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May 7, 1999 Vol. 99.3

IN THIS ISSUE:

Mark Your Calendar

Production

Pest Management

Agents Corner

Degree Day Accumulations

Production:

PROPER ADJUSTMENT OF HAY CONDITIONERS REDUCES DRYING TIME

Hay producers in Pennsylvania list unpredictable weather as the number one reason for not being able to make quality hay. However, the amount of time that hay lays in the field and is exposed to rain can be shortened without additional cost to the farmer. Before farmers go to the hay field this spring with their mower-conditioner, they should spend a few minutes adjusting it. Many conditioners have not been adjusted since they were bought and this could be costing the farmer thousands of dollars per year in hay quality and production.

The conditioner crushes or crimps the stem of alfalfa and speeds up drying. Properly adjusted conditioners can cut drying time in half! Quicker drying reduces the risk of the mowed hay being rained on, synchronizes the drying of leaves and stems which can reduce leaf shatter, and allows for quicker regrowth of the crop because the hay will not be lying on the stubble for so long. All of these advantages can result in higher quality hay and improved yields which is equivalent to dollars in the bank.

When properly adjusted, the conditioner should crimp the stem every 3 to 4 inches. The two basic adjustments that affect the extent of crimping are the space between the crimping rolls and the pressure on each roll. The rolls should be adjusted to be as close as possible to each other without touching. Used rolls may not be perfectly round so they will need to be adjusted at the fattest part of the rolls.

The correct amount of pressure on the rolls is not as easily determined as is the space between rolls. Enough pressure should be applied to adequately crimp the stems and not damage the leaves. Damaged leaves are more prone to leaf shatter than leaves that are not damaged. Damaged leaves can be identified because they will turn dark green or black after crimping. There should be less than 5% damaged leaves with properly adjusted conditioners.

The frequency that conditioners will need to be adjusted depends on the extent of use and the amount of soil or sand particles that are run through the conditioner. Soil and sand will cause the rolls to wear faster and cause more frequent adjustment.



CHECK MOISTURE BEFORE BALING HAY

Baling hay at the optimum moisture content can be a tricky business, which often involves some guesswork and cooperation from the weather. Baling at moisture levels above the optimum will cause heating and spoilage of the hay. Conversely, baling at moisture levels below the optimum causes excessive leaf loss, which translates into lower quality hay. The optimum moisture for baling is not a constant and depends on the bale size being used.

Moisture for small rectangular bales should be no higher than 20%, unless a preservative is used. The upper moisture limit in large bales, both round and rectangular, is about 16% to avoid excessive heating during storage. If large round bales are stored outside and uncovered, moisture content at baling can be up to 20%.

Determining moisture content can be done with a microwave oven or Koster moisture tester before baling, or an electronic moisture meter at baling. When using an electronic moisture meter, probe from the end of rectangular bales and through the rounded diameter of round bales. At least five probes of each bale should be taken and the readings should be averaged. If readings vary more than three percentage points, more probes should be taken and the average re-calculated.

Many factors can affect a meter's accuracy such as bale density. Tightly packed bales will give the most accurate readings. The use of chemical preservatives is another factor that may affect the accuracy of electronic moisture meters. Some chemicals such as propionic acid can increase readings as much as four percentage points. If preservatives are used and the instruction manual for the moisture meter does not provide information about effects of chemicals on meter performance, contact the manufacturer for additional information.

HOW HAY HANDLING METHODS COMPARE

Table 1.
Treatment Average drying days* Production
cost ($/ton)		 Feed cost per
cwt. of milk
Cut 1 Cut 2 Cut 3
 
Mowed only, full swath, raked 8.1 5.5 5.0 69 $4.77
Conditioned, narrow swath 6.0 4.4 5.7 56 4.52
Conditioned, wide swath, raked 4.5 3.8 5.2 58 4.56
Conditioned, tedded, raked 3.9 3.5 5.0 65 4.74
Conditioned, inverted, narrow swath 4.3 3.8 5.0 64 4.71
Chemically conditioned, raked 3.8 3.0 3.7 59 4.57
 
*Based on 26 years of weather for East Lansing, Mich.

Source: Dr. Alan Rotz, at the USDA Pasture Laboratory in University Park, PA. Although this weather from Michigan may be different than in Pennsylvania, the trends and findings should be applicable.

Marvin Hall, Agronomy, Forages

SETTING SOME GOALS FOR YOUR CROP ADVISOR

I recently heard a presentation on "Setting a Performance Target for your Feed Consultant" by Dr. Larry Chase from Cornell. Many of the ideas presented were applicable to crop advisors as well. I tried to adapt this presentation to crop production.

Crop, dairy and livestock producers are increasingly relying on consultants or dealers to participate as part of their management team and help them with many farm level decisions. These professionals are expected to provide timely and accurate information and management recommendations. As the productivity of farms increase and management decisions become more complex, the expertise of the consultants needs to increase as well. It is the job of the farm manager to evaluate how well his consultants or dealers are functioning as part of their whole farm management team.

In a survey conducted on New York dairy farms, the characteristics of a feed industry professional that were most important to managers were: technical knowledge and its application, turnaround time, variety of services offered and a successful reputation. Least important characteristics were member of the local community, product with service, and free service with product. Thus, successful feed or crop professionals need to understand and apply technical information, provide service on a timely basis and offer a variety of services.

Some basic skills that are essential for ag service providers in our region include: being able to work as part of a team, understand at least one segment of a dairy/livestock operation, the ability to analyze records, make objective observations, honesty and integrity.

Crop producers should be thinking about how they might evaluate the crop production professionals that work with them on their farm. Do they put together cropping recommendations that are designed to enhance yield or profitability? Are they a source of management ideas? Do they take into account your goals and constraints in developing recommendations? Is there an imbalance between sales and objective advice? Do they challenge your management program or always agree with you? Do they provide recommendations based on research? Do they use your farm records as a basis for recommendations? Do they attend continuing education programs on a regular basis? Do they read trade magazines and present you with new concepts? Do they make appointments with you and keep meetings organized, short and to the point? Do they invite you to educational meetings? This is not a complete list of performance objectives but it is a start. The key is that farm managers should identify those things that are most important to them and communicate them to the professionals that are advising them on their operation. Consultants need to know what is expected of them so they can adjust their approach accordingly. If this process is effective, in the end it will result in improved crop production advisors and ultimately better crop management decisions on the farm.

Greg Roth, Agronomy,
Corn and Sorghum Management

SOYBEAN ESTABLISHMENT

Soybean planting will be in full force shortly. Establishing a vigorous uniform stand is key to profitable yields. The following are a few points to consider as we enter the planting season.

1. GENERAL COMMENTS Soybean seed are sensitive to rough handling prior to and during the planting operation. Their chemical composition and thin seed coat make them more prone to damage then other grain seed. Therefore, do not drop bags of seed and be sure planters, particularly drills, are adjusted so the seed coat is not broken during the planting operation.

Soybean seed require more water for germination then many other grain crops. This is the reason the old adage " if the soil is dry, don't try" is appropriate for soybean establishment. In addition to adequate soil moisture, there should be good seed to soil contact to assure adequate water movement into the seed.

2. SEEDING DEPTH Seed should be placed 1 to 1.5 inches deep. Planters should be adjusted so that the seed depth is as uniform as possible.

3. PLANTING DATE The optimum planting date for soybean is the same as the optimum date for corn. It is normally suggested however, to plant corn first and then immediately start planting soybeans. This is because corn tends to be more responsive to early planting.

4. PLANT POPULATION The desired plant population for full season soybeans is 150,000 plants per acre. This population is suggested for all row spaces. Seeding rates required to obtain the desired population will need to be adjusted relative to soil and planter conditions. The following are guidelines for making adjustments in seeding rates.

Increase the seeding rate per acre by:
   5% for each rotary hoeing
   10% for rough seedbeds
   10% for short season varieties
   10% for cold soils
   15% for no-till
Decrease the seeding rate per acre by:
   10% if lodging is a problem
   10% if planting a lodging susceptible variety

5. ROW SPACING Most soybeans in Pennsylvania are planted in narrow rows, seven to fifteen inches. Research indicates that yield will be higher in narrow rows then wide rows, especially when planted after mid-May. We suggest planting 30 inch rows by May 10 in order to reduce the yield loss potential from wide rows.

Pest Management:

SOYBEAN SEED TREATMENT FOR DISEASE CONTROL

The use of seed treatment for disease control in soybeans has not been a common practice in Pennsylvania. Soybeans tend to emerge rapidly when planted in warm moist soils encountered during late May and early June. With the trend for earlier planting, or when planting into cold wet soils, it may be necessary to consider a fungicide seed treatment. Cool or wet soils increase emergence time and allow disease organisms more opportunity to attack the seed. Seed treatments typically offer the greatest benefit when the seed or seedling is under stress during the first two weeks after planting. Examples of stress are heavy rains, soil compaction, surface crusting, cool soils, deep planting, reduced seed quality, and dry soils.

The most common seed and seedling diseases are caused by species of the following fungus organisms; Phytophthora, Pythium, Rhizoctonia and Fusarium. Phytophthora sp. and Pythium sp. are prevalent under wet soil conditions and produce a soft rotting of the seed or seedling before or after emergence. This is often referred to as damping-off since it occurs under damp soil conditions. With damping-off, a dark brown or black rot girdles the seedling stems, and the plant dies.

Rhizoctonia sp. and Fusarium sp. occur under drier soil conditions. Rhizoctonia sp. produces reddish lesions along one side of the stem and do not girdle the stem. Plant growth is reduced but death is not common. Dry rotting of the roots can be observed with Fusarium sp., as well as some reddening of the roots.

Nitrogen fixing bacteria, found in inoculants, are sensitive to chemical seed treatments. If a seed treatment is required and an inoculant is being used, apply the seed treatment first and several days in advance of the inoculant if possible. It is best not to use a seed treatment on fields that do not have a history of soybeans. Successful production in these fields requires introduction of a high population of viable nitrogen fixing bacteria. Under these conditions, it is best to plant quality seed and delay planting until the soil is warm.

Elwood Hatley, CCA, Agronomy

POSTEMERGENCE HERBICIDE APPLICATION TO CORN

Herbicide labels that refer to corn height in inches are ambiguous. The labels do not specify what the measurement boundaries are on the corn plant (e.g., ground surface to tallest, free-standing, point, ground surface to whorl, base of stalk to fully extended leaf, etc.). The leaf number method generally begins by counting the first rounded leaf or coleoptile (this first leaf sometimes rapidly matures and falls off), continues up past the last visible leaf collar to the uppermost leaf that is 40 to 50 percent exposed. This leaf typically has its leaf tip pointing downward. This method usually results in the addition of one or two leaves more than the leaf collars method. The number of visible leaves and height does not always give a true indication of the crop stage. The more exact method of growth staging is to use a method that corresponds to the number of leaf collars. This system describes the growth of young corn by counting the number of leaves that have exposed leaf collars, beginning with the first or rounded leaf. The collar is a light colored band that appears where the leaf attaches to the stalk or sheath. A plant with four leaves with visible collars would be called a four-leaf or a V4 plant.

Exact growth staging can be important, since some postemergent herbicide applications applied after the labeled stage may cause a decrease in the reproductive capacity (yield) of the crop. In general, applications made prior to the V3 stage provide the greatest crop safety. Some labels, especially those on newer products, provide several ways of determining growth stage. Until there becomes a universal rule throughout the crop protection industry for staging crop growth, we will have to continue to use a number of methods. Following is a list of herbicides and their post application restrictions (Table 2).

Table 2. Postemergence Herbicide Application Restrictions for Corn
Herbicide Over the top application Use of drop nozzles Comments
Accent and Celebrity <20" tall (free-standing)
or <6 collars (V6 stage) 		20" - 36" tall or
V6 - V10 stage 		---
Aim Up to 8-leaf collars When necessary ---
Atrazine 12" tall --- ---
Banvel or
Clarity		 1 pt - 8" tall or 5 leaves
1/2 pt - 8"-36" tall or 15 days before tassel emergence 		--- Do not apply Banvel near soybeans if corn is >24" tall, soybeans are >10" tall, or have begun to bloom.
Basagram No restrictions --- ---
Basis Spike to 4 leaves (2 collars)
or 1/2" to 6" tall		 --- Do not apply to corn having 3 collars or >6"
Basis Gold up to 12" tall --- Do not apply to corn >12" tall or exhibiting 6 collars.
Beacon 4" - 20" tall (free-standing); 6 collars maximum For splits, 20" tall to before tassel emergence ---
Bladex 90DF Emergence to 4 leaf stage --- Do not apply if 5th leaf is visible.
Buctril 1 pt - emergence to tassel

1 1/2 pt - 4 leaves to tassel 		--- Post application before 3 leaf stage may result in corn leaf burn.
Buctril + Atrazine 1 1/2-2 pt - emergence to 12" tall
3 pt - 4 leaf to <12" tall 		--- Post application before 3 leaf stage may result in corn leaf burn.
Distinct 6 oz - 4-10" tall
4 oz - 10-24" tall 		--- Corn height is measured to the arch of the highest leaf that is >50% emerged
Exceed 4" to 20" tall or <6 collars >20" to 30" tall ---
ExtrazineII DF Before 5th leaf is visible or <8" tall --- For best results, apply from emergence to 2 leaf stage.
Hornet Emergence (spike) up to 20" tall (V6 stage) --- ---
Laddok S-12 Spike to 7 leaves or up to 12" tall --- ---
Lightning Spike through 48" tall When necessary Apply to IMI corn hybrids only
Liberty Emergence to 24" tall or
seven collars (whichever comes first)		 24" to 36" tall Apply to Liberty-Link or GR corn hybrids only
Marksman Emergence to 5 leaf stage or up to 8" tall --- ---
Northstar 4" to 20" tall (<6 collars) >20" to 36" tall ---
Permit Spike to 48" tall When necessary If tank mixed: with 2,4-D, apply up to 8" tall corn; with Banvel or Clarity apply up to 36" tall corn.
Poast Plus or Poast Emergence to onset of pollen shed When necessary, as dictated by corn canopy and weed height Apply to Poast Protected corn hybrids only
Pursuit No restrictions on label (Apply before weeds are over 3" tall) When necessary Apply to IMI corn hybrids only.
If tank mixed, use most restrictive application timing.
Resource 2-leaf to 10-leaf stage
(collars must be visible) 		When necessary, to direct below corn leaves ---
Roundup Ultra Up to 30" tall (V8 stage) --- Apply to Roundup-Ready hybrids only
Sencor Emergence to pretassel When necessary See tank-mix partner.
Scorpion III Up to 8" tall >8" or V5 (prevent contact with corn) ---
Shotgun Spike to 4 leaf or up to 8" tall 5 leaf or 8"-12" tall ---
Spirit 4" to 20" tall or <6 collars >20" to 24" tall ---
2,4-D <8" tall 1/2 pt - 8" to 36" tall ---
Tough No restrictions on label When necessary Best to apply before 4-leaf stage of weeds but can vary with tank-mix partner.

DELAYED PRE HERBICIDE APPLICATIONS IN CORN

Table 3. Maximum corn and weed size for delayed preemergence herbicide applications.
Herbicides Maximum corn size Maximum weed size
Atrazine 12 inches 1.5 inches
Atrazine + Bladex 90 DF or Extrazine II 90 DF 4-leaf 1.5 inches
Banvel or Marksman + Bladex 80W or 90DF 4-leaf 1.5 inch grass
Banvel or Marksman + Dual or Lasso EC 3 inches 2-leaf grass
Banvel or Marksman + Frontier 8 inches 1 inch grass
Marksman + Prowl 2-leaf 1 inch grass
Bicep II + Prowl 4-leaf or 2 collars 1 to 2-leaf
Bicep Magnum TR 2 inches 2-leaf
Bladex 80W or 90DF 4-leaf 1.5 inches
Bullet or Micro-Tech + atrazine 5 inches 2-leaf
Dual or Micro-Tech + atrazine, Bullet 5 inches 2-leaf
Dual II, (Dual II + atrazine), Bicep II, Bicep II Magnum, Bicep Lite II, Bicep Lite II Magnum 5 inches 2-leaf
Dual II or Dual II Magnum + Banvel 5 inches 3-inch pigweed
Dual II + Marksman 3 inches 2-leaf
Frontier 8 inches before emergence or by tank-mix partner
Frontier + Accenta 8 inches 3 inches
Frontier + Beacon 8 inches depends on weed (see Beacon label)
Guardsman, LeadOff 8 inches 1.5 inches
Harness or Harness Xtrac 11 inches or by tank-mix partner before emergence or by tank-mix partner
Princep before emergence before emergence
Prowl + Accentb or Prowl + Accent + Beaconb 6-leaf see herbicide labels
Prowl + Atrazine, Prowl + Bladex 90DF, or Prowl + Banvel 4-leaf 1 inch
Prowl + Beaconb 6-leaf depends on weed (see Beacon label)
Prowl + Poast Plusd 6-leaf depends on grass (see Poast Plus label)
Python WDG 2-inches (spike) before weed emergence
Surpass, Surpass 100, FulTime, or TopNotche 11 inches or by tank-mix partner before emergence or by tank-mix partner
a May use a reduced rate of Frontier and Accent under certain conditions.
b Accent rate of 1/3 to 2/3 oz/acre and Beacon rate of 3/8 to 3/4 oz/acre; when tank-mixing all three herbicides-Accent rate is 0.33 oz/acre and Beacon is 0.38 oz/acre.
c May be tank-mixed with Accent, Atrazine (Harness), Banvel or Clarity, Marksman, Permit, or Pursuit (IMI-corn).
d For use in Poast Protected corn only, Poast Plus rate of 12 to 24 oz/acre.
e May be tank-mixed with a number of different products including Accent, Banvel or Clarity, Prowl, Pursuit (IMI-corn), etc. See a herbicide label for specific information.

A number of residual herbicides can be applied after planting up until corn and weeds reach a certain size or growth stage. The greatest risk of failure comes with trying to control annual grasses such as foxtail and panicum after they emerge. However, several products are now available to control emerged grasses (Accent, Basis, Roundup Ultra on Roundup Ready corn only, Pursuit on IMI-corn only and Poast/Poast Plus for Poast Protected/SR corn only.) For most products, do not apply in liquid fertilizer if corn has emerged or injury may occur. Some early-postemergence considerations are listed in the previous table.



USING THE ROSETTE TECHNIQUE TO CONTROL CANADA THISTLE

An article was recently published in Weed Technology (Weed Technol. 12:699-706) by Miller and Lym from North Dakota State University looking at using a technique adapted from fallow crop production systems for Canada thistle control in corn and soybean. The system the researchers examined compared spraying Canada thistle in the fall with a systemic herbicide in the rosette stage of growth vs. after it has bolted. In fallow systems, it has been shown that herbicide translocation to the roots can be four times greater in Canada thistle rosettes than in bolted plants, resulting in better long-term control. In a fallow system periodic tillage is often used to knock back emerged plants and thus keep them in the vegetative rosette stage of growth. In general, Canada thistle shoots that emerge in August and September will not bolt until the following spring, but rather remain in the rosette stage in the fall because of the decreasing day length in late summer.

Miller and Lym compared cultivating corn or soybean three times (twice in June and once in July) vs. applying a postemergence herbicide in-crop. The researchers then compared the performance of several fall treatments following these early summer applications. In theory, the in-crop cultivation treatments should temporarily control Canada thistle yet still allow new shoot emergence in late summer and fall. If the "in crop" herbicide treatments were "too" effective, then new shoots of Canada thistle will not emerge in late summer and fall and thus a fall herbicide application would not be very effective. Therefore, the rosette technique in this system is defined as summer cultivation followed by fall herbicide.

The researchers planted early maturing corn and soybean varieties in 1994 and 1995 near Fargo, North Dakota to allow harvest of both crops by mid to late September. Early summer treatments were applied to prebud to early bud Canada thistle and included the treatments shown in Table 4. Fall treatments were applied in October and compared Stinger (clopyralid) +2,4-D applied at 0.5 pt + 1 qt, Roundup (glyphosate) at 1 qt, and Banvel (dicamba) at 1 qt. All fall treatments included NIS at 0.5% v/v.

Eight months after the fall applied treatments, the rosette technique (cultivation followed by fall herbicide) was equal to or better than the in-crop followed by fall herbicide treatment (conventional) in corn and equal to the conventional treatments in soybean (Table 4). In corn, grain yield in the cultivation treatment was comparable to yield in the herbicide treatments, while in soybean, the cultivation treatment resulted in a slight decrease in yield probably due to Canada thistle plants left within the row after cultivation. The performance of the fall herbicide treatments was similar in corn and soybean. In 1995, Canada thistle control 8 months after application averaged 77% with Roundup, 48% with Stinger plus 2,4-D and 55% with Banvel. In 1996, control averaged 60% with Roundup, 82% with Stinger plus 2,4-D and 67% with Banvel.

Table 4. Canada thistle control 8 mo. after fall treatment as affected by in-crop postemergence treatments (averaged across fall applied treatments).
Treatment Rate/A Year
1995 1996
Corn   % Control
Cultivation (3 times) --- 56 74
Banvel + NIS 1 pt + 0.5%v/v 43 58
Stinger 0.5 pt 56 83
LSD (0.05   NS 12
Soybean    
Cultivation (3 times) --- 53 57
Basagran fb Basagran (w/MSO) 1 qt fb 1qt (+ 1 qt) 42 52
Basagran + Pursuit + Dash 1.5 pt + 0.5 fl. oz + 1 qt 54 55
LSD (0.05   NS NS

Finally, the researchers also compared the absorption of Stinger by leaves and the translocation to roots from rosette treated vs. bolted Canada thistle plants in a laboratory study. They found that indeed twice as much Stinger made it to the roots of rosette treated plants. Increased absorption and translocation of Stinger by rosette stage plants compared to bolted plants was likely the reason for the increased control observed in some field studies.

In summary, the rosette technique of using cultivation during the first half of the growing season in corn or soybean followed by a fall applied herbicide treatment provided about the same Canada thistle control as an in-crop herbicide treatment followed by a fall applied herbicide treatment. In theory, this technique could reduce herbicide inputs and could improve long-term Canada thistle control. However, timely cultivation and several cultivation trips across the field may be necessary in the corn or soybean to avoid potential yield losses due to weed competition. Also, early maturing corn or soybean grain varieties or possibly corn silage will be necessary in order to utilize this type of weed management system and the crop must be planted in conventional rows (i.e. 30 inches). Finally, this type of study proves once again how difficult it is to manage herbaceous perennial weeds such as Canada thistle; the average control achieved by these treatments was about 60% the year after application. Longer term management approaches are needed that include tillage, crop rotation, and effective herbicides.

Bill Curran & Dwight Lingenfelter,
Agronomy, Weed Science


INSECT ALERT

The following insects can be active during this time period. This does not mean they have been seen in the state, but 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 webpage, http://www.fra.cas.psu.edu/. Also, insect and insect injury images for all crops are being added to the new Agronomy Guide web site. Other web sites of interest include the University of Maryland's Pest Report in http://pest.umd.edu/ipm/AgIPM/CropAndIPMReport/CropIPMReport.html). Information on insect trap data and other IPM information can be found under http://www.udel.edu/IPM/. This web site contains black cutworm data from a network of 50+ pheromone traps operated by Terra Inc., Bridgeville, DE (Galen Dively). The data is for Delaware, but may provide an alert to future black cutworm injury in Pennsylvania. A web site of the Maryland Department of Agriculture operated by Dick Bean has information from a network of black light and pheromone traps. You can access the data at ftp://ftp.mda.state.md.us/plantpro/blt/weekly/ or call 800-492-2106. Again, the information is not for Pennsylvania but can provide an alert to pending insect problems.

Corn
billbug black cutworm flea beetle
garden symphylan grape colaspis  
seed corn maggot slugs sod webworm
thrips white grub wireworm
Soybeans
bean leaf beetle seed corn maggot  
Alfalfa
alfalfa weevil potato leafhopper  
Small Grains
aphids cereal leaf beetle  

As newly planted crops begin to emerge any of the above insects are potential pest problems. Be aware of what each insects injury symptoms look like and how to identify each pest.

alfalfa weevil
Galen Dively of Maryland has reported slow development of weevil problems. A few fields have been above economic thresholds, but most are indicating relatively low populations. I have received no reports of alfalfa weevil injury in Pennsylvania to date. However, young larvae can be found feeding on alfalfa plants, but degree-day accumulations are still below those needed to enter the peak injury period. See Table 5 (on page 13) for the degree day accumulations for your general area. Significant feeding activity should begin at about 280 to 300 DD using base threshold temperature of 48°F (Table 7). The warmest area in the state, York County, has reached 275 DD. Therefore, the southeast and south central counties should expect to see evidence of injury within the next week. Cooler areas can expect injury symptoms in about a week to 10 days. Watch fields with a southern exposure for first signs of weevil damage, particularly high knolls in the field. The dry weather will help survival of larvae, so keep your eyes open.

aphids
Grain aphids are active, but high numbers have not been reported.

black cutworm
Moths have already entered the state and deposited eggs on winter annual weeds, such as common chickweed or mustard species, and small grains and grasses. Fields that will be planted into fields with these weeds or grasses should be protected against the pest or scouted from crop emergence to V5 (ca. 18 inches) and spray if a problem develops. If these weeds or crops are plowed down or burnt down by a herbicide at least 10 days before planting (weeds must be brown), damage from the pest can be avoided or minimized. Injury symptoms typically show up about 300 DD after the peak moth flight is captured in a pheromone trap. We do not have a pheromone network in Pennsylvania, but this time is typically from mid-May to mid-June, with peak activity about the first week of June.

cereal leaf beetle
Galen Dively is reporting low levels of cereal leaf beetle activity in Maryland and that numbers are down from previous years. I have received no indication of economic problems in Pennsylvania.

seed corn maggot
According to the degree day accumulations in the state, 450 DD is needed to avoid injury by the first generation of seed corn maggot. Fields planted after 450 DD should have a low risk of injury from the pest. However, a seed treatment should still be used in fields that will be planted into an old pasture, hay field or rye mulch that has recently been plowed down. The decay process is attractive to flies that are seeking out sites to lay their eggs.

Dennis Calvin, Entomology

Agents Corner:


ADAMS COUNTY

A small amount of corn has been planted, however soil temperatures have remained on the cool side. Several corn silage test plots will be established throughout the county. These plots will measure yield, and will also measure total digestibility.

This year's spring alfalfa seedings are looking great. The warm weather last month allowed for uniform germination with above average populations. In established alfalfa, weevils are present with populations increasing. Most fields have not reached an economic threshold and at this stage, mowing is recommended. The very earliest buds are evident on the alfalfa. Now is the time to begin mowing for optimum quality. If you must choose between harvesting haylage and planting corn, mow haylage. Maximize the relative feed value that is available in your haylage. Hiring a custom operator to plant corn, while you harvest a high quality haylage, is a great investment.

Powdery mildew and septoria leaf blotch have been found in a majority of the wheat fields. Scouting, along with any necessary fungicide application, can help preserve your maximum yield potential. With the current temperature conditions, wheat should begin "heading out" within a week.

Larry Swartz
Adams County

BERKS COUNTY

Spring has been a contrast in weather. Rumor of corn planting started back in late March/early April, then spring rains fell. Now we are experiencing a "hold rain" pattern. Although tillage can be done on the wettest of soils, most producers would agree that a good shower is needed.

In between tillage and planting, rye and barley are being cut for silage and wheat has been observed with flag leaves. Last fall was extremely dry and some small grain plantings show uneven growth. I have had several calls on failed fall forage seedings too.

Memorial Day weekend will mark the one year anniversary a tornado moved through Berks County. It cut a swath starting in Leesport, through Lyons, Bowers and then skipped through eastern Berks into Lehigh County. Thankfully, no injuries resulted. The major issue farm families faced (besides the initial emotional shock) was rebuilding or restoring houses, barns and storage sheds. Families, with the help of volunteers, gleaned the fields for trash wherever the twisters path was cut. Despite these efforts, many tires went flat when field work resumed. The real education came when farm families revisited their insurance policies. A lesson learned was "check that insurance policy for catastrophic loss".

Mena Hautau
Berks County

CENTRE/CLINTON COUNTIES

Growers have taken advantage of nearly two weeks without rain and planted a lot of acres. While corn planting is continuing, it is well ahead of many years. Likewise, soybean planting is progressing nicely. It appears that there will be a lot of Roundup ReadyÒ soybeans in this area this year. The oat crop is emerging and can be found in various stages of growth, depending on seeding date. Wheat and barley have begun to grow rapidly with a week of warm temperatures. Some leaf diseases have been noted on both, but nothing alarming.

Alfalfa fields are growing well. The alfalfa turned green and immediately began growing rapidly this year, preventing some growers from spraying for weeds, as planned.

No major pest problems have been noted so far this season...but it's still early

Gary Dauberman
Centre/Clinton Counties

CORN POPULATION IN THE SW

For the past three years farmers in Fayette and Westmoreland County have been participating in an ongoing corn population study. In 1996 kernel drop goals were 22K, 25K, and 28K; in 1997, 24K, 27K, and 30K; and in 1998, 27K, 30K, and 32K. Each year we kept increasing the plant population in an attempt to locate a maximum for the soils the farmers in the SW are working with.

During the 96 season, corn suffered very little from drought stress, similar to the 98 season. In 1997, the corn suffered significantly from low soil moisture in many locations around the area.

The following tables summarizes the yield results for the three years:

1998 Corn Population Results
Name 27,000
kernels/A		 30,000
kernels/A		 32,000
kernels/A
  --------------- Bu./A ---------------
Burd** 136 137 155
Shaffer* 106 123 98
F&F** 122 136 137
* Corn showed signs of nitrogen deficiency.
** No-till

1997 Corn Population Results
Name 24,000
kernels/A		 27,000
kernels/A		 30,000
kernels/A
  --------------- Bu./A ---------------
Burd** 114 130 136
Forejt 89 104 93
F&F** 112 109 104
* Burd Farms had significantly better rainfall in 1997 than the other two.
** No-till

1996 Corn Population Results
Name 22,000
kernels/A		 25,000
kernels/A		 28,000
kernels/A
  --------------- Bu./A ---------------
Burd** 122 139 123
Shaffer 151 126 146
Stouffer*** 83 98 102
F&F** 115 114 133
** No-till
*** Late Planting

By design the only controlled variable was the variety of seed, each year all the cooperators used the same variety. All other input variables were controlled by each cooperator with the anticipation that soil pH and fertility levels would not be a limiting factor.

In 1998, two of the three plots demonstrated yield increases at the highest population when there were no visible deficiencies in the corn.

Clearly the three years of data demonstrates a yield advantage with planting populations in excess of 28,000 kernels dropped per acre or harvest time population of 28,000 to 30,000 plants per acre. (Of course, there should be no other significant limiting variables.)

Even with dry weather conditions, such as in 1997, harvest time populations of 28,000 to 30,000 plants per acre didn't create a significant yield disadvantage. This supports the recommendation to maximize planting population to the capability of the hybrid and not anticipated weather conditions.

Summary

If other crop inputs, such as lime, fertilizer, herbicides, etc. are up to recommended levels, then why not maximize yields with recommended planting populations? This "on farm" data would support plant populations of 28,000 to 32,000 per acre in SW Pennsylvania conditions.

Finally, if producers are planting higher populations, but still can't maintain 90% germination and establishment, then a closer look at the corn planter for repairs and maintenance would be desirable.

Don Fretts
Fayette County

SUSQUEHANNA/BRADFORD COUNTIES

It's been a while since I've contributed to the Field Crop Newsletter and I welcome the opportunity again. We're off to a warm and dry spring this year and field work is progressing at a steady pace well ahead of the historical norm. J. Craig Williams, Tioga County Agent, reported to me that he had 15 acres tilled and planted to corn on May 1! I suppose that date might be noteworthy only to those who understand northern Pennsylvania. But, as those of you around the state who know Craig will understand, he has a tale for everything. He tells of a sales rep and two teen-age nieces each clad in bell bottoms being held hostage until his planting was done. Can you imagine trudging behind a corn planter throughout a 15 acre field making sure the drive chains on the units kept from jumping the sprockets?

But, Craig's story is similar to others I am hearing. With the favorable weather and a little help most folks are off to a good start in their fields. The winter has been very kind to our alfalfa crop and growth to this point appears about average. The forage grasses could use a little rain to boost their growth but it seems to be a sacrifice many are willing to endure so long as we're able to keep our other field work underway. We're looking forward to a good start.

Mark Madden
Susquehanna/Bradford Counties

Degree Day Accumulations:

1999 DEGREE DAY ACCUMULATIONS

To track corn and insect development, compare the 1999 cumulative degree-days shown in Table 5 to the required values in Tables 6 and 7. Choose a location that is closest to your site when making a comparison.

Table 5. Cumulative Degree Days for Corn and Insects for the Period Ending May 2, 1999
    Corn Insects
County Location 1999 30-year ave. SCM/SB AW BCW CRW ECB
    50F 50F Diff 40F 48F 50F 53F 55F
Erie Waterford 21 13 8 377 142 106 63 42
Crawford Meadville 21 14 7 430 166 125 76 52
Mercer Mercer 21 14 6 448 174 131 81 56
Bradford Towanda 20 14 6 425 157 116 67 44
Lycoming Montoursville 20 15 4 496 188 142 86 58
Tioga Mansfield 20 13 7 377 138 100 58 38
Susquehanna Montrose 19 11 7 325 114 81 45 28
Butler Butler 21 16 5 507 199 152 96 67
Indiana Indiana 20 16 4 510 199 152 96 67
Lawrence Lawrence Jct 21 14 7 426 164 124 75 51
Blair Martinsburg 19 15 4 492 190 144 90 62
Centre State College 19 15 5 470 179 134 82 56
Columbia Bloomsburg 19 16 4 520 197 149 91 62
Clearfield Curwensville 20 14 5 456 174 131 80 54
Dauphin Elizabethville 19 16 3 568 220 167 105 73
Bedford Bedford 19 16 3 566 224 171 109 78
Mifflin Belleville 19 16 4 533 206 157 98 68
Northumberland Sunbury 19 16 3 558 215 163 102 70
Lehigh Trexlertown 19 17 2 594 229 173 109 75
Schuylkill Hegins 19 16 3 531 203 153 95 65
Westmoreland Greensburg 20 16 4 523 206 157 100 71
Somerset Somerset 19 13 5 429 165 124 77 53
Washington Washington 20 17 4 582 235 181 118 85
Franklin Chambersburg 19 18 2 643 258 197 128 91
York York 19 18 1 682 275 210 136 98
Lancaster Ephrata 19 17 2 607 236 179 114 80
Berks Hamburg 19 17 2 605 235 178 112 78
Corn degree-days based on a May 1 starting date. Insect degree-days based on a January 1 starting date.


Table 6. Cumulative Degree-Days Required for Insects to Reach key Periods for Scouting or Management
  Maturity rating (days)
80 90 100 110 120
50% Silking 1100 1150 1250 1300 1400
Black Layer Formation 1900 2100 2300 2500 2800


Table 7. Cumulative Degree-Days Required for Insects to Reach key Periods for Scouting or Management
  Stalk Borer Alfalfa Weevil Black Cutworm* Corn Rootworm European Corn Borer Seed Corn Maggot
Adlt Emrg 5% Hatch 1st Gen 2nd Gen
SB AW BCW CRW ECB1 ECB2  
Initiation 1400 300 91 1283 380 WCRW** 558 1550 450***
Termination 1700 500 430 2253 478 NCRW** 1228 2045  

*Degree-day accumulation should begin at first moth capture in a black light or pheromone trap.
**These values represent degree day accumulations for optimal timing of Furadan 4F post emergence applications. WCRW-Western Corn Rootworm, NCRW-Northern Corn Rootworm
***This number of degree days represents the number of degree days required from plowdown of green vegetation until it is safe to plant corn or soybeans and avoid seed corn maggot injury.

Dennis Calvin, Entomology

William S. Curran
Associate Professor Weed Science
email: wsc2@psu.edu

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