Field Crop News

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

June 10, 2005    Vol. 05:06

IN THIS ISSUE:

Mark Your Calendar

Weather Outlook

Production

Pest Management

Agents Corner

MARK YOUR CALENDAR

PENN STATE-PASA ECOLOGICAL WEED MANAGEMENT FIELD Day

Monday, June 13, 1:30-5pm, Rock Springs
Agronomy Farm Pavilion, Centre County
Cost: Free
Refreshments will be provided.

For those trying to get ahead of their weeds, June is a critical month. WeÕll start this afternoon field day with an introduction to Ecological Weed Management, which will include a lesson on weed identification and life cycles. We'll move to the cover cropping trials where no-till, rolling, herbicides, shallow till and other methods of management are under trial. A team of Penn State researchers will discuss using cover crops to manage weeds and improve soil quality, as well as present information on the role of ground beetles in weed seed predation.

This field day will also afford us an opportunity to get an update on the "transition experiment" where Penn State researchers are transitioning corn and soybean crops from conventional to organic production. Presenters from Pennsylvania Certified Organic will be on hand to explain alternative methods of weed and cover crop management that comply with USDA certification standards. WeÕll learn what farmers can do to manage crops during the transition period and hear about current marketing opportunities for organic grain. In addition, 3.0 Pest Management CEUÕs will be offered for those that are Certified Crop Consultants.

To register, please call Pennsylvania Association for Sustainable Agriculture (PASA) at 814-349-9856 ext. 7 or register online at www.pasafarming.org.

PASTURE, WHEAT, AND IPM FIELD DAY

June 21 from 5:00 to 9:00 p.m. at the Don and Jeff Byerly Farm and the Elvin Stoltzfus Farm in Lewisburg, PA, Union County.

Get information on no-till renovations of pasture, sweet corn IPM, novel crop biostimulants, and prospects for alternative winter wheats. Neighboring farmers Don and Jeff Byerly and Elvin Stoltzfus have teamed up with Penn State county and state extension personnel and several agri-businesses for four on-farm research or demonstration projects. The overall objective of the field day is to identify and highlight some opportunities for improving farm productivity and profitability. The event will begin with an evening cookout featuring meats processed and sold through the Byerly brothers' retail market. Discussions of the four field projects will follow.

Pasture renovation studies on the Byerly farm are documenting the yield and quality of two dozen grasses and legumes when no-till drilled into existing pasture. Of interest to some farmers is the novel approach of banding herbicide at the time of no-till drilling. Plots were seeded in August 2004 and are presently being evaluated. The Byerly farm is one of six farms in the north central and northern areas of Pennsylvania participating in this pasture study. Dave Hartman and Ron Hoover will lead the discussion. The project is supported by a grant from the Northeast USDA-SARE program and by donations of forage seed from Kings Agriseeds, P.L. Rohrer Seeds, The Keystone Group, and Seedway.

Many Pennsylvania flour mills and bakeries are interested in specialty and locally-grown flours. This interest coupled with farmers' desire to find a crop with greater market value prompted a field comparison of several alternatives to our standard soft red winter wheat. Included in the agronomic and food quality evaluations are hard red winter wheat, soft white winter wheat, soft red winter wheat with strong gluten, and spelt. The plots on the Stoltzfus farm are headed out and will be in great shape to view during the field day. Research and extension participants from PSU include Greg Roth, Erick DeWolf, Shaun Heinbaugh, and Tom Murphy working with Tim Lightner of Helena Chemical Co.

Offering worm-free ears of sweet corn to customers while minimizing the amount of pesticide used to control these pests continues to challenge farmers. Extension agent Norm Conrad will lead a demonstration and discussion in a Byerly sweet corn field that will focus on the use of pheromone lures, insect traps, and economic thresholds to help farmers best determine when control measures are necessary.

Also being evaluated on sweet corn is a novel plant biostimulant from China. The product is a blend of three soil microbes that have been found to enhance root uptake of nutrients. The product has been and continues to be tested on several crops. The implications of this type of technology could include reduced fertilizer inputs while maintaining crop yields and quality. Reduced rates of commercial fertilizer not only reduce input costs but can reduce the opportunity for these nutrients to move into ground or surface water. Norm Conrad and Rick Paulsen will lead the discussion of this technology.

Questions about the event can be directed to Ron Hoover via email at rjh7@psu.edu or by calling 814-865-6672. The cost of registration is $10. Participants are asked to pre-register and receive directions to the farm electronically with the Pennsylvania Association for Sustainable Agriculture (PASA) at www.pasafarming.org and clicking on the "Farm-Based Education" page, or by calling the PASA office directly at 814-349-9856.

Ron Hoover, rjh7@psu.edu
On-Farm Research Coordinator, Crop and Soil Sciences

TWILIGHT FIELD MEETING

Wheat varieties will be featured at a Twilight Field meeting on Monday evening, June 27 in Lehigh County. Greg Roth will discuss new hard red and soft red winter wheat varieties and their management.

Visitors will be able to see 24 wheat varieties at an on-farm replicated field trial just prior to harvest. The plot is located at the Sterling and Ruth Raber Farm. From Rt 78 take Rt 100 north 3.5 miles, Turn right on Windy Road. The program begins at 6:30 PM. For more information contact Bob Leiby at rel5@psu.edu 610-391-9840.

Bob Leiby, rleiby@psu.edu
Lehigh County Extension

AGRONOMY-INDUSTRY FIELD DAY, JULY 7, 9:30 AM-3:30 PM, LANDISVILLE

Penn State will host a joint Agronomy-Industry field day on July 7 at the Southeast Research and Extension Center near Landisville, Lancaster County. The field day will feature faculty and staff from Penn State's Departments of Crop and Soil Sciences, Entomology, and Plant Pathology and Cooperative Extension Service, discussing the latest developments and key topics in agronomic crop and soil management. In addition, representatives from industry will be present to discuss and showcase their latest technologies. The field day will run from 9:30 am to 3:30 pm, and pesticide and CCA credits will be available. See the registration brochure in this issue of Field Crop News. Please note that pre-registration by July 1 is required in order for us to plan for lunch.

Dave Johnson, dhj3@psu.edu
SE Ag Research and Extension Center, Landisville

REGISTER NOW FOR THE ROCK SPRINGS WEED AND OTHER PESTS TOUR - JULY 12, 2005

33rd Annual Agronomic Weed Management (and other pests) Research Tour at Penn State

July 12, 2005 at the PSU Agronomy Research Farm, Rock Springs, PA (Meet at the Agronomy Farm, Rock Springs, Rt. 45 west of State College). A number of experiments will be showcased and available for viewing plus the latest information on herbicide resistance, weed competition, and cover cropping and weed management research. See the new PSU cover crop roller and hear about our first year experience. Hear about Roundup Ready alfalfa and its status.

Also, hear about the new pest prediction models, corn rootworm management, and the latest about soybean rust as well as other important diseases. Pest Mgt. CCA CEU's will be available.

Agenda:

Pre-Registration for this event will be $10.00 and includes lunch. Registration the day of the event will be $15.00. Please pre-register one week prior to the event (by Tuesday July 5) with Lisa Crytser by phone (814-865-2543), fax (814-863-7043), email (lac8@psu.edu), or mail (registration form) so we can accommodate luncheon needs.

WEATHER OUTLOOK

A remarkable turnaround has occurred in the weather pattern not only in Pennsylvania, but also across much of North America. One of 10 coolest Mays on record is being replaced by an exceptionally warm period during the first half of June. Precipitation has become more regular in frequency, but more sporadic in coverage. Still, most sections are averaging about 1-2 inches below normal rainfall since May 1. Much warmer nights during the last week have boosted growing degree days.

Expect the early season heat wave to persist until at least Tuesday, June14 and perhaps until later Thursday, June 16. Thunderstorms will be scattered across the state each afternoon and evening with more storms likely in western sections during Saturday and eastern sections on Sunday.

The remnants of the first tropical storm of the season may add to the thunderstorm rainfall between later Tuesday and Wednesday.

More seasonable and less humid weather will return by Friday, June 17, but there are indications that this respite will be short-lived with hazy, very warm and humid weather expected again between June 19-23. The unanticipated early season warmth has cast doubt on the forecast of a hot conclusion to what was expected to be a cool summer, though it was very warm in early June last summer and that heat dissipated quickly.

Paul Knight, pgk2@psu.edu
Pennsylvania State Climatologist

PRODUCTION

WARM WEATHER SPURS CORN DEVELOPMENT

The above average temperatures we have experienced this week should spur our crop development in corn and get our crop somewhat back on schedule. Our crop has generally been shorter than normal with many experiencing some purple corn symptoms. With the dramatic increase in temperature, we should see much of this purpling disappear soon. Also, often corn begins to lose the pale yellow color and take on the deep green color with the onset of these high temperatures. The combination of warm temperatures and moist soils from the thunderstorms earlier in the week should cause corn to grow rapidly with little stress. Prior to V10, corn will generate a new leaf stage about every 85 Growing Degree Days (GDDs), and at current conditions, that's about one every four days. After V10 growth accelerates, with a new leaf every 50 GDDs. One symptom to be on the lookout for is onion leafing, where the top leaf remains unfurled after emerging from the whorl. This commonly occurs when corn begins a rapid growth spurt after a slow growing period. This resembles a growth regulator herbicide injury symptom but usually only lasts a week or two before the top leaf unfurls naturally. After the leaves eventually unfurl they sometimes result in yellow tops. For more information see this excellent article (http://www.agry.purdue.edu/ext/corn/news/articles.04/TwistedWhorl-0607.html ) by my colleague Bob Nielsen at Purdue University. The rapid growth conditions may also stress our ability to make postemergent herbicide applications at the appropriate growth stage. With the crop growing rapidly and some reports of corn being smaller than usual at a particular growth stage, it may be common to find that some corn fields may have already passed the acceptable growth stage for an application.

Marvin H. Hall, mhh2@psu.edu
Forage Management, Crop and Soil Sciences

PEST MANAGEMENT

FARMING TOO UGLY

THE PRO'S AND CON'S OF NOT USING A BURNDOWN HERBICIDE IN NO-TILL SOYBEANS. (ADAPTED FROM ARTICLES BY CHRIS BOERBOOM, UNIV. OF WISCONSIN, EXTENSION WEED SCIENCE)

We recently visited a number of no-till soybean fields in Southeastern Pennsylvania in search of glyphosate resistant horseweed (marestail) - we found it, but that's another story. Obviously, no-till soybeans offer a great option to manage soil erosion and with Roundup Ready soybeans, managing weeds in no-till soybeans can be relatively easy. However, we were surprised by the number of fields that are being managed with a single application of glyphosate. The typical scenario involves planting soybeans with no burndown and then spraying them for the first time 2 to 4 weeks after emergence. My first reaction was to conclude that growers should not be tempted to cut corners in Roundup Ready soybeans and skip the burndown treatment. However, I also realize that it is very important to consider the economics of growing soybeans and consider what weed control costs relative to what you might lose in yield. However, it is also important to consider the long-term management implications of this strategy - one of which might be greater selection for herbicide resistant or tolerant weeds.

Fortunately, there has been some research examining the impact of single pass programs in no-till Roundup Ready soybeans on soybean yield and profitability. First, you might think that glyphosate (Roundup, Touchdown, Glyphomax, etc.) kills all weeds, even big weeds, and that you could wait until the soybeans are up and spray glyphosate just once to kill all the weeds. The potential problem with this approach is two-fold. First, the weeds growing before the soybeans are planted will get large and competitive earlier in the season. They can start cutting into soybean yields earlier than expected. In addition, if glyphosate resistant or tolerant weeds are present, this either means ineffective control or increased costs due to the addition of other herbicides or application timings. There is still the potential for two applications in these fields when the first application timing is not completely effective.

In full-season soybeans, we generally recommend spraying glyphosate at the V3 to V4 soybean stage (about 4 to 5 weeks after planting) because common weeds that grow up to this time wonÕt reduce yield. But this assumes weeds were controlled with a burndown treatment or with preplant tillage. Weeds that have a week, or two, or more head start on soybeans will need to be controlled earlier.

In our recent trip to the Southeast, it was easy to spot fields where a burndown treatment was not used because of the relatively large weeds compared to the soybeans (see photo below). Most likely there will be a yield loss in these fields because of the competition from the weeds, which should have been killed by the burndown treatment. Although soybeans are resilient, yield loss can occur due to reduced soybean stand as well as competition for limited resources (water, sunlight, and nutrients).

An image of a soybean plant among weeds.

To help prove the point that the burndown treatment is cost effective, the following is some data from the Univ. of Guelph in southern Ontario, Canada. The researchers compared different timings of glyphosate in no-till Roundup Ready soybeans in five experiments. They used the equivalent of 22 oz/A of Roundup Weathermax in all applications. Soybean yields with a single preplant burndown treatment were low as expected because of weeds that emerged after planting (Table 1). Soybean yields were higher with a single application in season at either the unifoliate or 1 to 3 trifoliate stages. However, competition from weeds emerging before soybean planting reduced the yields with the 1 to 3 trifoliate stage timing.

Soybean yields were the greatest when either a preplant burndown treatment was followed with glyphosate at the 1 to 3 trifoliate stage or an early post timing (unifoliate) application was followed with a second treatment. Gross returns (crop value minus costs of treatment) also showed that it was profitable to make the burndown treatment. In these experiments, the burndown treatment added an extra $26/A return over the single application at the 1 to 3 trifoliate stage. Certainly the cost of the herbicide as well as application costs will impact profitability.

Maybe more importantly, it appeared to be less risky if a burndown treatment was used in combination with glyphosate in season. The variation in gross return measured how consistent the results were between the different experiments (Table 1). The preplant burndown treatment followed by glyphosate in crop had the lowest variation. In other words, this treatment was quite consistent (or had low risk) in producing high yields and high gross returns. That's a good combination to have.

Table 1. Average soybean yields and gross returns from glyphosate treatments applied at different timings in five no-till soybean experiments.
Source: Swanton et al. 2000. An economic assessment of weed control strategies in no-till glyphosate-resistant soybean (Glycine max). Weed Technol. 14:755-763.
Timing Soybean Yield Gross Return Variation in gross return
(bu/A) ($/A) ($)
Weedy Control 14 88 66
Preplant 22 119 81
Unifoliate 36 207 73
1-3 trifoliate 35 200 70
PP + 1-3 trifoliate 42 226 52
Uni + 1-3 trifoliate 42 223 62

We conducted a similar experiment at Rock Springs in 2003. In this trial, we included glyphosate applied at planting time (0 weeks) up to glyphosate applied 4 weeks after planting. In addition, we included a no herbicide treatment, a sequential application which would be a more standard practice (0 weeks followed by (fb) 5 weeks) and a glyphosate plus residual herbicide applied 1 week after planting. In this study, soybeans were planted on May 22, 2003 with a grain drill in 7 inch rows.

Granted, weed severity in this study was pretty intense with common ragweed being the dominant species. And in the end, weed density and severity will likely be the determining factor on how herbicide application timing impacts yield. In this study, a single application of glyphosate produced a minimum of a 27% yield loss and up to 52% when applied at soybean planting time (Table 2). The glyphosate plus residual treatment was not very effective in this study because the residual herbicide was imazethapyr (Pursuit) which did not effectively control the ragweed.

I believe that the bottom line is that without a two-pass program, a 10% yield reduction is not unusual and it could be much more than that. So, determine the cost/benefit ratio of making that burndown herbicide application (including application costs) and decide whether you should be doing a better job at managing those weeds at planting. Other factors should also include the potential to select for resistant or tolerant species with that single application. The presence of glyphosate resistant horseweed should definitely be considered.

No-till crop production should be managed for the long haul with effective stewardship practices in place. If possible, don't just think about the economics of this year, but also the future and use a weed management strategy that is sustainable.

Treatment Yield (bu/A) Reduction (%)
No herbicide 8 83
0 weeks (burndown) 23 52
1 weeks 26 46
2 weeks 32 33
3 weeks 34 29
4 weeks 35 27
Plus residual @ 1 week 33 31
0 weeks fb 5 weeks 48 0
LSD (0.05) 6

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

INSECT ALERT

The following insects can be active during this time period. This does not mean they have been seen in the state, but that it is the period of time when they can injure crops. Insects that have been reported are shown in bold type and specifics about their management are presented in individual articles. Pictures of each corn insect species, economic thresholds, and scouting guidelines can be seen on the worldwide web at (http://www.ento.psu.edu/) under the Extension and Outreach section. Also, insect and insect injury images for all crops are being added to the new Agronomy Guide (http://AgGuide.agronomy.psu.edu).

Corn
Soybeans
Alfalfa

Corn Rootworm - The corn rootworm development model indicates that egg hatch is beginning in the southern areas of the state. The front entrance into the first instar is 5% egg hatch. This means that 95% of the population is still in the egg stage and will be hatching over the next three to four weeks. Peak egg hatch is about 10 days after an area reaches 5% egg hatch. Therefore, in southern York County, 50% or peak egg hatch should occur around June 26. Currently, we are running about a week behind normal in the timing of egg hatch. Central Pennsylvania should expect the beginning of egg hatch in about a week to 10 days and northern Pennsylvania is about three weeks. Egg hatch in northern areas will be earlier along the Susquehanna River.

Web site screen capture

Armyworm - No reports of this pest have been received. However, watch corn fields that were planted in rye or other small grains. Peak activity is usually seen in late June and early July.

Black cutworm - Some reports of the pest have been coming in, although pressure appears to be normal to low this year. Watch for plants cut-off at or near ground level, particularly in fields that had significant common chickweed, other winter annual weeds, a cover crop, and those along rivers and streams. Scouting should take place once a week to prevent missing damage. Once larvae reach 1 1/2 inches in length they have completed the majority of their feeding and control will have little value. Plant cutting usually begins when the larvae are about 3/4 inch long.

European corn borer - The model indicates that the adult flight and egg laying period has begun in the southern and central areas of the state. Only corn fields that are at V7 (seven fully emerged leaves) and above are attractive to females looking for sites to deposit their eggs. In central Pennsylvania, no fields have reached this stage of development, so the early emerging adults will move to other crops or weeds to lay their eggs. Given the asynchrony between this years flight of over wintering individuals and corn development first generation populations are likely to be low in corn fields. In southern areas of the state, early-planted corn fields that have reached at least the V7 stage of development and sweet corn are likely to be magnets for females and may have heavy infestations.

Potato leafhopper - No reports have come in yet about PLH. However, the most recent front of storms that moved across the state could have transported leafhoppers into the state. Watch fields closely over the next few weeks.

Soybean aphid - Overwintering egg numbers of this pest were reported to be high in Ontario, Michigan and Ohio. It is too early to tell, but pressure from the pest could be high later in the season. No aphids have been detected in soybeans in Pennsylvania to date. However, the initial immigrates should begin to move in during mid-June to early July. In past years, the initial numbers remained low until about mid-July when the population began to build rapidly. By the second or third week of August populations peaked.

Tables 3 and 4 show information on soybean aphid development under variable temperature conditions. This work was conducted by Wilma Aponte at Penn State. As can be seen in Table 3, the aphids completed development from birth to adult most rapidly at 30 °C (86 °F). However, adult longevity, total days of reproduction and number of offspring were highest when the aphids were exposed to 25 °C (77 oF). Reproductive rate and survival of the pest declined rapidly both above and below 25 °C. Based on these studies, it appears that the aphid should build up its population most rapidly when temperatures are between 75 and 86 °F. This is the typical range we see during mid-July to mid-August when populations are building rapidly.

Table 3. Developmental times (days) spent in each A. glycines nymphal stages when reared under five average temperature regimes.
Tempature 1st Nymph 2nd Nymph 3rd Nymph 4th Nymph Birth - Adult
16 °C 3.6 3.8 4.0 4.0 13.5
22 °C 2.2 1.7 1.7 2.2 7.7
25 °C 2.0 1.5 1.5 1.8 6.5
30 °C 1.7 1.2 1.3 1.7 5.5
32 °C 2.0 1.5 1.4 1.6 6.4
Table 4. Developmental times (days) spent in A. glycines adult stages when reared under five average temperature regimes.
Tempature Pre-Reprod. Adult Birth to 1st Reprod. Reprod. Days Longevity Total Offspring
16 °C N/A N/A N/A 7.7 N/A
22 °C 0.3 8.2 3.6 7.6 7.1
25 °C 0.4 6.9 21.9 25.4 42.2
30 °C 0.6 6.1 9.7 14.9 24.4
32 °C 0.9 7.3 9.3 13.8 12.6

Dennis Calvin, dcalvin@psu.edu
Entomology

Agents Corner

Capital

Timely rains over the course of 24 hours, across the region late during the week of June 3, provided one half to three quarters inch of well needed rain. Thunderstorms on Monday, June 6 provided additional rain however most was lost, taking soil and nutrients with it in many instances. Corn and soybean crops are rapidly playing catch up with normal weather conditions. There was no knee high corn by the 4th of June this year. In most cases corn was actually stunted and post applications of grass herbicides based on leaf stage and not corn heights. Del Voight is reporting that based on historical weather data we are nearly three weeks behind in growing degree days.

Second cutting of alfalfa will soon be ready for harvest as many producers took advantage of ideal hay weather in mid May and harvested alfalfa early. Timothy is heading and orchardgrass is "dusting". A lot of grass stands remain to be harvested. Small grains look short but well grained out. Barley is yellowing rapidly and direct cut for barlage will quickly be upon us. No problems with head scab or mildew to be reported at this time.

Question on minds of growers at this time is the soybean rust situation. Rumors of limited availability of fungicides, crop insurance requirements, and concerns for storage requirements for unused products have been raised. Reports from the south are flying around the coffee shops.

Paul Craig, phc8@psu.edu
Dauphin County

Central

The needed rains of the third week of May slowed some of the field work but it is back in full swing now. The rains and warmer temperatures have increased the growth of the forages and emergence of the crops. Pastures and fields are looking good.

Some producers have taken off their first cuttings of forages. There are still fields of corn that must be planted but producers saw that their forages were maturing and needed cut to obtain optimum quality.

Susan Alexander, skm3@psu.edu
Jefferson County

Northwest

The arrival of some heat and rain the second week of June was just what he doctor ordered for the majority of the crops. The corn seemed to double in size in the matter of one day and has better color now. A few growers are respraying due to lack of control from some pre-products, but overall the corn crop is beginning to look pretty good. Soybeans have emerged and are also growing rapidly. I look for the first round of Glyphosate applications to begin soon.

Hay harvest has all but stopped, except for some silage being slipped in between showers. However, a large portion of first cutting has been completed. Earliest cut fields have 3+" regrowth. Those needing to make dry hay canÕt decide when to mow with the forecast showing thunderstorms every day. Sweeps of new seeding alfalfa has yet to show any potato leaf hoppers, but I expect them soon.

The oats have responded well to the rain and are growing nicely. Barley is beginning to dry down and wheat has flowered. The Fusarium Head Blight risk map is showing low risk for infection. However, wheat planted into corn stover is at a moderate to high risk for infection, these fields will need to be monitored closely.

Kevin Fry, ksf107@psu.edu
Armstrong County

Southeast

Hot and humid weather is making the corn and soybeans grow now that we have some moisture. Thunderstorms Monday the 6th gave anywhere from 1/4" to over an inch or more across the region. Corn is around V3-V5 and soybeans are emerging to around V3. Some replanting has occurred, but respraying corn is more common this year. Hay making is being attempted between rain showers, with some producers having better luck than others. Hay yield is about average, but in the droughty ground it looks to be below average. Strawberry producers are having a good crop this year after a couple tough years. Early sweet corn did not emerge very well and there are quite a few poor sweet corn stands, later corn is doing well. Our GDD's are now about average thanks to the recent heat, but we were behind. Thanks to the dry weather in May most of the corn and beans were able to be planted on time.

Andrew Frankenfield, adf13@psu.edu
Montgomery County

Southwest

The situation in the southwest corner of the state is changing. For several weeks we have been experiencing cooler than normal temperatures. Along with the temperatures, adequate rainfall is the norm. Not too much, but adequate to keep crops growing.

Corn and soybean planting finished earlier than the past two years, but 1st crop hay harvesting is a bit behind schedule due primarily to rain shower activity. Small grain crops are maturing normally and wheat had pretty good conditions to set grain and fill.

With respect to pests, alfalfa weevil damage was minimal. Weed pests on corn and soybeans are extremely variable. Just in recent days, some fields, tilled and no-till, are looking pretty ugly, due to broadleaf perennials rapid growth. In addition, I have experienced very few phone calls relative to pest problems in crops.

Warmer weather finally arrived on June 5th and the corn seemed to just "jump" toward the sun. So with some better growing conditions the crop related tasks should get caught up quickly.

Don Fretts, dcf3@psu.edu
Fayette County