Field Crop News

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

May 19, 2009    Vol. 09:11

IN THIS ISSUE:

• Weather Outlook
• Frosty Mornings Stress Crops and Agronomists
• Assessing Corn and Soybean Stands
• Armyworm: Time to Begin Scouting for this Pest
• Marketing: What to do? What to do?
• Control and Timing Pasture Weeds
• Update on Black Cutworm and Bean Leaf Beetles
• Wheat Scab Assessment Tool Available
• How Much Nitrogen is Still in Your Fields?
• Upcoming Events

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

Daybreak readings ranged from the low 20's to mid 30's in the mountains on Tuesday and this should be the end of the cold snap. High pressure will stall over the region for the next few days providing mainly clear skies and a marked warming trend. Each afternoon from Wednesday through Friday will be quite warm as many places will reach into the 80's and a few hot spots in southeastern Pennsylvania will touch 90. Winds will be light and dew points will stay at moderate levels, so drying conditions will be good.

As the holiday weekend begins, a cool front will slip southward across the state and stall near the Mason-Dixon Line. Only some broken clouds and isolated showers will accompany the front late Friday or Saturday. It seems that enough cooler, drier air will circulate into the state to bring some sunshine and seasonably mild conditions for Sunday, though the southern counties may not break out of low clouds and could have some drizzle. Later Sunday, a more moist flow from the southeast is expected to develop and this should bring humid air into western areas on Monday and probably duller skies and perhaps some late day or nighttime showers on Memorial Day in many sections. A couple of days of warm, sticky weather are possible at the middle of next week before a final cool shot for May arrives for May 29–31.

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 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.

Frosty Mornings Stress Crops and Agronomists — Greg Roth, Grain Crop Management Specialist

Some parts of the state experienced frost on Monday and Tuesday morning this week, causing some concern for farmers in some parts Pennsylvania. Crops potentially affected include corn, soybeans, wheat and barley. Locally, temperature reached about 30 degrees in some of the low spots near Rock Springs, with the lowest temperatures occurring near sunrise.

Corn in some of our studies was in the two leaf stage and has shown some frost injury from the frost on Monday and will likely show more damage from following Tuesday’s frost event. I suspect that these plants will rapidly regrow with the warm temperature forecast later in the week. Plan on evaluating frost damaged fields later in the week for signs of recovery.

Soybeans can tolerate lower temperatures (about 28°F) and longer period of low temperatures than corn. Our frost events seemed to be short in nature, and temperatures only declined to about 30 degrees F so I am suspecting good survival from early planted emerged soybeans. Soybeans can also have multiple growing points that they can regenerate from. Plan to assess soybeans in about a week for injury and survivability. This factsheet from Purdue provides some good pictures of injury symptoms.

Barley can also be susceptible to freeze damage, particularly during the flowering stage. All but one of our barley lines had already headed out and flowered last week, and should have escaped the serious injury. Several years ago we did have a late spring frost that caused almost complete sterility of some of our barley lines. My scouting this morning indicated most of the barley heads were wet and not frosted, so I am encouraged that damage will be minimal.

Wheat can also experience freeze injury in the spring. Generally wheat in the boot stage requires two hours of exposure to 28°F but wheat that is heading or flowering can be injured with two hours of exposure to temperatures of 30°F. Typical symptoms are floret sterility, spikes trapped in the boot showing twisted effects on emergence, and some leaf discoloration. Anthers are particularly sensitive to low temperatures and can be killed in the boot or heading stage wheat. Consult this Kansas State bulletin for details on scouting freeze damaged wheat. My inclination is that our frost event was not severe enough to cause widespread damage to wheat and barley, but we may see some isolated symptoms in certain fields or parts of fields that experience the lowest temperatures.

Assessing Corn and Soybean Stands — Del Voight, Acting Grain Crop Specialist

As Corn and Soybeans begin emerging most farms will have 1 or 2 fields in question as to emergence and stand. Many factors come into play as the crop emerges. Insects, fertility, diseases and compaction can severely impact viable plant stand. Here are the factors to consider for replanting efforts.

1. What is the ideal planting date for your area? In the Agronomy Guide, the state is broken into climatic zones and the research in PA when 100% of your yields are achieved at a set population is listed below.
   1. Corn
      1. Zone 1 — 5/15-5/25
      2. Zone 2 — 5/1-5/15
      3. Zone 3 — 4/25-5/7
      4. Zone 4 — 4/15 to 5/1
   2. Soybeans — The state is divided into group zones and is much more difficult to assess. In the major soybean growing areas it is recommended to get the ideal yield to plant between May 10 and May 20. Further research is needed to assess the extremely early plantings with new seed treatments and its impact on yield.
2. What is the population?
   1. Corn — Estimate population by walking the field and counting the number of plants in a given row length. Do this in at least 5 areas of the field and average the total counts to arrive at a population. I use 17.5 feet for 30 rows which is 1/1000 of an acre so I can simply add 1000 to my counts and get a population.
   2. Soybeans — Again estimate the population by counting plants in several areas of the field. There are a number of methods to assess soybean stands from row counts to hula hoops. Pick one and go with it.
   3. How even is the population across the field?
      1. This might take standing on the top of your truck but generally if you see that large areas are devoid of plants this will impact your decision. If more than a third of the area is lost you will need to factor that into your population counts.
3. What is the replanting date?
   1. Once the ideal date for 100% of yield is known then later plantings can be compared to the ideal and calculations may be made to determine the need to replant.
   2. Is there a replant policy from the seed company?
4. What impact does late planting date and lower populations have on yield?
   1. Corn (see Table 1)
   2. Soybeans
      1. May 10 – 100%
      2. May 20 – 98%
      3. May 30 – 95%
      4. June 10 – 88%
      5. June 20 – 76%
5. What are the costs to replant?
   1. In most cases it will take a burn down material to kill the corn and the addition Seed costs.
6. What herbicide was used that might impact replants?
   1. Most corn herbicides labeled allow for replants. Products like Prowl are prohibited however in past experience by no till and get the seed below the herbicide zone as worked well.
7. Example, If you planted a field with a 150bu/acre yield potential for Corn on April 30th at 30,0000ppa however(due to insect or disease) there are only 20,000ppa standing in the field, then according to the research, the potential yield remains at close to 92% of yield level(12bu/acre loss. The question then is what would the yield be if you replanted and established 30,000ppa on May 29?. If you replanted on May 29th at 30,000 you would get 81% of yield. Then you can calculate that you will lose about 19% of your potential yield. If you had 150 bu/acre potential, you would lose 19% of your potential yield. That would equate to 28.5 bu/acre loss due to late planting. That difference (28.5 less 12 bu/acre or 16.5 bu/acre) is the difference, in this case a loss, to replanting. At 5 dollar corn this would equate to $82.50/acre loss by replanting. Further one needs to also subtracting the replant herbicide costs of 10 dollars to kill the existing corn(add more for custom applications) and another 50 dollars for seed (plus custom plant charges) and the benefit to replanting would be even less. This would be the process to arrive at a decision. Once that is made then the uniformity of stand and other aspects enter in the decision.
8. This interactive site from Missouri takes into account the questions you need to ask yourself. One may place in it the specific yield potential and a date and it will give you some idea of the cost of replant. This is based in Missouri however most will apply to Pa conditions and steer one to the right answers Here is the link to actually use the program. Calculating corn and soybean replant decisions.
9. Resources useful in assessing poor stands and other emergence-related maladies are listed below: (Source R Elmore Iowa State University)
   1. Information on normal corn root development
   2. Early-season corn stress and some things that go wrong
   3. Rootless corn syndrome
   4. Uneven corn emergence and heights due to variable soil conditions and planter adjustment: with a tool to assess uneven emergence
   5. Problem stands and replant decision making:
   6. Off-color corn

Table 1

Planting date	Plants/A at harvest
	10,000	12,500	15,000	17,500	20,000	22,500	25,000	27,500	30,000
	% of optimum yield
Figures shown are most applicable to corn fields with greater than 125 bushels per acre. Source: University of Illinois
April 10	62	70	76	82	86	90	92	94	94
April 15	65	73	79	84	89	92	95	97	97
April 20	67	74	81	86	91	94	97	98	99
April 25	68	75	82	87	92	95	98	99	100
April 30	68	75	82	87	92	95	98	99	100
May 4	67	75	81	86	91	94	97	99	99
May 9	65	73	79	85	89	93	95	97	97
May 14	63	70	76	82	86	90	92	94	95
May 19	59	66	73	78	83	86	89	90	91
May 24	54	62	68	74	78	82	84	86	86
May 29	49	56	63	68	73	76	79	80	81

Armyworm: Time to begin Scouting for this Pest — Jeffrey Graybill, CCA Lancaster County

What follows is a fact sheet on Armyworm ID and control which was copied with some editing from the Penn State Entomology Fact Sheet Archive.

The armyworm, Pseudaleta unipuncta (Haworth), is a native species widely distributed throughout the United States east of the Rocky Mountains. It has long been known to be an occasional serious pest of small grains and corn. However, with the increase of reduced-tillage culture and planting corn into sod and rye cover crops, armyworm damage to corn has increased sharply during the past decade.

The armyworm primarily feeds on plants in the grass family but under hunger stress also will attack some legumes and other plants. Conventional-tilled corn is seldom damaged. First generation larvae are active from mid-May to mid-June, and can cause extensive defoliation to small corn plants. Stand losses are usually low to moderate but in some cases may be severe enough to warrant control or replanting. The moths are uniformly pale brown. There is a prominent white dot near the center of the front wings, and the wing-spread is about 1½ inches. The moths hide in the grass and trash during the day. Strong flyers, they are active at night.

Armyworms overwinter as partially grown larvae under plant trash and in clumps of grass, and as pupae in the soil. Moths emerge from early May to early June. There is also the likelihood of moth immigration during this period. Egg laying begins soon after emergence.

Newly hatched larvae are mostly pale green. During the day, they hide in the folded leaves in the whorl of the corn plant. Upon becoming about half grown (¾ to 1 inch) their body color becomes basically brown with considerable color variation among individual worms. Full-grown worms are about 1½ inches in length with a narrow broken white stripe down the center of the back. There also are stripes along each side of the body. The larvae feed on the leaves at night.

The caterpillar stage lasts about 3 weeks, but the caterpillars are usually 10 to 14 days old before damage is noticed. Those larvae that reach maturity dig into the soil to pupate. Next generation moths emerge about 15 to 18 days later.

Conventional-plated corn occasionally may be damaged by caterpillars that originate in a nearby small grain field prior to migration. When armyworms are numerous, small corn plants may be completely eaten.

On very rare occasions, larvae of the second generation may attack corn in late July and August. These caterpillars hide under stones and clods during the day, then feed on grasses and lower corn leaves at night. However, the type of damage is much different than that caused by the first generation. They seldom destroy any leaves above the ear.

Corn fields likely to be attacked should be checked every few days from late May through the first 2 weeks of June. Look for leaf feeding and presence of caterpillars in the whorl. Control action usually is not profitable unless 10 percent or more of the plants are infested. A number of insecticide sprays and baits can be used as a rescue treatment. Check the current issue of the Penn State Agronomy Guide for materials and dosage rates. You also may check with your county extension agent and local farm supply dealer for suggested controls.

Marketing: What to do? What to do? — John Berry, Penn State Marketing Specialist

Trying to get a handle on how new crop grain prices might trend I see the USDA’s Crop Progress report showed only 48 percent of the crop planted as of May 10, equal to last year’s slow pace and behind the 5-year average of 71 percent (which includes the slow pace of last year). So far, the corn market has had only a modest reaction to the planting delays. Delays are severe in Missouri, North Dakota, and much of the eastern Corn Belt, but planting has been rapid in the large corn producing states of Iowa, Minnesota, and Nebraska. My aunt and uncle are visiting from southern Illinois this week. They report that planters have yet to leave the shed to plant the first acre this spring in their community. A colleague in southern Maryland reports similar conditions on the lower Delmarva.

Are the wonders of contemporary hybrids going to overcome the yield depression typically expected of late planting? The decision of reducing 2009 corn acres and switching to planting beans is upon many farmers in several states. What is your guess on corn harvest and bean harvest if this continues to occur? We have historically low carryovers with corn and any significant reduction (or anticipated reduction) in the 2009 harvest will spike the markets quickly.

Is the world financial condition stabilizing? The strength of the U.S. dollar has major impacts on the bushels of grain going off-shore. Recent dollar values are slipping below levels we saw this past winter. This works in favor of grain marketers, yet without international economic growth our major importers will eventually reduce their demands for ag products.

Looking at market data I see the DEC corn contract has shown some life lately, but I keep thinking of the strong seasonal tendencies in commodities and wonder when/if peak prices will have been achieved. Our friends in South America are not faring exceptionally well this year, China has yet to decrease demand much and prices shown in the bean markets continue to strengthen.

At the cash harvest bids offered today — we have some opportunity to lock in a positive return to our grain enterprises (especially if we did not buy too many inputs last fall/winter).

We have a solid handle on what it cost to plant an acre this year. If today’s corn and soybean price does not suit — I ask “What price would make you happy?” What percentage of our 2009–2010 farm income is already locked in? How much risk our we taking with our marketing plan today? Staying current with what is happening in the grains is easier if you participate in educational programs. Opportunities to learn from each other and industry experts are available yet this spring.

On 6/22/09 Paul Craig is hosting a grain marketing seminar in Dauphin County. On 6/23/09 Tom Murphy is hosting a grain marketing seminar in Lycoming County and on 6/24/09 John Berry is doing the same in Lehigh. These seminars feature Ed Usset from the University of Minnesota. Contact the appropriate fellow to get additional information.

Control Timing and Pasture Weeds — William Curran and Dwight Lingenfelter, Penn State Weed Science

We received a call on Monday about bulbous buttercup in a grass pasture. This and other buttercup species have those distinctive yellow flowers which are starting to appear in the southern half of the state (see accompanying photo). The flowering stage is an excellent time to attempt some control of this poisonous perennial plant. A number of common plants can be poisonous when eaten in sufficient quantity by livestock (Table 1), so monitor those pasture and hay fields closely. Remember that perennial weeds like bulbous and creeping buttercup are most sensitive to control with a systemic herbicide when they are in the bud to bloom stage and in late summer. Biennials including musk and plumless thistle, burdock, wild carrot, etc. should be treated before they begin to bolt (they are bolting now or very soon) and the smaller the better. Late fall or early spring is even a better time to treat them. And finally, control summer annual weeds as soon after they emerge as possible when they are most sensitive to chemical control. Table 2 provides a quick management summary for some common weeds of pasture.

Table 1. Selected poisonous plants of Pennsylvania.

Common Name	Problems/Symptoms	Toxic Ingredient - Toxicity
(Information adapted from Fishel 2000; Hardin 1973; and Hill and Folland 1986).
Buttercups	Leaves and stem especially in flower. Dried hay loses toxicity - anorexia, weakness, convulsions, breathing difficulty, death.	Protoanemonin - toxicity reported to vary with species, age, and habitat.
Cherry, black	Leaves (wilted leaves are worse), stems, bark and fruit - anxiety, staggering, breathing difficulty, dilated pupils, bloat, death.	Cyanogenic glycosides - Less than 0.25 lb leaves (fresh weight) can be toxic to 100 lb animal.
Hemlock, poison	All plant parts - salivation, vomiting, diarrhea, weakness, paralysis, trembling, dilation of pupils convulsions, and coma.	Coniine and others - 0.5 to 4% (fresh weight) equivalent of cattle weight is toxic.
Locust, black	Leaves (especially wilted), seeds, and inner bark - Causes weakness, depression, anorexia, vomiting and diarrhea.	Phytotoxin robin, glycoside robitinm - bark extract and powder in amount equivalent to 0.04–0.1% of animal weight toxic to horses. Cattle 10-times more tolerant.
Milkweeds	Stems, leaves, and roots - muscle tremors, spasms, bloat, difficult breathing.	Glycosides and galitoxin - varies.
Nightshade species	Vegetation, unripe fruit - loss of appetite, salivation, weakness, trembling, paralysis.	Solanine - toxic at 42 mg/kg (LD50)
Pigweed species	Foliage - kidney disease, weakness, edema, rapid respiration.	Nitrates nitrate oxalates, unknown - sheep, hogs, and young calves most susceptible.
Pokeweed, common	Entire plant, especially roots - gastrointestinal cramps, weakened pulse, respiration, salivation.	Phytolacctinm - 10 or more berries can result in toxicity to humans.
Snakeroot, white	Leaves and stem - constipation, loss of appetite, salavation, rapid respiration. Toxin passes through milk (milksickness).	Trophine alkaloid - varies from 1 to 20% of animal body weight. Toxin cumulative.
St. Johnswort	Flowers and leaves - photosensitivity	Hypercin - uncertain

Table 2. Management guidelines for some problem weeds of pastures.

Weed	Cultural/Mechanical	Chemical	Other
Annuals
Winter annuals (Mustard species, common chickweed, etc.)	Mow after bolting to prevent seed production	Apply an effective herbicide in fall or spring prior to bolting	Most winter annuals emerge by late fall - a smaller percentage will emerge in early spring - prevent seed production to prevent spread.
Summer annuals (Pigweed species, common lambsquarters, common ragweed, etc.)	Keep pasture full and competitive. Mow after bolting to prevent seed production	Apply an effective herbicide in early summer	Prevent seed production to prevent spread
Biennials
Biennials (common burdock, bull and musk thistle, poison hemlock, etc.)	Mow after plants have bolted but before seed set to prevent seed production. Remove or dig individual plants by hand	Apply an effective herbicide to rosettes in the spring or fall	Prevent seed production to prevent spread. Several insect biocontrol tools may help with thistles in the future
Perennials
Creeping perennials (Canada thistle, horsenettle, etc.)	Mow to suppress vegetative growth and prevent seed production	Spray with an effective systemic herbicide at bud to bloom stage or in early fall prior to frost	Most perennials spread by both seed and vegetative structures.
Woody perennials (multiflora rose, autumn olive, etc.)	Mow to suppress and prevent seed production - remove roots by hand or with heavy equipment.	Spray with an effective systemic herbicide at bud to bloom stage or in early fall.	Rose rosette disease has spread as far North as Central PA and may impact this weed in the future.

Update on Black Cutworms and Bean Leaf Beetles- John Tooker, PSU Entomology Specialist

Black cutworm: three of the trap locations in our new black cutworm monitoring network detected significant flights this spring. The earliest of these flights was in Berks County, just south of Kutztown at a trap maintained by Mena Hautau. Black cutworm cutting damage tends to occur 300 Fahrenheit degree days after these flights. The trap south of Kutztown has accumulated approximately 260 degree days, so cutting damage can be expected within a few days. However, there is variation around the timing of this cutting, so folks should keep a close eye on their fields. We have already encountered leaf damage caused by smaller larvae and a few instances of cutting damage—most of these reports have been in Berks County, which appears to be a risky area for damage this year. The other traps that detected significant flights were in Westmoreland and Lycoming Counties. The traps have accumulated approximately 160 and 130 degree days, respectively, so if weather is good cutting could be expected in the next week or two. Black cutworm populations tend to be spotty so it is best to vigilant and watch fields for damage, particularly if you are near areas where significant flights have been detected, but also in other parts of the Commonwealth.

Bean leaf beetle: it is getting close to the time of year when we can expect to see bean leaf beetle (BLB) in the earliest-emerging soybean fields. Bean leaf beetle populations can be pretty variable across the state and this variability is often a function of the cold weather beetles experienced over the winter: the colder the winter weather, the more BLB that will fail to survive until spring. Using the PA-PIPE system we have generated a map illustrating the expected BLB mortality for the state and it is displayed below. Based on accumulated freezing temperatures over the course of the winter, it estimates the percent of beetle populations that were killed. If you are in an area that had low mortality, your risk of greater BLB populations is higher and you would be wise to keep an eye on your early soybean fields where damaging populations of BLB tend to develop first. For those in areas of PA that had high mortality, your risk for BLB problems is lower but it would not hurt to check the earliest fields.

BLB does not usually cause extensive damage to soybean seedlings and any damage that is caused can often be tolerated by the young plants. Adults feeding on young soybean leaves make circular holes between the major veins and these holes should appear quite different than the jagged holes caused by grasshoppers or caterpillars. Coloration of adult BLB is variable, but can range from yellowish-brown to green to red and they usually have four black spots on their wing covers. They always have a black triangle just behind their thorax. They overwinter in leaf litter and become active in April when they tend to move into alfalfa or other legumes to feed and begin mating. When soybean emerges, adults move into these fields, feeding on young seedlings (V1- or V2-stage) and laying eggs. The larvae feed on soybean roots and develop into the next generation of adults, which tend to be more economically important, causing damage by feeding on soybean pods as they are filling.

Seed treatments can be used to combat such early season BLB damage, but if populations are large and stand establishment appears doubtful, a rescue treatment may be warranted. One of the published thresholds for BLB says to treat young soybeans if 20% of plants are defoliated, beetles cause gaps in rows of one foot or more, or beetles defoliated at least one seedling per foot of row.

Wheat Scab Assessment Tool Available — Del Voight Penn State Extension Lebanon Co.

Below is essentially a reprint of an article we ran two weeks ago. Now is the time to assess potential for head scab and take appropriate action:

Once the flag leaf emerges it’s the time to begin assessing the presence of wheat diseases. $3.50/bu wheat versus $10.00/bu wheat certainly demands a closer look at wheat disease management. Here are some ideas to think about. As the flag leaf emerges weather, varietal resistance, yield potential and nitrogen management practices will determine the economic injury of diseases to your crop. The recent dry weather has halted most disease movement and growth. Recent rains however may increase the infection and subsequent growth of powdery mildew and septoria leaf blotch diseases in wheat. We most often think of the powdery mildew to persist in warm but humid conditions that produce an inter- canopy infection generally while the septoria persists in warm but wet rainy conditions that splash the spores up from the soil to the plant leaves.

Head Scab caused by Fusarium graminearum is one disease that cannot be scouted for easily. However new technologies allow for accurate assessment of the risk of head scab in your field. To utilize this technology log onto the internet and navigate to http://www.wheatscab.psu.edu/ Follow the online options and determine the need to treat. Again there are few varieties available that are resistant to head scab so treatments may be an option.

1. What disease are you seeing? Follow this link to determine which disease you have predominately in the field. This link is an assortment of videos to further understand the growth and development of diseases.
2. The following Web site will provide direction to the fungicide you choose as well as assess how the disease will respond to changing weather conditions.
3. What is the yield potential? Consider disease treatments when high yield conditions of 70 plus bushel wheat is possible and has been achieved in the past. A stand that was planted early, at a high population and is dense will create a more disease prone environment.
4. How much N and when was it applied? Applications of less than 60lbs of N do not normally increase the disease pressure as much as the worst case scenario of 120 lbs of N applied all in the spring at GS 4–5. Split applications will decrease the severity of disease infection as well.
5. Check the lower leaves and it relationship to the flag leaf. Most diseases can be assessed visually by observations and determining if the disease has come to within the first two leaves of the flag leaf. Presence near the flag leaf may require treatment depending on the infection percent.
6. Check your variety label. Many varieties are resistance to many diseases. The level of resistance will determine the impact of a fungicide application. Lost your tag. To check your variety follow this link to the Ohio State Wheat Variety evaluation test for disease resistance.
7. Weather impacts the disease and if dry warm weather is forecasted factor that into your decision.
8. I use the Wheat Decision Guide for Multiple Leaf Diseases that is available on the internet. It has been tested in different parts of the U.S and in other parts of the world and received great reviews from the journals. Print and fill in the risk factors based on in field view and determine the need to treat.

Finally, if you do decide to treat use the proper fungicide those with activity on head scab are listed, follow labeled rates. Below I have included a table and included the ball park cost per acre for each.

Efficacy of Fungicides for Wheat Disease Control and Their Relative Cost per Acre

Product	Rate/A	Powdery Mildew	Stagnospora leaf/glume Blotch	Septoria Leaf Blotch	Tan Spot	Leaf Rust	Head Scab	Cost per Acre
Tilt 3.6 EC	4 fl. oz	+++*	+++	+++	+++	+++	+	7.78
PropiMax 3.6 EC	4 fl. oz	+++	+++	+++	+++	+++	+	9.21
Quadris 2.08 SC	6.2 (to 10.8) fl. oz	+(+)**	+++	+++	++++	++++		12.59–21.94
Quilt 200 SC	14 fl. oz	+++	+++	+++	+++	+++		13.125
Stratego 250 EC	10 fl. oz	++	+++	+++	+++	++		12.5
Headline 2.09 EC	6.0 (to 9.0) fl. oz	++	+++	+++	+++	++++		11.72–17.57
Proline 480	4.3 to 5.7 fl. oz per acre	+++	+++	+++	++	++	+++ 75% head emergence	9.9–13.13
Caramba		+++	+++	+++	+++	+++	++	?

How Much Nitrogen is Still in Your Fields? — Jonathan Rotz, Nutrient Management, Cumberland County

With another wet spring how can we tell how much nitrogen is still in our field and how much has been lost to leaching losses and de-nitrification? We are also faced with high inputs that are already putting a squeeze on the profitability in corn. This combination of factors warrants the use all available tools to maximize your return per acre. Two of these tools are the Chlorophyll Leaf Meter or SPAD meter and the Pre-Sidedress Nitrogen Test (PSNT). These tests will help you hone in on your nitrogen fertility requirements to decrease the amount of nitrogen you would waste by over fertilizing while making sure you have enough nitrogen left for your yield goals. These tools are designed particularly for areas that have received manure in the past and will have residual nitrogen from these applications. These tests are relatively simple; however directions must be followed to have an accurate measurement and thus an accurate recommendation.

The SPAD meter is a hand-held device that measures ‘greenness’ of the corn plant. This test must be done on plants between leaf stage 6 and 8 (typically 10–20 inches tall). Typically most producers will use the two step method where the first reading is taken at leaf stage 6 and a second reading may be taken a week later if needed. Only fields that have currently received less than 15 lbs. of N are eligible for this test. This includes any nitrogen put on with starter and/or with your spray materials. If more than 15 lbs. of commercial N per acre has been applied use the PSNT (see below). Once eligible fields are identified you will need to either acquire a meter (approx. $1500) or find one available through your local extension office or conservation district. For accurate readings the meter must be calibrated prior to measuring each field (for calibration technique ask the technician you get it from or consult your manual). Once calibrated you need to take a series of 30 readings from each field. Try to pick representative plants to sample when sampling in your fields. Make sure the reading is being taken on leaf five when sampling an individual plant (remember leaf one is often hard to find or no longer present at this time). Additionally, this reading must be taken a half inch away from the edge of the leaf and at about three-quarters the length of the leaf. Close the meter on the leaf and wait for the ‘beep’ and reading to appear. Once this is complete go to the next plant and repeat the procedure. This will be repeated for each of the 30 plants and the meter will automatically average the readings. Again, make sure you take representative samples of the plants across the whole field. After 30 readings have been taken the meter will automatically average all readings and display this average. If the average meter reading is less than 42, sidedress with 80lbs. of nitrogen. Fields with average meter readings of 42–45.9 can either be tested again in 4 to 7 days or sidedressed with 50 lbs. of N. Fields with average readings over 46 require no commercial N. A more in depth discussion of this entire process is available online at http://pubs.cas.psu.edu/FreePubs/pdfs/uc147.pdf.

Another test available is the Pre-Sidedress Nitrogen Test or PSNT. This soil test will make a measurement of nitrates available. This measurement will then be used as part of an equation to create a recommendation for nitrogen to be applied. For this test allow enough time for lab turn around before you sidedress. Most labs give rapid turnaround on this test. The Ag Analytical Services Lab at Penn State will fax, phone, or email results within 24 of receiving the sample. Depending on how long it takes you samples to get to the lab, try to take samples at least one week before you are planning on sidedressing. A 12 inch soil sample is required for the PSNT. If 12 inches is not possible sample as deep as you can. Take 10 to 20 samples per field in a random pattern making sure to stay away from areas where nitrogen may have been banded earlier this year. Do not use this test on fields where fertilizer or manure has been injected. Once you have the sample collected from a field, crumble and thoroughly dry the soil as quickly as possible prior to sending it to the lab. Samples that are not dried within 24 hours can give erroneous results. Send the sample to a reputable lab and request a soil nitrate test. After receiving your results in the mail, calculate nitrogen application rate from nitrate PPM by the following equation.

With these tests you will be able to maximize your yield while minimizing your costs for nitrogen fertilization. Again these tests are to be utilized to assist in the guess work associated with fields that have received manure in the past. They are not necessarily good tests for fields that have received their fertility from commercial fertilizers. More information is available online or at your local extension office on Agronomy Fact Sheet 17. Additionally, you can find educational videos demonstrating how to do both of these processes at http://cmeg.psu.edu/cmegpubs.cfm.

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.

Farming for Success Field Day: SE Field Research and Extension Center, Landisville, June 30

Whether you are an experienced crop producer, are interested in learning more about no-till farming systems, or want information on soil quality and fertility, this field day is for you! Come listen to informational speakers, discuss your needs with local Ag industry professionals, or catch a no-till planter demo in the field. The Farming for Success field day is an opportunity not to be missed and it’s here in your backyard! Join us on June 30th and expand your knowledge!

June 30th, 2009 — 8:30am to 4:00 pm

• No-Tilling Tips
• Nitrogen & Manure Management
• Soil Quality & Fertility
• Equipment Expo & Demonstrations
• Cover Crops
• Fungicides: Costs and Benefits
• And much more!

Questions or for sponsorship info: Jeff Graybill, 717-394-6851, jgraybill@psu.edu

REGISTRATION FORM

Cost: $3.00 Pre-registered (by June 29th) $5.00 At-the-door

Checks should be made payable to: PSCE Program Fund

To Register: Contact

Lancaster County Cooperative Extension 1383 Arcadia Road, Room 140 Lancaster, PA 17601 717-394-6851 LancasterExt@psu.edu

(or call 717-394-6851) by noon, June 29th

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.

Contributors: State Specialists: Dr. Bill Curran & Dwight Lingenfelter (Weed Science), Del Voight (IPM), Dr. Greg Roth (Grain Crops & Bio-fuels); Dr. John Tooker (Entomology). Extension Educators: Kevin Fry (Armstrong), Mena Hautau (Berks), Jeffrey Graybill (Lancaster), John Rowehl (York), H. Grant Troup (No-till Specialist- Capital Region), Mark Madden (Sullivan), Joel Hunter (Crawford), Jonathan Rotz (Cumberland), Susan Alexander (Jefferson), Craig Williams (Tioga).

Editor: Jeffrey Graybill, MS, CCA, Lancaster County Agronomy Educator

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.

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