Group Title: Agricultural research (Washington, D.C.)
Title: Agricultural research
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Title: Agricultural research
Uniform Title: Agricultural research (Washington, D.C.)
Physical Description: v. : ill. ; 25-28 cm.
Language: English
Creator: United States -- Science and Education Administration
United States -- Agricultural Research Administration
United States -- Agricultural Research Service
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Place of Publication: Washington D.C
Publication Date: February 1998
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Agriculture -- Research -- Periodicals   ( lcsh )
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Statement of Responsibility: U.S. Department of Agriculture.
Dates or Sequential Designation: Began with vol. 1, no. 1 (Jan. 1953).
Issuing Body: Vols. for Jan./Feb.-Nov. 1953 issued by: Agricultural Research Administration; Dec. 1953-<Sept. 1976> by: Agricultural Research Service; <June 1979>-June 1981 by: the Science and Education Administration; July 1981- by: the Agricultural Research Service.
General Note: Description based on: Vol. 27, no. 7 (Jan. 1979).
General Note: Latest issue consulted: Vol. 46, no. 8 (Aug. 1998).
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FORUM


Restoring Stream
Corridors
Interest in restoring stream corri-
dors is expanding nationally and
internationally. More and more news
and feature stories, case studies, and
published papers are discussing
stream corridors as critical ecosys-
tems for thousands of plants and
animals-supporting interdependent
uses and values.
The 1992 National Water Quality
Inventory, which covered about 18
percent of U.S. rivers-nearly
643,000 miles of our waterways-
stated that only 56 percent supported
multiple uses. Such uses include
drinking water, fish and wildlife
habitat, recreation, and agriculture, as
well as flood prevention and erosion
control.
In the remaining 44 percent of
stream miles inventoried, sedimenta-
tion and excess nutrients were seen as
the most significant causes of degra-
dation. Sediment problems resulting
from soil eroding from watersheds
and streambanks do irreparable
damage. The sediment clogs streams
and ditches; bottom lands become
flooded; and, as water quality de-
clines, fish and wildlife habitats
degrade or disappear.
In January 1995, representatives of
the U.S. Department of Agriculture,
U.S. Department of the Interior
(USDI), U.S. Environmental Protec-
tion Agency (EPA), and U.S. Depart-
ment of Defense began a landmark
cooperative effort. Its goal was to
create a common reference document
for federal agencies, interdisciplinary
teams, and others to use in restoring
the nation's stream corridors.
Sixteen federal agencies are now,
in fact, collaborating and pooling their
resources to produce a handbook
titled Stream Corridor Restoration:
Principles, Processes, and Practices.


This is not intended to be a policy
document. Rather, it combines gener-
ally accepted principles of stream
corridor restoration into a single
source, with guidelines for planning
and design. It contains field-tested
methods and approaches that empha-
size the benefits of least-intrusive
solutions to restoring stream corridors
that are both ecologically derived and
self-sustaining.
National geologist Jerry M.
Bernard and national landscape archi-
tect Ronald W. Tuttle, who are with
USDA's Natural Resources Conser-
vation Service (NRCS) in Washing-
ton, D.C., are leading the interagency
team in this effort.
In developing the publication, they
worked closely with experts from
several USDA agencies (the NRCS;
Agricultural Research Service;
Cooperative State Research, Educa-
tion, and Extension Service; and
Forest Service) and several USDI
agencies (the Bureau of Land Man-
agement, Bureau of Reclamation, Fish
and Wildlife Service, National Park
Service, and U.S. Geological Survey),
as well as with the EPA, Tennessee
Valley Authority, U.S. Department of
Housing and Urban Development,
U.S. Army Corps of Engineers,
National Oceanic and Atmospheric
Administration, and Federal Emer-
gency Management Agency.
Nongovernment experts from
universities, consulting companies,
and other organizations were also
contracted to write portions of the
stream corridor restoration document.
Use of the techniques described in
the handbook can help improve many
of the nation's million miles of rivers
that are currently estimated to be
degraded due to erosion, sedimenta-
tion, or excess nutrients. Following
principles described in the handbook,
farmers and land-use managers can
increase streams' water quality and


aesthetic value and maintain agricul-
tural sustainability.
Prescribed restoration activities can
range from simple management
actions like planting grass hedges at
the edge of fields to filter excess
nutrients and sediment from runoff
water to complex problem solving,
such as was done in the Demonstra-
tion Erosion Control project.
This project is an ongoing congres-
sionally mandated collaborative effort
to promote the use of environmentally
sound solutions to correct problems
caused by flooding, erosion, and
sedimentation within the Yazoo River
basin in Mississippi-one of the most
channel-erosion-prone areas in the
United States. [See "Streams of
Conscientiousness," Agricultural
Research, October 1993, pp. 12-13.]
The 700-page handbook will be
available in March 1998 in two forms:
as a printed, loose-leaf publication
that can be easily updated and in an
electronic file on the Internet that will
provide wider access and facilitate
rapid updates and add-ons, as needed.
For more information, access the
Stream Corridor Restoration Hand-
book homepage at http://
www.usda.gov/streamrestoration/

David A. Farrell
ARS National Program Leader for
Hydrology and Remote Sensing


Agricultural Research/February 1998








February 1998
Vol. 46, No. 2
ISSN 0002-161 X


Agricultural Research is published monthly by
the Agricultural Research Service, U.S.
Department of Agriculture, Washington, DC
20250-0301.
The Secretary of Agriculture has determined
that this periodical is necessary in the transac-
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Dan Glickman, Secretary
U.S. Department of Agriculture
I. Miley Gonzalez, Under Secretary
Research, Education, and Economics
Floyd P. Horn, Administrator
Agricultural Research Service
Ruth Coy, Acting Director
Information Staff
Editor: Lloyd McLaughlin (301) 344-2514
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Agricultural Research



Natural Environmental Protection Agents 4

Biofilms Less Likely on Electropolished Steel 1 U

Keeping Freshness in Fresh-Cut Produce 12

IntelliGin-Improved Cotton Ginning Technology 15

INTERBULL Shows How U.S. Bulls Stack Up 16

Pigeonpea, a Summer Legume for Wheat Growers 1 7

New Process Improves Wheat Flour Separation 1 7

Starry Sky Beetle 1 08

Science Update 19







Cover: Soil scientists Harry Pionke (left) and Ron Schnabel examine a switchgrass
stand. Relatively small buffer areas not only can protect nearby streams from
agricultural pollutants, but also provide habitat for ground-nesting birds and forage
for beef cattle. Photo by Scott Bauer. (K7956-15)





In the next issue!


(*- Biotechnology Research and Development Corpora-
tion-marking the 10th year of a public-private partnership
that really works.

(- A new mechanical harvester being tested in Florida
could revolutionize the U. S. citrus industry and give
growers an edge over competition from imported orange
juice.

a- There are recommended dietary allowances of nutri-
ents for teenagers and for women nursing a baby. But
should there be special nutritional guidelines for teenage
nursing mothers? Some preliminary research suggests it
might be a good idea.


Agricultural Research/February 1998






BRIAN PRECHTEL (K7952-5)


quiet stream or creek can
make for pleasing
scenery, especially
during the fall, as the trees' leaves
blaze a fiery orange. But there is
more at work here than just natural
beauty. These forest buffers protect
the stream water by removing
pollutants in farm runoff.
Historically, farmers have cleared
these riparian areas to make more
room for growing crops. Urban
sprawl has also claimed its share,
compromising water quality in the
process. According to a U.S. Envi-
ronmental Protection Agency survey
released last year, pollution is a seri-
ous problem in 21 percent of the na-
tion's 2000 or so watersheds. Agri-
culture's part in this is substantial.
But now, a new trend in farming is
taking root. It calls for restoring the
land closest to streams, rivers, and
other vulnerable waterways with
plantings of native vegetation. It's a
form of environmental stewardship
farmers are embracing. For these
natural buffers protect stream water
by capturing much of the sediment,
nitrogen, phosphorus, and other
agricultural chemicals borne in runoff
or groundwater.

Installing Buffers
Ecologist Richard Lowrance of
USDA's Agricultural Research
Service has been studying these
riparian buffer zones for over 20
years and is a firm believer in their
importance to ensuring safe, clean
water.
"The challenge now is to re-
establish buffers where they no
longer exist and to maintain the ones
we do have," says Lowrance, who is
based at ARS' Southeast Watershed
Research Laboratory in Tifton,
Georgia. A similar philosophy is
behind the National Conservation


To measure nitrogen runoff in the Pacific northwest, plant physiologist Steve Griffith
collects water samples from a monitor well inside the riparian zone near the Calapooya


River.

Buffer Initiative program, which
USDA's Natural Resources Conser-
vation Service (NRCS) established
in 1997.
Lowrance and other ARS re-
searchers studying riparian zones
work on or near heavily farmed
watersheds. This places them in the
heart of the action, helping farmers
adapt buffer conservation strategies
to their regions' specific soils,
climate, topography, and hydrologi-
cal patterns.


In Mississippi, for example,
springtime rains can cause runoff so
powerful that it carves deep gullies
in valuable farmland-deep enough
for a grown man to stand in. Erosion
pulls valuable topsoil off the land,
dragging it into lakes and streams
where it becomes a pollutant. If
farmers want government aid, they
must develop a conservation plan to
address the problem.
For the past 50 years, farmer
have used grass waterways-which























































look like waterlines during a heavy
rainstorm but otherwise appear to be
just patches of tall grass. Water
always seeks the land's lowest level,
and these pathways protect the soil
and slow the flow down just enough
to prevent a gully.
In 1993, the NRCS invited eight
states to evaluate grass hedges as an
alternative form of erosion control,
based on that agency's interim
national standards. Hedges are dense
patches of thick-stemmed grasses

Agricultural Research/February 1998


that stand strong against the deluge,
trapping sediment. Last year Missis-
sippi became the first state to adopt
grass hedges as an approved erosion
control technique.
Unlike the waterways, hedges
slow runoff like water running
through a fine-mesh sieve. They are
arranged in narrow strips, like ladder
steps. They don't follow a pathway
straight down. Soil accumulates just
above the strips and erodes slightly
just below them.


"One good thing about grass
hedges is farmers can work around
them," says ARS agronomist Seth M.
Dabney. "If they're tilling, all they
have to do is drive the tractor be-
tween the hedges. But grass water-
ways can be damaged by tillage, so
farmers should raise their tractors'
equipment before going over them."
Dabney, who works at ARS'
National Sedimentation Laboratory in
Oxford, Mississippi, tested various
thick-stemmed grasses as hedge
makers. He found that two native
American grasses, switchgrass and
eastern gamagrass, were the top
performers.
"Switchgrass and gamagrass are
both native plants," says Dabney.
"They're not going to upset the
natural ecosystem balance or become
an invasive weed."
Dabney says the plants could also
be used to stem erosion on road and
building construction sites. Because
they are attractive plants, he adds,
they could be left behind as part of
the landscaping.
Vetiver, an Asian grass, has poten-
tial for erosion control in the south-
ernmost part of the United States,
such as south Texas and Florida, and
for some U.S. territories.

Grass Hedges-Plus
Hedges are more effective when
used with other soil conservation
methods.
Dabney's colleague, agricultural
engineer Keith C. McGregor, found
that hedges reduced runoff in conven-
tionally tilled soils. The most effec-
tive plan, however, was using no-till
methods and hedges together. A no-
till crop without hedges, but with a
winter wheat crop, came in a close
second.
All of these conservation methods
helped lessen runoff. Worst by far
was using conventional tillage alone.













"The thing we need to do now is
test grass hedges to find out their
maximum potential and their limita-
tions," says McGregor. "Everyone
agrees they slow erosion down, but
we need to be sure about what they
can and can't do."
"Tilling, which is basically just
stirring the soil, is great for weed
control, so you don't need as much
pesticide," says Dabney.
"Many farmers won't or can't give
it up. The good news from this study
is that if they feel they must till, they
can be confident that planting grass
hedges will help reduce erosion."

The Grass Is Just as Green in
Nebraska
John E. Gilley, an agricultural
engineer in the ARS Soil and Water
Conservation Research Unit at
Lincoln, Nebraska, also conducts
research on grass hedges. His col-
league, researcher Larry A. Kramer,
works at ARS' National Soil Tilth

JOHN GILLEY (K7965-1)


Laboratory in Ames, Iowa. Their
studies measured sediment loss on
cropland farmed under two different
tillage systems: minimum tillage and
no-till.
Using a rainfall simulator, they
first measured sediment loss on bare
cropland that had been planted with
corn the previous few years. They
compared the amount of soil loss
from this field to that from fields
with grass hedges 2 feet wide and
about 6 inches high.
"The narrow grass hedges reduced
sediment delivery by 45 percent on
the no-till treatments and 75 percent
on the tilled plots," says Gilley.
"This means a substantial amount of
sediment is being trapped by the
hedges along the hillslope that would
otherwise have been transported
down."
The ARS scientists say the narrow
grass hedges also are a cost-effective
alternative to more expensive tech-
nologies, such as terraces. Terraces


At the USDA Deep Loess Research Station near Treynor, Iowa, a rainfall simulator is used
to evaluate the effectiveness of grass hedges in removing sediment, nutrients, and herbicides
from runoff. Water samples are obtained from collection units above and below the grass
hedges.


soil scientist Kon Schnabel (lett) and
technician Chad Penn check a water
sample collected at the outlet of a
watershed with both forested and grassed
riparian buffers. The impact of riparian
zone management on water quality can best
be evaluated within streams of treated
watersheds.


cost about $330 per acre to install;
grass hedges cost about $30 per acre.

The Buffer's Unsung Heroes
Helping farmers protect stream
water using grass buffers also is a
major goal of soil scientist Ron R.
Schnabel at ARS' Pasture Systems
and Watershed Management Re-
search Laboratory in University
Park, Pennsylvania.
Of particular interest to Schnabel
is what happens beneath the soil-
especially among the roots of grass
and forest buffers. There, soil-
dwelling bacteria consume nitrate
and other nutrients from excess
fertilizer and manure that has
leached into shallow groundwater.
Nitrate leaching is of special
concern in Pennsylvania, says
Schnabel, because of the state's
prominence in the Chesapeake
region and the highly porous layers

Agricultural Research/February 1998


4
i4













of lime, shale, and sandstone bed-
rock beneath the soil surface.
For their part, the bacteria help
protect stream water by converting
the soil's store of nitrate into atmos-
pheric nitrogen, a process called
denitrification. In low-lying farm
areas, denitrification processes
within a buffer can help remove up
to 50 percent of the nitrate, says
Schnabel.
But these helpful bacteria require
more than nitrate alone. They need
energy stored in organic carbon in
the form of sugars, amino acids, and
other things that seep from plant
roots or decomposing material in the
soil. Oxygen must also be scarce.
Without these conditions, the
bacteria may not proliferate, and the
buffers lose their ability to control
nitrate losses.
Another of Schnabel's goals is to
identify species of cool- and warm-
season grasses that will foster a
thriving microbial community. He's
now conducting studies to that end at
six experimental sites in Pennsylva-
nia, New York, and New Jersey in
cooperation with NRCS scientists.
"We're looking at the soil organic
matter under warm-season grasses,
cool-season grasses, and wooded
areas," says Schnabel. "One question
we want to answer is: Do any of
these vegetation types offer an ad-
vantage in fostering denitrification?"
With a grass buffer, he adds,
"farmers also have the option of
harvesting it as feed."
On another front, the ARS lab is
teaming up with NRCS and Pennsyl-
vania State University scientists to
map watershed hot spots. These
include areas where nutrients like
phosphorus can most easily wash
from crop fields or pasture into
stream systems and rivers like the
Susquehanna.
"Phosphorus loss to streams is
primarily a surface runoff phenome-

Agricultural Research/February 1998


.- -





Soil scientist Marife Corre prepares to
analyze soil samples from a riparian buffer.
The carbon and nitrogen status of riparian
zone soils indicates their potential to
remove nitrate from shallow groundwater
and to improve water quality.


non," notes Andy Sharpley, ARS'
principal scientist on the project.
"We're trying to identify regions in
watersheds where riparian buffers are
most likely to have an impact on
nutrient losses to streams."
The Susquehanna is of particular
interest because it eventually feeds
into the Chesapeake Bay. If nutrients
go unchecked, the Susquehanna-
more than any other river in Pennsyl-
vania-is likely to pollute the bay's
delicate ecosystem.
"That makes people take notice,"
says Sharpley.

Of Farms and Pfiesteria
Most recently, that fragility came
to public and scientific attention with
outbreaks of Pfiesteria piscicida, or
Pfiesterialike organisms, in several
tributaries of the Chesapeake along
Maryland's Eastern Shore. Biologists
are now taking a close look at the role


of runoff from crop fields on the
peninsula, where nutrient-rich
chicken manure is used as fertilizer.
A dinoflagellate with many
different forms, Pfiesteria in its most
aggressive state produces toxins that
kill fish. It is the culprit behind fish
kills in waterways of Maryland,
Virginia, North Carolina, and other
Atlantic seaboard states.
For better or worse, last summer's
outbreaks on the Eastern Shore lent
urgency to a new, $200 million, State
Enhancement Program by the USDA
and the state of Maryland. An-
nounced in October, the 15-year
program calls for the establishment
of buffers along 5,000 miles of
streams and other sensitive water-
ways in Maryland by the year 2002.
Whether in the form of grass
hedges, filter strips, or forest buffers,
Lowrance agrees that "if we're going
to improve water quality in agricul-
tural areas, we'll have to start at the
streams and work our way back."

Zoning Out in Forest Buffers
Since the mid-1980s, Lowrance
has been at the forefront of ARS
studies using both natural and
managed riparian forest buffers. The
NRCS defines a managed forest as
having three zones. In essence, they
are mimics of nature's own design,
notes Lowrance.
The first zone extends at least 15
feet from the streambank and is
planted with native species of
hardwood trees. This zone is a
permanent planting and should be
left untouched, except for the remov-
al of select or fallen trees.
The second zone, at least 20 feet
wide, can be planted with conifers,
hardwoods, or shrubs, depending on
the landowner's preference. It can be
managed for timber or other forest
products, as long as zone one isn't
affected. The third zone, the one













closest to the crop field, is a grass
filter strip. It traps sediment and
disperses runoff leaving the field in
channels.
Lowrance and colleagues at ARS
and the University of Georgia at
Tifton have conducted many studies
testing the effectiveness of buffer
design on the coarse alluvial soils of
the 129-square-mile Little River
Watershed, in Georgia's Tift, Turner,
and Worth Counties.


Aerial view of the Calapooya River and the
forested riparian area next to a turf grass
field near Corvallis, Oregon.

In one study, conducted from 1992
to 1994, the scientists tracked the
movement of two common herbi-
cides, atrazine and alachlor. Each
March, they applied the herbicides to
a cornfield bordered at its lowest end
by a 150-foot grass and forest buffer.
After the experiment's first year, they
clearcut one block of the field's forest
buffer, thinned another, and left intact
a third block of mature forest closest
to the stream.
The scientists measured the
concentration of the chemicals in
each block throughout the year. Their
results showed virtually equal con-


centrations among the three block
treatments.
"This showed us that both the
riparian forest buffer and the grass
filter were effective at removing the
herbicides from surface runoff during
storms and from shallow groundwa-
ter," says Lowrance.
Compared to herbicide concentra-
tions of 34 parts per billion (ppb) at
the field's edge, the scientists detect-
ed the chemicals at concentrations of
only 1 ppb or less near the stream.
The findings suggest that portions
of riparian forest can be harvested for
timber without compromising the
buffer's integrity. Selective cutting
can also promote regrowth.

A High-Tech Component
Not all of the Tifton research takes
place along streams, creeks, and
other waterways of the Little River
Watershed. Now, scientists can also
run computer simulations from their
lab, using software they developed
called REMM-short for Riparian
Ecosystem Management Model.
With this software, they can
simulate the movement of water,
nutrients, sediment, and carbon in
runoff or groundwater passing
through a buffer. They can also test
the effectiveness of a particular
buffer design against different soil
types, land elevations, or fertilization
practices.
REMM "gives you a tool for
predicting what's most likely to
happen, which is better than a seat-
of-the pants guess as to how wide a
buffer should be," says one of the
model's developers, ARS agricultural
engineer Randy Williams, who is
based at Tifton.
His colleagues, ARS soil scientist
Robert K. Hubbard and university an-
imal scientist G. Larry Newton, will
put REMM to work this spring when
they conduct a pilot study at a com-


mercial hog farm in Tift County.
Their study calls for applying a liq-
uid form of hog manure, called efflu-
ent, directly to a grass and pine for-
est buffer on the farmer's property.
Effluent provides farmers with a
cheap source of fertilizer for crops.
"But it's more difficult to control
nutrients in the manure than it is in
commercial fertilizer," notes
Lowrance.
Study results could show whether
surplus manure can be used to
fertilize the buffer's trees and grasses
for harvest, without allowing nutri-
ents to wash into nearby waterways.

Safeguarding Oregon's Fisheries
While Lowrance's research has
focused on riparian wetland buffers
in well-drained watersheds of the
southeastern United States, little
work has been done to determine
how effectively the buffers work on
poorly drained soils in the West.
To help answer this question,
plant pathologist Stephen M. Griffith
and colleagues at Corvallis, Oregon,
have been conducting studies for the
last several years on poorly drained
soils in western Oregon. In 1995,
they began monitoring nitrogen
movement in groundwater from
grass seed fields through a riparian
zone bordering Lake Creek in the
southern Willamette Valley.
About half of all the cool-season
forage and turf grass seed in the
world is grown in the Pacific North-
west. The reason: The poorly drained
soils won't support traditional crops.
To grow ryegrass and other seeds,
however, farmers usually have to
add from 125 to 210 pounds of
nitrogen per acre per year-creating
potential for nitrogen runoff in
surface and groundwater, Griffith
says.
"There is a lot of concern about
ground and stream water quality in


Agricultural Research/February 1998


























At tne Lake Ureek riparian test area
located next to a turf grass field near
Corvallis, Oregon, scientists evaluate
grass hedge and tree buffers. Note white
pipes used in sampling shallow
groundwater in left background.

the Pacific Northwest, with respect to
salmon and trout and safe drinking
water," Griffith says. "Little is
known of how nonpoint-source water
pollution is related to agricultural
practices."
So in 1995, the scientists enlisted
the help of local grower Don Wirth,
who planted perennial ryegrass on
waterlogged clay soils near Lake
Creek.
The ryegrass was fertilized in the
fall of 1995 and again in late winter
1996. A 100-foot-wide riparian zone
of three grasses-tall fescue, mead-
ow foxtail, and velvetgrass-buffered
the ryegrass field from the creek. The
riparian zone had not been cultivated
since 1975.
To measure waterflow beneath the
soil surface, the researchers installed
18 wells, ranging about 3 to 5 feet
deep, in three lines from the creek
through the riparian zone and up to
the edge of the cultivated ryegrass
field. Oregon State University and
EPA scientists also participated in the
experiment. The group collected
water samples every 14 days from
September 1995 to April 1996.
During that time, 36 inches of rain
fell-just under the 30-year average
of 37 inches.

Agricultural Research/February 1998


The scientists found that the
ryegrass crop used most of the total
nitrogen fertilizer applied. The
riparian zone helped use up the rest of
the nitrogen as groundwater carried it
from the ryegrass field toward the
creek.
"This study shows that established
riparian buffers can really help soak
up excess nitrogen-even in poorly
drained soils," Griffith says.
Studies like this show that nature's
buffers and wetland areas do have an
important role to play in today's
agriculture. "But we'll never want to
give people the impression that
buffers are substitutes for sound
agricultural practices," cautions
Lowrance.
"In order to reduce water quality
problems, we're going to have to do
everything together," he says. "That
means using buffers in concert with
practices like integrated pest manage-
ment, nutrient management, and no-
till."-By Jan Suszkiw, ARS. Jill
Lee, Dawn Lyons-Johnson, and
Sean Adams of ARS contributed to
this story.


Richard Lowrance and Robert K.
Hubbard are at the USDA-ARS
Southeast Watershed Research
Laboratory, P.O. Box 946, Tifton, GA
31793; phone (912) 386-3462, fax
(912) 386-7215, e-mail
lorenz @tifton.cpes.peachnet.edu or
hubbard@ tifton. cpes.peachnet. edu
Stephen M. Griffith is with the
USDA-ARS National Forage Seed
Production Research Center, 3450
SW Campus Way, Corvallis, OR
97331-7102; phone (541) 750-8742,
fax (541) 750-8750, e-mail
griffits@ucs.orst.edu
Ron R. Schnabel is at the USDA-
ARS Pasture Systems and Watershed
Management Research Laboratory,
Curtin Rd., University Park, PA
16802-3702; phone (814) 863-0939,
fax (814) 863-0935, e-mail
rrs7@psu.edu
Seth M. Dabney is at the USDA-
ARS National Sedimentation Labora-
tory, Upland Erosion Processes
Research Unit, 598 McElroy Dr.,
Oxford, MS 38655; phone (601) 232-
2975, fax (601) 232-2915, e-mail
dabney@sedlab.olemiss.edu *


BRIAN PRECHTEL(K7951-9)


Technicians Rick Caskey and Shirley King collect water samples from monitor wells in a
turf grass field near Corvallis, Oregon.








Bacterial Biofilms Less Likely on

Electropolished Steel


:,; ; hen the news came out
:; that stainless steel can
harbor bacterial biofilms,
a Dallas, Georgia, company decided
to test its metal against other materi-
als. The results were good news for
anyone wanting to reduce bacterial
cross-contamination in poultry.
Cross-contamination occurs as
poultry is processed and bacteria from
carcasses attach to wet steel surfaces
on processing equipment. When the
bacteria accumulate, they develop an
increasingly complex matrix by
attaching to each other and forming a
bacterial film that stubbornly resists
normal washing.
Wayne Austin is vice president of
Simmons Engineering Company. The
firm specializes in poultry processing
machines. Austin knew that ARS'
Judy W. Arnold was testing various
kinds of steel for resistance to bacteri-
al attachment. So he asked her to
include his company's electropol-
ished steel as part of her research
protocol.
Test results showed that the
process developed by Simmons to
give their machine steel a shiny,
chromelike appearance also kept
bacteria at bay.
Arnold, a microbiologist in the
ARS Poultry Processing and Meat
Quality Research Unit at Athens,
Georgia, found surface finishing
treatments such as polishing, sand-
blasting, and grinding all reduced
buildup of bacterial biofilms. But
eletropolishing seemed to work the
best.
Electropolishing involves placing
steel in an acid bath, then running an
electric current through the solution.
Arnold has a theory about why this
prevents bacterial biofilms: The
process may change the electrical
charge on the metal. Bacteria are
negatively charged, and the charge on
a given surface can affect how well
they attach to it.


Arnold's findings are important.
One reason is that the federal HACCP
(Hazard Analysis Critical Control
Points) inspection policy requires all
meat producers to identify potential
contamination areas and take preven-
tive measures. The findings are
especially important to the poultry
industry because of the fast-paced
production.
"Some of our evisceration ma-
chines can process 90 to 140 birds a
minute," says Austin.
"If eletropolishing can prevent the
cross-contamination of bacteria
between birds and the buildup of
bacteria over time-that's an impor-
tant quality control."
But it's not just equipment manu-
facturers who worry about cross-
contamination. ARS sponsored a
special forum on poultry research at
which Arnold presented findings that
caught the attention of Michael
Robach, vice president of food safety
at Continental Grain.
Headquartered in Gainesville,
Georgia, Continental Grain is the
sixth largest broiler producer in the
United States. The company distrib-
utes 1.2 billion pounds of ready-to-
cook meat and 100 million pounds of
ready-to-eat chicken each year.
Robach says he plans to use
Arnold's slides of bacterial biofilms
on steel to make a point when train-
ing plant managers on sanitation and
safety.
"We want to show them that just
because a steel surface looks clean
doesn't mean it's bacteria-free," he
says. "Our safety protocol includes
using chlorine dioxide to disinfect,
and we replace our processing
equipment regularly."
Arnold says the surface treatments,
scouring and others, could be more
effective than some cleansers and
may also reduce the amount of
chemicals required to keep plants
sanitary.


"I think industry executives get
tired of people throwing chemicals at
them as the only solution to Salmo-
nella," says Arnold. "What I have to
offer will be an effective part of
contamination prevention-perhaps
with reduced environmental impact."
Arnold says she now plans to
explore how and where various
bacterial species develop biofilms in
processing plants. She will also
SANDRA SILVERS (K7970-4)


As bacteria accumulate on surfaces, they
exude a complex matrix of fibrils that
connect cells, and many bacteria align side
to side. Magnified about 2,500x.


explore new chemical pre-treatments
to prevent biofilms.-By Jill Lee,
ARS.
Judy W. Arnold is in the USDA-
ARS, Poultry Processing and Meat
Quality Research Unit, Russell
Agricultural Research Center, 950
College Station Rd., Athens, GA
30604; phone (706) 546-3515, fax
(706) 546-3548, e-mail
jarnold@negia.net *


Agricultural Research/February 1998







Most of the surfaces in a
food processing plant are
made of stainless steel that
is susceptible to bacterial
attachment, as seen here.
Magnified about 500x.


When bacteria attach to a
surface, they produce
extracellular polymers that
anchor the cells and provide a
favorable site for attachment
and growth of more bacteria,
other microbes, and debris.
Magnified about 10,000x.


Slainless %leel that has been eleclropolished shous
significanlfl Ifeer bacterial cells and beginning biofilni
I'ormalions. Magnified about 700\.


'the bacterial composite forms a biofilm
that is resistant to cleaners and sanitizers.
Magnified about 1,500x.


Agricultural Research/February 1998







Keeping Freshness in Fresh-

Cut Produce


J uicy, sliced strawberries,
diced beets, quartered
tomatoes, slivered bell
peppers, and chopped celery-
nutritious, fresh-cut fruits and vegeta-
bles for salad bars and individual and
family servings-are not just for
restaurants. Nearly all major grocery
chains are now carrying them. In great
demand by health-conscious North
Americans, fresh-cuts are also becom-
ing more popular in Europe and Asia.
Sales of fresh-cut produce-a
mushrooming industry-are expected
to skyrocket to $19 billion by 1999.
Packaged salads alone brought $889
million in 1995, with 8 out of 10
consumers surveyed buying them.
"Maintaining quality of fresh-cut
and intact produce is a major concern
of the industry and a top ARS prior-
ity," says Kenneth C. Gross. A plant
physiologist, Gross heads the ARS
Horticultural Crops Quality Laborato-
ry (HCQL) in Beltsville, Maryland.
"Industry has been searching for
alternative methods to protect fresh-
cuts from decay and to prolong shelf
life," he says. "Our scientists have
discovered natural ways to reduce
deterioration and decay and extend
the shelf life of produce without the
use of undesirable chemicals." [See
"Cut-Ups!" in Agricultural Research,
January 1997, pp. 20-21.]

Using Natural Compounds
Fresh fruits and vegetables, wheth-
er whole or cut up, must be kept at
temperatures between 320F and 50F
to reduce the chance of bacterial and
fungal attack.
"Cool temperatures keep some
harmful microorganisms at bay, but
the cold can also cause injury," says
Chien Yi Wang, a horticulturist at the
HCQL. "Although the tissue is still
living, it is weakened by an inability
to carry on normal metabolic process-
es. And symptoms of chilling injury,


such as pitting or other skin blem-
ishes, become evident when the
produce warms up."
Wang has successfully used many
treatments to alleviate such damage.
But his best success came when he
found that sweet-smelling methyl
jasmonate protected zucchini
squash, sweet peppers, and grape-
fruit from chilling injury and
doubled their shelf life.
"Jasmonates were first detected as
fragrant compounds of essential oils
in plants of the genus Jasminum,"
says Wang. "This group of
natural compounds is found KEITH W
in all plants, but in significant Ns'
amounts in jasmine and
honeysuckle.
"We knew that many of
the physiological responses
to jasmonates are similar to
the effects of abscisic acid,"
he says.
Levels of that plant
hormone, which stimulates
the natural separation of
leaves and flowers from
parent plants, increase when
plants are subjected to
environmental stress. "In
several plant species, abscisic s
acid also increases protection To dei
against chilling injury," says hortic
Wang. "We thought that elasti
methyl jasmonate might
induce a similar response."
Subsequent research with HCQL
chemist J. George Buta showed that
methyl jasmonate may reduce
chilling injury by regulating levels
of abscisic acid and polyamine
compounds produced from amino
acids that stabilize plant cells.
Squash treated with methyl jas-
monate showed no deterioration
from cold-storage temperatures for
up to 8 days, while untreated squash
started to deteriorate after just 4
days.


How Does Methyl Jasmonate
Work?
"Well, it's a fascinating com-
pound," Buta says. "Chemically, it's
associated with environmental stress.
Apparently it's produced because of
the stress and somehow serves as a
signal, in the form of a chemical
vapor, to turn on natural defense
mechanisms."
Buta says that methyl jasmonate
elicits compounds in living plants
that make them more resistant to
temperature changes and attack by


termine the overall textural quality of a tomato,
ulturist Judith Abbott measures the fruit's
c and viscous properties.


insects, bacteria, and fungi. He
thinks it turns on nucleic acid
synthesis, which results in producing
defense proteins. These proteins, in
turn, cause the production of antifun-
gal or antibacterial compounds. And
methyl jasmonate elicits the same
response in harvested produce,
which is still-living tissue, as it does
in growing plants.
Produced commercially, methyl
jasmonate is relatively inexpensive,
and only small amounts are needed
to be effective.


Agricultural Research/February 1998






KEITH WELLER (K7945-2)


"You can buy 25 milliliters-
not quite an ounce-for about
$30. This is enough to treat
truckloads of produce. Also, it
acts quickly-within a couple of F
hours after application," Buta U
reports, "and leaves no residue."
Produce should be treated at
about room temperature (68F).
Application can be either by vapor or
use of a wick in a closed container.
HCQL plant pathologist Harold E.
Moline exposed strawberries to
methyl jasmonate vapor for 24 hours
at 681F and controlled gray mold,
Botrytis cinerea, a major fungal
disease of postharvest fruits and
vegetables, for up to 14 days in
storage.
"Methyl jasmonate not only
reduced the mold, but it enhanced
the flavor of the strawberries as
well," Moline says. "And treatment
didn't affect the firmness of the
fruit."
Refrigeration and modified
atmospheres are now used to fight
fungal decay of strawberries. But
gray mold is still a problem with
these methods.
Buta and Moline also treated
fresh-cut celery and green peppers
with methyl jasmonate vapor.
Treatment eliminated browning and
decreased bacterial growth a thou-
sandfold on both products for up to 2
weeks at 500F. It controlled soft rot
on the peppers.
Buta and Moline have successful-
ly used methyl jasmonate to slow
down grey mold on grapes.
"Using too much could be detri-
mental and hasten deterioration,"
Buta cautions. "But if the right
amount is used, under proper storage
conditions, methyl jasmonate may be
a practical treatment to ensure the
safety of many fresh-cut and whole
fruits and vegetables."
The scientists have been just as
successful with other natural com-

Agricultural Research/February 1998


lant pnysioiogist Ken tross examines tomato truit
ised in the beta-galactosidase genetic engineering
research program.


pounds. For example, a banana turns
brown almost as soon as you cut it,
making it one of the most difficult
fresh-cut products to protect from
deterioration. For this reason,
bananas can't be used in salad bars.
But Buta and Moline have suc-
ceeded in keeping banana slices from
browning for 2 weeks and have also
reduced microbial growth.
"Using a mixture of citric acid and
N-acetylcysteine-a common,
sulphur-containing amino acid-we
kept banana slices for 14 days at
400F," Buta reports. "They didn't


KEITH WELLER (K7947-12)


In studies aimed at maintaining quality of
whole and fresh-cut produce, visiting
Korean scientist Ji Heun Hong (right) and
technician Norman Livsey measure the
respiration and ethylene production of
tomatoes treated with a naturally occurring
volatile.


I brown." This research finding
allows bananas to be marketed as
fresh-cut.
In other, preliminary studies,
the treatment also kept fresh-cut
slices of apple, pear, peach, plum,
nectarine, and avocado from
browning and reduced their
decay. In fact, it worked better than
the treatments that industry is now
using. Treated apples held up well for
as long as 50 days in cold storage,
and in all cases, flavor was not
affected.

But What About Texture?
An important aspect of the fresh-
cut industry that, to date, has been
given little research attention is that
of texture-for both fresh-cut and
intact produce.
"Texture is vitally important,"
says Judith A. Abbott, an HCQL
horticulturist. "To test a tomato's
firmness, we squeeze it. But we need
a better guide to firmness if the fruit
is intended for the fresh-cut market,"
she says.
"Fresh-cut produce must have a
reasonable shelf life-time to move
through the commercial distribution
system. The time between when
produce is cut and when it is con-
sumed is very important. If not ripe
enough, it won't taste good. But if
the product is cut at too ripe a stage,
then it will deteriorate even more
rapidly."
Although tomatoes or cucumbers
in the produce bin may have been
pulled from the vine several days
before purchase, they are still living
and undergoing biological processes,
such as ripening. Cutting them opens
a Pandora's box. A cut is a wound:
Wounds make produce ripen faster
and increase its susceptibility to
attack by pathogens.
All of these factors greatly affect
produce texture.












Abbott is investigating the texture
of fresh-cut tomato slices. She has
used different types of probes and
developed measuring methods with a
force-deformation testing machine to
test the firmness of different tomato
varieties.
"The fruit needs to be firm enough
to withstand mechanical handling.
And commercial slicing machines
literally throw a tomato against the
slicing blades," Abbott says. "But
once the tomato is sliced, it keeps
changing. In fact, it continues to ripen
right up to the moment you eat it."
The method now used to test whole
tomato firmness can't be used for
slices. Besides, the mechanical
properties sensed by your hand when
you squeeze a whole tomato and
those sensed in your mouth when you
eat it are quite different. Different
methods are needed to evaluate the
eating quality of tomato slices and
wedges, as well as other cut produce.
With the fresh-cut industry grow-
ing at a rapid pace, volume of pro-
duce handled makes it impossible to
hand slice. Therefore, the food
industry needs varieties that can
withstand a little rough handling but
still end up with good eating texture.
Abbott and Gross are looking at
different genetic lines for varieties
that best suit the fresh-cut industry.
Abbott is also reviewing different
ways to sanitize and handle produce
after it has been cut to ensure that
texture is maintained. In addition to
tomatoes, she is experimenting with
whole and cut apples, cantaloupes,
honeydews, and watermelons.

Manipulating Genes
Along with Gross, David Smith is
taking a different approach to the
texture issue. A molecular biologist at
HCQL, Smith has just cloned part of
a gene responsible for making a
protein, which is an enzyme, that
breaks down the cell wall in toma-


KEITH WELLER (K7946-5)


w*


i


To prevent browning and microbial
growth, fresh-cut peach slices were dipped
in naturally occurring compounds, amino
acids, isoascorbic acid, and sorbate. The
darker peach slices were not treated.


Horticulturist Chien Yi Wang (left) and
technician Hilarine Repace evaluate
chilling injury of cucumbers and zucchini.


toes. This cellular activity may cause
some softening, which leads to
texture changes that could end in
deterioration and decay.
"There is a critical relationship
between texture and quality and
postharvest shelf life," Smith says.
"And although other processes are
involved in fruit softening, the
breakdown of the structure of the cell
wall is probably the most critical."
As tomatoes ripen, their cell walls
go through several changes generated
by many enzymes. According to
Smith, these enzymes include a group
called beta-galactosidases. He has
identified and cloned a family of
seven beta-galactosidase genes in
tomatoes that includes the gene
responsible for degrading cell wall
structure.
"We're collaborating with two
research groups in the United King-
dom to study the particular role of the
gene involved in fruit softening,"
says Smith. "We're not sure just what
the functions of the other genes are."
Smith is considering potential
possibilities for using the cloned
gene. "We can use the antisense
approach, whereby we put the gene
back in the opposite way it originally
was, to knock out its function," he
says.
"Or we can use co-suppression, in
which we add back multiple copies of
the gene that tells the plant to shut off
all functions associated with these
added genes. No one has figured out
yet how this works; it just does."
According to lab director Gross,
"We expect to have transgenic plants
within a year."-By Doris Stanley,
ARS.
Scientists in this article can be
reached at the USDA-ARS Horticul-
tural Crops Quality Laboratory,
Bldg. 002, 10300 Baltimore Ave.,
Beltsville, MD 20705-2350; phone
(301) 504-6128, fax (301) 504-5107;
e-mail kgross@asrr.arsusda.gov *


Agricultural Research/February 1998








IntelliGin-

Improved Cotton Ginning Technology


H igh-quality cotton can come
at high costs to the farmer
and, ultimately, the con-
sumer. One reason is that all cotton
goes through the same cleaning and
drying sequence-without regard to
differences in moisture content,
color, or foreign matter. The result:
lower quality cotton and higher loss
of lint.
Improved ginning technology
developed by ARS scientists may
soon correct this.
"We have developed a computer-
ized system to automatically measure
the quality of cotton at various stages
of gin processing," says W. Stanley
Anthony, who heads the U.S. Cotton
Ginning Research Unit at Stoneville,
Mississippi. [See also "Improved
Ginning for Better Cotton," Agricul-
tural Research, December 1992, pp.
16-18.]
"Sensors determine the quality of
incoming cotton and send the infor-
mation to a computer. Once the color
of the cotton, foreign matter, and
moisture content are known, the
software decides the best sequence of
machine-cleaning and drying to get
the best market quality and value."
The gin process control system
also considers the performance
characteristics of gin machinery, such
as foreign matter removal, fiber loss,
and fiber degradation.
The system allows ginners to
customize their ginning process for
each farmer so as to increase farmer
profits. For instance, if a farmer
knows the market price for various
grades of cotton in advance, the
ginner can integrate the actual market
price with initial cotton quality
information and determine the
sequence needed to optimize dollar
returns for that farmer.
Before this invention, assessing
the effect each ginning process would
have on cotton properties was nearly


Agricultural Research/February 1998


impossible. Now, the new gin
control system determines when
cotton needs two lint cleaners and
when it needs only one. It also uses
the pricing schedule of whatever
merchant is going to handle the
cotton for the farmer.
"It prepares the cotton to meet
market prices," says Anthony.
Research at field gins from 1994
to 1997 shows that finetuning
ginning operations nets cotton
farmers additional profits of $10 to
$20 per bale. One gin in Alabama
increased returns to farmers by
$16.72 per bale on about 42,000
bales in 1994, worth over $700,000.
In 1995, the increased per-bale
return was $21.
And the process control system
saves the ginner nearly $1 per bale
in reduced energy costs.
Anthony and others at the
Stoneville lab developed eight
different patents involving the
process control system. ARS
agricultural engineers Richard Byler
and Oliver McCaskill, who is now
retired, are co-inventors on some of
them.
The patents cover automated
cotton extraction and grading
equipment, automated sampling
devices, electrical moisture sensors,
automated calibration devices,
automated directional valves for
seed cotton and lint, computer
simulation software, optimization
software, machinery performance
characteristics models, and related
inventions.
The control system technology
for cotton ginning has been licensed
exclusively to Zellweger Uster, an
equipment manufacturer, and will
be commercially available in 1998
under the trade name IntelliGin.-
By Tara Weaver, ARS.


W. Stanley Anthony is in the
USDA-ARS Cotton Ginning Research
Unit, 111 Experiment Station Rd.,
P.O. Box 256, Stoneville, MS 38776-
0256; phone (601) 686-3094, fax
(601) 686-5483, e-mail
anthonys@ars.usda.gov *





Cotton's Path Through the
IntelliGin

Module feeder-Compacted
cotton as it comes from the field
begins processing here. Video
camera and moisture sensors in
the feeder relay information about
color, trash, and moisture to a
computer.
Dryers-Cotton may bypass
the dryers completely or dryer
temperatures may be adjusted
higher or lower, depending on
instructions from the computer.
Cylinder cleaners and stick
machine-One or more stages
may be needed, depending on the
intended market quality of the
cotton.
Gin stand-Removes fibers
from the seeds. Sensors again
relay quality information to the
computer.
Lint cleaners-The computer
controls the number of cleaners to
achieve the best end quality and
value.
Bale press-Sensors measure
the final quality immediately
before the cotton fiber, or lint, is
pressed into 500-pound bales
ready for marketing.













INERBULL

Shows How

U.S. Bulls

Stack Up


Holstein dairy cows.


The secret is out: America's most
productive dairy cows can now be
bred to the world's best bulls, thanks
to an international dating service for
dairy cattle.
"INTERBULL-The International
Bull Evaluation Service-is like a
consumer report that objectively rates
bulls raised worldwide, based on an
extensive list of important quality
standards," says ARS geneticist Rex
L. Powell. He works at the Animal
Improvement Programs Laboratory
in Beltsville, Maryland.
The lab's researchers devise, test,
and implement genetic evaluation
techniques to improve the productivi-
ty and health of dairy cattle and
goats-thereby keeping U.S. dairy
producers competitive in today's
marketplace. Powell's job is to en-
sure that quality standards for U.S.
cattle remain the world's best.
"The United States is the world's
top exporter of bull semen, with sales
of about $60 million a year," he says.
Powell has been the U.S. represen-
tative to INTERBULL since its be-
ginning in 1983 and serves on its
board of directors. Headquartered in
Uppsala, Sweden, INTERBULL
boasts 34 member countries.
"INTERBULL's objective is to in-
ternationally evaluate bulls that have
been properly tested in different
countries-currently 20 and growing.
This information enables breeders
worldwide to select the best bulls


from around the world to sire daugh-
ters," Powell says.
INTERBULL combines national
evaluations of nearly 90,000 recent
bulls from six breeds of dairy cattle.
Its objectives are to improve milk
yield and quality; improve resistance
to diseases, like mastitis; and increase
the value of dairy cows-all while
protecting genetic diversity.
Each year, the laboratory processes
millions of new records that track im-
portant genetic traits in daughters,
such as milk production and composi-
tion. For example, how much and
what quality milk does each tested an-
imal produce? How much fat and pro-
tein are contained in the milk?
These records are the result of pro-
duction testing programs of the Na-
tional Dairy Herd Improvement Asso-
ciation and contribute to an accumu-
lated file of about 128,000 American
bulls and their 20 million daughters.
"U.S. dairy farmers and breeders
need and use this information to breed
the best bulls with their best dairy
cows," says Powell. He is an expert
on interpreting this genetic informa-
tion for the entire nation and relating
it to INTERBULL's international
standards.
Powell's work ensures that the
semen U.S. breeders and farmers
purchase nationally and internation-
ally is the best for their intended
purpose, because some animals
naturally do best under certain climate


and production conditions. Powell's
efforts also make foreign breeders
and dairy farmers aware of the
superiority of U.S. germplasm.
Powell is working to improve
INTERBULL itself. For while the
United States and Canada currently
evaluate milk production four times a
year, most countries and INTERBULL
evaluate bulls only twice yearly.
Powell would like to see international
evaluations also done quarterly.
He would also like to see added to
the INTERBULL evaluation list other
important genetic traits, like confor-
mation, longevity, and somatic cell
count. This count is the number of
body cells (largely leucocytes) per
milliliter of milk and is a measure of
udder infection, or mastitis.
For his work on improving genetic
analysis of dairy cattle, Powell recent-
ly received the annual Award in Ani-
mal Breeding from the American
Dairy Science Association. To help
producers make sense of so much
data, Powell ensures that most of IN-
TERBULL's information is available
in a user-friendly form on the World
Wide Web at http://www.aipl.arsusda.
gov/-By Hank Becker, ARS.
Rex L. Powell is at the USDA-ARS
Animal Improvement Programs Labo-
ratory, Bldg. 236, 10300 Baltimore
Ave., Beltsville, MD 20705-2350;
phone (301) 504-8334, fax (301) 504-
8092, e-mail rexpowel@ggpl.arsusda.
gov *


Agricultural Research/February 1998









Pigeonpea-A Summer Legume
for Wheat Growers

Pigeonpea may be on its way to becoming a favorite
rotation crop for U.S. wheat growers. At least that's
what ARS scientists at the Grazinglands Research
Laboratory in El Reno, Oklahoma, are investigating.
"We are evaluating performance of pigeonpea as an
alternative summer legume crop that can be planted after
wheat," says ARS agronomist Srinivas C. Rao. "We are
looking for a variety that can grow and mature between
the time wheat has been harvested, which is usually
June, and replanting that occurs before the first frost in
October.
"Pigeonpea varieties mature in 120 to 250 days. So
some will fit into this narrow window with just enough
time to reach maturity before cold weather hits," Rao
says.
Rao brought several different varieties of pigeonpea
germplasm from the International Crops Research
Institute for the Semi-Arid Tropics in Hyderabad, India.
More than 90 percent of the world's pigeonpea crops are
grown there.
Several varieties from the institute's germplasm col-
lection show promise. Rao is also looking at Georgia-2,
a variety developed by Sharad Phathak, a scientist with
the University of Georgia.
Pigeonpea grows well in tropical and subtropical
environments, but they can also tolerate drought-an
added bonus for Southern Great Plains states that may
not get much rain during summer months.
Rao says pigeonpea leaves and stems can provide
high-quality forage for grazing livestock at a time when
productivity of warm-season forages is declining. This
little green vegetable, which looks similar to sweet green
peas, contains 17 percent protein.
The Grazinglands Research Laboratory is looking at
the crop's nutritive values and their effect on animal
performance, but no results are yet available. Another
advantage of this promising crop: "Pigeonpea has the
potential to protect soil from erosion and degradation,
while adding nitrogen to the soil for next year's wheat
crop," says Rao.-By Tara Weaver, ARS.
Srinivas C. Rao is at the USDA-ARS Grazinglands
Research Laboratory, 7207 West Cheyenne St., El Reno,
OK 73036; phone (405) 262-5291, fax (405) 262-0133,
e-mail srao@grl.ars.usda.gov *


New Process Improves Wheat
Flour Separation

Wheat flour can be separated into gluten and starch
more efficiently thanks to a new, environmentally friendly
process developed by ARS scientists that uses ethanol
instead of water.
Each year, about 2 billion tons of wheat flour undergo
processing that yields some 300 million pounds of gluten, a
crucial protein in the food industry. After gluten removal,
the remaining wheat starch can be used as a thickener or in
a host of nonfood products, such as cosmetics or cardboard.
Gluten helps bread to rise by trapping the gases pro-
duced by yeast. Without added gluten, whole-grain breads
would be too heavy to rise adequately. Added gluten also
strengthens hot dog buns so they can open without break-
ing. Pet foods and some breakfast cereals use gluten as an
additional protein source and binding agent.
Since 1835, the predominant commercial separation
method has required washing the starch away from the
gluten with water-up to 30 tons of liquid per ton of
recovered gluten. The resultant sticky gluten dough is dried
slowly to keep the protein intact.
The wastewater contains fiber, small amounts of starch
and protein, and gums called pentosans. "These leftover
ingredients can spoil, so the water can't be reused for
long," says ARS chemical engineer George H. Robertson.
The wastewater must be expensively treated before it can
be discharged.
The new technique that Robertson and colleagues
invented at the ARS Western Regional Research Center in
Albany, California, replaces the water with ethanol.
"Our process takes about half the time of the traditional
methods," says Robertson. "Because the gluten breaks into
smaller clumps and dries faster, we can use a lower temper-
ature, which protects the protein properties," he says.
Also, virtually all of the ethanol can be directly reused,
requiring no discharge. Another plus: Laboratory tests
show the protein may be stronger than that derived from
water-separated gluten.
In both processes, filters separate the wheat starch from
the liquid after the gluten is removed. The new method
(patent application no. 08/879,560) is ready for pilot-scale
testing and available for licensing.-By Kathryn Barry
Stelljes, ARS.
George H. Robertson is in the USDA-ARS Process
Chemistry and Engineering Research Unit, Western
Regional Research Center, 800 Buchanan St., Albany, CA
94710; phone (510) 559-5621, fax (510) 559-5818, e-mail
grobertson@pw.usda.gov *


Agricultural Research/February 1998








Starry Sky Beetle-The Latest Amityville Horror


I n China, it's called the starry
sky beetle because of the white,
celestial markings on its black
body. But in the United States, this
latest alien insect immigrant is
commonly known as the Asian
longhorn beetle, Anoplophora
glabripennis.
"Whatever name you use," says
Steven W. Lingafelter, "this pest and
related species could have a devas-
tating economic impact in the United
States. It could cause millions of
dollars in damage to ornamental
trees and to the maple syrup and
lumber industries." Lingafelter is a
systematic entomologist with the
Agricultural Research Service.
"This woodboring pest is native to
China, Japan, and Korea and has a
natural range broad enough to
guarantee it can live in most sections
of this country," he says.
The Asian longhorn beetle was
first discovered on maple,
horsechestnut, and elm trees in
Brooklyn, New York, in October
1996. Last July, workers there began
cutting down, chipping, and burning
trees to slow the pest's spread. Since
then, the beetle has moved on to
other communities in New York, and
other specimens have been seen
across the country. In Amityville and
Greenpoint, New York, the beetle is
attacking many types of maple and
horsechestnut trees.
Recently, adults and larvae have
been intercepted in forest product
shipments in California, South
Carolina, and Canada. Early identifi-
cation and cargo fumigation have so
far prevented establishment of this
species in these other areas.
That's where Lingafelter's work
has been pivotal. He is an expert on
the Asian longhorn beetle's family,
Cerambycidae. It's his job to distin-
guish this new pest from hundreds of
other related native woodboring
beetles.


Since the larvae of the Asian
longhorn beetle closely resemble
many native species, regulatory
agencies charged with containing the
pest rely on the expertise of ARS'
Systematic Entomology Laboratory
(SEL) to identify any suspicious
beetles. Correctly assigning names is
a crucial first step to effective
control methods.
Alien pests intercepted at U.S.
ports of entry are routinely sent to
the SEL, which has facilities at the
Smithsonian Institution's Museum of
Natural History in Washington,
D.C., and at Beltsville, Maryland.
There the agency's systematic
entomologists maintain the
world's largest collection of
agricultural pests of quarantine
significance.
Despite efforts to monitor U.S.
borders for uninvited pests, some
escape detection. Researchers
believe this Asian longhorn, like
many other woodboring beetles,
entered the United States in
wooden crates and braces used to
transport cargo in ships. Since the
larvae of these beetles live in and
feed on the wood, they are easily
overlooked.
"This family of woodboring
beetles occurs worldwide,"
Lingafelter says. "The adults are
characterized by an elongated body
and very long antennae-usually at
least as long as the body. They
generally live as larvae for 1 to 3
years inside wood or roots before
emerging as adults. They do their
worst damage as larvae-the life
stage when they bore holes in the
wood of living trees.
"Of the thousands of native
species of longhorned woodboring
beetles in the United States, most
cause little harm to living trees,"
says Lingafelter. "They consume
dead wood, making them important


primary decomposers in our forest
ecosystems.
"However, some-like the cotton-
wood borer of the Great Plains,
Plectrodera scalator, a close relative
to Asian longhorn beetle-have
caused millions of dollars in losses to
U.S. trees," he says.
A USDA advisory committee that
includes ARS and two sister agen-
cies, the Forest Service and the
Animal and Plant Health Inspection
Service, is preparing a nationwide
strategy to eradicate the new pest.


Asian longhorned beetle, Anoplophora
glabripennis, shown on a cross-section of a tree
it has damaged, creates large holes that inhibit
the vascular system and ultimately kill the tree.


"Besides chipping and burning all
affected trees, other possible
controls-birds, parasitic wasps,
other beetle larvae, and robber fly
larvae-should also be studied," says
Lingafelter.-By Hank Becker,
ARS.
Steven W. Lingafelter is at the
USDA-ARS Systematic Entomology
Laboratory, U.S. National Museum
of Natural History, NHB 168, Wash-
ington, DC, 20560; phone (202) 382-
1793, fax (202) 786-9422, e-mail
slingafe@sel.barc.usda.gov *


Agricultural Research/February 1998












Gel Could Stop Two Mites With
One Treatment
Formic acid mixed with a food-
grade gel protects honey bees from
tracheal and varroa mites, the two
worst bee pests in this country. In
field tests, the experimental ARS
product killed up to 84 percent of
varroa mites and 100 percent of
tracheal mites. The gel could help
gain U.S. Environmental Protection
Agency registration of formic acid to
combat both mites. Currently, in the
United States, the only registered
control for varroa mites is fluvali-
nate; and for tracheal mites, menthol.
Formic acid has proved effective
against the pests. But in liquid form it
evaporates quickly and must be
applied several times per season.
Sealing acid and gel in a plastic bag
would provide a longer lasting
product requiring less handling. The
bag could be sliced open inside the
hive. Formic acid would evaporate
and leave behind a harmless residue.
ARS scientists are seeking patent
protection.
Mark Feldlaufer, USDA-ARS Bee
Research Laboratory, Beltsville,
Maryland; phone (301) 504-8205, e-
mail mfeldlau@asrr.arsusda.gov


LILA DE GUZMAN (K5069-23)
f- x..,.,.-


Tracheal mites infest the breathing tube of
a honey bee. Left unchecked, these
parasites live, feed, and reproduce,
eventually blocking oxygen flow and
killing their host. Magnification about
140x.


7 p date


Nationwide Poultry Microbe Hunt
Under Way
Scientists have begun a 1-year
survey to learn where chicken
pathogens such as Salmonella and
Campylobacter can get their start at
farms. The survey could also supply
producers with a new way to track
and control bacterial risks-and
reduce food-safety risks for con-
sumers. Five top poultry producers
have invited ARS scientists to
conduct the study, the largest of its
kind in the United States. Scientists
will sample 25 sites on 10 farms in
Arkansas, California, Georgia,
Maryland, and Mississippi. Sites
will include feed bins, hatcheries-
even farmers' boot soles. DNA tests
will distinguish among the bacteria.
Salmonella and Campylobacter can
enter the food supply at various
places-from the hatchery to the
consumer's kitchen. Proper cooking
and handling remain the best
protection.
Norman Stern, USDA-ARS
Poultry Microbiological Safety
Research Unit, Athens, Georgia;
phone (706) 546-3516, e-mail
nstern@ars.usda.gov

Helpful Wasp Recruited To Fight
Cotton Pest
Scientists will be closely watch-
ing some cotton fields in Califor-
nia's San Joaquin Valley. Will the
tiny black wasps they released help
growers get a grip on cotton aphids?
The aphids feed on plant sap and
excrete a sticky goo that contami-
nates cotton fibers and can jam
cotton gins or equipment at textile
mills. But the female Lysiphlebia
japonica wasp attacks the aphid by
injecting one of her eggs inside it.
The larva that hatches feeds on the
pest, killing it. The project is a
cooperative effort of two ARS labs
in California, the California Depart-


ment of Food and Agriculture, and
University of California Cooperative
Extension Service, with support from
the California Cotton Pest Control
Board. ARS scientists were first to
import the wasp-an Asian native-
and determine how to lab-rear it for
outdoor tests. The cotton aphid and
other aphids cost California cotton
growers more than $11 million in
1996. ARS scientists in Florida are
evaluating the wasp's ability to
attack citrus pests.
Raymond K. Yokomi, USDA-ARS
Horticultural Crops Research
Laboratory, Fresno, California;
phone (209) 453-3021, e-mail
ryokomi@ lightspeed. net

Papaya Enzyme Tenderizes
Abalone
Tender, tasty blue abalone,
Haliotisfulgens, sells for about $50 a
1-pound can on the West Coast.
More consumers may someday enjoy
a more affordable abalone-the black
abalone-as a result of a cooperative
project between ARS and the Univer-
sity of Georgia. Black abalone, H.
cracherodii, is sold for about $10 a
pound, mainly in Mexico. Its taste
and nutritional value are essentially
the same as those of its higher priced
blue cousin. What's missing is
tenderness. Papain, an approved
papaya enzyme, will break down
abalone collagen, but how much is
enough to tenderize black abalone
without compromising flavor? To
determine this, scientists began with
a texture analyzer. It compared the
force needed to mechanically "chew"
both blue and modified black aba-
lone. The scientists then checked and
refined their conclusions by recruit-
ing taste-testers for a 12-week
project.
Brenda Lyon, USDA-ARS Quality
Assessment Research Unit, Athens,
Georgia; phone (706) 546-3167, e-
mail bglyon@athens.net


Agricultural Research/February 1998






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