Farming for Success 2012” Field Day which will be held at the PSU Southeast Agricultural Research and Extension Center (SEAREC), on June 21st.

Respected and informative speakers will address numerous production agriculture topics. In total, 14 different topics will be available to choose from. A sampling of topics includes:

• Perdue Soybean Crushing Plant Update: Hear directly from Perdue, details and progress toward receiving local beans for 2013, Dick Cole & Peter Heller, Perdue Agri-business
• All about Drills: Proper drill calibration and establishment are the essential first steps to reaping the many benefits of forage and cover crop species. See various brands of drills, & chat with representatives, Steve Groff, Cover Crop Solutions, LLC.
• See research being conducted on the farm and view field demonstrations including the new poultry litter (sub-surfer) manure injection system.
• Local ag sponsors will have equipment on display and personnel on hand to help you improve your crop production practices and answer your questions.

The program begins promptly at 9:00 AM, and concludes by 3:00 PM. Pre-registration cost: $5:00 (if received by noon of June 29th). Walk-in registration: $10.00. Registration includes a BBQ lunch. For preregistration and information contact Jeff Graybill, Penn State Extension in Lancaster County, 717–394–6851. The Penn State Southeast Agricultural Research and Extension Center (SAREC) is located at 1446 Auction Rd., Manheim, PA 17545.

Strategies for Soil Health and Nutrient Conservation Field Day – June 27, 2012

A comprehensive cropping systems field day is planned for June 27, 2012 at Penn State’s Agronomy Research Farm located on the Russell E. Larson Agricultural Research Center ten miles west of State College. The event will begin with registration and light refreshments at 8:45 at the Livestock Evaluation Center located approximately 1.5 miles east of the Ag Progress Days site. A review of the highlights of three different experiments will be included. The field day participants will be able to spend time listening to researchers and several farmers who are practitioners of some of the ideas being investigated. Attendees will hear about and see research in progress for five specialty areas being studied.

To register for the field day OR learn more about the full day event, please go online to: http://extension.psu.edu
Click on “Events”
Click on “Strategies for Soil Health and Nutrient Conservation Research Tour”
Registration can also be accomplished by calling: 877–489–1398 or contacting Ron Hoover, rjh7@psu.edu

Heritage, Organic and Specialty Crop Production Twilight Tour – June 28, 2012

The date of the tour is June 28, 2012, 6–8pm at the Russell E. Larson Agricultural Research Center at Rock Springs, Gate G and hosted by the Penn State Extension Crop Management Team

Tour research plots and variety trials to see:

• Emmer, einkorn, and spelt variety trials (organic & transitioning)
• Wheat variety trials (soft & hard, winter & spring, heritage & modern varieties are included, organic & transitioning)
• Fava bean seed production (organic)
• Heritage hulless oats (non-organic)
• Soybean performance after different histories of tillage, weed management, and crop rotation (organic).

Please RSVP to Charlie White at cmw29@psu.edu or 814–863–9922 if you plan to attend. The research center is 2.5 miles west of Pine Grove Mills, PA along Rt. 45. Enter at Gate G and follow signs to parking. Research and demonstration projects on the tour are supported by the USDA Organic Research and Extension Initiative, the USDA Risk Avoidance and Mitigation Program, and the Northeast SARE Pennsylvania State Program.

Contributors: Extension Educators: Jennifer Bratthauar (Franklin), Joel Hunter (Erie), Mark Madden (Bradford), Dwane Miller (Schuylkill), John Rowehl (York), Nicole Santangelo (Potter), Mena Hautau (Berks), Del Voight (Lebanon). Extension Specialists: Bill Curran, Dwight Lingenfelter, Crop and Soil Sciences, John Tooker, Entomology.

Editor:Mike Fournier (Bucks)

Real time pest and heat unit activity: http://agsci.psu.edu/news/spotlight/pa- pipe

Calendar of Events: http://extension.psu.edu/cmeg/events

If you have any questions or would like to suggest a topic, please contact your local Extension Educator.

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