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: September 1999
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Full Text
D U.S. Department of Agriculture Agricultural Research Service


September 1999


Tiny- Phorid Fly Attacks, Beh ds Feisty Fire Ants!! (p. 4)
How'd You Like More Lusci s Strawberries? (p. 12)
Giving Piglets a Goo ead Start (p. 1i)

:: A AAAiiiii


.** *



Hope for Fire Ant

Do insects exist only to make life
more difficult for people? Some would
say yes, preferring to squash the small
critters at every opportunity.
But many insects do, indeed, serve a
purpose in the world-pollinating crops,
for example. Those insects have an indi-
rect though important role in feeding the
Then there are beneficial insect pred-
ators and parasites, such as flies and
wasps that attack other insects, thus help-
ing to maintain an ecological balance.
These beneficial form the basis of our
biological control research, keeping pest
insects like boll weevils, corn borers, and
fruit flies from destroying millions of
dollars in crops.
But what happens when an insect is
both a helpful predator and a pest? What
happens when this insect tips the eco-
logical scales? Many states are finding
Red imported fire ants heavily infest
more than 300 million acres in 12 south-
ern states and Puerto Rico: Texas, Okla-
homa, Arkansas, Louisiana, Alabama,
Mississippi, Florida, Georgia, North and
South Carolina, Tennessee, and Virgin-
ia. Recently they've become established
in limited areas in California and New
Fire ants are thought to have come
into the United States on contaminated
ships arriving in Mobile, Alabama, from
South America in the early 1930s.
They've spread slowly but steadily. De-
pending on soil types and seasons, their
colonies may be entirely underground or
in mounds ranging from 6 to 18 inches
high. This causes trouble in areas such
as playgrounds, parks, beaches, and wild-
life refuges. The ants' aggressiveness and
ability to reproduce and outcompete oth-
ers for food have allowed them to dis-
place many beneficial insects and other
animals that make up our important

These tiny pests, generally known for
their burning sting, have caused billions
of dollars in damage and control costs
since entering the United States. Scien-
tists believe red imported fire ants have
flourished here because they have no
natural enemies. The ecological balance
has shifted in their favor. U.S. red im-
ported fire ant densities are about five
times those in their native South Ameri-
can habitat.
Researchers with the Agricultural
Research Service's Center for Medical,
Agricultural, and Veterinary Entomology
in Gainesville, Florida, are trying to even
the ecological playing field by working
with state government and extension
representatives to release natural fire ant
enemies from South America.
In 1998, ARS scientists, along with
representatives from the Council of State
Governments' Southern Legislative
Conference, initiated a National Fire Ant
Strategy to help tackle the fire ant
problem. In each of the infested states,
an appointed state government repre-
sentative and a team of state researchers
work with ARS scientists and state
extension personnel in cooperative field
The goal is to reduce imported fire ant
infestations to levels below economic
thresholds on agricultural lands. One way
to help achieve this is by using biologi-
cal controls to help tip the scale in favor
of native ant species. In the past 2 years,
ARS scientists have been working with
state personnel on releasing biological
control agents in 10 states.
ARS kicked off the first of these re-
leases in July 1997. Tiny Brazilian phorid
flies, Pseudacteon tricuspis, were re-
leased at sites in Gainesville, Florida.
Phorid flies are deadly enemies of fire
ants, stinging them and depositing eggs
inside their bodies. Each fly larva even-
tually grows and moves into the host
ant's head. When the larva is mature, it
decapitates the ant and completes its de-
velopment inside the severed head. Sci-
entists believe these parasitic flies help

reduce fire ant populations in South
America-and could do the same in the
United States.
The second biological control agent
release took place in Hope, Arkansas, in
May 1998. ARS scientists, in coopera-
tion with Arkansas officials, released fire
ant larvae infected with Thelohania so-
lenopsae, a microorganism from South
America that infects fire ant colonies and
chronically weakens them. Unsuspecting
worker ants transfer the pathogen to the
queen through food exchange. The dis-
ease slowly reduces her weight and the
number of eggs she lays. The pathogen
ultimately infects all workers, eventual-
ly weakening the colony and causing its
ARS scientists provide the biological
control agents and train state personnel
on their release. ARS scientists also pro-
vide specialized expertise, data manage-
ment, and interpretation of data from
field releases of biological controls. Co-
operating states have provided some
funding to supplement federal resources
and personnel to rear and release biolog-
ical control agents and to assist in mon-
itoring their impact.
Although ARS has also developed
other strategies for controlling fire ants,
including commercially available baits,
our current emphasis is on biologically
based technologies.
This latest endeavor with fire ants has
opened the doors for large-scale cooper-
ation among many states. The combined
efforts could soon make it possible for
native ants to have a chance to thrive and
compete again.

Richard J. Brenner
Research Leader, Imported Fire Ant and
Household Insects Research Unit
Gainesville, Florida

Agricultural Research/September 1999

September 1999
Vol. 47, No. 9
ISSN 0002- 161 X

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. Depanmenr ..t agriculturee
I. Miley Gonzalez, Under Secretary
Research, Education, and Economics
Floyd P. Horn, Administrator
Agricultural Research Service
Sandy Miller Hays, Director
Information Staff

Acting Editor: Linda McElreath
Act. Assoc. Ed.: Robert Sowers
Art Director: William Johnson
Photo Editor: Anii, Daniel.
Staff Photographer Scott Bauer

(301) 504-1658
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(301) 504-1607

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and may be reprinted without permission. Non-
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color transparencies. Order by photo number and
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This magazine ma' reponr research involving pes-
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their use. nor doe-s i impl\ that uses discussed
herein have been registered All uses of pesticides
must be registered by appropriate state and/or
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Reference to any commercial product or service
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Agricultural Research/September 1999

Agricultural Research

Ouch! The Fire Ant Saga Continues 4

Forage To Make Taste Buds Tingle 9

Nonfattening Food Additives-From Sugar? 1

Building a Better Berry 12

Activated Carbons in a Nutshell 14

Improved Lure for Malaysian Fruit Flies 17

Aloha! to Hawaiian Bananas 17

Helping Piglets Survive and Thrive 18

Pitting Two Fungi Against Tough Pests 20

Diapers for On-the-Run Livestock 22

Sunflower Bee's a Great Pollinator 22

Science Update 23

Cover: Fire ants will do anything to resist attack by the tiny phorid fly measuring
only about one-sixteenth of an inch. A highly specific natural enemy, the female
pierces a fire ant's cuticle to deposit an egg. After hatching, the larva wiggles into
the ant's head and releases an enzyme that later decapitates it. Photo by Sanford
Porter. (K8575-22)

In the next issue!
- FINDING A NICHE: Small-scale farmers in Appalachia face
special challenges but are producing highly marketable consumer
products-like wild leeks and chevon.

c- CARRYING STRAINS OF NEWCASTLE: Pet and wild birds, as
well as poultry, can spread new strains of this serious avian disease
from country to country. ARS scientists are working on two fronts to
protect U.S. poultry flocks.

(' SEED SAVERS: A unique alliance between scientists and or-
ganic growers in the Farmer Cooperative Genome Project could
bring more natural diversity to crop plants.

Agricultural Research/September 1999

:,;;;'; ~.

: :i:

4: ';- ; I





S n.I ..

* . ....

/ he latest news in
the world of fire
ants: The tiny pests
with a ferocious sting
are spreading. Until re-
cently, red imported fire ants occupied
more than 300 million acres in 12 south-
ern states and Puerto Rico. Now they've
become established in California and
New Mexico.
As the ants spread, the race to stop
them is even more intense for a team of
Agricultural Research Service scientists
at Gainesville, Florida. There, research-
ers at ARS' Center for Medical, Agricul-
tural, and Veterinary Entomology are
seeking new ways to keep this pest in
"Our goal is to try to reduce their num-
bers so native ant species can compete,"
says entomologist David F. Williams. He
is the lead scientist on the fire ant bio-
control project in the center's Imported
Fire Ants and Household Insects Re-
search Unit that is headed by Richard J.
Fire ants are thought to have spread
to the United States from their native
South America via contaminated ships
in the early 1930s. Since then, their
spread has been slow but steady. "We
believe imported fire ants have flour-
ished in the United States because they
have no natural enemies here. We're try-
ing to change that by working with state
cooperators to introduce natural ene-
mies," Williams says.
ARS and representatives from the
Council of State Governments' Southern
Legislative Conference initiated a Na-
tional Fire Ant Strategy in 1998 to help
tackle the fire ant problem. One of the
group's objectives is to reduce pesticide
use by substituting biological controls.
In the past 2 years, ARS scientists have

Fire ants often nest where gopher tortoises
lay their eggs, in aprons around the edge of
their tunnels. At Camp Shelby, Mississippi,
cooperator Tom Estes examines gopher
tortoise eggs for signs of fire ant injury.

Agricultural Research/September 1999

dispatched new artillery to help control
fire ants: a slow-acting disease and a
decapitating fly.

Microbial Combatants on the Move
Thelohania solenopsae, a microor-
ganism from South America, infects fire
ant colonies and causes disease. Williams
says workers probably transfer the patho-
gen to the queen through food exchange.
As the disease slowly reduces her weight,
she lays fewer and fewer eggs, and all
are infected with the pathogen, further
weakening the colony.
Williams says colonies generally die
within 9 to 18 months. However, in lab
studies, he found that after 3 months the
infected colonies were smaller than
healthy ones. The microorganism doesn't
harm plants or native ant species. And
after years of testing, it's been found only
in red and black imported fire ants.
Williams works closely with ARS'
South American Biological Control Lab-
oratory in Buenos Aires, Argentina, to
get this and other biological controls
through quarantine and into the United
States. Natural enemies of imported lire
ants are also native to South America.
In 1996, the scientists discovered that
the Thelohania pathogen wasn't confi ined
to its native land, but had already infected
fire ant colonies in Florida, Mississippi.
and Texas. This opened the door for
releases in Florida, Arkansas, Oklahonm,.
Mississippi, Louisiana, Tennessee.
North and South Carolina, Ala-
bama, and Georgia.
"Since our first release in 1998
in Florida, Thelohania has spread
to more than 75 percent of the
colonies we're monitoring," says
Williams. "But it will take long-
er to see a major impact."
Entomologist David H. Oi,
who works with Williams on eval-
uating Thelohania and other bio-
logical controls, says they know the
organism kills the colonies. "But we
want to see how it is passed to the
queen. This is one of few microbial

agents that infect mated queens and pass
on to her eggs," says Oi.
"We want to find out if infected vir-
gin queens can mate and then spread the
disease to their offspring. If so, this will
be a natural way to distribute Thelohania,
besides introducing infected brood into
existing colonies," says Oi. The scien-
tists hope to get the answer in a study
they will start this year.
Even more powerful than Thelohania
is another pathogen called Vairimorpha,
which Williams says is not that differ-
ent. When combined with Thelohania,
it kills colonies in 2 to 6 weeks. "The
problem is, about 20 percent of fire ant
colonies in South America contain The-
lohania, but only 1 percent contain Vair-
imorpha," Williams says. "It's so rare,
hard to find, and also hard to keep alive
to study. There's a lot we don't know
about it, but we're excited about finding


Biocontrol Agents-Taking Hold and Spreading

Insect Snipers
Another line of defense that "has fire
ants literally on the run is the phorid fly,
Pseudacteon tricuspus, their mortal en-
emies," says ARS entomologist Sanford
D. Porter. "The ants will run and hide,
freeze, stop foraging, or twist upside
down so the flies don't sting them. The
only way they could have evolved these
defensive behaviors is if the flies had
some effect on fire ant populations."
The phorid flies hover over the fire
ant mound, then zoom in to pierce an
ant's outer cuticle and deposit an egg un-
derneath. The egg quickly hatches into a
fly maggot, or larva, that moves into the
ant's head. When the maggot is mature,
it releases an enzyme that causes the
ant's head to fall off-decapitation. Us-
ing the ant's head as a safe hideaway, the
fly completes its development inside.
"One female phorid fly usually con-
tains a hundred or more torpedo-shaped
eggs, so she can make multiple attacks,"
says Porter. Porter released thousands of
the tiny flies in July 1997 in Gainesville.
Since then, he's released them in Okla-
homa, Arkansas, and Alabama.
"The exciting part is that the Brazil-
ian parasitic flies released in Florida have
survived for nearly 2 years. They've gone
through many generations and appear to
be permanently established," says Por-
ter. "Fly populations are still growing,
so it may take 1 to 2 years before they
have a noticeable impact."
What's next? "We have a new, small-
er phorid fly species, Pseudacteon cur-
vatus, which will attack smaller-sized
fire ants," Porter says. "We have found
at least 20 species of phorids in South
America that specifically attack fire
Porter says this new species is even
better, since scientists can rear it more
easily. He has completed host-specificity
tests and is planning on seeking per-
mission to field-test P. curvatus. They
have tested the flies with different foods,
animal dung, and human waste to ensure
they're not attracted to anything other

than fire ants. He says the flies aren't
visible unless you kick over a fire ant
The scientists are hoping these two
flies and other natural enemies will even-
tually tip the ecological balance against
fire ants in the United States, so they will
no longer be the dominant species. Fire
ant populations are greater here than in
South America, where natural enemies
appear to keep them in check.
Still waiting to be called to duty is
Solenopsis daguerrei, a parasitic ant
discovered in Argentina in 1930. This ant

lo e'aluale Ihe allure o a ir
ant bait. biological technician '
Terr) Krueger positions
parIiclet containing a queens %l
produced pheromone.


Fire ants will
try hard to
avoid the sting
of a phorid fly
(top, center).
Once deposited,
an egg quickly
hatches into a
larva that
eventually kills
the host by
Shown about
nine times
actual size.

An enzyme released by
the mature phorid fly
larva decapitates its
fire ant host. Photo by
Sanford Porter.

Agricultural Research/September 1999


In less than 10 seconds, an unwary
scientist was stung over 250 times on one
leg when he carelessly knelt on a collapsed
fire ant mound. The sterile pustules
developed to this stage in 3 days.

Agricultural Research/September 1999

is unusual because it produces no work-
ers. Williams says the Solenopsis queen
uses her mandibles to clamp onto a fire
ant queen's body. Like a wolf in sheep's
clothing, the parasitic ant queen chemi-
cally disguises herself, mimicking the
natural attractants of the fire ant colony;
otherwise, she would be killed. The fire
ant queen becomes debilitated and lays
fewer eggs, weakening the colony.
Williams says they are still trying to learn
more about S. daguerrei.

Tracking the Enemy
It would also help scientists if they
could find out where fire ants may start
new colonies. Entomologist Dana A.
Focks, an expert on computer modeling,
is working on that. He's focusing on
when and where winged ants, called
alates, mate and start new colonies.
"No really good models exist that can
predict where alate flights might have oc-
curred or could possibly occur." says
Focks. "We want to build a satell e-
based program to find if one has
taken place."
Mating depends on tem-
perature and weather, but '
most fire ants emerge in ,P
warm weather after rain-
fall. Focks is working on a
cooperative grant project.
with IBM, Inc., Johns i.
Hopkins University in
Baltimore, Maryland, and
the National Aeronautics
and Space Administration to
develop a tracking system
that can predict when alates
have emerged or will emerge.
Focks says this will ultimatel\

This scanning electron micrograph shows a
side view of the hooked ovipositor of
Pseudacteon curvatus, a very small fire ant-
decapitating fly from South America.
Magnified about 200x.

A microbial pathogen, Thelohania
solenopsae infects all growth
stages of the fire ant but is most
debilitating to the fire ant queen.
Magnified about 800x.

save money for nurserymen who typi-
cally have to treat their plants and sur-
rounding areas with insecticides to en-
sure they don't transport ants from
infested areas to noninfested ones. They
generally do this before shipment.
"We're hoping that in the future a per-
son can go to the Internet and get site-
specific information on whether a flight
occurred, based on weather conditions,
temperature, and other information.
Nurserymen could use this information
to keep from re-treating their stock un-
necessarily," Focks says.

Attacks on Animals
Another growing problem with fire
ants is their ecological impact, especially
on endangered vertebrates and inver-
tebrates. Entomologist Daniel P. Wojcik
is working with many environmental and
conservation groups to keep fire ants
from harming endangered species like
Stock Island tree snails, gopher tortoises,
Florida grasshopper sparrows, saltmarsh
rabbits, and sea turtles.
"Only 300 female green sea turtles are
nesting in the world, and most of them
are in Florida. Fire ants attack the im-
mature turtles, either killing or blinding
them," he says. "Sometimes young tur-
tles wander across a fire ant mound. Fire
ants usually sting them as a defensive
response. But they will also attack and
feed on anything that doesn't move, in-
cluding animals."
An emerging anomaly and problem
with fire ants is polygyne, or multiple-
queen, colonies. "These 'super colonies'
are more problematic than monogyne, or
single-queen, colonies because, collec-
tively, they lay more eggs and are harder
to control," says chemist Robert K.
Vander Meer.
Many people think if you kill the
queen, you kill the colony. But this isn't
true if there are workers left, says Vander
Meer. Workerless colonies will adopt
new queens, which provides one expla-
nation as to why ants have reinfested
treated areas and may be related to how

polygyne colonies form.
The queen controls adoption and oth-
er colony functions through phero-
mones. Vander Meer says the ultimate
goal is to find these pheromones and use
them to help decrease fire ant popula-
tions. Scientists in this research unit have
developed and applied for patents on
new repellants, attractants, and multiple-
species ant baits, all of which could soon
help ease the fire ant burden.-By Tara
Weaver-Missick, ARS.
This research is part of Arthropod
Pests of Animals and Humans, an ARS
National Program described on the
World Wide Web at http://www.nps.ars.
The scientists mentioned in this arti-
cle are in the USDA-ARS Imported Fire
Ants and Household Insects Research
Unit, 1600 SW 23rd Dr, Gainesville, FL
32608; phone (352) 374-5903, fax (352)
374-5818, e-mail rbrenner@ *

SCOTT BAUER (K8574-1 )

Entomologists David Williams (left) and
David Oi compare a fire ant colony infected
with the Thelohania solenopsae pathogen
(left) to an uninfected one.

Most people think of Buenos Aires as
a vacation spot. But for ARS entomolo-
gist Juan Briano and biologist Luis Cal-
caterra, it's a place for serious research.
ARS' South American Biological Con-
trol Laboratory in Argentina helps the
agency's North American scientists study
exotic pests from Latin America.
Some pests are quarantined from im-
port to the United States, so ARS' inter-
national locations are vital to studying
them in their original environments.
Researchers in Buenos Aires helped
ARS scientists from Gainesville, Florida,
identify biological controls for fire ants,
and now they are helping to ensure that
these useful ant-busters don't harm na-
tive U.S. species.
One biocontrol agent they studied was
Thelohania solenopsae. a pathogen that
weakens and eventually kills fire ant col-
onies. "To study field host specificity of
Thelohania, we traveled to rural areas of
the Buenos Aires Province," explains
Briano. "'We put 300 bait traps in 30 field
sites. We captured many ant species and
took them back to the lab. There we froze
them, ground them in water, and checked
for the presence of Thelohania. We found
it only in fire ants."
Briano and Calcaterra traveled to the
San Eladio area 80 kilometers west of
Buenos Aires to check for a parasitic ant,
Solenopsis daguerrei. That area is heav-
ily infested with fire ants. and S. daguer-
rei has infested many of the colonies.
"We checked a total of 4,131 fire ant
nests and 185 nests of other ant species
and found the parasite only in fire ant
nests." says Calcaterra.-By Jill Lee,
formerly with ARS.
Juan Briano is with the -USDA-ARS
South American Biological Control Lab-
oratory c/o Agriculture Counselor, U.S.
Embassy. Buenos Aires, Unit 4325, APO
AA4 34034-0001; e-mailjabriano@ mail.

Agricultural Research/September 1999

Forage To Make Taste Buds Tingle

J ust as chefs in a fine restaurant are intent on creating
meals to delight your taste buds, ARS scientists are busy
sleuthing the secrets of how to tempt palates of rumi-
nants like cattle, sheep, and goats.
Knowing more about the cues that govern cattle's culinary
choices can mean healthier animals that make better weight
gains and bigger profits for ranchers. The research can also
help plant breeders avoid the pitfall of developing a new for-
age that grows fast and has high yields-but doesn't appeal to
animal diners.
ARS soil scientist Henry F. Mayland at Kimberly, Idaho, is
coordinating a series of ARS and university studies designed
to reveal "just what is it about certain forages that makes ani-
mals keep coming back for more."
In perhaps the best known of these tests, Mayland-along
with ARS colleagues Dwight S. Fisher at Watkinsville, Geor-
gia, and Joseph C. Burs at Raleigh, North Carolina-showed
that cattle, sheep, and goats prefer hay harvested in the after-
noon to that cut in the morning.
"The animals," says Mayland, "apparently discriminate on
the basis of total nonstructural carbohydrates-the easily di-
gestible starches and sugars in the forage."
"Our feeding study," Mayland points out, "was likely the
first to show up to a 50-percent difference in forage prefer-
ences based on time of day the forage was cut."
Follow-up experiments with alfalfa hay showed the same
trend. "The bottom line," notes Dwight Fisher, "is that farmers
may get better performance from their livestock if they feed
them hay harvested in the afternoon. It's an easy, practical way
to enhance profits at no extra cost."
Other research scrutinized different chemical and physical
characteristics of forages. For one investigation, scientists
analyzed some 50 different chemicals given off from freshly

harvested samples of 8 different kinds of tall fescue grass and
nearly 100 chemicals from tall fescue hay.
Robert A. Flath, formerly with ARS at Albany, California,
did the work in collaboration with Mayland and Glenn E.
Shewmaker, who is now at the University of Idaho. Cattle
preferred fescues with high levels of a volatile-that is, easily
vaporized-natural chemical known as 6-methyl-5-hepten-2-
one. But they didn't like fescues with high amounts of two
other volatiles, (Z)-3-hexenyl propionate and acetic acid.
However, a study of two other classes of chemicals in these
fescues-amino acids and nonvolatile organic acids-showed
no link to forage choices.
Other experiments are probing the effects of other chemi-
cals, including the minerals calcium, magnesium, and potas-
sium, along with physical characteristics such as plant height
or the amount of energy an animal has to invest to tear off a
mouthful of grass.-By Marcia Wood, ARS, and Jill Lee, for-
merly with ARS.
This research is part of Soil Resource Management, an ARS
National Program described on the World Wide Web at http://
www. nps.ars.
Henry F Mayland is in the USDA-ARS Northwest Irriga-
tion and Soils Research Laboratory, 3793 N. 3600 E., Kimber-
ly, ID 83341; phone (208) 423-6517, fax (208) 423-6555, e-
Dwight S. Fisher is with the USDA-ARS Southern Piedmont
Conservation Research Laboratory, 1420 Experiment Station
Rd., Watkinsville, GA 30677; phone (706) 769-5631, ext. 268,
fax (706) 769-8962, e-mail
Joseph C. Burns is in the USDA-ARS Plant Science Research
Unit, Room 1119, Williams Hall, Box 7620, North Carolina
State University, Raleigh, NC 27695; phone (919) 515-7599,
fax (919) 515-7959, *

Agricultural Research/September 1999

Nonfattening Food Additives-From Sugar?

M any consumers probably
don't know that a gum
exuded from an African
tree species is a key ingre-
dient in their food. Gum arabic from the
Acacia tree is used as a thickener and
stabilizer in a variety of products, such
as citrus-based soft drinks, medicine
capsules, and cosmetics.
Because gum arabic prices often fluc-
tuate, food processors want a more reli-
able domestic substitute-and they may
soon have it, thanks to Agricultural Re-
search Service scientists.
The U.S. domestic beet and cane sugar
industries, armed with a powerful new
strain of a microbe developed by ARS
researchers, may someday produce a
product called alteran. This alternative
to gum arabic could, as a nonfattening
food ingredient alone, eclipse the present
gum arabic market. The United States
buys thousands of tons of gum arabic
annually from the Sudan and other coun-
tries at volatile prices that are sometimes
higher than $5 per pound.
As an emulsifier, gum arabic helps
water and food oils mix and

stay mixed. Food processors use it in
small amounts to make icings stick to
cakes, prevent syrups from crystallizing,
and maintain a foamy head on a glass of
beer-all without changing flavor.
Some gum arabic is used as a bulking
agent or filler to provide a desired tex-
ture in cosmetics and in industrial prod-
ucts like ink and adhesives.
"We've recently developed ways to
produce 100-liter batches of alteran that
can be tested as bulking agents in a vari-
ety of applications," says Gregory L.
C8t6. He is an ARS chemist at the Na-
tional Center for Agricultural Utilization
Research (NCAUR) in Peoria, Illinois.
The next goal: Find a way to make
alternan that consistently emulsifies at
least as well as gum arabic. Already,
some forms of alternan show great prom-
ise as emulsifiers.
The ARS scientists have patented
three alternan-related inventions in the
past 2 years. One defines methods for
rapidly identifying microorganisms that
produce large amounts of

desired versions of alteran.
"When the gum arabic substitute is
commercialized, we expect its produc-
tion cost will be similar to that of dex-
tran, which currently wholesales for
about $3 per pound," says Timothy D.
Leathers, an NCAUR geneticist.
Both carbohydrate polymers, alternan
and dextran have much in common. In
the early 1950s, ARS researchers devel-
oped an efficient process for making dex-
tran that was quickly commercialized.
Dextran was used as a blood extender to
save uncounted American lives during
U.S. involvement in the Korean conflict.
The extender is still used today.
Alternan is made by an enzyme called
alternansucrase produced by the Leu-
conostoc mesenteroides bacterium. To
recast sugar into alternan, C6td, Leath-
ers, and their coworkers use this enzyme
to break down sugar and reassemble the
fragments-glucose units-into the
polymer alternan. The pattern of sugar
linkages distinguishes alteran from dex-
tran, its chemical and biological cousin.
Biochemist Jeffrey A. Ahlgren has
developed several physical and bio-
chemical ways to examine alternan. Its
various forms and sizes affect its po-
tential usefulness in different applica-
"One form produced by a novel pat-
ented enzyme is a molecule composed
of four glucose units in circular struc-
ture," says Ahlgren. "The compound
looks interesting, but we don't yet
, know what use might be made of it."

Agricultural Research/September 1999

Join Us As Partners?
All the recent ARS inventions on al-
ternan are available for licensing. Be-
sides finding a way to quickly identify
microbes whose enzymes prodigiously
produce alternan, the scientists have
identified improved strains of L. me-
senteroides. And they have identified
bacteria and enzymes that break down
"Presently we're trying to develop
new versions of alternan that will in-
clude small amounts of proteins," says
Ct&. Proteins are believed to give gum
arabic much of its emulsifying capaci-
An industrial partner in the research
could help ARS scientists determine
processing conditions that could ensure
that an alternan-protein compound is
consistently as good an emulsifier as
gum arabic. A cooperative research and
development agreement might entail
temporary use of a company's scaled-
up research equipment in a recently
renovated pilot plant at NCAUR.
Joint research could also determine
the potential of an alternan-derived
product for use as a probiotic. A pro-
biotic is a nutrient that promotes
growth of beneficial, rather than har"ii -
ful, microbes in an animal's gut.
C8t6 says alternan's first use in
foods may be in the form of broken r
fragments that could serve as bulk- i
ing agents. As food companies use
artificial or alternative sweeteners,

they typically use bulking agents to
make up for the loss of product volume.
Bulking agents also help powdered food
products such as cake mixes flow
smoothly as they are processed.
The major coproduct of alternan syn-
thesis is fructose. Consequently, when
alternan becomes commercialized, the
beet and cane sugar industries may be-
gin marketing high-fructose syrup to
sweeten profits.
The ethanol industry could also ben-
efit from commercialization of alternan.
Leathers has found that an abundant co-
product of ethanol-corn condensed
distillers' solubles, or CCDS-works as
well as much more costly materials as a
nutrient for L. mesenteroides. Now,
CCDS, which sells at about 2 cents per
pound, is put in animal feeds. If CCDS
becomes more valuable as it's put to
more use, it could enhance ethanol's
competitiveness with petroleum, while
expanding markets for corn products.
From an L. mesenteroides strain, the
Researchers hope to clone the
K WELLER (Ka84..

gene responsible for producing alternan
and to genetically engineer another mi-
croorganism to produce greater quanti-
ties of the enzyme. A longer term goal is
to genetically transform certain plants to
efficiently produce large quantities of al-
ternan.-By Ben Hardin, ARS.
This research is part of New Uses,
Quality, and Marketability of Plant and
Animal Products, an ARS National Pro-
gram described on the World Wide Web
at http://www.nps.ars.
grams/cppvs. htm.
Gregory L. Cote, Timothy D. Leath-
ers, and Jeffrey A. Ahlgren are in the
Biopolymer Research Unit, National
Center for Agricultural Utilization Re-
search, 1815 N. University St., Peoria,
IL 61604; phone (309) 681-6591, fax
(309) 681-6689, e-mail +

(at r ou&oj ionpects improved strain os
bcrium hat Produces s eucoostoc lleseteroide the
Pou alternan. 11e1os0 "

Agricultural Research/September 1999

- ~C- r-~13I~ r I-L L C~ _r



E arly in the next century, a
whole new strawberry may
grace our tables and our taste
buds with its beauty and unique
new flavors and textures. This year and
next, six researchers across the country
are selecting the best parents for recon-
stituting the commercial strawberry.
With clipboards in hand, the scientists
roam plots of 20 to 40 elite genotypes of
two species from North and South Amer-
ica, scoring each for about 18 character-
istics growers and consumers prize. Their
mission: Broaden the genetic base of to-
day's strawberry and build a bigger, bet-
ter one in the process.
The six researchers are evaluating the
original two parent species of today's
commercial strawberry, Fragaria x anan-
assa. It got its start accidentally some 250
years ago in a European botanical
garden-the result of a chance hybrid-
ization between two New World species.
One parent, F virginiana-good at
tolerating heat and drought-arrived in
Europe from North America by the late
1500s, possibly brought back by the leg-
endary navigator and explorer Jacques
Cartier. In the early 1700s, a French spy
carried F chiloensis, the other parent,
from Chile. Acclaimed in Chile for its
large fruit, it was a big disappointment
in Europe. The spy had unwittingly col-
lected only female plants that failed to
produce fruit... until they were planted
among F virginiana clones years later.
"Now we can pick the most outstand-
ing genotypes of those two parent spe-
cies for breeding," says ARS geneticist
Stan C. Hokanson, who is at Beltsville,
Some of the elite genotypes come
from the ARS National Clonal Germ-
plasm Repository at Corvallis, Oregon.
Others were recently collected in native
habitats from Chile to the U.S. Rockies
to Ontario, Canada, and evaluated by
enthusiasts like James E Hancock.
Professor of horticulture at Michigan
State University in East Lansing, Han-
cock oversees the evaluation project. He

says about 10 serious evaluations have
been done with New World genotypes.
"We tried to pick the best from these
and select a representative sample. It's
like doing the final cut."
Besides Hokanson, Hancock's other
cooperators are ARS geneticist Chad E.
Finn at Corvallis; James J. Luby, profes-
sor of horticulture at the University of
Minnesota in St. Paul; Barbara L.
Goulart, retired associate professor of
horticulture at Pennsylvania State Uni-
versity in University Park; and Thomas
M. Sjulin, research department manager
with Driscoll Strawberry Associates,
Inc., of Watsonville, California.
"The beauty of testing in multiple
sites is that each site has a different stress
regime," says Hokanson at Beltsville's
Fruit Laboratory. "The sites provide ex-
treme cold, high heat, dampness, wide-
ly varying soil quality, and different in-
sects and diseases for us to evaluate
genotype response."
Each genotype usually has something
to offer, says Hokanson. For example,
"one with small fruit may have fruit
quality traits or disease resistance we can
use." Researchers may also find geno-
types to extend the fruiting season. The
first strawberries to market command the
highest prices. In Hokanson's plots last
April, most of the species collection was
in flower when commercially available
cultivars were just waking from their
winter naps.
One Peruvian genotype flowered
nearly 2 weeks before the earliest culti-
vars. "It's exciting to find these kinds of
outliers. They provide much more po-
tential for improvement," Hokanson
says. He adds that one genotype from
Alabama and another from Mississippi
were disease free last fall, "when all the
cultivars were covered with leaf spot,
scorch, and powdery mildew."
The researchers will also be looking
for new sources of the day-neutral habit
that keeps today's cultivars bearing fruit
in cycles throughout the growing season.
Until the late 1970s, commercial plants

Small-fruit geneticist Stan Hokanson
displays several elite wild
strawberries collected by
collaborators. The small, highly
aromatic berries (left) are from
plants collected in Alberta, Canada.
The larger berries are from a type
collected in Alaska that ma) pro'e to
be cold hard>.

fruited for only a few weeks each sea-
son. Then Royce Bringhurst of the Uni-
versity of California at Davis collected
a subspecies of E virginiana that blooms
out of season in Utah's Wasatch Range.
Genes from that mountain clone revolu-
tionized the industry.
Strawberries are grown around the
world, mostly in the Northern Hemi-
sphere. The United States, the leading
producer, accounts for about 20 percent
of the total, followed by Spain, Japan,
Poland, Italy, Korea, and China. The
lion's share of U.S. fresh-market
production comes from California and
Driscoll's Tom Sjulin hopes to find
genes for pest and disease resistance. He
says some of the wild material promises
good resistance to two diseases that
plague growers in other parts of the
country: verticillium wilt and red stele.
"There will be fewer and fewer chem-
icals in the future," says Sjulin, noting
the impending loss of methyl bromide
and possibly other important soil fumi-
For California growers who plant a
new crop each year, Sjulin wants to find
genes that direct more energy into flow-
ers and less into runners, as well as genes
that trigger flowering under a wider
range of temperatures. And he would like
to capture the succulent taste of some
eastern-grown strawberries for new West
Coast cultivars.
ARS' Finn wants "to get a species
core we know quite a lot about. Hope-
fully, other researchers will build on this
information," he says.
Finn planted extra F ch.f'if siit.eno-
types in his plots at Corvallis because
this species is indigenous to mild West
Coast climates from northern California
up to British Columbia, as well as down
to Chile. "We have a better chance of
growing them here," he says.
Most strawberries grown in the Pa-
cific Northwest are for processing. So
Finn will be watchful for fruit having
rich color, high acidity, and high sugars

to fulfill processors' wish lists. And he
hopes to find some novel characteristics.
"Maybe there's something out there that
doesn't rot for 2 weeks after harvest."
Sjulin says it will take at least 12
years-more likely 15 to 20-to get de-
sirable traits from F virginiana and F
chiloensis into a commercial variety.
Fortunately, he adds, "Driscoll takes the
long view on variety development and
is committed to maintaining a broad ge-
netic base."
The evaluation project is supported by
a USDA small-fruit germplasm evalu-
ation grant. Hancock's group at East
Lansing multiplied the genotypes and
distributed plants to cooperators. Every-
body got a core group of about 20
genotypes. Some got more because of
geographic location.
"It's amazing how many people have
been willing to cooperate on this," says
Hancock, who began the project 6 years
ago with Luby and Adam Dale, profes-
sor of horticulture at the University of
Guelph. Ontario. "We're I.! f~rids-- t
share a common interest."
Adds Hokanson, "What really makes
this interesting is that we know how the
cultivated strawberry originated acciden-
tally, and now we can go back and do it
better."-By Judy McBride, ARS..
This research is part of Plant, .I h ,-
bial, and Insect Genetic Resources, Ge-
nomics, and Genetic l,.'L: .'. an
ARS National Program described on the
World Wide Web at Sa~qr 'p i-. .t 6 .Ps..

Stan C. Hokmason is at ie (USDA-ARS
Fruit ., i .. BL '. 01h.l Bl Rl. R, ,."re"
10300 BAcwinw, A-.. eh, i.i, MD
20705-2350; phone (301) 5tu -fr -S. fax
(301) 504-5062, e-mail -.-k e,'
Chad E. Finn is in the !USDA-ARS
flb n tlrc:wd Ci 'Iy Ri, Vw rl U nit, 3420
N.W. OrchailAre., Cordlis; OR 97330-
5098; phone (541) 750-759, fmr (541))
750-S-64, e-mail.iL,,, ..
edu. *

Agricultural Research/September 1999 Agricultural Research/September 1999

Some "Trash-Talk" Worth Listening to-

Activated Carbons in a Nutshell

new kind of recycling is
under way in the Com-
z modity Utilization Re-
/ search Unit located at the
Southern Regional Re-
search Center (SRRC)just outside down-
town New Orleans. But don't expect to
find crushed soda cans, plastic water
bottles, or musty-smelling newspapers
heaped at this high-tech facility.
A team of chemists there led by
Wayne E. Marshall is recycling trash of
the agricultural kind-like discarded
soybean hulls and the shells of various
edible nuts.
About 50 million tons of these and
other assorted agricultural wastes are
generated each year.
The pecan industry, for example, gen-
erates about 59,500 tons of shells from
its harvests. Growers and processors ab-
sorb some of the cost of shell disposal
by grinding them up and selling them as
livestock bedding, mulch, or other low-
value commodities.
The shells alone bring in a pittance:
about $2 a ton. But Marshall's group is
on the verge of delivering what could
amount to an economic boom. Since
1993, they have been perfecting an ar-
ray of techniques to make charcoal-like
substances called activated carbons from
pecan, almond, and most recently, mac-
adamia nut shells.
"We're looking at creating new uses
and value-added products from these
commodities," says Lynda H. Wartelle.
She and Marshall are with USDA's Ag-
ricultural Research Service. Their waste-
recycling unit is operated by the SRRC.
Today's usual activated carbons are
made from coal, peat, coconut shells, and
wood, says Marshall. Working like char-
coal "sponges," they adsorb from the air
or water many types of organic com-
pounds-like benzene, toluene, and ac-
etonitrile, as well as metals such as lead.
Carbon uses run the gamut: from fish
tank filters and tap water purifiers to
wastewater treatment and air pollution
monitoring and control.

In the United States, such applications
consume over 300 million pounds of ac-
tivated carbons annually-about half the
600 million pounds used worldwide.
"One of the selling points for this ap-
proach is that we're looking to make use
of very low-value agricultural wastes. In
this case, we're using a waste to clean
up other wastes," says Christopher A.
Toles, formerly with ARS but now with
Northeastern University in Boston, Mas-
sachusetts. "And the nutshells we're
working with are renewable on a yearly
The team, looking to collaborate with
industry, recently negotiated a coopera-
tive agreement with a Georgia-based
^'U tC'flDJC' -I fnI C

Scanning electron micrograph shows the
effect activation has on the gross structure
of nutshell carbon granules. While it is
impossible to see active micro- and meso-
pores, the large pits are significant evidence
of gasification. Magnified about 40x.

firm to test granular forms of the nutshell
Their work has also sparked interest
from commercial nut growers and trade
groups like the Almond Hullers and Pro-
cessors Association. Under a special
grant, that California-based organization
supplies the scientists with large amounts
of shells for their research.
The team sees other potential avenues
for their emerging technology: electro-
pating companies, mining operations,
and jewelry makers. All are industries
that use activated carbons to help remove

contaminants in the wastewater they gen-

A Tough Nut To Crack
Marshall's team is now testing acti-
vated carbons made from macadamia
shells supplied to them by a Hawaiian
nut processor.
The shells derive their density and
strength from two components-lignin
and cellulose. Density and strength are
key to the shell's conversion to carbons.
That's because they must withstand
grinding and exposure to temperatures
of up to 900 oC in combination with
steam, certain gases, or acids.
Such treatment activates, or opens,
millions of microscopic pores in the car-
bonized shells, enabling them to hold
onto chemical molecules like benzene.
Another step, called oxidation, confers
a negative charge to the shells that helps
capture metal ions, such as those in so-
So porous are today's activated car-
bons, notes Toles, that a single gram can
have over 900 square meters of surface
area. A pound can have up to 465,000
square meters-owing to the materials'
micro-, meso-, and macro-sized pores.
Of the nutshell carbons examined thus
far, macadamias adsorb the broadest
range of organic molecules. "We're still
trying to figure out what makes the mac-
adamia's nutshell carbons so effective in
this regard," says Wartelle. She also com-
pares the nutshell carbons to commercial
organic adsorbents made from natural
and synthetic materials.

Chalk It Up to Charcoal
In one comparative study with six
commercial adsorbents, use of activated
macadamia shells led to a three- to four-
fold increase in the ability of a standard
Environmental Protection Agency air

Chemists Wayne Marshall and Lynda
Wartelle air-sample volatile organic
compounds to determine the adsorptive
properties of nutshell carbons.

Agricultural Research/September 1999


Agricultural Research/September 1999

II ~








'" 7-?



Kaw macaaaima nut snenl place in a special oven by cnenust utrls loles will be
carbonized and activated at temperatures above 800 oC.

sampling procedure to detect benzene at
concentrations of 100 parts per billion.
Benzene is used in fuels, dyes, solvents,
and many other pro-
ducts but becomes
a contaminant upon
escape into the envi-
The nutshell car-
bon also worked well
in small-scale studies
to remove copper from
industrial wastewater.
Wartelle is particular-
ly encouraged by the carbon's potential
as an adsorbent material for gas chro-
matographic analysis of air.
Right now, the cost for such analyti-
cal carbons can run as high as $13 per
gram, she reports. Eventually, the mac-
adamia shells might supplement this spe-
cialty market.
"We also hope to do more work with
some of the other harder nutshells, like
those of hazelnuts, black walnuts, and
Brazil nuts, and to try to investigate the
properties that make them a good air
sampling carbon," says Wartelle.

Nut Just a Pipe Dream
To foster commercial collaboration,
the team has applied for patent protec-
tion on its activation procedures. Use of
these methods, Toles estimates, could
yield about 3,000 tons of activated
carbon material from the 14,600
tons of macadamia shells now avail-
Marshall stresses that the idea is
to supplement-not displace-exist-
ing carbon resources.
"Coal and coconut shells are two
really big resources," Toles says. "But
when you make carbons from
coal, you're competing
with people who use it for
Coal also generates
considerable ash and
sulfur. But the nutshells,
when activated, release
very little. "We're hoping
that making activated car-
bons from nutshells will cre-
ate a slightly 'greener' technology than
making them from coal," Toles says.
And like many standard commercial
carbon products, Wartelle adds, "the nut-

shell carbons can be used over and over
again for laboratory sampling."
The same properties that make the
nutshell carbons so promising for indus-
trial cleanup might also lend themselves
to more mundane applications, like pu-
rifying tap water.
"Ultimately," says Toles, "we think it
might be interesting to devise a taste and
odor nutshell carbon to supplement char-
coal carbons already on the market for
water purification."
Now, that's not such a nutty idea.-
By Jan Suszkiw, ARS.
This research is part of New Uses,
Quality, and Marketability of Plant Prod-
ucts, an ARS National Program de-
scribed on the World Wide Web at http:/
/www. nps. ars. usda. gov/programs/
Wayne E. Marshall and Lynda H.
Wartelle are in the USDA-ARS Commod-
ity Utilization Research Unit, Southern
Regional Research Center 1100 Robert
E. Lee Blvd., New Orleans, LA 70124;
phone (504) 286-4207, fax (504) 286-
4367, e-mail
marshall@nola.srrc. *


Macadamia shell pieces before and after

Agricultural Research/September 1999

Improved Lure
for Malaysian Fruit Flies

A new lure spells trouble for the Malaysian
fruit fly. ARS researchers in Hilo, Hawaii, and
Albany, California, have developed a blend of
compounds as an improved means to detect, sur-
vey, and control the pest.
Sometimes called the solanaceous fruit fly, the
Malaysian fruit fly, Bactrocera latifrons, lays its
eggs in peppers, tomatoes, eggplants, and cucur-
bits. A relative of the infamous Mediterranean
fruit fly, it is about the size of a common house
fly. It has a rusty-brown abdomen, bright-yellow
stripes at the base of its wings, and a single black
spot at the tip of each wing.
Native to South and Southeast Asia, the Ma-
laysian fruit fly has now established itself on all
major islands of Hawaii. If undetected in contra-
band produce, it could hitchhike to the continen-
tal United States and pose a considerable threat
to mainland agriculture.
The easily made blend combines a colorless
chemical called alpha-ionol and cade oil-a dark-
brown liquid from prickly juniper, Juniperus
ARS scientists Roy T. Cunningham at Hilo,
Robert A. Flath at Albany, and Terrence P.
McGovern (deceased) had earlier patented alpha-
ionol as a Malay fly lure. Now, ARS experiments
in Hawaii with more than 1 million lab-reared
Malaysian fruit flies have shown that adding cade
oil to alpha-ionol makes the lure more effective.
Cunningham and Flath (now retired) and Nicanor
J. Liquido, formerly with ARS at Hilo, along with
Grant T. McQuate of ARS at Hilo, are currently
seeking a patent for their invention.
Made without need for solvents or additives,
the blend can be applied easily to wicks like those
used in standard insect traps. Traps holding wicks
treated with the new blend could be used in de-
tection programs in states like California. There,
pest control workers monitor traps year-round to
detect outbreaks of other insect species before
they build up.-By Marcia Wood, ARS.
For technical information about patent appli-
cation number 09/120,521, "Attractantsfor Bac-
trocera latifrons (Hendel)," contact Grant T
McQuate, USDA-ARS U.S. Pacific Basin Agri-
cultural Research Center Stainback Hwy., P.O.
Box 4459, Hilo, HI 96720; phone (808) 959-
4300, fax (808) 959-4323, e-mail mcquate@ +

to Hawaiian Bananas

Freshly harvested bananas from Hawaii may
soon begin reappearing in mainland markets
thanks to extensive research by ARS scientists in
Hilo, Hawaii.
Hawaii's banana growers haven't shipped the
fruit to the mainland since 1984. That's when ethy-
lene dibromide gas, used to disinfest bananas and
other fruits of any hitchhiking fruit flies, was
banned. But now ARS experiments demonstrate
conditions for safely shipping the bananas without need for disin-
festation treatment.
Mediterranean and oriental fruit flies, already established in
Hawaii, are a constant threat to mainland agriculture. They can at-
tack more than 200 different fruits and vegetables.
In laboratory and outdoor experiments, ARS entomologist John
W. Armstrong and colleagues showed that the bananas won't harbor
these pests if shipped full-size, green-skinned, and without cuts or
Armstrong and co-workers did the work at ARS' U.S. Pacific
Basin Agricultural Research Center in Hilo.
Besides helping Hawaiian growers resume shipments to the U.S.
mainland, the ARS studies are helping them capture sales in new
foreign markets such as Japan.
The scientists used laboratory-reared medflies and oriental fruit
flies and tested thousands of bananas from nearly two dozen planta-
tions throughout the state.
"Our tests," says Armstrong, "showed that risk of infestation by
the oriental fruit fly and medflies is negligible under normal com-
mercial conditions." As a result, USDA's Animal and Plant Health
Inspection Service approved new, workable regulations for shipping
the bananas.
The varieties tested included three different kinds of the familiar
Cavendish-type banana, as well as the specialty Hawaiian apple
banana, which has a very sweet, custardlike flavor. Says Armstrong,
"This is a superb banana for niche markets on the mainland or in
foreign countries."
Collaborators in the experiments included the University of Ha-
waii Cooperative Extension Service and the Hawaii Banana Indus-
try Association. Banana growers in Hawaii produced about 21 mil-
lion pounds of bananas, worth about $7 million, in 1998.
The United States annually imports more than 8 billion pounds
of bananas. They are good sources of potassium, vitamin C, and
fiber.-By Marcia Wood, ARS.
4_ John W. Armstrong is at the USDA-ARS U.S.
Pacific Basin Agricultural Research Center,
Stainback Hwy., P.O. Box 4459, Hilo, HI 96720;
phone (808) 959-4336, fax (808) 959-4323,
A t e-mail *

Agricultural Research/September 1999

Helping Piglets Survive and Thrive

good start in life is no easy task,
even though raising hogs is
among the most technological-
ly advanced of animal indus-
tries. Of every 10 pigs born alive, at least
1 doesn't survive more than a few days.
Those losses alone reduce swine pro-
ducers' net income by several hundred
million dollars a year.
Some piglets handle stress poorly, are
prone to disease, weigh less than their
siblings at weaning, and require an ad-
ditional week or longer of care and feed-
ing before going to market. Faster growth

along with their University of Missouri
colleagues are researching piglets' sus-
ceptibility to death, disease, stress, and
poor growth. "Our goal is to find ways
to improve their well-being and to opti-
mize cost-efficient growth," says Mat-
teri. Pigs that grow well when quite
young generally gain more weight per
pound of feed consumed after weaning
and have less carcass fat when they reach
market weight.

You Can Lead a Pig to Food ...
A major limitation to improved neo-
natal growth is poor feed intake. That's

Animal physiologist Robert Matteri examines the growth of bacterial cultures containing
cloned DNA of genes for appetite control.

would lower housing, feeding, and oth-
er costs.
"Reducing the average time from birth
to market by just 1 day could translate
into an annual income boost of tens of
millions of dollars for the nation's swine
producers," says ARS animal physiolo-
gist Robert L. Matteri. He's based in the
ARS Animal Physiology Research Unit,
at Columbia, Missouri.
Matteri's team of three ARS scientists

why the scientists are looking at a variety
of hormones involved in appetite control.
The researchers must conduct extensive
physiological research before they can
develop practical farm procedures for
using hormones like neuropeptide-Y,
leptin, and orexins in the forms of orexin-
A and orexin-B.
Matteri and ARS animal physiologist
Cheryl J. Dyer became interested in or-
exin after University of Texas scientists

saw a sixfold increase in feed intake in
rats given brain injections of the hor-
mone. The researchers in Missouri then
found that a single injection in the upper
hind leg muscles of 3-week-old pigs in-
creased feed intake 18 percent, though
for only a short time.
These initial findings earned the Na-
tional Pork Producers Council's innova-
tion award for basic research earlier this
year at the Midwest Animal Sciences
meeting in Des Moines, Iowa. More re-
search should show whether two or more
well-timed injections can help improve
growth rates enough to be worthwhile.
Dyer and Matteri cloned the orexin
molecule chemically. When analogs,
which are smaller but potent synthetic
versions, of orexin are designed and
mass-produced, Dyer says, the cost of
injections should become fairly inex-
If treatments with hormones such as
orexin could help all littermates grow at
nearly the same pace, meat packers' dis-
counts of $0.50 to $2.50 per hundred-
weight on lightweight hogs could be
avoided. And if all hogs could be mar-
keted together, farmers could take better
advantage of an "all-in, all-out" inven-
tory management system that helps break
disease cycles. This system-marketing
all animals at the same time-allows pro-
ducers to completely empty housing for
thorough, periodic sanitation.
The scientists are researching another
way to deliver orexin. They have cloned
the genetic material, or DNA, that directs
orexin production and have integrated it
into another piece of DNA called a mam-
malian expression vector. The next step:
injecting the new DNA, a so-called de-
signer gene, into the animals' own cells
to see if they will produce larger amounts
of biologically active orexin.
The research on appetite regulation
being conducted at Columbia comple-
ments ongoing work at other ARS labo-
ratories. ARS researchers at Athens,
Georgia, and Beltsville, Maryland, are
studying the biology of leptin, a hormone

Agricultural Research/September 1999

Animal physiologist Jeff Carroll analyzes
swine tissue to determine the presence of
stress-responsive hormones.

that also controls appetite. The goal of
these coordinated, and often collabora-
tive, ARS research efforts is a working
understanding of the biological control
of feed intake as it relates to animal pro-
duction, health, and well-being.

Birth and Other Stresses
Besides affecting appetite, hor-
mones-in complex ways-exert major
impact on swine health in production en-
vironments. There, for better or worse,
stress is encountered-especially at
birth-as pigs are weaned, handled, and
moved about. In researching hormones
that indicate stress, ARS animal physi-
ologist Jeffery A. Carroll and his col-
leagues in Columbia have found that
stress during birth may pla. jan im-
portant role in preparing a tcLtu, I. i
life beyond the womb.
In the experiments, ,ome
young pigs were born natu l -
ly while others came into the
world via cesarian section
At birth, blood and tissue
samples from the two
groups contained some
similar but other strik-
ingly different hormone
and chemical levels.
Two weeks later, more
similarities and differ-
ences appeared, giving
insights on lasting ef-
fects of birth experienc-

es. The researchers concluded that by pre-
venting the stress of natural birth, surgi-
cal birth inhibited the pigs' growth.
Diet may also have an important link
with stress. Carroll has just begun re-
searching the effects of new protein sup-
plements like spray-dried plasma on the
secretion of stress-related hormones af-
ter animals are confronted with real or
simulated disease. This research is aimed
at identifying and controlling responses
to stress.
In a multifaceted study of newborn
piglets' general ability to develop resis-
tance to diseases, Carroll and Matteri
have been exploring the effects of envi-
ronmental temperature. The research has
shown that the piglets, lacking the abili-
ty to develop an acute fever, actually be-

come hypothermic-that is, lose body
temperature-during a disease challenge.
Chilling may, and often does, lead to
The scientists treated piglets with an
anti-inflammatory drug similar to aspi-
rin and ibuprofen before injecting them
with a lipopolysaccharide from killed
bacteria to simulate infection by a live
disease organism. The drug prevented
hypothermia. More important, by observ-
ing chilling and changes in body chem-
istry in pigs with and without the drug,
the scientists are now on the way to find-
ing ways to improve growth and reduce
sickness and death among young pigs.-
By Ben Hardin, ARS.
This research is part of Animal Well-
Being and Stress Control Systems, anARS
National Program described on the
World Wide Web at http://www.nps.ars.
usda. gov/programs/appvs. htm.
RobertL. Matteri, JefferyA. Carroll, and
Cheryl J. Dyer are in the USDA-ARS
Animal Physiology Research Unit, 920 E.
Campus Dr, University ofMissouri, Co-
lumbia, MO 65211; phone (573) 882-
1047, fax (573) 884-4798, e-mail
CarrollJA @ missouri. edu
[Dyer] +

Animal physiologist
Chter I Di er observes
hliallh.. Ill-day-old

, _


To measure dosages needed to control insect pests, entomologists Stephen Wraight (left) and John Vandenberg apply fungal spores to
test insects in a plastic tower.

Could natural fungi help rein in
important insect pests of vege-
table and cereal crops?
Very possibly, according to
ARS entomologist John D. Van-
denberg. He has been focusing on wheth-
er two parasitic fungi in particular-
Beauveria bassiana and Paecilomyces
fumosoroseus--could become biological
controls for diamondback moths and
Russian wheat aphids.
"The Russian wheat aphid is a major
pest of U.S. winter wheat and barley,"
says Vandenberg. "And the diamondback
moth is a worldwide pest of cabbage,
broccoli, canola, and other cruciferous
"Each year, farmers worldwide spend
more than $1 billion to control diamond-
back moths-primarily with chemical
insecticides," he notes. But in many ar-
eas, the moth has become resistant to
conventional insecticides, as well as to
natural bacterial controls such as Bacil-
lus thuringiensis, or Bt.

In Vandenberg's tests so far, the moth
succumbed to both fungi, while only the
Beauveria had much impact on the aphid.

Alternatives to Bt
At least 10 other insects, including
Indian meal moths, have developed some
resistance to Bt, especially where farm-
ers have used it extensively. But fungi
are promising alternatives, according to
Vandenberg, who is based at ARS' U.S.
Plant, Soil, and Nutrition Laboratory in
Ithaca, New York.
"With P. fumosoroseus," says Vanden-
berg, "field studies on application rates
and residual effects on subsequent pop-
ulations are needed to select appropriate
strains. We also need to better understand
and manage the fungal infection pro-
In laboratory studies, Vandenberg and
Cornell University graduate student Jen-
nifer Altre compared eight strains of P.
fumosoroseus for their ability to infect
and kill the diamondback moth.

"We found dramatic differences
among these strains in their relative vir-
ulence, spore size, germination speed,
and ability of spores to attach to the sur-
face of the insect," says Vandenberg.
"The highly virulent strains have larg-
er spores that attach easily to the insect's
cuticle and germinate quickly. A strain
with smaller spores doesn't attach well,
germinates slowly, and isn't able to in-
fect the moth."
In laboratory experiments with B.
bassiana, all larval stages of the moth
were susceptible to infection. But larvae
exposed to the spores shortly before
molting avoided infection because they
quickly shed their cuticle.
"Larvae died more quickly at moder-
ate temperatures and when exposed to
higher doses of B. bassiana spores," he
says. "These studies will help us to pre-
dict the success of timely applications of
field-applied fungi."
In related research, Vandenberg and
Anthony M. Shelton, a Cornell Univer-

Agricultural Research/September 1999

Could diamondback moths and Russian wheat
aphids succumb to these two biocontrol fungi?


sity entomologist investigated B. bas-
siana for diamondback moth control on
cabbage seedlings grown in
screenhouses. Farmers who grow
cabbage rely on these seedlings, which
they transplant and grow in their fields.
"Commercial crucifer seedlings can
be contaminated with insecticide-
resistant diamondback moths," Vanden-
berg says. "By the time these seedlings
become established in the field,
diamondback moth larval populations
can be high enough to require control."

A Commercial Product Works
Vandenberg and Shelton applied
Mycotrol, a commercial formulation of
B. bassiana, to infested cabbage seed-
lings. Mycotrol was developed through
a cooperative research and development
agreement between ARS and Mycotech
Corporation of Butte, Montana. In
March 1995, the U.S. Environmental
Protection Agency approved its use on
a variety of pests and crops.
Vandenberg and colleagues were the
first to field-test Mycotrol's effective-
ness on the diamondback moth. They
found that weekly or twice-weekly ap-
plications significantly reduced insect
populations and damage to seedlings,
compared to water-sprayed controls.
"This treatment is as effective as
conventional insecticides," Vandenberg
says. "The fungus persists on treated
leaves for more than 2 weeks to pro-
vide continued protection."
Both Mycotrol formulations-as
wettable powder and as an emulsifiable
suspension-reduced moth larval pop-
ulations when applied to larger plants
in the field. Multiple applications also
improved performance. Field trials are
under way using Mycotrol in combina-
tion with conventional insecticides for
season-long management of diamond-
back moths and other pests.
"These findings will allow industrial
producers to select more useful strains
of both fungi," he says. "It will help
farmers more efficiently apply fungi for

Agricultural Research/September 1999

safe, effective biological control of the
diamondback moth. These fungi should
also work to control other moth pests."

Control of Russian Wheat Aphids
Vandenberg has also explored both
fungi for control of the Russian wheat
aphid, Diuraphis noxia. This aphid
spends the winter primarily on wheat
and barley throughout its North Ameri-
can range-16 states and 2 Canadian
provinces. Since invading the United
States in about 1986, the 1/16-inch-long
green aphids have cost growers more
than $850 million in insecticide treat-
ments, crop yield losses, and other costs.
In field studies, Vandenberg and
University of Idaho entomologist Larry
E. Sandvol infested plots of spring-
planted wheat with the Russian wheat
aphid. They then tested spores of B.
bassiana and P. fumosoroseus for their
ability to control the pest.
"We found significant reductions in
aphid populations over all three seasons
after spraying B. bassiana as Mycotrol,"
he says. Sampling 4 days after spray-
ing revealed that 52 percent of the
aphids on wheat tillers-shoots that
sprout from the plant's base-were in-
fected with the fungus.
In 1997 and 1998, Vandenberg and
Sandvol applied Mycotrol once to larg-
er, 1-acre plots using a moveable pipe
irrigation system. Aphid populations
dropped significantly within 2 to 3
weeks after spraying.
He says these studies showed the po-
tential for controlling the Russian wheat
aphid using fungi. They proved that the
treatment works on a large scale and has
commercial potential.
Vandenberg says that although oth-
ers have shown that other strains of B.
bassiana work against this aphid, this
is the first time Mycotrol's effectiveness
on the Russian wheat aphid has been re-
Tests with P fumosoroseus were in-
conclusive. The fungus reduced Russian
wheat aphid in 1995, but not in 1996,

Ltunurea Lneauvera oassiana fungus.

The green diamondback moth larva on the
left is alive and healthy, the reddish one on
the right was recently killed by Beauveria
bassiana spores, and the one in the middle
is covered with spores that have erupted
from within.

after one or two applications.
To find ways to improve the field sta-
bility of this fungus, Vandenberg and
Sandvol are cooperating with microbi-
ologist Mark A. Jackson. He is in the
Fermentation Biochemistry Research
Unit of ARS' National Center for Agri-
cultural Utilization Research in Peoria,
Illinois.-By Hank Becker, ARS.
This research is part of Crop and
Commodity Pest Biology, Control, and
Quarantine, an ARS National Program
described on the World Wide Web at
John D. Vandenberg is at the USDA-
ARS U.S. Plant, Soil, and Nutrition Lab-
oratory, Tower Rd., Ithaca, NY, 14853;
phone (607) 255-2456, fax (607) 255-
1132, e-mail *

Diapers for On-the-Run Livestock

In the spring of 1998, some of the lambs frolicking on steep,
grassy West Virginia hillsides wore diapers-toddler size.
They wore them for only a few days, with frequent changes.
But their unusual attire was part of ARS animal scientist
Kenneth E. Turner's data collection method for comparing the
nutritive value of various legume-grass combinations for
grazing livestock. The lamb's "playpen" was a fenced-off
pasture at ARS'Appalachian Farming Systems Research Center
in Beaver, West Virginia.
The research, which Turner also plans for beef cattle and
goats, is designed to measure nitrogen lost from the sheep.
Knowing how much is excreted by animals in urine and feces
helps him and his colleagues recommend the best combina-
tions of plants and livestock.
The nitrogen measurements enable him to figure out how
thoroughly the animals digest the plants and how much of the
plant protein is used in making lean muscle for beef cattle, goats,
and sheep.
Another concern: Wasted protein, in nitrogen form, becomes
a contaminant if it is converted to nitrate and winds up in ground-
water. "We want to help farmers control nitrogen losses to the
environment at the source-the animal's diet," says Turner.
"In several years of research, we have so far found that live-
stock contribute significant amounts of nitrogen and other nu-
trients to pasture land through their urine and feces," Turner
says. "This needs to be credited to the overall nutrient manage-
ment plan for a farm before adding commercial fertilizer," he
says. "By using more intensive grazing methods-such as di-
viding larger pastures into several smaller paddocks and mov-
ing livestock to new paddocks more often-we can more evenly
distribute urine and feces in pastures as livestock graze. This
prevents manure nutrients from being concentrated around wa-
tering troughs and trees used for shade by livestock."
The diapers, which at first were placed over the genitalia of
male lambs, were wrung out to collect urine. The animals also
wore a canvas bag that collected feces.
But the diapers didn't work as well as hoped; lambs appar-
ently frolic more than toddlers. So, in spring 1999, Turner
switched to female lambs fitted with a urinary catheter bag
hooked to the fecal bag, which was strapped securely but com-
fortably to the lambs' hindquarters.
"It's the same type of thing scientists do for animal nutrition
studies where livestock are placed in a metabolism chamber
for 24 to 72 hours to collect all the feces and urine and to con-
trol what the animal eats, Turner says. "But we needed port-
able collection devices for animals on the run in a small pas-
ture."-By Don Comis, ARS.
Kenneth E. Turner is at the USDA-ARS Appalachian Farm-
ing Systems Research Center, 1224 Airport Rd., Beaver, WV
25813-9423; phone (304) 256-2843, fax (304) 256-2921,
e-mail *

Sunflower Bee's a Great Pollinator!

SA hard-working native bee can some-
_. ', times top the pollination prowess of the do-
-. mesticated honey bee-even when badly
outnumbered. "In our experiments using
outdoor enclosures," says ARS entomolo-
gist Vincent J. Tepedino, "sunflower leaf-
cutting bees spread out evenly among sun-
flowers instead of visiting just the plants
nearest their nesting boxes."
Tepedino has affectionately nicknamed
the bees "megapugs," short for Megachile pugnata. They're
native to southern Canada and most of the United States ex-
cept the lower Mississippi Valley and Gulf Coast.
Dark-colored and about 3/4- to 1-inch-long, the bee forages
on sunflowers and other species in the sunflower family. It
uses leaf pieces and moistened soil to make partitions between
compartments, or cells, that house its young.
"Megapugs could be used wherever sunflowers are grown,"
Tepedino notes. "They are charming and dutiful. Every sun-
flower grower should have a bunch."
Tepedino used four 100-by-20-foot screened enclosures,
owned by Pioneer Hi-Bred International, Inc., at Woodland,
California, for the experiment. One kind of sunflower pro-
duced significantly larger and heavier seeds after being polli-
nated by the megapugs than when pollinated by domesticated
honey bees, Apis mellifera.
The test was the first using sunflower leafcutting bees to
pollinate hybrid sunflowers in field cages, says Tepedino. In
earlier work, other ARS researchers at Logan, Utah-where
Tepedino is based-scrutinized megapug performance in open
fields. There, too, the bees were better than honey bees as out-
door pollinators of sunflowers.
In the new test, Tepedino enclosed bees within the four cag-
es, each with about 600 sunflower plants inside. For around 2-
1/2 weeks, about 100 sunflower bees in each of two cages per-
formed pollination chores. Meanwhile, a few thousand
domestic honey bees-over 10 times more than the mega-
pugs-performed the same task in two other cages.
For one type of sunflower, there was no significant differ-
ence in the size of seeds harvested or the total seed weight per
flower head. For the second kind of sunflower included in the
experiment, however, those pollinated by the sunflower leaf-
cutting bee produced seeds that were about 30 percent larger,
on average, than seeds on plants pollinated by honey bees. Total
seed weight per flower head was also about 30 percent greater.
Tepedino expects to have results of a follow-up study late
this year or in early 2000.-By Marcia Wood, ARS.
Vincent J. Tepedino is at the USDA-ARS Bee Biology and
Systematics Laboratory, 5310 Old Main Hill, Logan, UT84322;
phone (435) 797-2559, fax (435) 797-0461, e-mail andrena@ *

Agricultural Research/September 1999

Healthy Animals on the Web
ARS has a new on-line source for
news and expert resources on the health
and well-being of agricultural animals
and fish. Updated quarterly, the "Healthy
Animals" web site is designed for veter-
inarians, researchers, producers, animal
industry groups, and others. It provides
web links to recent ARS research accom-
plishments about the health of cattle,
chickens, turkeys, swine, sheep, goats,
horses, and catfish and other aquaculture
fish species. It also supplies pertinent
research information on deer and other
Site visitors can find out how to con-
tact any of the two dozen ARS research
groups conducting studies aimed at pro-
tecting and improving farm animal
health. An index lists 70 animal health
topics-from specific diseases to broad
subjects like nutrition-along with the
ARS locations conducting the research.
The site does not provide treatment ad-
vice for sick animals or give individual-
ized recommendations. To receive an-
nouncements of each new issue, contact
Kathryn Barry Stelljes, ARS Information
Staff; phone (510) 559-6069, e-mail
stelljes @ "Healthy An-
imals" can be found at http://www.ars. Caird Rexroad, Jr.,
Assoc. Deputy Administrator for Animal
Production, Product Value, and Safety,
Beltsville, Maryland; phone (301) 504-
7050, e-mail

Turkey Syndrome Yielding
Its Secrets
Scientists have pinned down the first
internal target of a mysterious disease
that has been killing turkeys in the South-
east since 1995. ARS and North Caroli-
na State University scientists found that
Poult Enteritis Mortality Syndrome
strikes first in the thymus, the disease-
fighting lymphoid gland. PEMS is appar-
ently a deadly combination of viruses.
Specific agents have not yet been identi-
fied. But the syndrome leaves a turkey's
immune system highly vulnerable to mi-

Agricultural Research/September 1999

crobes and parasites. In infected flocks,
PEMS mortality ranges from 25 to 96
percent. Some birds recover, but they at-
tain no more than about 40 percent of
market weight. From a turkey sick with
PEMS, the scientists recently isolated a
virus from the thymus, where very few
viruses are known to grow. They are at-
tempting to identify this virus and deter-
mine its disease role. The research will
aid in developing diagnostic tools and
treatments to prevent future outbreaks.
Already, outbreaks in the Southeast have
cost the turkey industry millions of dol-
lars in losses. Other outbreaks have oc-
curred in Texas and Virginia. Stacey
Schultz-Cherry, USDA-ARS Southeast
Poultry Research Laboratory, Athens,
Georgia; phone (706) 546-3432, e-mail
sschultzcherry @ sprynet. com.

License for Aerial Spray
A new nozzle and aerial spray system
for agricultural aircraft has taken off for
the marketplace. Spectrum Electrostatic
Sprayers of San Antonio, Texas, licensed
the ARS technology and is evaluating a
commercial prototype. Earlier ARS stud-
ies suggest the new system could reduce
spray drift from aircraft. This year, larg-
er studies are evaluating this benefit.
Compared to conventional systems, the
new one can apply a much lower volume
of spray per acre. That means a plane can
treat more acres during a flight, before
having to return to the airport to reload.
ARS tests suggest other benefits, in-
cluding improved insect control. ARS ag-
ricultural engineer James B. Carlton, now
retired, invented the nozzle and electro-
statically-charged spraying system.
Chemicals that may be applied with it
include liquid formulations of pesticides
(herbicides, insecticides, fungicides) and
fertilizers. Airplanes annually spray mil-
lions of acres of grain, cotton, and vege-
tables to control crop pests. Additional
millions of acres are sprayed to control
mosquitos or other pest outbreaks. Ivan
W Kirk, USDA-ARSAreawide Pest Man-

agement Research, College Station, Tex-
as; phone (409) 260-9584, e-mail

Do Some Crops Need a
If Alan Olness has anything to say
about it, the N-P-K trio (nitrogen/phos-
phorus/potassium) of soil tests may
someday form a quartet, with a V for
vanadium. A little-known but abundant
trace element, vanadium captured the
ARS soil scientist's interest a decade
ago. He found it mysteriously reduces
soybean yields. Afew years ago, he and
colleagues confirmed earlier work sug-
gesting some plants take up vanadium
instead of the essential phosphorus.
Soybeans, corn, tomatoes, impatiens,
petunias, and many other plants have no
use for vanadium, only a useless appe-
tite for the stuff. So, crop yield and qual-
ity may suffer. Olness' current studies
aim at seeing if soil type is related to
high vanadium content. He also plans a
phosphorus advisory so farmers can ac-
count for the vanadium effect.
Because standard soil tests don't
measure vanadium, they could result in
inaccurate phosphorus recommenda-
tions. Ten years ago, Olness developed
a test that does measure soil vanadium-
and its ratio to phosphorus and other key
nutrients. The test could be used to re-
calculate phosphorus recommendations
up or down after researchers redetermine
the optimum economic amounts of phos-
phorus. An alternative might be to breed
crop varieties with a "V-chip" trait to
block or neutralize the pesky element.
Scientists have already identified a soy-
bean whose yield seems relatively im-
mune to vanadium. Next question for
researchers: Exactly how does this soy-
bean manage this feat? Once they know,
they might be able to breed the trait into
other crops. Alan E. Olness, USDA-ARS
North Central Soil Conservation Re-
search Laboratory, Morris, Minnesota;
phone (320) 589-3411, e-mail aolness@
mail. mrsars. usda. gov.

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scientists and colleagues in Israel and Canada. For details about scale
insect biology, classification, distribution, controls, and more, go to

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