Field Crop News

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

June 24, 2005    Vol. 05:07

IN THIS ISSUE:

Mark Your Calendar

Weather Outlook

Production

Pest Management

Agents Corner

MARK YOUR CALENDAR

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

The dry start to the growing season has been aggravated by the heat wave during the first ten days of this month. Rainfall is averaging between a few tenths and one and half inches below normal for June and between 2 and 4 inches below normal since late April. A few spots in the middle Susquehanna valley have measured less than half their usual precipitation in the last 60 days. A recent cool spell was accompanied by only a few showers, but considerable cloud cover lowered evaporation rates. The spate of very warm nights from June 5-14 gave a large boost to growing degree days statewide.

Expect the final week of June to be sultry with hazy, hot and humid conditions. A cool front will push into the state during the weekend (June 25-26) with scattered thunderstorms and a tempering of the humid air. However, much of the time from June 27-30 will be very uncomfortable with limited relief from isolated afternoon storms. A push of Canadian air will arrive around July 1st with more seasonable conditions expected until July 4th. Heat and humidity will likely return between July 5-8. Rainfall will continue to be below average with pockets of drought stress developing - first in the Susquehanna Valley and in parts of southeastern Pennsylvania.

Comparisons with previous late springs still show a likelihood of cooler weather in the eastern United States for the summer, though more cases indicate the cool air likely to be over the Southeast and Gulf States, rather than in the Northeast.

Paul Knight, pgk2@psu.edu
Pennsylvania State Climatologist

PRODUCTION

SPELT: AN OLD TIMER MAKING A COMEBACK

On a crop tour last week in Union County, we encountered many spelt fields along the way, confirming to me that spelt production is alive and well in the state. It seems that spelt production is growing in some areas of the state. We have been evaluating spelt in our alternative wheat trial studies so we are also observing it on a regular basis.

Spelt (Triticum spelta) is a relative of wheat that had been grown in Europe and made its way to the U.S. in the 1800s. Unlike wheat, the kernels remain on the hulls, resulting in a grain with a feed value similar to oats. Spelt can be dehulled and used for flour or flour additives. Some growers have been successful in identifying markets for spelt for flour purposes, particularly organic spelt. Purity Foods, Inc. (http://www.purityfoods.com) is a major processor of organic spelt and has helped to develop a market for the grain during the past few years.

Many spelt varieties are taller and a bit later than wheat, making spelt an attractive crop for straw production. The bushel weight of spelt averages about 28 lb/bushel. In our trials last year, yields of the spelt variety "Sungold" averaged about 3100 pounds per acre compared to 4400 pounds per acre for our soft red winter wheats. With some more experience on our part, we might be able to improve our spelt yields in the future. Management of spelt is similar to winter wheat, planted in late September and October at a rate of 100 pounds per acre. Slightly lower nitrogen fertilizer rates may be appropriate for spelt because of its taller straw and also some claim that it is a better scavenger of N than wheat. In our disease evaluations last week, the Sungold spelt seemed to have good resistance to septoria leaf blotch and some resistance to leaf rust compared to other wheats in the trial. Sungold is one of several varieties developed in Ohio recently by the Sunbeam Extract Company.

Spelt is a crop that seems to be well adapted to organic production. It works well as a winter grain and cover crop in the typical small grain/clover, corn, soybean rotation used by organic grain producers. The taller plant height should result in higher straw or residue yields. Also, its ability to yield well at lower N rates is useful on organic farms. Compared to wheat, the grain is a bit more resistant to storage problems due to its husk coverage and its higher protein and fiber levels make it work well as part of a dairy or horse grain mix.

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

PEST MANAGEMENT

Common pokeweed at soybean harvest.

POKEWEED CONTROL

(Here is an article written by Glenn Nice, Bill Johnson, and Tom Bauman from Purdue University that discusses a relevant problem to Pennsylvania.)

Similar to the last couple of years, we have observed a number of fields where common pokeweed really took off in early June. During this part of the growing season it is becoming a familiar sight to see pokeweed and its red stems and large leaves standing like botanical sentries in our fields. By mid July however, we typically observe the brown to black corpses of common pokeweed after the postemergence herbicides have been applied... if herbicide treatments were made in a timely manner.

However, since the weed is a perennial, it might be premature to claim victory on pokeweed at that point. You have probably won the battle, but not the war. The root balls of this perennial weed can be very large, as large as a bowling ball, making control of this weed fairly difficult with single postemergence herbicide treatments. Many of the healthy plants we see this year are new growth from root balls that persist from year to year.

Common pokeweed seedling.

Another thing that makes pokeweed a management challenge is the fact that seeds can be dispersed by birds. The ripe fruit are eaten by birds and the seed pass through the birds and are dispersed wherever the birds decide to leave their mark.

Control of pokeweed in emerged soybeans

Field studies by researchers at Southern Illinois University (SIU) reported that glyphosate controlled pokeweed 88% or higher¹. Control was increased when glyphosate was tank mixed with FirstRate or Synchrony STS in soybean. FirstRate and Synchrony STS alone provided 68 and 38% control. So, specific recommendations would include the following: 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 GT tank mixes. FirstRate seemed to provide similar control in the SIU studies, but we don't have quite as much experience with FirstRate on pokeweed than we do with Classic + Harmony GT.

Ripening berries of common pokeweed.
Control of pokeweed in emerged corn.

In the same SIU report common pokeweed control in corn with Lightning; dicamba [Banvel, Clarity, Sterling]; Celebrity Plus; and Callisto (3 oz/A) was 90% or better. So specific recommendations would include the following: 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. Other effective treatments for non-transgenic corn include Northstar, Yukon, dicamba (1 pt/A) and Distinct (4 to 6 oz/A), dicamba + Spirit, Callisto (3 oz/A). Apply when plants are less than 12 inches tall if possible.

Control of pokeweed in pastures and non-cropland.

Pokeweed in pastures or on non-crop areas can also be a problem. Pokeweed can be toxic to cattle, sheep, humans, turkeys, swine, and horses. For more information on pokeweed toxicity see the following web page (http://www.vet.purdue.edu/depts/addl/toxic/plant40.htm).

In the same study mentioned above, glyphosate at 0.75 to 1 lb ae/A was used on 6, 12, 24, and 48 inch tall pokeweed. All treatments provided above 95% control but obviously would kill most other species including desirable grass forages. For grass pastures, Crossbow can provide the equivalent of 80% control with a 1.5% v/v mixture or 4 qt/A rate².

Since pokeweed is a perennial, the most effective technique for control will be to include fall herbicide applications in addition to in-crop treatments. Apply glyphosate + 2,4-D in the fall before the ground freezes if green leaf tissue is present to absorb the spray solution.

Reference:

¹Scott A. Nolte, Bryan G. Young and Gordon K. Roskamp. 2002. Common Pokeweed Control in Corn and Soybean. North Central Weed Science Society Abstracts 57:122.

²Mark M. Loux, Jeff M. Stachler, Bill Johnson, Glenn Nice, and Tom Bauman. 2005. Weed Control Guide for Ohio and Indiana. Ohio State University.

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 Rootworm model.

Corn Rootworm - The corn rootworm development model indicates that egg hatch is well underway and the most advanced stage of development is 3rd instar in the southeastern areas of the state. In the central and northern areas of the state, the most advanced stage should be first instar with possibly some second instars. The front of entrance into each instar is when 5% of the total population has reached that stage. This means that 95% of the population is still in earlier stages of development and will reach the most advanced stage within 7 to 14 days. Because of the earlier planting in some areas and the delay in rootworm hatch, we are seeing treated fields where significant numbers of larvae are present and feeding on roots. These fields may need a rescue treatment of Furadan 4F to prevent significant root pruning. Fields planted in late April and the first week of May will reach 7 to 8 weeks since the soil insecticide or seed treatment was applied. None of these products are expected to provide a high level of protection beyond 6 to 8 weeks. Everyone should check fields that are at risk of rootworm injury by pulling or digging up plants and looking for larvae. Small larvae can be observed by placing the root system of plants in a 16 oz. solo drinking cup that has had the bottom removed. The solo cup should have a screen big enough for larvae to move through placed in the bottom. The bottom of the cup should be cut off and filled with water and then the top with the screen placed in the bottom portion of the cup with water. As the roots dry, the larvae will migrate down and fall into the water to be counted. This is a good way to check for small (1st instar) larvae because they will enter the root to feed.

Black cutworm - This appears to be a very light year for black cutworm.

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.

European corn borer model.

European corn borer - The model suggests that the most advanced stage of European corn borer in the southeastern areas of the state are 4th instars. In most years, the model's prediction would be correct but this year few corn fields were at a stage that was attractive to females during the beginning of the egg laying period. Therefore, the most advanced stage is likely 2nd or 3rd instar in most fields. The adult flight period is still actively underway in most areas of the state. Corn fields with at least five fully expanded leaves will attract females to lay eggs, but the tallest corn will attract the most females.

Soybean aphid - Del Voight was the first to report soybean aphids from soybean fields in Lancaster County. The numbers were very low and will likely stay low until mid-July when populations have traditionally begun to grow rapidly. Over the last four years, soybean aphid populations have peaked during the first to third week of August. The economic threshold for this pest is 250 aphids per plant. More information about the pest can be found at http://www.ento.psu.edu/extension/factsheets/soybeanAphid.htm. Another excellent source of information is at the U. of Minnesota website (http://www.soybeans.umn.edu/crop/insects/aphid/aphid.htm). At this site, information on how to scout for the pest can be found. 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°F). 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 average 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.

Potato leafhopper - Low populations are being reported around the state. However, I have not yet heard of any fields above the economic threshold. Unless we start getting more frequent storm fronts moving into the state out of the Gulf of Mexico, it is unlikely that we will see wide-spread high pressure from the pest during the second and third cuttings.

Bean Leaf Beetle Ð Feeding by overwintering adults is now dropping off rapidly. First generation adults (offspring of overwintering adults) will show up later in the season when pod fill is occurring. To estimate the timing of first generation feeding, accumulate 1212 degree days, using a base threshold of 46°F from soybean emergence in the field (not from when adults were seen). Daily degree days are accumulated by adding the maximum and minimum temperature for a 24 hour period and then subtracting 46°F. If the average temperature for the 24 hour period is less than 46°F, then zero degree days are accumulated. By summing up the daily degree days for soybean emergence, an estimate of when to look for first generation adults can be made.

Economic Thresholds for First Generation Bean Leaf Beetles (average number of beetles per 20 sweeps) Source: Marlin Rice - Iowa State University Integrated Crop Management Newsletter 2001.
Management Cost ($/Acre)
$/bushel 7 8 9 10 11 12 13 14 15
15 2.0 2.2 2.5 2.8 3.0 3.3 3.5 3.8 4.1
14 2.1 2.4 2.7 2.9 3.2 3.5 3.8 4.1 4.3
13 2.3 2.6 2.9 3.2 3.5 3.8 4.1 4.3 4.6
12 2.4 2.8 3.1 3.4 3.7 4.1 4.4 4.7 5.0
11 2.6 3.0 3.3 3.7 4.1 4.4 4.8 5.1 5.5
10 2.9 3.3 3.7 4.1 4.4 4.8 5.2 5.6 6.0
9 3.2 3.6 4.1 4.5 4.9 5.3 5.8 6.2 6.6
8 3.6 4.1 4.5 5.0 5.5 6.0 6.5 7.0 7.5
7 4.1 4.6 5.2 5.7 6.3 6.8 7.4 7.9 8.5
6 4.7 5.3 6.0 6.6 7.3 7.9 8.6 9.2 9.9
5 5.6 6.4 7.2 7.9 8.7 9.5 10.3 11.1 11.8
4 7.0 7.9 8.9 9.9 10.9 11.8 12.8 13.8 14.8

Dennis Calvin, dcalvin@psu.edu
Entomology

Agents Corner

Central

We've been getting by for quite some time on intermittent rain shower activity and certainly could use a significant rainfall soon to really make things boom. However, during the last few weeks spring planted crops have really started to look like something after weeks of suppression from cold and dry conditions.

Haven't heard from anyone about leafhoppers in alfalfa although I suspect they are here or at least on their way. Second cutting looks good and is ready to be harvested or is being harvested. People trying to make dry hay have been frustrated by cloudy days and sprinkles. Saw a few fields of grass being mowed this morning that will not make good forage even if it doesn't get rained on.

Managed grazing has provided the usual challenges of late spring. This year there seems to be an unusually large amount of reproductive growth and a relatively small amount of leafy growth. The cold, dry conditions of April kept a lid on the grass explosion, but when the conditions were right in May, seedheads "just came out of nowhere". Unmanaged and over-stocked grazing are looking pretty poor due to the dry conditions.

Wheat is starting to turn color. Crop is shorter than usual, again due to dry conditions in April. Haven't seen any lodging, it all seems to be standing well.

Corn finally looks a lot more robust than just a couple weeks ago. Like many areas of the state it got off to a very slow start. Some corn in certain localities has started to show drought stress just in the last few days. From the leaf burning I've seen it looks like a lot of corn has been side-dressed in the last week. There are a few poor stands here and there.

Soybeans have also perked-up significantly in the last few weeks. Good stands are apparent now that weeds are backing down with recent applications of Roundup.

Seems like an unusually large amount of tillage performed this year.

Dave Hartman, dwh2@psu.edu
Columbia County

Northwest

Greetings from the great Northwest. The season is progressing rather well at this point with scattered showers and thunderstorms bringing some moisture to most areas. Corn is generally at the four-leaf stage across the area. Some stands, especially conventionally tilled acres, are spotty from the cool, dry, slow start to the season. As usual, weed control is quite variable depending a lot upon timing of application and of showers. Spring burn down of sods - always challenging - seems a little tougher than usual. Again, there are numerous examples of the effects of timing. In general, some applications that were done too early and probably more that went on too late, including delayed second ("cleanup") applications both presented unacceptable competition. In one new no-till planting into a well manured, spring-killed sod, slugs were using the remnant of the seed slot for shade and moisture, putting one to two slugs in close proximity to nearly every tender and susceptible corn spike. Although corn generally can out pace slug damage, we felt the threat in this instance justified treatment of the area with metaldehyde.

Another observation, although hard to quantify, is that there seems to be a substantial increase in no-till acres in our area this year, perhaps attributable to three main factors. Certainly higher fuel (and fertilizer) costs had many producers looking for cost savings. Secondly, with the annual Tri-State Conservation Tillage Conference educational efforts over the past few years in combination with the recent no-till successes of innovative local producers willing to share their experiences and knowledge with others, we are positioned on the steep part of the learning curve for no-till in our area. Thirdly, it seems the acceptance and adoption of glyphosate-resistant (Roundup Ready®) corn has also been a significant contributor.

Soybean development pretty much mirrors that of corn. Producers are concerned and apprehensive about the real potential for facing the challenges of soybean rust. In our efforts, we have focused on making sure producers are prepared and educated as best they can be about "How to Best Apply Fungicides." We are urging producers to consider the latest in application technology such as the air-assisted technology (OSU and Myers Equipment), proper nozzle selection for critical droplet size (medium to fine), and twin (two directional) nozzles or nozzle bodies for better canopy penetration. Check out http://ohioline.osu.edu/aex-fact/0526.html for a useful reference on this information. With some diligence and preparation in the application area, coupled with watchful eyes for the arrival and early development of the disease, a thoughtful fungicide strategy, and a little luck, we hope to be as prepared as possible if and when the rust occurs in our area.

Second crop hay is coming off now, especially grasses, many of which were cut for first crop about four weeks ago. Quantities of first cutting were average or slightly above (1.5 to 2.0 tons DM/a) and quality was good, although protein levels were lower (generally less than 20%). Second cutting looks typical, slightly less tonnage, and hopefully as good or better quality. Weather for forage harvesting is much better than usual. Good results with first and second crop hay harvest and some good spring-seeded new stands coming along with the cooperative weather conditions present a fairly optimistic prospect for the dairy and livestock producers so far.

Good growing to all!

Joel M. Hunter, CCA, jmh7@psu.edu
Northwest Dairy Team, Crawford County

Southeast

Various activities for this week include cutting second harvest of alfalfa and grass hay, harvesting barley for grain and straw and field work after barley. Oats are now maturing but will lack straw yield, with short stems. Wheat also is ripening rapidly.

A wide variation in corn crop growth is seen around the county, anywhere from V3 to V6. This is related to planting date, soil moisture conditions, weed pressure and soil type. Some post-emergent spraying caused crop injury, but the weeds are now under control. Plants are growing on deeper, stored moisture in the field.

Soybeans have emerged and are closing in rows, but there is little canopy closure. Weeds are out competing glyphosate-tolerant soybeans that have not been sprayed. I saw a field where timely cultivation was used for weed control! Double crop beans have emerged, but germination is very spotty.

In short, we could use a nice gentle rain.

Mena Hautau, mmh10@psu.edu
Montgomery County

Southwest

The finishing touches are being put on this year's corn crop. Most of the crop that was planted in mid May is in V6-V8 and really taking off with the heat and side dressing. Soybean fields are being sprayed and are outgrowing the Bean Leaf Beetle feeding IÕve been seeing. Oats have headed and as of yet there is no barley harvested; however it is close.

Second cuttings of alfalfa have begun on the heels of first cuttings trying to get finished. Leafhopper pressure has reached thresholds of spraying in many fields and producers are spraying those fields not going to be harvested in the next week or so.

For the most part things are pretty good here, other than the crops could use a drink along with a few others.

Kevin Fry, ksf107@psu.edu
Armstrong County