Website Address: http://fcn.agronomy.psu.edu/
Vol. 96:6
May 31, 1996
IN THIS ISSUE:
Announcements
Production
- Poor Persistence of 'Matua' Prairie Grass
- Update on Pre-Sidedress Soil Nitrate Test for Corn
Pest Management
- Herbicides Cleared for Postemergence Application to Corn
- Postemergence Herbicide Use in Soybeans
- Corn Insects
- Alfalfa Insects
Agent Observations
- Mifflin - Juniata - Perry
ANNOUNCEMENTS
Pequea-Mill Creek Project Field Day Tour - June 11, 1996. CCA credits will be awarded for participation: 0.5 SF, 1.5 SW and 0.5 CP.
ANNOUNCING IPM WORKSHOPS
"Integrated Pest Management: Decision-Making for Field Crops". As part of a pilot
project, Penn State Cooperative Extension Specialists Dennis Calvin and Steve Spangler,
as well as Project Associate Lyn Garling, will be offering hands-on IPM training
for decision-makers in field crops (corn, alfalfa, soybeans and small grains). If the
workshops are successful, attempts will be madeto expand these efforts in future years to other counties. The sessions will be held from 9-noon at a local farms in York, Franklin, Blair and Bradford Counties, in cooperation with the County Cooperative Extension offices and Crop Management Association personnel. Topics will include IPM updates, practical techniques for scouting, identification, pest interactions, and decision-making about management tactics for key insect and weed pests. The early season session will be followed by a late summer session at the same location to view and discuss late season problems, planning for next year and to evaluate results of earlier management actions.
Intended audience includes field technicians (CMA, CCA, private consultants, agency
personnel), Cooperative Extension agents, and farmers who scout their own fields.
Participants will be provided with manuals containing identification guides, decision-making tools and in-depth practical information on a number of topics. Sessions are
free of charge but registration is required by calling the numbers below. Registration
is limited to 18 participants so that meaningful discussion in the field is possible.
Pesticide Applicator and CCA Continuing Education Credits have been applied for.
An evaluation will take place at the end of the session. For registration, further
information and directions, call contact numbers for the participating counties.
PARTICIPATING COUNTIES
York County
Contact: John Rowehl
York Co. Cooperative Extension
(717) 840-7408
When: June 18, 9-noon
Farm host: Robert Smyser, York, PA
Franklin County
Contact: Bob Kessler
Franklin Co. Coop Extension
(717) 263-9226
When: June 19, 9-noon
Farm host: Wayne Beidel, Newburg, PA
Blair-Bedford County
Contact: Amanda Ritchey
Blair Co. Cooperative Extension
(814) 695-5541, Ext. 210
When: June 20, 9-noon
Farm host: Ray Mowry, Roaring Springs, PA
Bradford County
Contact: Mark Madden
Bradford Co. Coop. Extension
(717) 265-2896
When: June 27, 9-noon
Farm Host: Kevin Potter, Wyalusing, PA
Steve Spangler & Dennis Calvin
PRODUCTION
POOR PERSISTENCE OF 'MATUA' PRAIRIE GRASS
'Matua' is a variety prairie grass that was developed in New Zealand under grazing
conditions. The USDA-Pasture Laboratory and Penn State University have been conducting
research with Matua for almost 10 years and have found it to be very productive.
It is a tall growing
perennial grass that is suited to well drained soils with medium to high fertility
levels and a pH of 6.0 or greater. It is a type of bromegrass, but is different
from smooth bromegrass in that it does not have rhizomes and it produces seed heads
in each growth period, especially during the summer. Herbage and immature seedheads of prairie
grass are highly palatable. In addition, it continues to grow later in the fall
than most cool-season forage grasses which makes it an ideal grass for extending
the grazing season well into the fall.
However, we have experienced sporadic problems with Matua persistence from one year
to the next. Persistence was a problem again this past winter in that none of the
Matua in our variety trails or research trails survived. Through research we thought
we had narrowed the persistence problem down to one of fall management. That is, not
harvesting Matua in the fall reduced persistence and harvesting in the fall improved
persistence. But not this year. Regardless of our fall management Matua died!
As you consult and advise with farmers that are considering Matua prairie grass in
their forage system make sure that they are aware of this problem!
Other prairie grass varieties have been developed and are being evaluated by Penn
State University for persistence and productivity. However, none of these varieties
are commercially marketed in Pennsylvania at this time.
Marvin H. Hall
UPDATE ON PRE-SIDEDRESS SOIL NITRATE TEST FOR CORN
The Pre-sidedress Soil Nitrate Test (PSNT) for corn has been used successfully in
Pennsylvania for several years. This N soil testing approach is based on taking
soil samples just before sidedressing- after the spring wet period but before the
period of major N demand by corn- and determining the nitrate-N available in the soil at that
time. If the test level is greater than 21 ppm NO3-N no sidedress N is recommended.
If the test is below this level, the results of the test are then used to make sidedress N recommendations. This test is primarily recommended for use on fields where there
are significant organic N contributions such as a history of manure applications
or forage legumes in rotation. It does an excellent job of verifying when these
organic sources of N are adequate for the crop. This test is of limited value on most fields
without organic N contributions, because these fields generally have low levels and
thus the standard recommendations are suitable.
Since this test is somewhat unique compared to regular soil tests, it is probably
worth while to review the procedures for using the PSNT since it will soon be time
to test. The PSNT procedure is as follows:
1. Only apply a minimum of fertilizer N in the spring. (Starter fertilizer and/or
N used as a herbicide carrier.)
2. Apply manure based on the history of the field, a manure analysis, how the manure
will be handled, and on crop requirements for N estimated from the expected yield
and crop history.
3. Take soil samples when the corn is 12 inches tall or at least a week before planned
sidedressing.
4. Sample the fields by taking 10 to 20 cores to a 12 inch depth if possible. If
not sample as deep as you can. Avoid starter bands and other atypical areas. Because
of sampling problems this test cannot be used on fields that received injected fertilizer or manure.
5. Combine and crumble the cores and dry as quickly as possible. Spread the samples
out in the sun or under a heat lamp in a well ventilated area to dry. The samples
must be dry within 24 hours.
6. The sample can be sent to a reputable soil testing lab for soil nitrate-N analysis.
A reliable field test kit for soil nitrate-N can be used to determine the nitrate-N
level in the sample.
7. Calculate the adjusted N recommendation from the worksheet below.
There are several areas that seem to cause the most problems with the PSNT. First,
many people try to take the test too early. It is important for the test to work
properly that the corn be at least 12" tall at the top of the whorl when you sample.
A second problem related to timing of sampling is taking samples immediately after a heavy
rain. Experience has shown that the test works best if you a allow 2 to 3 days following
a heavy rain before sampling for the PSNT. Sampling too soon after a rain can give a false low reading indicating that there is less nitrogen available than there
really is. Third, and this is the tough one, for the test to work the best the
samples should be taken to a 12" depth. Unlike phosphorus and potassium, nitrate
will readily move deeper into the soil. Everyone complains about this deep sampling but it
could be worse because taking deeper samples would be even better. Some states recommend
2 or even 4 foot deep samples for nitrogen testing. This 12" depth seems to be a
reasonable compromise between optimum accuracy of the test and sampling practicality.
Finally, the samples need to be dried immediately. They should be completely dry
within 1 day of when they are taken. I have seen sample nitrate nitrogen levels
increase by a factor of 2 to 3 times just from sitting around damp over a weekend.
Agronomy Factsheet #17 "Presidedress Soil Nitrate Test for Corn", which explains
the PSNT in detail, is available from Penn State Cooperative Extension offices.
Douglas Beegle
PEST MANAGEMENT
DUAL II, BICEP II, BICEP LITE II, HARNESS, HARNESS XTRA, SURPASS, SURPASS 100, AND
TOPNOTCH CLEARED FOR POSTEMERGENCE APPLICATION TO CORN
Although better late than never, EPA recently granted supplemental labels for postemergence
application of several new chloroacetamide herbicides or herbicide formulations in
corn. These clearances allow postemergence use of Dual II, Bicep II, Bicep Lite
II, Harness, Harness Xtra, Surpass, Surpass 100, and TopNotch in corn. Frontier,
Guardsman, Micro-Tech and Bullet already had this clearance. The following table
is a summary of label restrictions for "broadcast" applications of chloroacetamide products post to corn.
1 May be tank-mixed with Accent, Atrazine (Harness), Banvel or Clarity, Marksman, Permit, or Pursuit (IMI-corn)
2 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.
Bill Curran
POSTEMERGENCE HERBICIDE USE IN SOYBEANS
With the continuing wet conditions and delayed plantings, a postemergence herbicide
program can provide an effective weed control option. When using a POST program
consider crop and weed size, necessary adjuvant(s) and rate, rainfastness, and application
timing restrictions; see Table 2 for more information. Tank mixing
not only broadens the control spectrum, but is generally necessary for planned POST programs; Table 3 shows approved tank mixes.
Keep in mind that certain tank-mix combinations may cause antagonism. In most cases,
grass control is reduced when a broadleaf plus grass herbicide mixture is used.
To overcome this problem either increase the grass herbicide rate or apply the broadleaf
product a day or two after applying the grass herbicide. See current herbicide label(s)
for additional information on herbicide application information and precautions.
TABLE 2. Herbicide application rates, weeds controlled, spray additives, rainfastness, and application timings for postemergence soybean herbicides.
Dwight Lingenfelter and Bill Curran
CORN INSECTS
Continue Watching for Armyworm, Slugs, Cutworm. Armyworm, slugs, and cutworm can continue to be a threat for the next several weeks. Slugs may become particularly
important with the wet, cold weather. See the May 1 Field Crops Newsletter for more
detailed information.
European Corn Borer First Generation Flight and Thresholds. First generation moths
of the European Corn Borer were found in a pheromone trap last week in Centre County.
We can expect the flight to peak throughout the state in the next 3 to 4 weeks,
starting earlier in warmer areas. During 1995, we heard perhaps about more problems from
this insect than in any of the last five years. Field corn growers were reporting
heavy levels of stalk breakage, vegetable growers reported problems in sweet corn
(as always), peppers and snap beans, and potato growers are increasingly concerned. There were even reports of problems last year in New York apples. Although we do not normally treat for Europeancorn borer in field corn in Pennsylvania, it is a good idea to look for the damage. The simplest scouting method is to look for so-called "shothole" damage. The Agronomy
Guide lists a threshold of 75% of the plants with shothole damage as the level at
which treatment is economically justified. However, shothole damage does not give information
on the densities of larvae. The University of Iowa has thresholds for grain corn
based on live larvae (developed here in PA by Dennis Calvin and Bill Bode), and has a handy slide rule device with these thresholds (contact: 517-294-5247, "Integrated
Pest Management of First Generation European Corn Borer", IPM-37). To scout for
first generation corn borer using this midwest method, pull the whorls from at least
ten randomly-selected plants at five locations in the field (at least 100 feet from the
field edge). Divide the total number of larvae by the total number of plants, to
get an average number of larvae/plant. Based on this sample, treatment is economically
justified when the larvae per plant exceed the level shown in the following table,
and based on the chosen crop value and treatment cost. Generally, thresholds are
between 0.4 and 2.1 larvae per plant, depending on crop value and treatment costs.
ALFALFA INSECTS
As of May 29, reports from Franklin and York Counties indicate fairly heavy damage
from alfalfa weevil. Potato leafhopper had not been seen in Centre County, and there
have been no reports of problems from other parts of the state.
Steve Spangler & Dennis Calvin
AGENT OBSERVATIONS
Since my last contribution to Field Crop News, we have had a hard frost, four days
with 90 plus temperatures and more rain. The rain we have received over the Memorial
Day weekend should be great for the alfalfa seedings, the corn and soybeans that
are planted as well as activating pre-emergence herbicides applied during the past weeks.
Local producers have been able to plant the majority of the corn crop in the last
three weeks. Weather conditions have allowed the corn planted in mid-May to be almost
as tall as the corn planted in mid to late - April. The May 14 frost damaged emerged
corn but I haven't had any reports of dead corn plants.
Oats fields are looking fair to good while the wheat and barley have lodged slightly
from the past few days of rain. Foliar diseases on the small grains seem to be at
low levels so far this year.
The alfalfa harvest has begun in our area, a few producers baled some dry hay but
most fields were harvested as haylage or round bale silage. I have had a few reports
of heavy damage from alfalfa weevils. Most alfalfa is in the late bud stage. All
of the grass species have headed out by now with the timothy just coming out over the holiday weekend.
Greg Hostetter
Mifflin - Juniata - Perry Counties
William S. Curran
Associate Professor Weed Science
email: wsc2@psu.edu
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Website Address: http://fcn.agronomy.psu.edu/