*. a. I d
Tomorrow's amber waves of grain
will more likely be a mosaic of
highly specialized crops bred for
unique applications in manufactured
food and industrial products. The
Agricultural Research Service is
riding the crest of those waves,
producing new plants and products
that help meet the needs of consum-
ers, growers, and industry.
Finding new applications for
plant-based products is a full-time
job for ARS scientists who have
already come up with novel uses for
cornstarch, soybean and sunflower
oils, and many other agricultural
commodities. Their work has opened
new niche markets for farmers,
expanded consumer choices at the
grocery store, and lessened our
dependence on imported goods from
Traditionally, plant scientists have
primarily looked for ways to boost
crop yields. This is still a key
emphasis in plant development in
ARS, but researchers today are
taking a much closer look at the
genetic makeup of plants, too. The
goal now is to breed plants for
specific traits that meet the special-
ized needs of targeted markets.
Dig a ditch with a backhoe
powered by hydraulic fluid from
plants? Not only is it possible-a
commercial formulation may not be
far off. ARS researchers at the
National Center for Agricultural
Utilization Research at Peoria,
Illinois, have synthesized the fatty
acid estolides from a blend of
soybean, sunflower, and safflower
oils to produce a biodegradable base
for industrial hydraulic fluid. Cater-
pillar, Inc., manufacturer of heavy
equipment and one of the nation's
biggest users of hydraulic fluid, is
testing the prototype formulation at
its Peoria headquarters. If it plays in
Peoria, plant-based hydraulic fluid
could be a hit the world over.
Scientists at the ARS Range and
Pasture Research Station in Wood-
ward, Oklahoma, have transformed
corn to reproduce asexually, so seed
can be reproduced without cross-
pollination. The new corn was
developed using a gene from Eastern
gamagrass for a trait called apomixis.
Apomictic corn could revolutionize
agriculture by giving scientists a tool
for developing improved plant
varieties to retain desired traits. The
new corn varieties developed with
apomixis display better resistance to
cold and insects and are more tolerant
of drought and flooding.
ARS is also improving plants for
use in foods, and the proof is in the
pudding. Consumers now enjoy a
broader range of choices, including
more healthful margarine, salad
dressing, and dessert products. ARS
scientists have bred soybean varieties
that produce boosted levels of oleic
acids-a plant component shown to
lower cholesterol in some humans.
In fact, ARS researchers in coop-
eration with private industry partners
recently rolled out a new class of
sunflower called NuSun that produc-
es three times more cholesterol-
lowering mid-oleic acid than standard
types of sunflowers. Nearly 100,000
acres of the new sunflowers were
harvested in 1998 to meet the ex-
panding demand for healthful foods.
This boosted farm income and
pumped millions of dollars into local
Need to lose a few pounds? That
may be easier now, thanks to a plant-
based produced called Nu-Trim
recently formulated by ARS scien-
tists. Rich in beta-glucans, Nu-Trim
is a soluble gum found in oats and
barley. It's the latest in a growing
family of food additives called
designed to enhance the nutritional
quality of foods.
Nu-Trim is a creamy-textured food
additive that replaces dairy products
and coconut cream in baked goods,
salad dressings, and sauces. The
Food and Drug Administration
recently issued new rules allowing
foods containing at least 3 grams of
beta glucans per serving to claim
health benefits, such as lowering
blood cholesterol in a low-fat diet.
Genetic retooling also means
crops have the potential "right stuff"
for postharvest processing. ARS
scientists at Albany, California, are
reprogramming key genes in wheat to
improve its milling and mixing
quality. The result is a dough for
making today's light breads and
cookies that require different baking
conditions than more traditional fat-
laden varieties. That means lower
input costs for millers and bakers,
while consumers get a better tasting
product at a lower price.
ARS Information Staff
Agricultural Research/November 1998
Vol. 46, No. 11
Agricultural Research is published monthly by
the Agricultural Research Service, U.S. Depart-
ment of Agriculture (USDA). The Secretary of
Agriculture has determined that this periodical is
necessary in the transaction of public business
required by law.
Dan Glickman, Secretary
U.S. Department of Agriculture
I. Miley Gonzalez, Under Secretary
Research, Education, and Economics
Floyd P. Horn, Administrator
Agricultural Research Service
Sandy Miller Hays, Director
Editor: Lloyd McLaughlin
Assoc. Editor: Linda McElreath
Art Director: William Johnson
Acting Photo Ed.: Scott Bauer
Assoc. Photo Ed.: Anita Daniels
Information in this magazine is public property
and may be reprinted without permission. Non-
copyrighted photos are available to mass media in
color transparencies. Order by photo number and
date of magazine issue.
Agricultural Research magazine articles and
photographs are posted on the World Wide Web
monthly at http://www.ars.usda.gov/is/AR/.
Subscriplion requestl should be placed with New
Order,. Superninendent of DocumentK. P 0. Box
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Complimentary 1-year subscriptions are available
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and the news media. Send requests or comments
to: Editor, Agricultural Research, 5601 Sunny-
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This magazine may report research involving pes-
ticides. It does not contain recommendations for
7heir usc. nor d,-.e ; iimpl] that uses di,.cused
herein have been registered. All uses of pesticides
must be registered by appropriate state and/or
federal agencies before they can be recommended.
Reference to any commercial product or service
is made with the understanding that no discrimi-
nation is intended and no endorsement by USDA
The U.S. Department of Agriculture prohibits
discrimination in all its programs and aciii ities
on the basis of race. color. nrti.,nal o.ririn.
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Avenue, SW, Washington, DC 20i251-94 I 10. or
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opportunity provider and employer.
Agricultural Research/November 1998
Lab-Built Wheat Gene May Raise Dough Quality 4
New Live-Animal Test for Scrapie 6
Biodegradable, Plant-Based Hydraulic Fluid 9
Hydroponic Strawberries Avoid Soil Pests 10
Tanning Research Update 12
Biosensor Detects Chemical Residues 14
A Little Bit of Yew Helps Insecticides 14
Putting Forests on Farms and Farms in Forests
Particle Films: A New Kind of Plant Protectant 1 0
High-Tech Retrofitting of Farm Machinery 20
Range Reseeding Goes With the Flow 21
Venom Chemical Lures Bee Researchers 21
GPFARM Software Foresees the Future 22
Science Update 23
Cover: Yeast-raised breads will benefit from research on the genes in wheat and
wheat's wild relatives that produce high-molecular-weight glutenins-proteins that
are important to baking quality. Photo by Scott Bauer. (K7251-1)
In the next issue!
( Last year, botanist Diane Pavek traveled more than 12,000
miles exploring along rivers and streams in the Southeast. Her
mission: preserving populations of rock grape plants in their native
habitat. Her work is part of a National Plant Germplasm System
effort to preserve the wild relatives of U.S. crop plants.
(- Nu-Trim, a new food ingredient made from oat and barley
bran, may contribute to a healthier diet for some people, says
George E. Inglett, an Agricultural Research Service chemist.
(0- A diary of the Hong Kong poultry flu from May 21, 1997, to
the present time shows how public and private agencies world-
wide worked together to avoid an epidemic.
heat plants of the future might provide
grain for designer flours that yield deli-
cious, wholesome new breads, pastas, and
other appetizing foods. And giving some of
wheat's flour genes to other kinds of grains-barley,
oats, corn, rye, or rice, for instance-could lead the way
to innovative, versatile flours from these wheat rela-
tives, as well.
These futuristic flours are the target of genetic
engineering experiments conducted by Agricultural
Research Service scientists at the Western Regional
Research Center in Albany, California. They are investi-
gating proteins unique to wheat flour, called high-
molecular-weight glutenins. These glutenins are critical
to making strong dough. For dough, strength is an asset
because it leads to high-quality yeast-raised breads.
Strong dough, explains geneticist Olin D. Anderson,
is able to trap tiny bubbles of carbon dioxide gas formed
naturally by yeast during mixing and rising. Bubbles
enable dough to rise, helping form high, light, loaves.
Dough strength and the ability to contain gas bubbles is
known as viscoelasticity.
Wheat with a large amount of certain high-molecular-
weight glutenins yields flour that produces stronger
dough, larger bread loaf sizes, and light, finer-textured
breads. Recently, Anderson and geneticist Ann E.
Blechl became the first to use genetic engineering to
boost the amount of high-molecular-weight glutenins in
wheat kernels and the flour ground from those kernels.
They did this by using a gene gun to move copies of a
lab-built gene into wheat cells.
The gene gun fired gold particles coated with genes
that cue wheat plants to manufacture more glutenins. So
far, greenhouse plants with high levels of high-
molecular-weight glutenins retained the trait through
The researchers now want to fine-tune this strategy
for more precise control over wheat flour's glutenin
levels. With colleagues from Australia's Common-
wealth Science and Industrial Research Organization in
Sydney, they are testing flours made from kernels
harvested from these experimental plants.
No one knows exactly how high-molecular glutenins
work-only that they're vital for strong doughs and
great breads. To reveal more about the inner workings
of these proteins, Anderson is building and testing
Agricultural Research/November 1998
IlL LIIC IXL VVCLCIII IXrgIUunI NacCal .
geneticist Olin Anderson uses a sample
efficiently for new wheat genes. It can
genes, and perform other functions-(
tion of glutenins. then a human.
Some of these re-tooled
genes are longer versions of the naturally occurring ones.
Their central sections have more repeats of a portion of
genetic material thought to be key to viscoelasticity.
Anderson's tests showed that increasing the copies of those
portions of the genes increases dough-mixing time. That's
a boon to bakers, because increased dough-mixing time is a
key indicator of dough strength.
Scientists have anticipated that using genetic engineer-
ing to change a wheat-flour protein could change the
character of the resulting dough. The Albany team was the
first to succeed in doing that-using biotechnology.
Wheat glutenin genes inserted into other grains may
lead to unique, healthful products impossible to make
today. Moving one or two of wheat's high-molecular-
weight glutenin genes into barley, for example, might open
the door to popular new products from barley flour.
Currently, American-grown barley is used mainly for
malting and animal feed. Barley flour lacks the high-
molecular-weight glutenins that wheat flour boasts.
Although barley has flour proteins somewhat similar to
those in wheat, barley flour does not make a similar
Now, senior lab technician Jeanie Lin, who is with the
Albany team, has succeeded in moving wheat glutenin
genes into barley plants. And, says Lin, some of those
plants produced kernels with good levels of wheat glutenin
In another venture, Minnesota scientists using wheat
glutenin genes furnished by the Albany researchers have
produced oat plants with the borrowed wheat genes inside.
David A. Somers led that work at the University of Minne-
sota. He used a technique that he, Kimberly A. Torbert,
and geneticist Howard W. Rines of the ARS Plant Science
Research Unit in St. Paul, Minnesota, developed for
genetically engineering oats.
Like the barley foray, oat experiments may lead to
development of tasty new foods that rely on new oat flours.
Today's oats are grown mostly for animal feed or pro-
cessed into breakfast cereals and other foods for people.
The glutenin experiments with wheat target the protein-
rich portion of wheat flour. But flour's other main compo-
nent-starch-might also be re-worked through genetic
Agricultural Research/November 1998
11 LCIuI I II II1Killly, LalllulIIuai,
e-handling robot to search more
prepare DNA, identify specific engineering into a more
often faster and more accurately marketable product.
Wheat starch is com-
posed of molecules known
as amylose and amylopectin. Wheat flour low in amylose,
for example, is desirable for noodlemaking because it
improves noodle texture. Reduced-amylose flours may
also improve dough for frozen foods like pizza crusts or
ready-to-bake breads by helping maintain flavor.
Scientists suspect that boosting the amount of amy-
lopectin in starch may concurrently reduce the amount of
amylose, resulting in a value-added, low-amylose flour.
Geneticist Kent F. McCue, working with Anderson,
isolated two genes that direct wheat to make amylopectin-
producing enzymes known as starch-branching enzyme I
and starch-branching enzyme H. McCue and Anderson
used starch genes from corn to isolate the two in wheat.
With the wheat genes now in hand, genetic engineers
might soon be able to increase the ratio of amylopectin to
Modifying wheat starch could also make it more
suitable for any of hundreds of industrial uses ranging
from pastes to papers to textiles. -By Marcia Wood,
For more information on U.S. Patent No. 5,650,558,
"Glutenin Genes and Their Uses," Patent Application No.
08/785,716, "Altering Dough Viscoelasticity With Modi-
fied Glutenins," or Patent Application No. 60/059,257,
"Modification of Starch Branching Patterns and Chain
Length Distribution Via Transformation with Starch
Branching Enzymes," contact Olin D. Anderson, USDA-
ARS Crop Improvement and Utilization Research Unit,
Western Regional Research Center, 800 Buchanan St.,
Albany, CA 94710; phone (510) 559-5773, fax (510) 559-
5777, e-mail firstname.lastname@example.org. *
modified versions of other
genes that control produc-
T he first practical test
for diagnosing the sheep
disease scrapie in live
animals may help the
livestock industry gain the
upper hand on-and
of its worst problems.
Scientists with the Agri-
cultural Research Service
teamed with Washington
State University veterinar-
ians to invent the test.
Scrapie was inadvert-
ently introduced from
Europe in 1947. The U.S.
Department of Agriculture
has been trying to eradi-
cate it for decades, but the disease
has been intractable. Not only has it
been impossible to detect scrapie in
live animals, they can harbor it for up
to 8 years before showing disease
And scientists haven't fully
understood how it is transmitted.
Now they believe infectious agents
called prions are involved in causing
scrapie, but they are still investigat-
ing other theories also.
To glimpse what a quick, easy,
inexpensive scrapie test
might mean to the
endure without such a test.
Tom and Gail Sloan, sheep
breeders in Lawrence. Kansas.
specialize in producing breeding
stock from purebred Suffolk and i
Columbia flocks. In 1987. the\
purchased a yearling ram from a
large Suffolk breeder to upgrade
their family's flock of 25
At first the ram appeared
healthy, but over the next i
JACK DYKINGA (K8829-2)
several months he began losing wool
and seemed to have a skin problem.
The ram was ultimately found to
have scrapie, a brain disease that
causes sheep to behave erratically,
lose weight, and eventually die.
Per the federal regulations at the
time, the Sloans killed the ram and
all of his progeny, carried out a
rigorous cleaning program, and
instituted long-term monitoring to
eliminate all traces of the disease.
The Sloans bought
more ewes but again
learned too late they had
bought more scrapie.
After repeating the steps
for ridding the flock of
known and potential
scrapie carriers, they
spent 6 months searching
for a closed flock with a
good health program.
Once again, they inadvert-
ently purchased scrapie.
This time, the Sloans
destroyed all their Suffolk
sheep. They have pur-
chased a limited number
of Suffolks, but they keep
them at another farm.
"I'm afraid to let Suffolk sheep
back on our home farm because of
our experience with scrapie," Gail
says. "I'm not sure our family could
survive going through this again."
Effects Can Be Subtle
The Sloans' story gives only a hint
of the impact scrapie has on the U.S.
The incidence of scrapie seems
low-only a few dozen cases are
reported annually. Black-faced sheep,
including Suffolks, have had the
majority of the cases detected nation-
"Predation, foot rot disease, and
parasitism have a much higher
monetary impact on individu-
V al flocks." sa\ s Paul
Rodgers. At the Ameri-
can Sheep Industry
SV. irginia. Rodgers
is Director of
S Animal Health,
JACK DYKINGA (K8831-1)
Sheep in this flock being observed by ARS veterinary medical officer Don Knowles are in the early stages of scrapie infection. A new
monoclonal antibody test can detect telltale prions in lymphoid tissue taken from a sheep's third eyelid.
The disease's effect on the global
marketplace, though, is far greater.
"Countries that don't have
scrapie have shied away from
purchasing our sheep," says Ron
Young, an Ohio sheep producer who
serves on the board of directors for
the Suffolk Association. "American
sheep are big, meaty, and fast-
growing, so other countries are
hungry for our genetics. But from a
health protocol standpoint, we're
not able to export animals to those
Agricultural Research/November 1998
Other livestock exports are also
Scrapie is known as a transmis-
sible spongiform encephalopathy
(TSE). Related diseases affect cattle,
elk, deer, mink, cats, and humans.
Bovine spongiform encephalopathy
(BSE), the TSE of cattle-also
known as mad cow disease-has
been a problem in some other
BSE has never been detected in
American cattle, and a strict surveil-
lance and prevention program is in
place to prohibit its entry.
"Scrapie is a big stigma world-
wide, says Linda Detwiler, senior
staff veterinarian with the USDA's
Animal and Plant Health Inspection
Service (APHIS). "The fact that we
have scrapie affects our BSE sta-
tus-that is, other countries have not
declared us totally free of BSE for
trading purposes, even though we
don't have that disease-because
any TSE is considered a risk factor."
A Simple, Safe Test
The problem is that until now, the
only way to confirm any TSE has
been to examine the brain of a dead
animal. Now that could change.
A research team headed by ARS
microbiologist Katherine I. O'Rourke
discovered that prions collect in
pockets of lymphoid tissue in a
sheep's nictitating membrane, or
third eyelid. A veterinarian can take a
sample of the tissue with only a local
O'Rourke works in the ARS
Animal Disease Research Unit at
Pullman, Washington. Others on the
team include Donald P. Knowles,
who leads the Pullman lab, Timothy
V. Baszler and Steven M. Parish with
WashingtonState University in
Pullman, and Janice M. Miller at the
ARS National Animal Disease Center
in Ames, Iowa.
This test offers several advantages
over other options currently being
pursued. While abnormal prions are
known to collect in tonsils and other
lymphoid tissues, tests using those
tissues require a general anesthesia.
The ARS test is safer and easier and
will be much less expensive than
more invasive procedures.
Another advantage is that the new
test relies on a laboratory-built mol-
ecule known as a monoclonal anti-
body. A monoclonal antibody is a
specific series of amino acids that
recognize and bind to a specific pro-
tein, in this case prions. The antibody
can be standardized and replicated in-
definitely in the laboratory.
Other existing tests use rabbit
antibodies. Because one rabbit can
provide only a limited amount of
serum, it isn't possible for all copies
of the test worldwide to be identical.
Normal biological variation in
antibodies from multiple rabbits adds
variability to a test.
In the new test, a red color indi-
cates that scrapie prions are present
in the sample. The color comes from
an enzyme on a reporter molecule
that detects the monoclonal antibody
bound to prions. ARS has applied for
a patent on the monoclonal antibody
and testing for prions in ruminant
eyelids (Patent Application No. 08/
Before the test can be made
available, it must be validated and
receive regulatory approval.
Washington state University veterinarian
Steven Parish (left) and ARS' Don Knowles
apply topical anesthetic to a Suffolk ewe's
eye before taking an eyelid sample.
"We need to know whether and
how often the test produces false
positives or false negatives. So far,
the results look promising," says
APHIS is helping to provide the
ARS lab with scrapie-positive
samples. O'Rourke also plans to get
samples from New Zealand, a
scrapie-free country, as scrapie-
negative samples. The validation
could be completed within 2 years.
Even though the test is not yet
available, sheep producers are
"A preclinical, live-animal diag-
nostic test will allow us to eventually
eradicate this disease in the United
States and allow us new export
opportunities," says ASI's Rodgers.
The test will have two other
important uses: confirming scrapie in
dead animals and verifying recently
identified genetics that may indicate
susceptibility to scrapie.
"Sheep with certain genetics seem
more likely to show clinical signs of
the disease after exposure, but we
don't know if animals without the
sequences still carry and pass on the
prions," says O'Rourke. "Our new
test will help us determine the
relationship between genetics and
prion accumulation, which is crucial
to eradicating the disease," she says.
"Once we can definitely say that
an animal does not have scrapie,
we'll be able to open many doors for
purebred livestock breeders," says
breeder Young. "In the past, we've
just been throwing darts in the dark."
Another piece of the scientific
puzzle: At what age do prions
become detectable in lambs? The
new test has identified prions in 1-
year-old sheep. The lab's next step is
to follow, from birth, lambs born to
ewes known to have scrapie.-By
Kathryn Barry Stelljes, ARS.
Katherine L O'Rourke and Donald
P. Knowles are in the USDA-ARS
Animal Disease Research Unit, 337
Bustad Hall, Washington State
University, Pullman, WA 99164;
phone (509) 335-6020, fax (509) 335-
Agricultural Research/November 1998
gradable hydraulic fluid to
power heavy equipment is
just around the corner, thanks to a
new process that creates a key
component from vegetable oil.
Agricultural Research Service
scientists at the National Center for
Agricultural Utilization Research in
Peoria, Illinois, have made hydraulic
fluid that contains estolides from
oilseeds such as meadowfoam and
high-oleic soybean oil.
A class of long-chain esters,
estolides are the basic ingredient in
many hydraulic fluids. These fluids,
under pressure, transmit power to
moving parts of many machines,
including cars, bulldozers, tractors,
and most heavy equipment used to
build roads and structures.
The scientists began by making a
plant-based estolide from meadow-
foam seed, an oilseed crop ARS
researchers helped breed and develop
uses for. Grown primarily in the
Northwest, meadowfoam is an
ingredient in cosmetics and other
"We found that it also showed
promise as a basestock in hydraulic
fluid," says Terry A. Isbell, an ARS
chemist who helped develop mead-
owfoam. But poor low-temperature
properties and cost were prohibitive.
However, "We used the technolo-
gy developed for meadowfoam
estolides to make estolides from
other vegetable oils," Isbell says.
"We found that oils that are particu-
larly high in oleic acid, such as
sunflower, safflower, and some
soybean, would serve as a good
source of starting material for the
formation of estolides."
Petroleum-based hydraulic fluids
and lubricant basestocks do not
degrade well. Recently, construction
equipment manufacturers began
seeking a biodegradable alternative,
in response to tighter environmental
In tests, about 30 percent of a
petroleum-based hydraulic fluid
degraded in 28 days, compared to 80
percent for vegetable-based estolides.
The scientists' challenge: making
estolides in large enough quantities to
be economically feasible for commer-
cial manufacturers like Caterpillar, a
heavy equipment manufacturer with
Plant estolide-based hydraulic fluid could
replace conventional fluid in a wide range
of industrial and farm equipment. Here, a
specialized machine built for soil sampling
uses hydraulics to raise or lower its height,
adjust its width, and drive the wheels.
headquarters in Peoria. Caterpillar is
testing the new biodegradable hy-
draulic fluid in cooperation with ARS
and Lambent Technologies of Chica-
"The initial yield of estolides in
our tests with vegetable oil was very
small because our process wasn't
very efficient," says Isbell. "Estolides
have been made for a long time but
never in large enough quantities to be
practical on a commercial scale."
Serendipity helped overcome this
problem. "One day, Beth Stiner, a lab
technician formerly with ARS,
conducted an experiment mixing
vegetable oils with sulfuric acid. The
result was a very high yield of
estolides. We've adapted that reaction
for our work," says Isbell.
Researchers made estolides by
breaking vegetable oils into their two
main components: fatty acids and
glycerin. In doing this, they discov-
ered that sulfuric acid acted as a
catalyst to form the estolides.
Estolides form when two fatty
acids-the building blocks of vegeta-
ble oils-link together. ARS re-
searchers used a blend of fatty acids
that could be obtained from high-
Oleic acid is commonly used in
formulating food products that seem
to show potential for lowering blood
cholesterol in humans. It also dis-
plays chemical properties scientists
want in formulating biodegradable
A provisional patent has been filed
on this new product. Lambent Tech-
nologies, formerly Calgene, is
seeking licensing rights to market the
"Right now we're waiting for
Caterpillar to test the product and
give us their feedback," says Isbell.-
By Dawn Lyons-Johnson, ARS.
Terry A. Isbell, USDA-ARS New
Crops Research Unit, National
Center for Agricultural Utilization
Research, 1815 N. University St.,
Peoria, IL 61604; phone (309) 681-
6235, fax (309) 681-6524, e-mail
Agricultural Research/November 1998
--rTT I...-Il IC- -
Horticulturist Fumiomi Takeda inspects the size and quality of hydroponically grown
T he first recorded use of
hydroponics is in one of the
seven wonders of the
ancient world: the Hanging Gardens
of Babylon where, historians say,
plants were grown in a steady stream
of water. Centuries later, U.S. troops
stationed on infertile Pacific Islands
during World War II ate fresh fruits
and vegetables produced by
Hydroponics-from the Greek
words hydro (water) and ponos (la-
bor)-is the science of growing
plants without soil. Nutrients that
plants usually get from soil are added
Scientists with USDA's Agricul-
tural Research Service are success-
fully using this time-honored way of
producing crops at the Appalachian
Fruit Research Station in Kearneys-
ville, West Virginia.
There, they are using hydroponics
to grow strawberries without soil-
and even more, without pesticides.
But why hydroponics?
"Strawberry growers worldwide
fumigate the soil with methyl bro-
mide before planting to control soil-
borne insect pests, diseases, and
weeds," says Fumiomi Takeda, an
ARS horticulturist at
fumigation is essential
to get high yields an
"But with the fast-
approaching ban on
use of this chemical, growers are
anxiously looking for alternatives. It
is estimated that banning methyl bro-
mide will cut in half the annual pro-
duction of field-grown strawberries
in California and Florida, our major
But growing strawberries hydro-
ponically eliminates the need for
methyl bromide on this crop.
As for foliage pests, Takeda says,
"Two-spotted spider mites, thrips,
Agricultural Research/November 1998
mildew were the
major problems \ e nc ii entered in
our greenhouse production of straw-
berries. We used beneficial predatory
mites to control the thrips and two-
spotted mites. The mildew problem
can be resolved by moderating the
humidity level in the greenhouse and
by growing varieties that resist mil-
dew infection," he says.
In the Kearneysville greenhouse,
Takeda grew strawberries in round
pots, vertically stacked square pots,
and horizontal troughs similar to rain
gutters. [See "Trading Wastewater
for Crops," Agricultural Research,
February 1995, pp. 10-11.]
He used both established plants
and runner tips from greenhouse-
grown Chandler and Camarosa,
strawberry varieties developed in
California; Sweet Charlie, developed
in Florida; and Tribute and Prime-
time, developed by ARS in Belts-
ville, Maryland. He also included
freshly dug Canadian nursery plants
of Chandler, Camarosa, and Sweet
"We controlled temperatures at
680F during the day and 57F at
night, and we preconditioned trans-
plants for 150 degree-hours of chill-
ing at or below 450F. Combining this
with the natural photoperiod and sup-
plemental lights during overcast days
produced plants that yielded lots of
good-sized fruit," Takeda says.
Camarosa proved to be the most
productive variety. "We picked over
2 pounds of marketable strawberries
from each Camarosa plant," Takeda
reports. In soil fumigated with meth-
yl bromide, Camarosa and Chandler
will each yield over 2 pounds of
In late August, Takeda set runner
tips in bedding plant containers with
peat mixture to produce "plug"
plants. He misted the plants
intermittently until they had well-
Agricultural Research/November 1998
developed roots. On October 1, plug
plants and fresh-dug plants shipped
from Canada were placed in the
hydroponic growing systems.
Takeda subjected plants in troughs
to a continuous flow of recirculating
nutrient solution. He fed the plants in
pots intermittently with a nutrient so-
lution and also transplanted plug
plants to pots stacked to form towers.
"We harvested ripe fruit twice a
week from December to May, the pe-
riod when shipments of California
strawberries slow down. Fruit quality
and taste were excellent," he says.
Transplants or plug plants pro-
duced more fruit than field-nursery
plants. According to Takeda, the root
system of both types of plants re-
mained healthy throughout the 7- to
8-month growing period, with no
appearance of root diseases.
However, in the stacked-pot
towers, the top sections got
more light and therefore bore
healthier plants and more fruit.
Light intensity greatly affects
strawberry growth and development.
Since light levels reaching the plants
at the lower section of the towers
were only 20 percent of levels mea-
sured at the top, fruit production was
"Slightly taller pots spaced farther
apart on the towers would reduce this
problem," says Takeda.
Bruce Pape, an organic grower of
herbs and ornamentals on Maryland's
Eastern Shore, has been experiment-
ing with pot-grown strawberries as
ornamental plants. "We have some
specialty market outlets that would
probably be able to sell ornamental
strawberry plants quite well," he
says. "Consumers would not only get
a beautiful ornamental hanging bas-
ket, but a way to grow a few straw-
berries in the winter months as well."
Pape and his wife Carmen have ex-
perimented with several strawberry
Hydroponic systems reduce space
requirements and growing time need-
ed to produce a crop. Since there is
no soil involved, no tillage is neces-
sary-and there are no weeds to con-
tend with. The amount of chemicals
needed is reduced, since biocontrol
measures work better in the con-
trolled environment of a greenhouse
and there are fewer pests.
Environmental factors aren't a
problem in greenhouses since light-
ing, temperature, humidity, and irri-
gation can be controlled. Nutrients
used for plant growth are recyclable,
to be used again and again.
Using hydroponics also reduces
the cost and increases the efficiency
of labor. Field-harvesting straw-
berries involves back-
breaking labor, since
laborers must stoop to pick
the crop. Hydroponically
grown berries can be
harvested from a standing
-Although initial set-up costs for
hydroponic farming are high, growers
may recoup that cost by producing a
higher value product, increasing
yields, and spending less money to
control pests and diseases," says
Takeda. "Our research demonstrated
that two California strawberry varie-
ties can be grown by soilless means.
However, we need more research to
measure the performance of other
strawberry varieties and to investi-
gate the influence of plant type-
plug, fresh-dug, dormant, or single or
multiple crown-as well as planting
dates."-By Doris Stanley, ARS.
Fumiomi Takeda is at the USDA-
ARS Appalachian Fruit Research
Station, 45 Wiltshire Rd., Kear-
neysville, WV 25430-9425; phone
(304) 725-3451, ext. 12.
fax (304) 728-2340.
Tanning Research Update
T he process that turns raw
cowhide into supple leather
is a complex one. But scien-
tists at the Eastern Regional Research
Center (ERRC) in Wyndmoor, Penn-
sylvania, have come up with innova-
tive ideas to increase the efficiency of
processing those animal skins into
leather, while ensuring better quality
"Not only does our research
benefit the hides and tanning indus-
tries, it also promotes the health of
the environment," says William N.
Marmer. He heads the ERRC's
Hides, Lipids, and Wool Research
Unit, a part of USDA's Agricultural
"We have our own pilot plant tan-
nery here at ERRC," Marmer says.
"This is the only public facility of its
kind in the United States. Domestic
tanners come here to take short
courses sponsored by the U.S. leather
According to Marmer, cattle hides
are the most valuable coproduct of
the meat packing industry.
"Here in the United States, we pro-
duce about 35 million of them each
year," he says. About 60 percent are
exported as preserved hides-that's
more than $1 billion in foreign trade.
The remainder are tanned into about
$4 billion worth of finished leather
here in the United States."
Preserving Hides for Later
Throughout history, sodium chlo-
ride (NaC1), or common salt, has
been the key to preserving hides and
foods like fish and meat, primarily
because it draws water out of prod-
ucts. Early trappers favored salt to
cure meat and hides because it's easy.
Bacteria-which can destroy a hide's
quality-can't grow in the absence of
Salt is still used to preserve hides
that can't be immediately tanned. But
this salt curing puts a load on the
"Each salt-cured hide produces a
gallon of salt-saturated brine that
must be disposed of," says biochem-
ist David G. Bailey. "If a packing-
house cures 5,000 hides a day, it'll
have to dispose of 5,000 gallons of
ARS industrial specialist Gary Dimaio
(left) and biochemist David Bailey inspect a
cowhide being packaged for preservation
salt water. Tanneries must then wash
out that salt before converting the
hides to leather. But adding salt wa-
ter to soil lowers fertility and leeches
important minerals like magnesium,
iron, and manganese deeper into the
earth, away from plant roots."
Bailey's research has identified
three solutions to the brine problem:
potassium chloride, electron beam ir-
radiation, and gamma irradiation.
"We've shown that each of these
is an effective, viable alternative to
curing hides with common salt,"
Bailey says. "They're just not being
used by the tanning industry simply
because salt is cheap and easy to use,
and there is no mandate that prohibits
Using potassium chloride (KC1),
or potash, to cure hides would actual-
ly be beneficial to the environment
because potassium is a plant nutrient
that enhances growth. However, pot-
ash is a little more expensive than
NaC1, adding about $2 to the cost of
curing each hide.
"We found no major differences in
the quality of 2,500 hides tanned with
KCI compared to hides tanned with
NaC1," Bailey says. "And while there
are minor differences in the process,
there are no technical obstacles."
ARS scientists have a formal re-
search agreement with Kalium of
Canada, Ltd, and informal collabora-
tion with other hide processors and
Irradiation Also Works
Curing with electron beam irradia-
tion differs from gamma irradiation
simply in the source of the energy.
The electrons kill bacteria that would
otherwise destroy hides, and sterile
packaging then prevents reinfection.
Research shows that irradiation in the
presence of small amounts of bacteri-
cide prolongs the shelflife of treated
hides sufficiently for long-distance
shipping to a tannery and eliminates
the need for sterile packaging.
In electron beam irradiation, cath-
ode ray tubes similar to those in a
television set zap hides with energy
beams of 3 to 10 million volts. Gam-
ma rays, on the other hand, are pro-
duced by a cobalt source contained at
the bottom of a 20-foot-deep pool of
According to Bailey, both treat-
ments protect the hides effectively.
Gamma irradiation disperses elec-
trons more uniformly throughout the
hide, but electron beams treat a more
Agricultural Research/November 1998
Cost-wise, gamma irradiation is
more economical for very large num-
bers of hides, while the electron
beam approach favors smaller opera-
tions. Gamma irradiation takes hours;
electron beam, seconds.
"Garden State Tanning in Will-
iamsport, Maryland, is evaluating
leather made from hides preserved
with both these processes," Bailey
says. "Both irradiation methods are
already being used throughout the
world on a wide variety of products
including bandages and other soft
medical supplies. They're also used
to alter the physical properties of
In addition to disposing of waste,
another problem with using NaC1 to
cure hides is that the salt promotes
the growth of halophilic bacteria.
These salt-loving bacteria have been
associated with "bad" hides because
they cause a red pigmentation, called
red heat, on the hide.
Industry has always thought that a
hide with red heat must be tanned as
soon as possible because there is po-
tential for hide damage by these bac-
teria. Bailey and colleagues have
shown that at the point where red
heat becomes visible, hide damage
has already occurred.
Turning Waste Into High-Value
From 100 pounds of cattle hides, a
tanner gets only 50 pounds of
leather-and 50 pounds of waste.
"One of the chemicals used in the
tanning process is chromium-III
sulfate, which is nontoxic," says
Marmer. "Therefore, most leather
contains chromium. When tanners
shave the bottom sides of chromium-
tanned hides to give them a uniform
thickness, so-called chrome shavings
end up as waste that must be hauled
to landfills at a price. The tanning
industry generates more than 60,000
Agricultural Research/November 1998
metric tons of chrome shavings each
year," he says.
Marmer and chemists Maryann M.
Taylor and Eleanor M. Brown have
found a way to make two types of
protein from this waste and to recycle
the residual chrome back into the tan-
S.- - .
Chemists William Marmer and Maryann
Taylor look at material shaved from the
underside of hides. More than 60,000
metric tons of this waste-shavings
containing chromium-III sulfate used in the
tanning process-are generated each year
in the United States.
"We used a common laundry deter-
gent enzyme called alkaline protease
to break down the chrome shavings,"
Taylor explains. "Our initial product
was a low-value gelatin protein that
can be used in fertilizer and animal
"Our second-generation product
was a higher value protein, a technical
grade of gelatin that can be used in
making adhesives, industrial films for
packaging, and encapsulating agents
for industrial and agricultural chemi-
cals. We found that our gelatin has
functional properties equal-and in
some cases, superior-to commercial-
ly produced gelatins."
Taylor chemically purified the
chromium left over after the proteins
were removed and reused it as an
agent in the tanning process. "We got
leather of quality comparable to that
tanned commercially," she says.
Taylor has even found a way to
recycle the enzyme used to liberate
ARS holds two patents on the pro-
cess to convert the waste to protein
products. Scientists at Spain's CSIC/
CID national research laboratory and
at Ramon Llull University in Barcelo-
na collaborated on part of the re-
search. ARS also has a cooperative
agreement with ATO-DLO, a Dutch
institution, to develop applications for
the protein products.
Marmer would like to see the
chrome recycling process implemen-
ted at U.S. tanneries.
"The process, modified for use in
the Czech Republic by the Technical
University of Brno at Zlin, is now be-
ing used at a Czech tannery," Marmer
says. "We've determined through cost
analyses that the process is economi-
cally feasible."-By Doris Stanley,
Scientists mentioned in this article
are located at the USDA-ARS Hides,
Lipids, and Wool Research Unit,
Eastern Regional Research Center,
600 East Mermaid Lane, Wyndmoor,
[William N. Marmer] phone (215)
233-6585, fax (215) 233-6795, e-mail
[David G. Bailey] phone (215)
233-6486, fax (215) 233-6795, e-mail
dbailey @ arserrc.gov
[Maryann M. Taylor] phone (215)
233-6435, fax, (215) 233-6795, e-
[Eleanor M. Brown] phone (215)
233-6481, fax (215) 233-6795, e-mail
Biosensor Detects Chemical
Researchers are hoping a new biosensor may help
farmers and regulatory officials detect herbicides in soil
and water samples. The device relies on living organisms
or their byproducts to identify traces of chemical residues
in a matter of minutes.
Heavy applications of herbicides can leave environ-
mentally unsafe residues in soil and water. The biosensor
is made of a chlorophyll-protein complex-the green
proteins in plants used for photosynthesis-fixed on
electrodes that specifically measure oxygen levels. The
complex produces oxygen in the presence of certain
chemicals and light.
A liquid sample is passed through the biosensor. If the
sample contains a herbicide, the chemical will react with
the biosensor's proteins and inhibit oxygen production.
The electrode in the biosensor detects oxygen levels and
sends the information to a computer that displays the data
in graph form.
The test is ultrasensitive and works well at room
temperature or above. But "the chlorophyll-protein
complex from plants such as potatoes, peas, and broad
beans can't withstand high temperatures, so they are
unsuitable for use as biosensors," says molecular biolo-
gist Autar K. Mattoo.
The new device instead uses a protein complex from a
particular cyanobacterium-a bacterium that can fix
carbon dioxide in the presence of light and can grow at
very high temperatures-that isn't inactivated at warmer
temperatures a user might encounter in the field.
"If a biosensor is to be used repeatedly, especially in
the field, it requires a biosensing device that is stable at
ambient temperatures and doesn't require cooling," says
The new biosensor is easy to use and economical-
distinct advantages over currently available herbicide
detectors. "Other sensors are reliable," says Mattoo. "But
they require expensive equipment and lab analysis,
limiting the number of samples that can be analyzed."
This biosensor can run repeated tests in the field. The
scientists are working on a miniaturized commercial
version that should be available within the next 2 to 3
years. Mattoo co-developed the biosensor with scientists
from the Czech Republic and Italy through a grant
supported by the North Atlantic Treaty Organization.
More detailed information about this research will soon
be published in the journal "Biotechnology and Bioengi-
neering."-By Tara Weaver, ARS.
Autar K. Mattoo is at the USDA-ARS Vegetable
Laboratory, Bldg. 01OA, Room 246, 10300 Baltimore
Ave., Beltsville, MD 20705-2350; phone (301) 504-7380,
fax (301) 504-5555, e-mail email@example.com. *
A Little Bit of Yew Helps Insecticides
When a black vine weevil eats a yew leaf, it gets more
than food. The same plant that gives the insect nutrients
passes on a dose of a powerful chemical that can, when
combined with certain pesticides, lead to the bug's death.
The weevils, Otiorhynchus sulcatus, invaded the United
States from Europe in the early 1900s and are now a major
pest of small fruits like strawberries and ornamentals like
rhododendrons and begonias.
Scientists suspected the yew's qualities when they
noticed that pyrethroid insecticides killed black vine
weevils feeding on yew plants but not weevils on straw-
Robert P. Doss, a plant physiologist with the Agricul-
tural Research Service, discovered why.
"We've isolated three chemicals in the yew that act as
synergists to increase the effectiveness of pyrethroids," he
These are the first insecticidal synergists ever found in
the yew, which has been widely studied as a source of
Doss works in the ARS Horticultural Crops Research
Unit at Corvallis, Oregon. He collaborated with scientists
at Oregon State University in Corvallis and Washington
State University in Vancouver.
Pyrethroid insecticides are synthetic compounds based
on pyrethrins, natural insecticides found in a certain type
of chrysanthemum. They are popular because they are less
toxic than some other commonly used chemicals.
Pyrethroid-based products often contain a synergist to
increase their potency. For example, piperonyl butoxide
dramatically increases the potency of insecticides that kill
fleas on dogs and cats by disrupting a key enzyme in-
volved in insecticide breakdown by the insect. Piperonyl
butoxide is a synthetic version of a compound found in
sesame seeds. Doss believes the yew insecticide synergists
may work the same way.
The yew compounds have very complicated chemical
structures and took nearly a decade to isolate.
"Right now, these chemicals would be prohibitively
expensive to manufacture," Doss says. But discovering
their structure paves the way for developing cheaper
Doss' next step is to test the synergist-pyrethroid
combination on other weevils, as well as on moths,
crickets, and beetles that attack crops.-By Kathryn
Barry Stelljes, ARS.
Robert P. Doss is in the USDA-ARS Horticultural
Crops Research Unit, 3420 NW Orchard Ave., Corvallis,
OR 97330; phone (541) 750-8773, fax (541) 750-8764, e-
mail firstname.lastname@example.org. *
Agricultural Research/November 1998
Putting Forests on Farms and Farms in Forests
E astern Europe may have
something to teach America
about growing trees-
including American trees-on small
Soil scientist Charles M. Feldhake
and horticulturist Carol M. Schu-
mann at the ARS Appalachian Soil
and Water Conservation Research
Laboratory in Beaver, West Virginia,
look enviously at the many varieties
of American trees, like black locust,
that Europeans have selected for
livestock browsing and timber and
various other purposes.
When East Europeans think of
farms, they see a picturesque scene
with cows, goats, and sheep mixed in
with forests, orchards, and beehives.
Feldhake and Schumann think
that's a much more suitable model
for the Appalachian hill-
lands than the large SUSAN BOYER (
corn-soybean farms of
the Midwest. The steep
hills with shallow soils
can't take any tillage, so
perennials like trees and
shrubs are a natural for
Five years ago,
Feldhake began growing
1,200 black locust trees
on a steep, hilly pasture
nestled near the mixed
hardwood forest sur-
rounding the lab. The
trees are in rows about '
30 feet apart in a 5-acre Horticultur
watershed. Currently, 25 seedling,
sheep graze there.
Another 25 graze in an
adjacent 5-acre watershed without
"We want to find out whether the
trees can reduce nitrogen losses by
catching excess nitrogen from
livestock urine and manure,"
Feldhake says. "To check that, we're
measuring how much nitrogen leaves
Agricultural Research/November 1998
the two watersheds in subsoil water
and surface runoff."
Feldhake says trees add diversity
to a farmer's income. Black locust
can be cut and sold for firewood or
for pest- and rot-resistant fenceposts.
The flowers are good nectar sources
for honey bees. And during a heat
wave, sheep or other livestock can be
rotated to the shady, forested
With black locust, seedling
quality has been a problem. Selec-
ting for top-quality black locusts is a
low priority with breeders in the
United States. "There isn't the
commitment to this tree as a crop
that there is in a place like Hungary,"
Feldhake says ruefully.
But the scientists are testing trees
and shrubs with better breeding, such
ist Carol Schumann evaluates growth of a Chinese c
astanea mollissima, in a woodland agroforestry plant
as black walnut, honey locust, and
sea buckthorn on pastures in West
Virginia and at Virginia Polytechnic
Institute in Blacksburg, Virginia.
Feldhake says there has been
more selection for honey locust trees
because of interest in their pods as a
good source of sugar and protein for
European farmers grow the sea
buckthorn shrub for its berries, which
have a high vitamin content and
reputed medicinal value. They make
jellies and juices from the berries for
home use and roadside sales.
How about growing berries and
other fruits and nuts in forests? This
past winter, Schumann and Feldhake
literally cleared the way for that
unique vision, opening up a 1.2-acre
strip in the forest. In the spring, they
planted red oak tree seedlings. They
also planted faster growing trees and
shrubs for the short term: white pine,
Chinese chestnut, pawpaw, hazelnut,
blueberries, and raspberries.
The red oak will be the climax tree
in the long term, when it could be
selectively cut for high-value veneer.
The white pine will be ready for sale
as holiday trees beginning
December 2006. The
pawpaws and chestnuts will
bear fruits and nuts begin-
ning as early as 2008,
"We need to find out if
we can successfully grow
marketable products from
the shorter term plantings
without negative effects on
the red oaks," she says.
"In addition to meeting
research objectives, this site
is also designed to demon-
strate to local farmers that
they too can farm with trees
hestnut and shrubs," Schumann
ing. says.-By Don Comis,
Charles M. Feldhake and
Carol M. Schumann are at the USDA-
ARS Appalachian Farming Systems
Research Center, 1224 Airport Rd.,
Beaver, WV 25813; phone (304) 252-
6426, fax (304) 256-2921, e-mail
feldhake @ asrr.arsusda.gov
M microscopic mineral par-
ticles may help promote
around the world. Agricultural
Research Service and Engelhard
Corporation scientists have discov-
ered that films made from these
particles repel pests and may deter
disease attack when sprayed on
These particles have been special-
ly sized and shaped. Prototypes of
this particle film technology-called
HPF-have been successfully field-
tested in North America, Europe, and
Products, which will be commer-
cially available in 1999 in parts of the
United States for use on apples and
pears, will be cost-competitive with
conventionally used chemicals.
"Not only can agricultural prod-
ucts made from these particles cut the
amount of pesticides needed, they
may also boost plant health, aid fruit
quality, and over time, improve the
condition of the soil," says ARS soil
scientist D. Michael Glenn. He heads
the project, assisted by entomologist
Gary J. Puterka, at the ARS Appala-
chian Fruit Research Station in
Kearneysville, West Virginia.
"We've successfully tested HPF
technology on several insects and
mites and on disease-causing fungi
and bacteria," Glenn reports. "It
works not only on tree fruit crops,
but has potential to work on vegeta-
ble and field crops as well."
ARS has signed a cooperative
research and development agreement
with Engelhard Corporation of Iselin,
New Jersey, to develop and commer-
cialize the new technology. The
company has filed patents, including
foreign patent rights, on the particle
technology, with ARS as co-owner.
More patents may be forthcoming.
This research shows why USDA
joined with the U.S. Environmental
Protection Agency (EPA) and Food
and Drug Administration (FDA) in
1994 to establish a voluntary partner-
ship with industry to protect human
health and preserve the environment
by reducing pesticide use and risk.
In this case, industry became
involved early on, for it was a
particle provided by Engelhard
on a particular surface-making it
possible to engineer them for
"The films are made of micro-
scopic mineral particles of low tox-
icity," Glenn says. "Current proto-
type films are made by modifying
kaolin, a naturally occurring
After a season-long spray program using a particle film, soil scientist Michael Glenn (left)
and entomologist Gary Puterka note that this Sekel pear tree is healthy and insect-free.
Corporation-one of the largest
producers of specialized particles in
the world-that first aroused Glenn's
interest. As a leader in surface
chemistry, Engelhard can modify the
size and shape of particles and
control the way they are distributed
mineral that is generally regarded as
In fact, kaolin is approved by the
Food and Drug Administration as
an indirect food additive. It doesn't
harm earthworms or beneficial
insects like ladybugs and doesn't
Agricultural Research/November 1998
... A New Kind of Plant Protectant
affect crop pollination. HPF products
made from kaolin should reduce the
amount of conventional pesticides
needed for crop production. Engel-
hard produces kaolin commercially
for use in many products, including
pharmaceuticals, electrical insulators,
cosmetics, plastic extenders, paint,
and paper. The product is sprayed on
as a liquid, which evaporates, leaving
a film on the plant or crop surface.
Coating plants completely with the
liquid is very important. Since the
particles are sprayed on crops in a
water-based slurry, the material
Agricultural Research/November 1998
sticks to plant leaves, stems, and
fruit, forming a white powdery film.
No special equipment is needed for
application; traditional spraying
equipment can be used.
Does this coating interfere with
"Just the opposite," Glenn ex-
plains. "The properties of the parti-
cles are such that sunlight diffuses
into leaves, resulting in little reduc-
tion of light."
What's more, the reflective nature
of the particles reduces heat stress on
leaves and lowers the temperature in
a tree or plant canopy. As a result,
fruit will often have better color, less
sunburn, higher soluble solids,
reduced internal breakdown, and
The particle application may also
indirectly enrich the soil. While some
pesticides reduce earthworm popula-
tions, this material allows them to
move freely through soil, funneling
organic matter down from the surface
and making tunnels that increase
water infiltration and aeration.
Improved soil structure created by
earthworms aids plant growth and
According to Puterka, particle
technology works to deter insects and
mites in several ways. "The particle
film coats the plant, forming a
protective barrier," he says. "When
insects come in contact with film-
coated plants, tiny particles from the
coating attach to their bodies, agitat-
ing and repelling them.
"Even if the particles don't attach
to their bodies, the insects still find
the environment unsuitable," Puterka
reports. "Nonflying insects that are
unable to leave the plant thus become
confused and disoriented when the
particles attach to them. The pests are
unable to feed or lay eggs."
Another deterrent for insects, he
says, is that the white, highly reflec-
tive particle coating makes the plant
unrecognizable as a host. This may
be similar to the concept of white-
washes, which have been shown to
repel certain insects, such as aphids.
Which Pests and Diseases Are
For several growing seasons,
Glenn and Puterka have tested the
particles on a broad range of insect
pests and diseases on apple and pear
trees. The treatment was effective
against leafhoppers, leafminers,
spirea aphids, thrips, European red
mites, two-spotted spider mites, and
late-season apple diseases such as
sooty blotch and flyspeck.
"We also had high suppression
rates for the plum curculio and
codling moth but haven't yet reached
economic levels of control," Puterka
says. "Our most spectacular success
with the particle films to date has
been controlling arthropod pests and
diseases of pears. We've been able to
fully control pear psylla and pear rust
mite and to suppress fabrea leaf
spot-major problems for pear
According to Puterka, the particles
may be most applicable on crops that
will end up being washed and waxed,
like tree fruits, peppers, and cucum-
bers; or on root crops like peanuts,
potatoes, and sweetpotatoes. This, he
says, is because the white film left on
leaf, stem, and fruit can be either
allowed to weather off or removed
after harvest. Conventional packing-
house equipment removes the film.
ARS and Engelhard field-tested
particle films in 1997 and 1998 on
apples, peaches, and pears in Chile.
"We did the tests in Chile while it
was winter here in the United States.
Results were very successful," says
In one trial, several sections of an
abandoned pear orchard were select-
ed for particle film spraying. "At the
end of the season, we went back to
check progress and
Treated groups of
trees stood out in
the orchard like
tiny oases in a
desert," says Glenn.
"Trees in treated
areas were green
while those in
were starkly dif-..
ferent: sparse Untreated Sekel pc
foliage, small the same growing
leaves, and little healthy fruit.
new growth. And
the pears we
gathered from the treated areas were
the first harvested from that orchard
in 7 years. There was no fruit on the
trees that had not been sprayed with
the particle mixture."
In other Chilean studies, treated
peach trees yielded 50 percent more
fruit, while treated apple trees
maintained their yield.
In tests on tree crops in Italy,
particle spray increased color in
pears. But it didn't completely stop
aphids in apples, peaches, or pears,
nor the third generation of codling
moths. Nevertheless, Glenn says, the
Italian tests were successful, overall.
Finetuning the spray timings could
Treatment on apples in Kear-
neysville orchards increased tree
vigor, which allowed trees to support
more fruit and increased production.
When applied to a newly established
peach orchard, the treatment even
controlled Japanese beetles. Glenn
says this is an indication that the
particle film would work well for the
nursery industry, giving young trees
a chance to get a head start on growth
by preventing insect attack, while
reducing water stress.
Results were confirmed in collabo-
rative studies at ARS' Yakima
ears (left) show insect and disease symptoms while tl
conditions, but treated with a particle film, exhibit u
Agricultural Research Laboratory
horticulture research station at
Wapato, Washington. There, parti-
cle-sprayed apple and pear orchards
showed increased fruit size, red
color, and leaf photosynthesis, along
with cooler canopy temperatures.
These research results were
confirmed at six different fruit-
growing regions in 1998. Finetuning
the spray program increased efficacy
and reduced the number of sprayings
Growers Try It and Like It
Both conventional and organic
growers are excited about their field-
test results with the particle films.
Grower Eric Rice of Middletown,
Maryland, says, "The particle film
worked better than the crop protec-
tion methods we were using. Al-
though I'm impressed with what the
particle film did on my crops, one of
the major advantages this technology
has over conventional chemicals is
the aspect of grower/worker safety.
"A farmer is exposed to whatever
he applies to his crops. This particle
film comes from inert mineral
deposits, and we know that the FDA
regards it as safe. This means a lot to
growers," he says.
le exo Rice's acreage
flowers, and a
"I sprayed my
apple trees with
the mixture, and it
codling moth and
hose exposed to which are major
damaged, pests, and worked
says Rice. "We
don't have much
trouble with mites, aphids, and other
insects, probably because we use
beneficial predatory insects."
Results were more variable for
disease control, he says.
"The spray was completely
effective for fire blight, although
1997 might have been a year of low
incidence. Under organic guidelines,
we can spray streptomycin on fire
blight, but even then, we always get
a little infection. With the particles,
we didn't have a single incident of
However, the new treatment
didn't work as well with apple scab
the first year. Trees not suscepti-
ble-or with average susceptibili-
ty-to scab, fared well. But for gala
apple, which is highly susceptible to
the disease, the particles didn't
"I must say that our spray sched-
ule in 1997 for the galas was proba-
bly not properly targeted. We didn't
spray until after full bloom, and we
got infection on the fruit. But since
there was no infection on the leaves,
we know that the material must have
provided some measure of control,"
Rice reports. Adjusting the spray
schedule in 1998 brought excellent
Agricultural Research/November 1998
The Washington Tree Fruit
Research Commission-a grower-
funded organization that is a re-
search partner in the venture-is
testing the products in commercial
"We are interested in these
products for their insect- and dis-
ease-control potential, but primarily
for their horticultural benefits," says
James McFerson, a scientist with the
Commission. "We're evaluating the
products, which we applied with
typical airblast sprayers, on three 1-
acre, replicated test plots."
Ray Schmitten grows pears on
120 acres in the Wenatchee River
Valley of Washington.
"We sprayed our orchards KE
with kaolin products this spring
and got complete control of pear
psylla, our biggest pest prob-
lem," he says. "We used no other
products for this pest."
Pear psylla deposit honeydew
on leaves. But in areas where the
new products were used, there
was no evidence of this sticky
substance. For pear psylla, the
products worked better than
conventional pesticides. T(
Schmitten says the products pi
also completely controlled rust R.
mite and were effective on
codling moth, although it was
still early in the season for this
pest. Another unexpected
benefit, he says, was that the kaolin
products reduced the effect of a fine
fuzz that pear leaves produce, which
causes field workers to cough.
EPA Exempts Particle Film
In 1997, EPA granted an experi-
mental use permit for Engelhard and
ARS to field-test the material with
50 collaborators-including other
ARS and university scientists, as
well as growers-throughout the
Agricultural Research/November 1998
United States. The mineral particles
have been approved for use on
organic farms in Virginia, Maryland,
and Washington. Because the product
is chemically inert and low in toxici-
ty, EPA exempted the particle film
technology from pesticide tolerance
regulations and on March 17, 1998,
registered three prototype products
"It takes about 8 years for a new
pesticide to go through the EPA
registration process," says John
Mosko, marketing manager for
Engelhard. "But with help from
USDA, we dramatically stepped up
the trial program for these products
N HAMMOND (K8257-1)
technicians Adam Finkelstein and nharon Jones apply
Article film to blackberries using a handgun sprayer.
results with blackberries indicate a broad insect
after we saw such promising early
results. This will help us launch
particle film products commercially
"We're not touting these particle
films as a replacement for chemical
use. But we realize that growers need
alternatives to chemicals, especially
those that may have difficulty in
getting re-registered by EPA," he
Minor Crops Have a Major Need
The new Food Quality Protection
Act of 1996 sets a higher standard
for conventional pesticides, encour-
aging development of reduced-risk
products. Many so-called minor-use
pesticides may soon no longer be
available to growers. Potential regis-
trants will not seek re-registration if
there is insufficient economic
incentive to justify data requirements
or if new regulations require them to
cut back some uses. Minor-use
pesticides are applied to such crops
as fruits, vegetables, nuts, ornamen-
tals, and nursery products.
Grown on 8 million acres in the
United States, minor crops are
valued at around $24 billion
annually. This is about 40
percent of all agricultural crop
sales. "Growers of these crops
are going to be hurting for
alternatives to chemicals that
may not be available in a few
years," Mosko says. "Our new
particle technology can help
fill this void."
"We're fortunate that
Engelhard is our partner in this
venture to further develop new
technologies from these
mineral particles," says Glenn.
"This technology can help us
realize our goal of having 75
percent of U.S. agricultural
acreage under integrated pest man-
agement programs by the year
2000."-By Doris Stanley, ARS.
D. Michael Glenn and Gary J.
Puterka are at the USDA-ARS
Appalachian Fruit Research Station,
45 Wiltshire Rd., Kearneysville, WV
25430-9423; fax (304) 728-2340,
[Glenn] phone (304) 725-3451,
ext. 321, e-mail
mglenn @ afrs.ars.usda. gov
[Puterka] phone (304) 725-3451,
ext. 361, e-mail
email@example.com. usda.gov. *
of Farm Machinery
A s farming moves into the
21st century with tractors
carrying satellite navigation
receivers, radar guns, and computers,
one thing hasn't changed-do-it-
The urge of farmers to retrofit ex-
isting equipment to save money and
perhaps do the job better is infec-
tious. It spreads to private industry
and government representatives who
work with farmers. From this inter-
change, new farm equipment is born.
So it should be no surprise to see
this old-fashioned ingenuity blossom-
ing with futuristic precision agricul-
ture in equipment sheds at the Belts-
ville (Maryland) Agricultural Re-
search Center, or BARC, which is
part of USDA's Agricultural Re-
Precision agriculture means farm-
ing with on-the-go monitoring of
yields and soil types, as well as of
chemical and manure applications.
Global Positioning System (GPS) sat-
ellites are used to spatially locate
tractors and other farm equipment in
In the BARC equipment yard, Dan
Shirley sits in the cab of a tractor
towing a liquid manure tank. He
chuckles at the thought that "not for a
minute did the manufacturer of this
486 computer think it would be used
to control manure flow rates."
The tractor typifies space-age agri-
cultural tools: It sports a roof antenna
for satellite signals, a GPS receiver in
the cab, and a radar gun below the
cab's floor, to monitor ground speed.
Shirley heads a team of eight who
form the land operations branch for
the east section of the 7,000-acre re-
search farm. They are essentially the
farmers who see that the crops get
planted and the machines work.
Shirley and other crew members
use the equipment to make the cen-
ter's farming more sustainable eco-
nomically and environmentally. The
gear is also used in BARC's preci-
sion farming projects.
The center has a variable-rate liq-
uid manure applicator thanks primar-
ily to crew member John Bouma,
nicknamed "The Fabricator."
Bouma also devised one of the few
silage harvesters in the world with
on-the-go yield monitoring.
Rockwell International gave Bou-
ma a GPS receiver and computer and
a pair of light-beam sensors. The
parts came with no directions, but
Bouma figured them out himself,
wearing various hats including those
of mechanic, welder, engineer, and
researcher. He wore his pit-stop hat,
Adding sensors and computers to farm implements such as these can help farmers run more
cost-efficient and environmentally sound "precision agriculture" operations.
Dan Shirley, Beltsville Agricultural
Research Center farm operations branch
supervisor, inspects yield-monitoring
sensors his crew installed on a silage
too-building a bracket that not only
keeps the sensors aligned, but also al-
lows their removal and reinstallation
in 2 minutes. That's so the sensors
can be cleaned between silage loads
without affecting the alignment.
This bracket sandwiches the sen-
sors on the tube that sucks up har-
vested silage. The two sensors send
light beams to each other, through
holes drilled in the tube. The denser
the silage stream, the less light reach-
ing the sensors, indicating a higher
Not only did Bouma come
through, but he put on an artist's hat
for his standard final touch to equip-
ment modifications: painting the
bracket the same yellow as the New
Holland silage harvester.
Bouma succeeded so well with the
silage harvester that Rockwell has
sold two farmers on copying him.
Bouma also added a variable rate
capability to spreaders used to apply
dry fertilizer as well as liquid ma-
nure. His next assignment: do the
same with a dry-manure spreader.-
By Don Comis, ARS.
Dan Shirley is with the USDA-ARS
Farm Operations Branch, Bldg. 301,
10300 Baltimore Ave., Beltsville, MD
20705-2350; phone (301) 504-8448,
fax (301) 504-8403, e-mail
Agricultural Research/November 1998
Range Reseeding Goes With the Flow
How rain pulls the trigger to revegetate degraded desert
range: The action begins in a dry rill in the New Mexico
A short piece of 3-inch-diameter plastic PVC pipe lies
lengthwise, staked and fitted snugly in the rill, which may
be as small as 4 inches deep and 4 inches wide. Three
smaller seed-filled pipes inside the bigger pipe are glued
to its bottom, top, and side. When the rare rain comes, the
rill becomes a streamlet. The seeders can also be used in
The flowing water shortly breaks through a crepe paper
cap on one end of the outer pipe. Water then begins
shoving seeds from the lowest inner pipe through a mesh
screen and into the channel. Heavier rains push the seeds
out faster and lift the water higher in the pipe, so it goes to
work on the middle and top tubes. The seeds-sideoats
grama, a native prairie grass-flow down the rill. Down-
stream, they're deposited in their seedbed: a moist channel
bottom covered by a mulch of leaves and small branches
also dropped by the slowing waterflow.
This seed delivery package is being evaluated by Jeff
Herrick, a rangeland scientist with the Agricultural
Research Service's Jornada Experimental Range in Las
Cruces, New Mexico, and graduate student Ramon
Gutierrez of Mexico's Instituto Nacional de Investiga-
ciones Forestales, Agricolas y Pecuarias.
The package was developed by Gutierrez and ARS
scientists and costs about 75 cents. It exemplifies the new
remediation strategy at the Jornada of mimicking nature's
ways-relying heavily on trigger sites like the rill.
"Trigger sites have some natural advantage, usually
access to water," says rangeland scientist Kris M.
Havstad, who leads the ARS Jornada research team.
"This allows a little time and money to go a long way
toward encouraging protective grasses and other ground
cover on barren land. And the improvements can spread
into the surrounding areas, slowing down wind erosion
and desertification," says Herrick.
Another trigger site is a shallow basin where rainwater
"We plan to study the trigger areas to see if the plants
spread outward," says Herrick.-By Don Comis, ARS.
Kris M. Havstad and Jeff E. Herrick are at the USDA-
ARS Jornada Experimental Range, P.O. Box 30003,
NMSU, Dept. 3JER, Las Cruces, NM 88003-0003; phone
(505) 646-4842, fax (505) 646-5889, e-mail
Venom Chemical Lures Bee Researchers
A honey-making insect known as the Asian hive bee,
Apis cerana, has surprised and puzzled scientists.
They've learned that it hides a large amount of an oily
compound in an unexpected place-its venom sac.
The compound may be an active ingredient in what
some scientists think is an alarm pheromone-a sub-
stance that signals other bees to attack intruders. But until
now, pheromones had never been found in bee venom,
according to Justin O. Schmidt. He is with the Agricultur-
al Research Service in Tucson, Arizona.
"Other bees," says Schmidt, "apparently store phero-
mones in spongelike tissue at the base of the stinger."
Schmidt collaborated with researchers from England
and Brazil in analyzing more than 300 Asian hive bees
from Hong Kong, Malaysia, the Philippines, India, and
Japan. They found that A. cerana has "50 to 100 times
more of the pheromone component than other bees,"
The compound is (Z)- 11-eicosen-l-ol, or eicosenol, for
short. Scientists have known since 1982 that bees make
eicosenol. But why does A. cerana make so much of it-
and store it in the venom sac?
"It may be a tagging chemical to mark a potential
intruder to the hive and alert hivemates," says Schmidt.
"Or this bee may use eicosenol to mark patches of
flowers rich in nectar so other bees from the hive can
locate them quickly and easily. These are our best
Schmidt wants to not only pinpoint eicosenol's value
to this bee, but also find out if the chemical may have
other uses. "We're hoping further research will reveal
ways to use it to help European honey bees fend off
harmful mites, for instance," he says.
In the United States, the European honey bee, Apis
mellifera, is a key pollinator of crops and a source of
honey and beeswax.-By Marcia Wood, ARS.
Justin O. Schmidt is at the USDA-ARS Carl Hayden
Bee Research Center, 2000 E. Allen Rd., Tucson, AZ
85719; phone (520) 670-6380, ext. 109, fax (520) 670-
6493, e-mail firstname.lastname@example.org. *
Agricultural Research/November 1998
GPFARM Software Foresees the Future
F or the first time, Great Plains
farmers and ranchers will
have an electronic crystal ball
to foresee consequences of their
"Our new computer program will
give farmers and ranchers new
insight-stretching ahead as much as
10 or 20 years-into the economic and
environmental effects of what they
plant, when and how much they ferti-
lize, and the form of conservation
tillage they practice," says Agricul-
tural Research Service soil scientist
Lajpat R. Ahuja.
The new software, a decision
support system, is named "GP-
FARM"- short for Great Plains
Framework for Agricultural Resource
Ahuja heads the team of ARS
researchers that developed GPFARM
at Fort Collins, Colorado. Ahuja's
ARS colleagues include hydraulic
engineer James C. Ascough, II, soil
scientist Marvin J. Shaffer, range
scientist Jonathan D. Hanson, and
several support staff.
They devised the program in
collaboration with agricultural econo-
SCOTT BAUER (K8221-6)
To determine management units for a farm layo
Bruce Vandenberg (left), agronomist Debbie Ed
rangeland scientist Pat Bartling examine a soil s
screen shape palette allows them to draw the far
scanned aerial image. A custom toolbar at the to
them control the image and define resources an
mist Dana L. Hoag at Colorado State
Version 1.0 of GPFARM should
be released sometime this fall. Ahuja
says it will be the first agricultural
decision support system of its kind
designed to run under the Microsoft
Windows 95 operating system.
Simulation results are displayed as
narrative text, tables, and graphs. A
typical desktop computer can run
GPFARM for an average farm or
ranch in 30 minutes or less.
Earlier this year, the scientists
beta-tested a prototype with about 30
farmers, agricultural consultants, and
personnel at other USDA agencies.
Beta-tester Bill Gilbert has worked
for 18 years as a consultant to over
35 farmers in the Fort Collins area.
"GPFARM should lead to better
decisions-economic as well as
environmental-on a host of vari-
ables like applying water, fertilizers,
and pesticides," he says.
"GPFARM will allow managers to
design and compare alternative
strategies on the computer before
implementing them in the field,"
Ahuja says. The program has built-in
soils, land use,
about farm or
well as their
ut, systems engineer ment practices.
munds (center), and Then
urvey map. An on- GPFARM
m layout over a simulates
'p of the screen helps biological,
I operations for the
chemical, and physical interactions
between soils, crops, animals, and
climate. The interactions lead to
customized management decisions.
GPFARM also simulates how
decisions affect soil productivity,
animal production, soil erosion, and
quantities of nitrate and pesticides
leached from soil.
"The program even takes into
account factors affecting long-term
sustainability for economic and
environmental factors," Ahuja says.
Examples include loss of soil produc-
tivity due to erosion, changes in soil
organic matter content, and degrada-
tion of groundwater quality and
"We have been fine-tuning and
resolving over 200 comments and
suggestions from the beta-testers," he
notes. "As a result, we have made the
program easier to use by modifying
its look on the screen and improving
the ways in which users enter the
data and display the simulations. We
also strengthened the program's
capacity to simulate the growth of
irrigated crops," says Ahuja.
Future versions of GPFARM will
use geographic information system
(GIS) technology-a computerized
approach to storing and analyzing
geographic data. GIS will allow users
to evaluate environmental effects-
on and off the farm-of runoff,
chemical seepage, and erosion. It will
also allow gauging the off-site fate of
each chemical leached. -By Hank
Lajpat R. Ahuja is in the USDA-
ARS Great Plains Systems Research
Unit, P.O. Box E, Fort Collins, CO
80522; phone (970) 490-8315, fax
(970) 490-8310, e-mail
gpfarm @ gpsr.colostate.edu
GPFARM will be available free of
charge either on CD-ROM or via
downloading from the lab's web site
at www.gpsr.colostate.edu/GPSR. *
Agricultural Research/November 1998
Anti-Mite Gel Gets
A new gel treatment invented by
ARS scientists in Maryland has been
licensed to a private firm, moving the
product closer to helping beekeepers
stop varroa mites. The mites cause
economic losses for beekeepers, as
well as for U.S. farmers who depend
on honey bees to pollinate $10 billion
worth of crops. The struggle against
the mites became more difficult once
they began developing resistance to
the standard control, fluvalinate. But
ARS has now licensed a gel contain-
ing formic acid to Betterbee, Inc., of
Greenwich, New York. In field tests,
formic acid gel killed up to 84
percent of varroa mites. It also killed
100 percent of tracheal mites. Better-
bee must obtain U.S. Environment
Protection Agency approval before
selling the product to beekeepers.
They would simply place a small,
sliced-open plastic bag of the gel
inside a beehive. The formic acid
slowly evaporates, leaving a harmless
residue. Hachiro Shimanuki, USDA-
ARS Bee Research Laboratory,
Beltsville, Maryland; phone (301)
Ag Info Network To
Twenty-one U.S. and Canadian
universities and other organizations
aim to expand the global reach of
AgNIC, the Agriculture Network
Information Center, on the World
Wide Web. Their goal: make AgNIC
the world's most comprehensive,
helpful, and well-used agricultural
information resource. It could help
people around the world find reliable,
fast sources of agricultural informa-
tion-especially during drought or
other natural disaster. Visitors to
AgNIC at http://www.agnic.org can
find links to more than 900 data-
bases, a contact list of specialists, a
calendar of conferences, and other
agricultural information. A prototype
went on-line in 1995 through efforts
of Cornell and Iowa State Universi-
ties, the Universities of Arizona and
Nebraska at Lincoln, and the Nation-
al Agricultural Library, which is part
of ARS. AgNIC members plan to
continue expanding the subject-area
coverage and attract new members.
Organizations interested in joining
AgNIC can contact Melanie Gard-
ner, USDA-ARS National Agricultur-
al Library, 10301 Baltimore Ave.,
Beltsville, MD 20705-2351; phone
(301) 504-6780, e-mail
Reliable Pig Virus Test
A new genetic test quickly distin-
guishes a damaging pig virus from a
harmless strain of the same virus
used in a vaccine. The virus causes
PRRS-porcine reproductive and
respiratory syndrome. PRRS is one of
the world's most costly swine dis-
eases. It causes late-term fetal deaths,
abortions, weakness in newborn pigs,
and severe respiratory disease in
young pigs. When an outbreak
occurs, lab diagnosticians have
difficulty differentiating disease-
causing field strains from the vaccine
strain. But the new test developed by
ARS researchers in Iowa pinpoints
genetic markers in both field and
vaccine strains. The test is accurate
and takes only 2 days to report results
after the virus is isolated. ARS and
Laboratories of Sioux Center, Iowa,
evaluated the test under a cooperative
research and development agreement.
In a 1995 study of 286 herds, PRRS
virus-previously known as mystery
pig disease-was found in 60 percent
of the unvaccinated herds tested.
William L. Mengeling, USDA-ARS
National Animal Disease Center,
Ames, Iowa; phone (515) 239-8254,
e-mail wmengeli@ nadc.ars.usda.gov.
20-Year Test Finds
Sewage Sludge Safe,
Growing crops with municipal
sewage sludge is safe and beneficial
to crops and soil, according to a 20-
year study in Minnesota. A common
concern has been that sludge, or
biosolids, will put toxic heavy metals
into food crops. The study indicates
this won't happen if biosolids are
used correctly. Each fall, researchers
injected a liquid suspension of sludge
into the soil of fields used to grow
corn and reed canarygrass. Crop
yields were slightly higher with the
biosolids than with commercial
fertilizer. Importantly, no extra
metals showed up in the corn or grass
except slightly higher levels of zinc.
The zinc-well within safety guide-
lines-would be beneficial as a
dietary nutrient. The biosolids also
help return carbon to the soil. By
contrast, incinerating or composting
sludge results in loss of carbon to the
atmosphere as carbon dioxide.
Biosolids contain a slow-release form
of nitrogen less likely to be lost to
surface water or groundwater. Like
commercial fertilizers, however,
biosolids should be applied only at
rates that allow for nutrient uptake by
crops. Robert H. Dowdy, USDA-ARS
Soil and Water Management Re-
search Unit, St. Paul, Minnesota;
phone (612) 625-7058, e-mail
bdowdy @ soils. umn. edu.
Agricultural Research/November 1998
U.S. Department of Agriculture
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