CMEG Crop Management Extension Group

Field Crop News

Web site Address: http://fcn.agronomy.psu.edu/

June 2, 2009    Vol. 09:13

IN THIS ISSUE:

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

he boundary between warm, humid air and cooler air will stretch across Pennsylvania on Wednesday, and then move just south for a couple of days and finally straddle the Commonwealth for first part of next week. The positive side of this pattern is that no long dry periods are expected, nor should there be any persistent heat during the next 5–8 days. The negative side is that drying conditions will only be fair and a few cool nights are possible in the northern tier. The details of when and how much it will rain are difficult to pin down, but here is a snapshot of how things look now; most places have several hours of showers (t-storms) on Wednesday with more than 0.50" in many sections (some will get >1").  Showers linger across southern and especially southeast counties on Thursday. The rest of the state should be dry from Thursday into Saturday. A new cool front should push through late Saturday with only scattered showers at night or Sunday morning. A surge of warm, humid air later Sunday or Monday will touch off widespread showers (t-storms) with more than 0.25" in many sections.  The front should sag south of the region on Tuesday and there may be a spell of cool weather at mid-week.

There are still indications that a heat wave is likely (more than 3 days above 90°F) during the third week of June and it is possible that this may be the hottest weather of the year in some places. Odds still favor above average temperatures for the June period. A notable wet period is possible in the latter half of July or August.  The hurricane season should have a late start with notably fewer storms than recent years (perhaps less than 10). Very cool conditions are likely during September, with perhaps an unusually early end to the growing season in the northern counties.

Pokeweed Management — Bill Curran, Penn State Weed Specialist

It’s again the time of year that pokeweed starts to become very visible in soybean and corn fields around the state. Here are a few reminders about this prevalent problematic weed.

Pokeweed is a simple perennial emerging from the same taproot each spring and spreads within a field or between fields by seed production. It’s important to target the plants prior to successful reproduction since the seeds can persist up to 40 years in the soil and can be dispersed by birds (robins, starlings, others) potentially spreading new infestations wherever these birds fly and/or roost. Control of this weed is fairly difficult with single postemergence herbicide treatments and multiple tactics are often necessary. Regardless of the crop or herbicide treatment, make sure the spray boom height is up above the pokeweed and use spray tips and a carrier volume (i.e. > 10 GPA) to maximize coverage.

In corn, effective treatments include dicamba (Banvel, Clarity, Sterling) generally mixed with a sulfonylurea (Northstar, Yukon, Celebrity Plus, etc.), or Callisto or Status. Apply when pokeweed plants are less than 12 inches tall if possible. In Roundup Ready corn, use glyphosate (0.75 lb ae/A) when plants are at least 8 inches tall and make a second application if necessary.

In soybean, glyphosate is fairly effective and control can be increased by tank mixing with FirstRate, Classic, or Synchrony STS. Again, other factors (application timing, boom height, etc.) may also play a role in successful control. In Roundup Ready soybeans use at least 0.75 lb ae/A applied when pokeweed plants are at least 8 inches tall. Make a second application if necessary. In soybeans that are not Roundup Ready, use Synchrony STS (0.5 oz/A) or Classic + Harmony tank mixes.

Consider Spray Tip Selection for Postemergence Applications — Bill Curran, Penn State Weed Specialist

Selecting the correct nozzle spray tip is important for achieving successful weed control. With many of the postemergence applications starting to happen in corn and soybeans, remember that nozzle selection can make a difference. In our diverse agriculture that includes vegetables, tree fruit, and tobacco, spray drift can be a real concern. In most of our research trials with herbicides, we use air induction or venturi nozzles. Several different designs are currently being marketed by the different manufacturers. With these tips, the air-fluid mixture forms a larger droplet to help transport the droplet to the target reducing the potential for smaller driftable fines that can leave the field. Unless they are a newer specialty tip (i.e. extended range), it is important to maintain at least 40 psi as an operating pressure to maintain a uniform pattern while properly atomizing the spray solution. Do not add drift retardant-type products to the tank mix when using lower-drift tips as they can compromise the spray pattern. When using air induction or other types of nozzle tips that reduce the potential for particle drift, remember that herbicide mode of action may help dictate whether these lower drift tips are appropriate. In general, all systemic herbicides (herbicides that move through the vascular system of the plant called xylem and phloem) should perform well with lower drift tips. This includes glyphosate, the plant growth regulators, the ALS-inhibitors and most post corn herbicides. With large perennials like pokeweed, increase the gallonage to greater than 10 GPA (15 to 20 GPA is better) to ensure better coverage with the fewer larger droplets. Contact-type herbicides may not perform as well with lower drift tips. Contact herbicides including Gramoxone, Reflex, Cobra, Basagran, Buctril, etc. require greater coverage of the leaf surface area for best performance. Regular flat-fan tips are more appropriate for these types of products and higher spray gallonage (15 to 20 GPA) can improve performance. Ignite or glufosinate (formerly Liberty) is also a contact-type herbicide with limited movement through the vascular system of the plant and should also perform best with standard flat-fan tips or tips that provide more thorough coverage.

Scab Risk Update — Greg Roth, Grain Crop Specialist

Wet weather last week and this week has increased the risk for scab in wheat flowering in the central parts of the state. A similar situation exists in Ohio and was addressed in an article in the Ohio State Crop Observation and Reporting Network. Their recommendations are very relevant for our situation in Pennsylvania, so we have decided to reprint it here.

June 1: Scab Risk Update and Fungicide Efficacy against Scab after Flowering – Pierce Paul, Dennis Mills

Wheat flowered last week (May 25 – May 31) in some field in the northern third of the state and flowering continues in other fields during this week (June 1 – June 7). Depending on when flowering occurred, some of the fields in northern Ohio that flowered during the week of May 25 would have received rain on at least one day during flowering. In some areas, it rained on Tuesday (May 26), Wednesday (May 27), and Thursday (May 27) of last week and some of the fields that flowered early in the week received rain on all three days. The forecast is for more rain on Monday (June 1), Tuesday (June 2) and Wednesday (June 3) of this week. Again, depending on where the field is located, when flowering occurs, and the accuracy of the weather forecast, some of the fields flowering this week may receive rain on one day while others may receive rain on all three days. Fields that flowered or are flowering that received two to three days of rain during last week and another two to three days of rain this week would be at the greatest risk for scab development and vomitoxin contamination, especially those flowering this week (the week of June 1). Remember, scab develops best when frequent rainfall occurs shortly before, during, and shortly after flowering. For wheat flowering during the week of June 1, rainfall during the week of May 25 would have contributed to the production and spread of spores of the scab fungus (Fusarium graminearum), while rainfall this week would contribute to infection, scab, and vomitoxin contamination.

The three most effective fungicides against scab are Prosaro, Proline, and Caramba, at label–recommended rates. Prosaro is a combination product of Folicur and Proline that has similar efficacy to Caramba, Proline alone, or a tank mix of Proline (3 fl oz/A) + Folicur (3 fl oz/A). All of these fungicides will only suppress scab (efficacy between 45 and 55% reduction) and are most effective when applied to a resistant variety and applications are made at flowering. Some level of scab and vomitoxin suppression can be achieved with applications made up to 5 days after anthesis, but the overall efficacy is greatly reduced. A well timed fungicide application may be the difference between grain being penalized for high vomitoxin (dockage or price discounts) and receiving regular market price at the time of sale. However, it is difficult to tell when fungicide use for scab will be economical. For instance, for a field likely to have vomitoxin contamination between 3 and 4 ppm, an application with a 45 to 50% efficacy may be enough to lower vomitoxin levels below 2 ppm. On the other hand, if conditions are very favorable for scab development, vomitoxin contamination may be well above 8 – 10 ppm, and fungicides alone will not drop vomitoxin levels to 2 ppm. We can predict when the risk of scab will be high or low http://www.wheatscab.psu.edu, but at this time we have now way of telling beforehand when vomitoxin contamination will be 4 ppm or 10 ppm or 25 ppm.

There is some concern about vomitoxin contamination in the absence of scab symptoms. This is a very valid concern. In some years, vomitoxin may exceed 2 ppm in fields that look healthy. Our research suggests that at least three things may contribute to vomitoxin contamination of healthy–looking wheat: it depends on the variety, the weather conditions, and the amount of spores available. We have observed that if there are a lot of spores around and frequent rains occur between grain fill and harvest, the fungus may still infect the wheat and this late infection can result in vomitoxin contamination as high as 2–4 ppm. Fungicides applied at flowering will generally not protect against these late infections and later fungicide applications are illegal for the products listed above. Click on this link below for information on fungicide efficacy and pre–harvest intervals. http://www.oardc.ohio-state.edu/ohiofieldcropdisease/wheat/OFCDwheatfungicides.pdf

Too Late for Seeding Forage Crops (Except for Sorghums/Sudangrasses) – Paul H. Craig, Dauphin County Extension

The optimum time(s) for sowing most forage crops is early in the spring and again in mid–late August. There are multiple reasons for this including: available rooting zone moisture availability; weed competition; insect pressure; and summer high temperature stresses on young seedlings. Across Pennsylvania, late April/early May is usually the time period when spring seedings cease and plans are made for establishment in August.

Frequently referred to as a fall seeding, most successful seedings of alfalfa are actually mid to late summer seedings, usually early to mid August. Seeding into small grain stubble is the most common establishment practice at this time, however some late summer seedings are actually reseedings into unsuccessful spring establishments. Forage grasses are usually sown somewhat later, by mid–September.

Ideally summer alfalfa seedings should have 8 to 10 weeks of growth prior to the date of the first killing frost in your area. Seeding too late does not allow the seedling plants to develop adequate root carbohydrates for winter survival. Also later seedings can result in small root systems that may tend to increase the risk of winter injury from heaving before next spring.

Soil moisture conditions at establishment are critical. There is no sense making a seeding if adequate moisture is not available to ensure germination and development of small roots. Base your establishment decisions on existing soil moisture conditions and short term weather forecasts. Because of warmer soil temperatures with adequate soil moisture levels, summer seedings will germinate and develop much faster than spring seedings.

No till establishment in summer seedings is preferred if proper seeding equipment is available due to the advantage of soil moisture levels. If tillage will be used to prepare a seedbed be certain to consider the “fluffiness” of the seedbed. A loose seedbed in summer seedings can significantly reduce germination and establishment. In most tilled ground, the use of a cultipacker before and after seeding is beneficial. Seed at recommended seeding rates and at a depth of ¼ to 3/8 inch.

A question was raised this week from a producer who was unable to get his spring seeding completed. He was inquiring what his immediate plans should be in preparation for an August seeding. The field he is planning on sowing was planted to a rye cover crop in fall 2008 and burned off with glyphosate this spring. A soil test was taken but no fertilizer or lime has been applied.

In this situation the first option would be to apply any necessary lime to the field as soon as possible. Very soon annual and perennial weeds will regrow. If allowed to grow until seeding and then burned off with herbicides in August these weeds will create significant challenges for good seed placement with a no till drill. With this option an application of glyphosate and 2,4–D in early July will ensure control of perennials and annual summer weeds. Then immediately prior to an August seeding a second burndown with Gramoxone or glyphosate will be needed for additional emerged weed control. Applications of fertilizers should be made and then planting.

A second option would be to burn down the existing weeds now and plant sorghum sudangrass. Two cuttings are likely but it will be important to allow 2nd cutting to reach 30 inches in height before harvesting. Regrowth can then be treated with glyphosate and a seeding made by mid to late August.

Take the time now to start planning for your summer seedings. Review existing weed and soil fertility conditions. Watch soil moisture levels and weather patterns.

Cereal Leaf Beetle Causing Headaches – John Tooker, PSU Entomology Specialist

Cereal leaf beetle

Fig. 1. Cereal leaf beetle larvae feeding
on wheat in Bucks Co. Photo by Mike
Fournier (Penn State Cooperative
Extension, Bucks Co.).

More than a couple wheat and oat fields in Bucks County are experiencing heavy infestations of cereal leaf beetle, so it would be wise to be aware of this issue even though the best time to effectively control this pest has passed. This insect species is native to Europe and Asia and was first detected in the United States in 1962. It quickly spread eastward and is now an occasionally severe pest of wheat, oats, barley and rye. It tends to be a problem in thin (i.e., not well–tillered) stands or poorly established stands, so it can often be effectively controlled just by using good crop management practices. In many parts of its range, it is controlled by introduced species of parasitic wasps, but these wasps may not be well established in some parts of Pennsylvania and some states to our south.

Cereal leaf beetle has one generation per year. Adults pass the winter in leaf litter in wood lots, hedgerows, and similar areas. In March and mid–April as temperatures increase, adults fly to grain fields to lay eggs, which hatch and young larvae begin to feed. Larvae are a yellowish–orange color, but cover themselves with a layer of feces and mucus, giving them a shiny appearance (Fig. 1). This layer protects them from natural enemies and drying out and has been known to ruin a favorite pair of trousers as fields with heavy infestations are walked.

Older larvae do the great majority of damage, stripping off green tissue between leaf veins and skeletonizing leaves. Large populations can cause fields to turn white; indeed, this “frosted” appearance is often what tips growers off to the presence of damaging populations in their fields (see Fig. 1 & 2). Mature larvae burrow into the ground to pupate. Adults emerge about two weeks later, and will feed in small–grain and corn fields for a short time before remaining inactive for most of the summer. Adult feeding has not been shown to be economically significant and targeting adults for control has not been shown to be effective. In fall, adults fly to wooded areas seeking shelter for the winter.

Cereal leaf beetle

Fig. 2. A “frosted” wheat field resulting from heavy infestation of cereal
leaf beetle. Photo by Mike Fournier (Penn State Cooperative Extension,
Bucks Co.).

This pest is most easily managed earlier in spring when eggs or young larvae are present, so in–depth, localized scouting is necessary. Keep in mind that populations can be quite spotty so checking individual fields is often necessary. 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 that significant and if you see adults late in spring, it is likely too late to manage this pest. For insecticide options, please consult Penn State’s Agronomy Guide.

Garden Symphylans – John Tooker, PSU Entomology Specialist

Another issue that has appeared recently is infestations of garden symphylans. We have heard of an oat field in southern York Co. and a corn field in upper Dauphin Co. where the crop is struggling and slowly dying and small worm–like creatures have been recovered from the fields. These creatures appear to be symphylans, which are not insects, but small, centipede–like creatures that live in the soil, feeding on seeds and seedling roots. See Penn State’s fact sheet for more details: http://ento.psu.edu/extension/factsheets/garden-symphylan-as-a-pest-of-field-crops.

Symphylan damage can occur on its own, but often appears to be a consequence of some other problem with the field and these soil dwellers take advantage of already–stressed plants. As a result, symphylans are often blamed when other problems may be causative. Conversely, symphylans are often overlooked as potential pests causing a problem because they can be difficult to find in the soil. Unfortunately, because symphylans live underground, there is not much to be done in the current growing season to control symphylans. If particular fields have problems every year, a soil insecticide is a good bet, but low doses of insecticidal seed treatments do not always stand up to these non–insectans.

Upcoming Events

Weed Suppression and Biodiversity through Cover Crops and Field Edge Plants Field Day—Register Today

Agronomy Research Farm, Russell E. Larson Agricultural Research Center—Pennsylvania Furnace, Centre County

Wednesday, June 17 - 9:00am–4:00pm

$15 PASA Members, $25 all others. Lunch will be provided.

Register On-Line through PASA.

This field day is a collaboration between PASA and Penn State. This field day will focus on managing cover crops and field edge plants for weed suppression and biodiversity gains. Starting promptly at 9:00 am, the morning session will focus on integrating cover crops, cultural controls, and shallow tillage for weed control in grain production systems. Farmers and ag professionals interested in reducing tillage and improving soil quality will learn about cover crops and tools for effective weed management. Come get a first hand look at a cover crop roller and cover crop mulches, a high residue rotary hoe, a high residue inter-row cultivator, and other tools for enhancing weed management in high residue situations.

Starting at 1 pm, farmers, gardeners, and ag professionals will evaluate and gain a better understanding of how crops and field edge vegetation influence pollinators and biological control of insect pests. Learn to assess the effects of different plants in agricultural landscapes, and how to tailor plantings to enhance beneficial ecosystem processes.

Come for the morning, afternoon, or both and join us for lunch at 12 noon. Contact PASA (814-349-9856) or Bill Curran at Penn State (wcurran@psu.edu or 814-863-1014) for additional information.

Register for the Agronomic Weed Control Twilight Tour at Landisville, June 29, 2009

The Second Annual Twilight Weed Tour, Southeast Research and Extension Center (Landisville). Will be held begin at 4:30 pm on June 29, 2009. This is the evening before the “Farming for Success” Field Day on June 30. We will tour the weed control plots from 5:00 to 7:00 pm. You will have an opportunity to examine corn and soybean weed control trials including some cover crop control studies. The format of the program will allow time to view the various treatments /studies and discuss the results with those in attendance. We will finish the evening socializing with one another and enjoying a hot meal.

This event costs $25 per person and includes dinner and educational materials. To register, fill out and send in the form before June 24. Pesticide and CCA credits will be offered. Please contact John Bray or Del Voight at 717-270-4391 in advance if you need additional information.

Register Now for the Rock Springs Agronomy Weed Tour — July 9, 2009

Attend the Annual Agronomic Weed Control Research Tour at Penn State — July 9, 2009 at the Penn State Agronomy Research Farm, Rock Springs, PA (Meet at the Agronomy Farm, Rock Springs, Rt. 45 west of State College, enter Gate D). A number of experiments will be showcased and available for viewing including new corn, soybean, sweet corn, and potato weed control trials. New herbicides include Balance Flexx, the Kixor products (Sharpen, Integrity, and Optill), Corvus, Capreno, Envive, Halex GT, Ignite, Authority Assist and First, Sonic, and Valor XLT to name a few. You will have the opportunity to see Dupont’s GAT corn and potential programs for that. In addition see how the roller/crimper is working on cereal rye and hairy vetch in reduced and no herbicide systems.

Pest Management CCA CEU’s and Pesticide Recertification Credits will be available.

Agenda:

8:30–9:00 am - Registration
9:00 am–12:00 noon - Tour
12:00 noon–1:00 pm - Catered lunch

PreRegistration for this event will be $20.00 and includes lunch and a tour book. Walk-in Registration the day of the event will be $25.00. To register by credit card, go to http://guest.cvent.com/i.aspx?5S,M3,ea617e7d-a373-4a32-8029-ff1a08fb0b49 or contact Lisa Crytser in the Dept. of Crop and Soil Sciences at lac8@psu.edu or 814-865-2543.

Contributors: State Specialists: Marvin Hall, Doug Beegle, Erick DeWolf, Sjoerd Duiker, Greg Roth, Bill Curran, and Dwight Lingenfelter. Extension Educators: Paul Craig (Dauphin), Del Voight (Lebanon) Kevin Fry (Armstrong), Andrew Frankenfield (Montgomery), Jere Wingert (Franklin), Mena Hautau (Berks), Joel Hunter (Crawford), Jeff Graybill (Lancaster), and Dave Messersmith (Wayne).

No- till Field Crop Walk — June 11, 2009

Tuesday, June 11, 2009 10 a.m. to 12 p.m. (Held rain or shine) Peter Zettlemoyer Kempton, PA We will be touring a farm that Peter farms away from the home farm to have a view of various crops.

Sponsored by: Penn State Cooperative Extension — Berks County NRCS — Berks County

 

DIRECTIONS TO THE FIELD - Philadelphia Pike Road, Kempton, PA 19529
(If you need help with directions en route to meeting, call 610-310-0019.)

 
From I 78:

From I-78, take the Lenhartsville exit (exit #35). Travel north 4 miles to Kempton. At the Sunoco station south of town, turn left on Hawk Mountain Road. Travel 1 mile to New Bethel Union Church Road and bear right. Travel past the New Bethel Union Church. The road has a left bearing turn, which is Old Philly (“The Country Seat” is your landmark). Travel a mile to the field, which will be on your left. Look for signs.

 
From 143 North of Kempton:

Follow 143 past Kempton and at the Sunoco gas station, bear right on to Hawk Mountain Road. Follow the above directions.

Contributors:  Extension Educators:   Paul Craig (Dauphin), Kevin Fry (Armstrong), Del Voight (Lebanon), Mena Hautau (Berks), Tianna DuPont (Lehigh), H. Grant Troop (Lebanon), Susan Alexander (Jefferson), Mark Madden (Sullivan), Jeff Graybill (Lancaster), Joel Hunter (Crawford); Jonathon Rotz (Cumberland).

 

Editor: Susan Alexander

Upcoming Events

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

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

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

Readers can subscribe electronically to this newsletter at the Field Crop News Web site.

If you have problems subscribing or wish to cancel your subscription, please contact Lisa Crytser by e-mail at lac8@psu.edu or by phone at 814-865-2543.

Information presented above and where trade names are used, they are supplied with the understanding that no discrimination is intended and no endorsement by Penn State Extension is implied.

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