Field Crop News

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

May 26, 2009    Vol. 09:12

IN THIS ISSUE:

• Weather Outlook
• The New ACRE (Average Crop Revenue Election) Program of the 2008 Farm Bill
• Don’t Forget That Grain in Storage
• Control of Roundup Ready Corn: Volunteers or Replanting
• Considerations When Adding Residual Herbicides to Post Applications in Corn
• Keep Watch for Herbicide Resistant Weeds
• Topdressing Alfalfa
• Keep Hay of Different Qualities Separate
• Caution: Hot Hay
• Be Aware of Potato Leafhopper
• Mark Your Calendar

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

Ocean-cooled air will continue to cover the eastern half of the state on Wednesday with low clouds, drizzle and patches of intermittent rain. Readings will stay between 55–65°F in most sections east of the crest of the Alleghenies. Rainfall will generally be less than a tenth of an inch. Warmer and more humid air will return on Thursday (actually it will be warm and sticky on Wednesday in the western third of the state). An approaching cold front will trigger thundershowers in most places with about 0.25–0.50" of rain expected. It will be quite warm and humid in the eastern half and this is where a few strong to locally severe storms are possible during the afternoon. The first surge of cooler, drier air will arrive on Friday, probably triggering a residual thundershower in the eastern most counties. A second surge of cool, dry air will push in from the northwest on Saturday with widely separated thunderstorms developing in the northern half of the state during the afternoon. The northeast counties may drop into the 30’s by Sunday morning (from Bradford County to northern Monroe and Pike). A quick warm-up should occur on Sunday and June will begin very warm and become rather humid by Tuesday and Wednesday when a cool front will arrive.

There are indications that a heat wave is likely (more than 3 days above 90°F) during the second or 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 through August period, though may be the result of a very warm June, with a notable wet period in the latter half of July or August. The hurricane season should have a late start with notably fewer storms than recent years.

The New ACRE (Average Crop Revenue Election) Program of the 2008 Farm Bill — Craig Williams, Extension Educator

For producers wanting information comparing the new ACRE program of the 2008 Farm Bill with the traditional suite of programs see the following to links. The second link is a narrated presentation with 17 slides that explains the program and compares it to the traditional programs.

ACRE-farmdoc

http://www.farmdoc.uiuc.edu/presentations/2009%20items/ACRE-farmdoc/player.html

Don’t Forget That Grain in Storage — John Rowhel, Extension Educator

As temperatures get warmer, grain in storage should be checked weekly this time of year. For various reasons, warm pockets may develop in bins, causing moisture condensation that may result in growth of mold or increased insect activity. Check for odors by running the fan and smelling the exhaust air. A foul or musty odor is an early indicator of a problem. Probe the grain to check for insects and other problems. Aerating bins levels out differences in temperature within the bin but should be done properly. If you do an aeration always run the fan continuously for a complete warming cycle; i.e., until the warming front has moved completely through the grain. The grain in the bin should be level for more even air flow. The temperature of the grain should not be raised above 50–60 degrees. Higher temperatures will promote insect growth. So it is important to be cognizant of the air temperature during aeration and avoid aerating during periods when outside temperatures get too high before the aeration cycle can be completed. A fan sized for aeration (1/10 cfm/bu) will take much more time than a fan designed for drying (1 cfm/bu).

Control of Roundup Ready Corn: Volunteers or Replanting — Dwight Lingenfelter, Penn State Weed Science

There are times when corn has to be removed from a field with the intention of replanting a corn crop. Tillage is one effective method, but it is not appropriate in no-tillage situations. Use of glyphosate is highly effective for non-Roundup Ready corn. But, the challenge is in removing Roundup Ready hybrids. There are limited herbicides to consistently kill small corn plants. Gramoxone Inteon, Ignite, and Select are three products that have shown the most activity. Research conducted in this region with Gramoxone and Select demonstrated that Select was the most effective for corn 2 to 3 inches tall. For taller corn (4 to 6 inches tall), Gramoxone in combination with a photosystem II inhibiting herbicide (Sencor, Lorox, or atrazine) was the most effective. Ignite is a third option, but will not control Liberty Link hybrids.

Select Max: up to 6 oz of Select Max with a non-ionic surfactant at 0.25% v/v plus AMS at 2.5 to 4 lbs/A. Do not use a COC or MSO. Wait a minimum of 6 days from time of application until planting corn due to risk of crop injury. (Select Max will also control corn hybrids containing Roundup Ready and Liberty Link stacked traits.)

Gramoxone Inteon: 3 to 4.5 pt/A in combination with Sencor (4-6 oz/A), Lorox (1 pt/A) or atrazone (1 lb/A). (These photosystem II inhibitors are not added to control the corn, but are used to slow down the Gramoxone Inteon activity, which helps provide more consistent control.)

Ignite 280: 22 to 29 oz of Ignite. Ignite has not been as consistent for control corn as Gramoxone.

Since Gramoxone and Ignite are contact herbicides (i.e., they only affect leaf tissue that they touch), make sure to use spray volumes of at least 15 gallons/A and nozzles that produce finer droplets allowing for maximum spray droplet coverage on leaf surfaces.

(This information was adapted from an article by Mark VanGessel, Univ. Delaware)

Considerations When Adding Residual Herbicides to Post Applications in Corn — Dwight Lingenfelter, Penn State Weed Science

A number of residual herbicides can be applied after planting up until corn and weeds reach a certain size or growth stage. Herbicides such as Bicep II Magnum, Bullet, Dual II Magnum, and their generic alternatives can be applied to corn up to 5 inches tall. Acetochlor-containing products such as Degree (Xtra), Harness (Xtra), Fultime, Keystone (LA), Surestart, and generic alternatives can be applied to corn up to 11 inches tall. Herbicides such as Atrazine, Lumax, Lexar, Guardsman Max, and Resolve can be applied to corn up to 12 inches tall. And finally, Prowl H20 and Halex GT can be applied to 30 inch tall corn or less. Keep in mind there is always a potential for corn injury from certain herbicide formulations. As the weather gets warmer and the corn is rapidly growing, the corn can be more sensitive to certain formulations such as EC (emulsifiable concentrate) formulations as compared to encapsulated formulations (CS and ME). So for example, Degree Xtra and Prowl H20 are generally safer on emerged corn as compared to their counterparts Harness Xtra and Prowl 3.3EC, respectively. Also there is an increased crop injury potential when combining residual herbicides with loaded glyphosate products or adding additional adjuvants to the spray mix. For a listing of additional herbicides and maximum corn heights and information on maximum weeds sizes for these products please refer to Table 2.2-12 in the Penn State Agronomy Guide.

Keep Watch for Herbicide Resistant Weeds — Bill Curran, Weed Science Specialist

Glyphosate and ALS resistant weeds are becoming more common in Pennsylvania. We have had ALS-resistant pigweed, foxtail, and shattercane for several years. We discovered glyphosate resistant horseweed or marestail over five years ago which has populated many areas in the Southeast Region. Common lambsquarters is also frequently mentioned as a potential resistant species. Last summer we discovered our first population of glyphosate-resistant common ragweed. This population was identified in the Central Region becoming a problem in continuous soybeans managed with glyphosate. Dr. Mark VanGessel and his team at the University of Delaware has helped assay the level of resistance in this biotype and determined it has an 8 to 10 × level of resistance to glyphosate and a low percentage of the population may also have ALS resistance (technically called multiple resistance). The accompany photo is from a Delaware assay comparing susceptible ragweed collected from our Rock Springs research farm (lower row) and the resistant biotype (upper row). Under greenhouse conditions, even some of the susceptible plants managed to survive the 2 × rate (1.5 lb ae/acre) of glyphosate.

In Pennsylvania as in much of the US, glyphosate resistant soybeans (Roundup Ready) are planted on nearly 100% of the soybean acreage. Soybean growers appreciate how glyphosate gives consistent weed control with little soybean injury. Roundup Ready corn is quickly catching up being widely adopted by Northeast farmers. It is not uncommon for soybeans (and now corn) to receive two glyphosate applications during the growing season (especially no-till) which means weeds get a lot of exposure to glyphosate. Diversity in the weed management program is the key to preventing resistance. Diversity means alternative herbicides with different modes/mechanisms of action, different herbicide application timings, growing different crops, altering tillage methods, planting dates, etc. Certainly one of the most important points for both corn and soybeans as we move into early June is to scout fields and observe and manage problems when they are just beginning. If you see weed escapes in a field, ask yourself these three questions:

• Do patterns of weed escapes exist that would suggest application error or are they uniform throughout the field?
• Is only one weed species escaping that should have been controlled?
• Near the escaped weeds, have others of the same species been controlled (living and dead weeds)?

If you can rule out application error and if both living and dead plants of the same species are commonly found, you may have a resistant weed population. So think about resistance management and develop a well designed weed management plan to help keep glyphosate and other key herbicides useful well into the future.

Topdressing Alfalfa — Paul Craig, Extension Educator

The high costs ($800/ton) of potassium fertilizers have many alfalfa producers questioning or even limiting annual topdress applications. The question is asked whether this additional cost of production can be acceptable or if there are some management practices that could be considered for 2009. The following is a short review of the importance of potassium in profitable alfalfa production.

Potassium (K) is the major nutrient required by alfalfa. Each ton of alfalfa harvested removes 50 pounds of K. An average alfalfa yield can easily remove 200 to 250 pounds of K per acre per year. This can result in a rapid withdrawal of K levels. Potassium is important for stand persistence, longevity, winter hardiness, disease resistance and early regrowth.

Potash is mobile within the plant and therefore deficiency symptoms are first observed on older plant parts as the plant moves existing K in the older plant parts to younger leaves. Potassium deficiency symptoms in alfalfa are white spots on the outer leaf margins.

Within a soil there are 3 types of K: unavailable; slowly available; and readily available. Usually only the readily available K, which is K dissolved in soil water, is available for uptake by plants during the growing season. Soil testing measures the amount of readily available K. Slowly available K is trapped between clay layers in the soil and the release of this nutrient is dependent on soil clay types and usually released when soils become wet.

Potassium uptake by plants is affected by soil moisture. Higher moisture levels increases uptake but when soils are saturated root respiration is limited and uptake of all soil nutrients is restricted. Optimum soil temperatures for nutrient uptake are 60 to 80 degrees. Another factor that affects root uptake is the fact that potassium is only a moderately mobile nutrient in the soil. Unlike nitrogen, potassium does not move very far across the soil profile. Most K uptake is dependent on roots growing outward to obtain additional nutrients. The limited amount of small fibrous roots of alfalfa can limit K uptake in many locations.

Alfalfa has the ability to over-consume K when soil levels are high. This “luxury consumption” does not affect plant development but can result in high K testing forages and excessive removal of soil nutrients, in excess of the 50 pounds/ton guideline. When incorporating heavy manure applications prior to alfalfa establishment the availability of above optimum K levels may not serve as a guide for K levels throughout the lifetime of the stand.

So what should alfalfa producers do? Without adequate K levels optimum yields will be reduced. In addition low levels of K will greatly increase the risk of winter injury and stand losses next spring. High costs for topdressing and low milk and hay prices are forcing many changes to common management practices. The best answer would be to base additional applications on crop yield records and recent soil test levels. The previously noted comments indicate that additional K nutrients will be needed for maintaining high yielding alfalfa. One strategy, in the short term, may be to apply 100 to 200 pounds of K/per acre to 2nd or 3rd year stands after 4th cutting to provide adequate K for winter survival and to provide nutrients for next spring cuttings. Manures can also be applied to meet nutrient needs but that can present other challenges as noted previously in this newsletter.

Keep Hay of Different Qualities Separate — Marvin Hall, Penn State Forage Specialist

All the risk and luck associated with making excellent quality hay will be lost if hays varying in quality are mixed in storage. This may seem self evident but I frequently see cases where excellent and poor quality hays are mixed in storage. Designating different storage areas (different barns or different bays in a barn) for different quality hays and making sure employees understand these designations will help keep hays separate and make getting the correct quality hay to the correct livestock group feasible.

Caution: Hot Hay — Marvin Hall, Penn State Forage Specialist

The recent dry weather was perfect for drying forages for hay but this week’s forecast looks like some hay might be made a little too wet and get hot in storage. Heating of hay is a direct result of microorganism activity in moist hay. Even if excessive heating does not result in a fire, it will reduce forage quality.

The danger of fire from heating of hay of higher-than-optimum moisture can be decreased somewhat by “loose stacking” the bales so good air movement and ventilation can occur. Hay preservatives, which reduce fungal and bacterial growth, sprayed on hay during the baling process help reduce (though do not always prevent) excessive heating in higher moisture hay. Bales known to contain, or suspected of containing, excessive moisture can be temporarily loosely stacked outside, then moved inside after the danger of fire is past.

If there is a need to check the temperature of hay, it can be done by fitting a sharpened end on a 10-foot section of half-inch pipe, then driving it into the hay, followed by lowering a thermometer into the pipe. Temperatures below 120°F are normal, and 120° to 140° are in the caution range. Hay heating of 160° or higher is in serious danger of catching fire. Temperature can build in hay, particularly within the first week or two after baling, and therefore periodic monitoring of temperature until it is clear there is no danger of fire is advisable.

Be Aware of Potato Leafhoppers — John Tooker, Penn State Entomology Specialist

This is about the time of year that potato leafhoppers start colonizing alfalfa fields, so growers would be wise to keep an eye out for increasing populations of this pest. Potato leafhoppers are perennially the most damaging pest of alfalfa in Pennsylvania, but they can also cause economic damage in other legume forages and some vegetable crops. Their feeding reduces yield and quality (especially lower protein content), and can decrease stand longevity.

Potato leafhoppers are not year-round residents of Pennsylvania but migrate here each spring often on storm fronts, typically arriving in late May and early June. Potato leafhoppers can be frustrating due to the sporadic nature of their infestations—even in bad leafhopper years, many fields escape damage. Ideal conditions for potato leafhopper populations occur when an unusually hot summer follows a wet springs, so we may be in for a bad leafhopper year if the summer really heats up.

Once potato leafhoppers colonize alfalfa fields, adults deposit eggs into stems and leaf veins. In warm weather, these eggs will develop into adults in about three weeks, so populations can increase quickly. Even though young leafhoppers do not have functional wings, they can still get around pretty well because (not surprisingly) they are good hoppers.

For non-chemical controls, resistant varieties of alfalfa are useful. These lines are covered with fine hairs (the hairs are actually “glandular trichomes”), which decrease leafhopper feeding. Early harvest is another option, but this tactic is not guaranteed to reduce damage to stands because the hoppers will move to neighboring fields. Few natural enemies kill potato leafhoppers so natural control rarely materializes.

If damaging populations develop, insecticides are often the only option. To target leafhoppers most effectively, populations should be sampled and treatment applied only when economic thresholds are exceeded. In most years, it makes the most sense to start sampling in the first week of June and continue to do so periodically. Sample leafhoppers using 20 swings of a sweep net while walking a zig-zag pattern through a field and then count the number of young leafhoppers you catch (young hoppers are yellowish green; do not count adults). It is best to repeat this 20-sweep sample five times in different parts of the field. Take note of the size of the plants and then calculate the average number of leafhoppers per sweep. For example if 100 sweeps yielded 50 potato leafhopper nymphs, there were 0.5 leafhoppers per sweep. Consult Table 1 below to see if your populations exceed threshold. If plants are 4–8 inches tall, the hay is valued at $120 per ton, and it would cost $10 per acre to treat the field, you can see that your sample of 0.5 leafhoppers per sweep is greater than the value in the table (0.4), so the population would exceed threshold and treatment would be advisable. Plants taller than 12 inches can often tolerate leafhopper feeding without high losses. If damaging populations develop on plants 12-inches tall or greater and the plants are less than 50–60% in bud, it would be advisable to treat those fields as soon as possible. If plants are budded 60% or more, it probably makes more sense to harvest than to spray.

Table 1. Economic thresholds (# of leafhopper nymphs per sweep) for potato leafhoppers on plants of different sizes.

		Plants 0–4 inches tall
Value of hay per ton	$60	0.4	0.5	0.6	0.7	0.8	1.0
	$80	0.3	0.4	0.5	0.5	0.6	0.8
	$100	0.3	0.3	0.4	0.4	0.5	0.6
	$120	0.2	0.3	0.3	0.4	0.4	0.5
	$140	0.2	0.2	0.3	0.3	0.3	0.4
	$160	0.2	0.2	0.3	0.3	0.3	0.4
		$8	$10	$12	$14	$16	$20
		Cost of insecticide application per acre
		Plants 4–8 inches tall
Value of hay per ton	$60	0.7	0.8	1.0	1.0	1.8	1.7
	$80	0.6	0.6	0.8	0.9	1.0	1.3
	$100	0.4	0.5	0.6	0.7	0.8	1.0
	$120	0.3	0.4	0.5	0.6	0.7	0.8
	$140	0.3	0.4	0.4	0.5	0.6	0.7
	$160	0.3	0.3	0.4	0.3	0.5	0.6
		$8	$10	$12	$14	$16	$20
		Cost of insecticide application per acre
		Plants 8–12 inches tall
Value of hay per ton	$60	2.0	2.4	2.8	3.0	3.9	5.0
	$80	1.8	1.9	2.2	2.7	3.0	4.0
	$100	1.2	1.5	1.8	2.1	2.4	3.0
	$120	0.9	1.2	1.5	1.8	2.1	2.4
	$140	0.9	1.0	1.2	1.5	1.8	2.0
	$160	0.8	0.9	1.0	1.2	1.5	1.8
		$8	$10	$12	$14	$16	$20
		Cost of insecticide application per acre

Mark Your Calendar

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: County Educators: Kevin Fry (Armstrong), Jonathon Rotz (Cumberland), Joel Hunter (Crawford), Paul Craig (Dauphin), Susan Alexander (Jefferson), Del Voight (Lebanon), Mark Madden (Sullivan), Grant Troop (Lebanon). Department of Crop and Soil Sciences: Greg Roth, Marvin Hall, Ron Hoover, Dwight Lingenfelter, and Bill Curran. Department of Entomology: John Tooker. Meteorology: Paul Knight.

Editor: Joel Hunter (Crawford)

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&

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