Group Title: Agricultural research (Washington, D.C.)
Title: Agricultural research
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Title: Agricultural research
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Full Text

LU~Ptur







FORUM


Parasites: The
Problems Persist
In the mid-1800's, public health
concerns about pork infested with a
particular parasite-Trichinella
spiralis-were so widespread in
Germany that a butcher was jailed for
a month for violating local regula-
tions on meat inspection.
Around the same time, a German
meat inspector spent 6 months
behind bars for failing to check pork
that had caused cases of trichinosis
in German consumers.
Leading the push for public
education in Germany about the
dangers of Trichinella in pork was
pioneering parasitologist Rudolph
Virchow. Also a bluntly outspoken
member of the German parliament,
Virchow was once challenged to a
duel by the dictatorial Otto von
Bismarck, Prussia's famed "Iron
Chancellor."
Legend has it that Virchow pro-
posed fighting the duel with sausag-
es, one of which would contain Tri-
chinella-laden pork. Each combatant
would eat a sausage, with Bismarck
getting first choice. As the story
goes, Bismarck declined the proposi-
tion as too risky. And while that tale
isn't true, it underscores the undeni-
able impact of parasites on human
history-past, present, and future.
It is believed, for example, that the
biblical "fiery serpents" that torment-
ed ancient Hebrews by the Red Sea
were probably what we now call
guinea worms. As recently as 1991,
this parasitic scourge was the focus
of a United Nations World Health
Assembly resolution for eradication
worldwide by the turn of the century.
Another parasitic disease, schisto-
somiasis, causes blood loss and tissue
damage in as many as 300 million
people worldwide, with 1 of every 5
Egyptians believed to be infected.
And in this country, hookworm infec-


tion devastated the southern work-
force in the early 1900's and still
plagued the South as late as 1953.
In the economic arena, the United
States in the summer of 1880 found
its ground pork and sausage banned
from import into Germany-a ban
later expanded to all U.S. pork. The
reason was reportedly excessive
levels of Trichinella in American
pork products, although some observ-
ers have long argued that the real
threat was the overwhelming of
European markets by cheap and
abundant American pork.
The German ban on American
pork led to a long-running squabble
between the United States and
Germany. At one point, the United
States threatened to require manda-
tory certification of imported German
wines because, as the U.S. Secretary
of Agriculture explained, "certified
American meats are as wholesome as
foreign wines."
More seriously, human illnesses
attributable to foodborne parasites to-
day are monumental in their eco-
nomic impact. It has been estimated
that in the United States alone, losses
to congenital infection with a single
parasite, Toxoplasma gondii, total as
much as $8.8 billion annually, not-
withstanding the emotional price paid
by the families of T. gondii-infected
infants born blind, hearing-impaired,
or mentally retarded.
In the agricultural sector, under-
standing and control of parasitic
infections in livestock can contribute
not only to human well-being, but
also to the well-being of the
environment.
As the world's developing regions
struggle to feed themselves, meat and
dairy products play an important role,
especially where land is unsuitable
for other agricultural production.
To meet consumer demands for
meat and milk, the answer can't
always be simply to raise more


animals, because of overgrazing, soil
erosion, possible groundwater con-
tamination, and other environmental
problems that can result. Instead, the
projected 40- to 50-percent increase
in meat production needed in devel-
oping countries must come from more
efficient production-and that means
healthy animals.
How much of a toll can parasites
take on livestock? Consider these
facts: Theileriosis kills about 3 mil-
lion cattle annually in Africa, and tox-
oplasmosis is responsible for many
abortions and deaths among newborn
lambs and pigs in developing coun-
tries. Latin America has twice as
many cattle as the United States but
produces only half the beef because
of pests and diseases in its herds.
A worldwide 6-percent reduction
in losses from animal disease could
provide food for as many as 250
million additional people.
Let's not forget poultry, either. In
many developing countries, chickens
are a major source of dietary protein.
Yet a recent survey in Ethiopia found
73 percent of chickens were infected
with tapeworms and 88 percent with
nematodes, resulting in significant
weight losses in those birds. More
than 9 out of 10 chickens in Nigeria
have some form of wormlike parasite.
It seems obvious that understand-
ing and effectively controlling one of
humanity's oldest foes-parasites-is
key to the continued survival of many
millions of people around the world,
both in terms of ensuring an adequate
food supply and in reducing animal-
to-human disease transmission.
"Searching for Parasitic Roots"
[page 4] describes efforts to expand
our basic knowledge of these diverse
organisms' taxonomies, origins,
habits, and host relationships.

K. Darwin Murrell
Director, ARS Beltsville Area


Agricultural Research/December 1996








December 1996
Vol. 44, No. 12
ISSN 0002-161X

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Department of Agriculture, Washington, DC
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Floyd P. Horn, Administrator
Agricultural Research Service
Robert W. Norton, Director
Information Staff
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Agricultural Research/December 1996


Agricultural Research



Searching for Parasitic "Roots" 4

Hardy Oats Stand Up to a Cold World 8

New Red Clover Puts Pastures in the Pink 9

Speck Trek Tracks Hard-To-Dye Cotton 1

Mutant Corn Has Low Phytic Acid 12

Yeast Collection on the Rise 15

"Eye-in-the-Sky" Made More Useful to Farmers 16

Virus Zaps Pests, Speeds Medical Research 18

Killing Psylla in Cold Blood 20

1996 Index 22


Cover: Knowledge of parasite-host
relationships-even those with highly isolated
exotic species, such as these Chinstrap
(Pygoscelis antarcticus) penguins in remote
Antarctica-may provide basic information
for understanding the distribution of
economically significant parasites. Photo by
Eric Hoberg.





















































r1w






PHOTO BY ERIC HOBERG


"Besides telling us something
about their hosts' diet, behavior, and
habitat, parasites can tell us about
their geographical connections of
long ago," he says. "They are the
products of both a current environ-
ment and, at the same time, of a long
ancestry reflecting millions of years
of host association."

It Takes a Special Scientist
The task of discovering and scien-
tifically describing living organisms
is the responsibility of a highly spe-
cialized group of scientists who, like
Hoberg, are trained systematists.
They integrate the standardized
naming of organisms (nomenclature)
with understanding of evolutionary
relationships among species (phylog-
eny), to ultimately classify organisms
into hierarchical groups (taxonomy).
As taxonomists, systematists care-
fully examine living species and offi-
cially describe them by detailing their
distinguishing characteristics in very
exacting terms-morphological (form
and structure), biochemical, and mo-
lecular. Without the expertise of sys-
tematists, the millions of species of
organisms remaining to be de-
scribed-insects, fungi, bacteria,
nematodes, plants-cannot be recog-
nized and classified.
"These classifications represent ev-
erything we know about the relation-
ships among organisms," says
Hoberg. "Even more important, they
help predict species behavior. In a
sense, if we know which order, fami-
ly, or genus a parasite belongs to, we
can then predict with some certainty
what effect it will have on hosts in the
same or related families."

Field studies have taken ARS zoologist
Eric Hoberg across North America, Sibe-
ria, and Antarctica. At a camp on Talan
Island in Chukhotka, Russia, he sorts
specimens that will eventually be used in
supporting his Arctic refugium hypothesis
of host and parasite species development.

Agricultural Research/December 1996


Hoberg works at the Beltsville
(Maryland) Agricultural Research
Center, in the ARS Biosystematics
and National Parasite Collection Unit
that has historically concentrated on
parasites of food animals.
He is an expert in biodiversity,
cospeciation (evolutionary associa-
tions between parasites and hosts),
and biogeographic analysis (study of
the geographic distribution of living


systematists identity a male Nematodirus
spathiger nematode by studying its tail and
copulatory structures (magnified about
130x).


things). He has studied the systemat-
ics and evolution of tapeworms of
seabirds and of pinnipeds such as
seals and sea lions, as well as the
roundworms of ruminants.
"Parasites have characteristic host
and geographic distributions and pre-
dictable life cycles and transmission
patterns," says Hoberg.
He is associate curator of the
USDA-ARS U.S. National Parasite
Collection. His research has earned
him the H.B. Ward Medal from the
American Society of Parasitologists.


In 1994, ARS recognized him as Out-
standing Early-Career Scientist for his
creative studies of systematics, cospe-
ciation, and biogeography of parasites
in wild and domestic vertebrate hosts.
Hoberg and a small staff of ARS
parasitologists curate the collection,
identifying and naming all types of
parasites of vertebrates-nematodes
(roundworms), flukes, and tape-
worms-including avian and mam-
malian hosts.
Theirs is one of the world's largest
collections, with about 95,000 lots
representing several million speci-
mens. About 1,000 new groups of
specimens are added annually to the
collection. In recent years, Hoberg
has named 20 new species, 4 genera,
a family, and an order of parasites,
based on research he did alone and
with colleagues.

Building a Unifying Framework
Hoberg uses this vast collection
and his knowledge of parasite system-
atics to examine evolutionary rela-
tionships between hosts and parasites.
This research, called cospeciation
analysis, includes studies of contem-
porary and historical biogeography,
or distribution-that is, where hosts
and parasites now occur and where
they originated.
As a result of his work on tape-
worms of seabirds and pinnipeds, he
formulated the "Arctic Refugium"
hypothesis that recognizes the role of
global climatic fluctuations and
habitat distributions during ice ages
as determinants of the process by
which host and parasite species are
formed. It postulates that islands of
habitat suitable for occupation by
animals existed in northern regions
during the ice ages. And in these
islands, or refugia, isolation of small
populations of hosts and parasites
resulted in the origin of species.
This hypothesis has provided sci-
entists with a unifying framework for













understanding the history of marine
fauna in the North Pacific basin and
Holarctic region (northern North
America, Siberia, and Europe) over
the past 3 million years.
Concepts derived from these
studies are now being used to com-
prehensively evaluate the biogeogra-
phy and evolutionary history of
trichostrongyle (stomach and intesti-
nal) nematodes of cattle, sheep, deer,
and related ruminants across the
northern hemisphere.
"Most parasite systematists con-
centrate only on the parasites, and
most vertebrate systematists focus
only on free-living groups like birds,
fish, or mammals," Hoberg says. "An
integration of parasitology and verte-
brate biology, however, can give us
considerably more information.
"Knowledge of parasites applied to
questions of biodiversity can, for ex-
ample, tell us about historical or con-
temporary associations, what hosts
eat, and where they forage and spend
time, along with information on sea-
sonal migratory paths.
"It is also important to survey and
inventory parasites in order to docu-
ment biodiversity, so we can under-
stand what parasites typically occur in
a region. Then we can recognize the
introduction of potentially pathogen-
ic, or disease-causing species."
For example, intercontinental
movement of hosts such as ruminants
(cud-chewing grazing animals) and
ratite birds (ostriches, emus, and
rheas), accompanied by introduction,
establishment, and emergence of ex-
otic parasites, is a continuing problem
throughout the world.
"In the United States, we have re-
cently discovered a new species of
pathogenic nematode that is potential-
ly fatal to ostriches. And we have
identified numerous exotic nematodes
from wild antelopes imported from
Africa," says Hoberg.
This ongoing pattern of introduc-
tion of hosts and parasites highlights


The precise description of each species is
the cornerstone of the science of
systematics. Here, zoologist Eric Hoberg
makes detailed drawings of a previously
unknown tapeworm. (K7505-1)


the need to do exhaustive research in
systematics of nematodes in domestic
and wild hosts across Eurasia and
Africa. Historically, North American
and Eurasian faunas were linked by
the Bering land bridge, connecting
Alaska and Siberia. That established a
phylogenetic and biogeographic link
between the host and parasite faunas
of the Old and New Worlds that has
been significant for evolution of
trichostrongyle nematodes of rumi-
nants over the past 20 million years.
Broad-based studies of these
parasites are necessary to understand
the species diversity and structure of
the parasite fauna of both domestic
and wild ruminants, which is a mosaic
of ancient and recently introduced
species. Hoberg believes that systemat-
ics provides the foundation for under-
standing the history and biogeography
of such host-parasite relationships and
for predicting parasite behavior when
helminths are introduced to new hosts
or ecological settings.
Recently, Hoberg studied the history
of emergence of two serious parasites-
of sheep and of muskoxen-that could
have serious implications.
Nematodirus battus is widely re-
garded as the most pathogenic parasite
in lambs in the Northern Hemisphere.
Although the modern history of N.


battus is strongly tied to domesticat-
ed sheep, its ancestral host group has
remained a mystery.
Though it was probably inadvert-
ently brought into the United States
in the early 1980's, Hoberg discov-
ered N. battus in Oregon in 1984. A
1986 survey by the USDA's Animal
and Plant Health Inspection Service
showed that it had already become
established on both coasts.
"Pathogenicity of this parasite is
attributable to large numbers of de-
veloping larvae that are ingested
from pastures while sheep forage,"
says Hoberg. "In England, farmers
may lose up to a third of their lambs
because of this nematode."
Anthelmintic drugs now help to
prevent infestations. And local fore-
casting predicts the seasonal emer-
gence of parasite larvae, enabling
farmers to limit exposure of lambs.
It appears that international trans-
port of infected domestic sheep
spread the parasite across parts of the
Northern Hemisphere.
Hoberg and colleague Steven
Nadler at the University of Califor-
nia, Davis, conducted phylogenetic
analyses of molecular data that
support a history of its recent intro-
duction from the United Kingdom to
Canada and the United States.
Systematics was also used to
illuminate the historical host range of
this and related parasites. Hoberg
studied and analyzed the evolution-
ary relationships among 11 species of
Nematodirus from ruminants, includ-
ing N. battus. This species was found
to be closely related to species of
Nematodirus from deer-rather than
to those species that occur among
sheep and goats.
"This suggests that a host-switch
or colonization from deer resulted in
the occurrence of N. battus in sheep,"
says Hoberg. "And it tells us that the
parasite is not host-specific, limited
to a particular phylogenetically relat-
ed group of hosts. Instead, it is a po-

Agricultural Research/December 1996













tential problem to all domestic and
wild grazing animals, now that it is
present in North America."
Hoberg says there is a nematode of
muskoxen in the Canadian Arctic that
is still an enigma with respect to its
origins, contemporary host range, and
biogeography.
Umingmakstrongylus pallikuuken-
sis, recently named by Hoberg and a
Canadian research group, is the larg-
est known lungworm. Females are
over a foot and a half long, and males
and females live in massive nodules
in the lungs of muskoxen. Infected
muskoxen defecate larvae that infect
and develop in slugs and perhaps oth-
er mollusks that are likely ingested by
grazing animals foraging in meadows.
The lungworm, discovered in 1988
by Canadian biologists, apparently
causes sickness and possibly death in
heavily infected animals and reduces
their overall vitality. Hoberg, along
with Lydden Polley from the Univer-
sity of Saskatchewan and Anne Gunn
and John Nishi from the government
of the Northwest Territories, de-
scribed the lungworm's morphologi-
cal features and presented hypotheses
for its biology and biogeography in
the Arctic.
Hoberg believes that U. pallik-
uukensis may have implications for
managing wild ruminants in the Arc-
tic, since a major management prac-
tice for muskoxen involves the rein-
troduction of animals to areas where
these arctic ruminants were hunted to
local extinction in the last century.
"Such translocation could lead to
the introduction of parasites, along
with their hosts, or expose parasite-
free animals to infection," he says.
Hoberg's studies also show that U.
pallikuukensis is not an exotic para-
site but is apparently endemic to the
Arctic. However, the exceptionally
high prevalence of infection-near 90
percent in some areas-and its ability
to cause disease suggest it has recent-
ly emerged.

Agricultural Research/December 1996


The typical shape and color of eggs of the
disease-causing Nematodirus battus
nematode, shown in the uterus of a female
worm (magnified about 130x), help
identify the species.


"This parasite may have an adverse
impact on food resources, such as
muskoxen, which are a traditional
food source for native cultures in the
Arctic," he says. A multidisciplinary
team of scientists that includes
Hoberg and other parasitologists and
vertebrate biologists is working to un-
ravel the coevolutionary history of
this host and parasite.
Hoberg's research shows that para-
sites are of more than just intrinsic in-


terest because of their economic im-
pact on ruminant animals. It also
makes it clear that these obscure or-
ganisms tell us stories about the intri-
cate and complex history of hosts and
geographic regions.
Hoberg believes that knowing the
past is the key to understanding the
present. "Historical studies involving
parasites contribute to a predictive
foundation for understanding biotic
communities and environments," he
says. "These studies lead to substan-
tial progress in developing new diag-
nostic methods and assessments of
biogeography and host range of eco-
nomically significant parasites and
their allies.
"Parasites are powerful tools, or
keystones, for addressing questions of
the origin, maintenance, and distribu-
tion of biodiversity."-By Hank
Becker, ARS.
Eric P. Hoberg is in the USDA-
ARS Biosystematics and National
Parasite Collection Unit, Bldg. 1180,
10300 Baltimore Ave., Beltsville, MD
20705-2350; phone (301) 504-8588,
fax (301) 504-8979. *


ERIC HOBERG


I- **>.w -'
The muskox may be the sole host for the largest known lungworm, Umingmakstrongylus
pallikuukensi. This parasite infects up to 90 percent of the muskoxen in a region near the
lower Coppermine River in Arctic Canada.








Hardy Oats Stand Up to a Cold World


f all fall-sown grain crops,
oats are the most vulnerable
to freezing before spring.
But understanding how their natural
defenses work may uncover new
ways to toughen them up, a USDA
scientist says.
"Winter oats are grown mainly in
regions below Virginia. Barley, the
next hardiest crop, goes as far north
as Pennsylvania, wheat makes it to
the Dakotas and southern Canada,
and rye grows almost anywhere,"
says ARS plant physiologist David P.
Livingston. "But many farmers,
especially in Pennsylvania and Ohio,
would like to grow winter oats."
For all fall-sown crops, surviving
winter depends on the regenerative
part of the plant known as the crown,
which is usually underground where
the root and stem meet.
During cool fall weather, plants
slow their growth, diverting their
carbohydrates into this "biological
backpack" to fuel new spring growth.
The leaves and roots may die, but if
most of the regenerative cells in the
crown can keep the ice out, the plant
will survive to regrow in spring.
Livingston has been exploring
whether carbohydrates might play a
role in freeze protection.
The Russian scientist I.I. Tumanov
reported in 1931 that winter crops
have two distinct winter preparation
phases. In phase one-just above
freezing-the plant stores carbohy-
drates and undergoes other biochemi-
cal changes. But in the second
phase-just below freezing-the
plant seems to be using the sugars in
some way, as was reported by Soviet
scientist T.L. Trunova in 1965.
Livingston's mentor, ARS scientist
C. Robert Olien, was among the first
American researchers to explore the
second phase. He found plants moved
their sugars into the space between
the cells, known as the apoplast,


which is mainly water. This could be
a sophisticated survival trick.
"Ever notice how ice cubes will
stick to your fingers, especially if
they're clean? That's because the ice
molecules are playing tug-of-war
with your outer skin cells, vying for a
very thin moisture layer. It doesn't
hurt your fingers, but the forces can
rip the oat crown cells apart during
freezing," explains Livingston.

SCOTT BAUER


Winter oat seedlings grown by agronomist
David Livingston will be ready in about 3
weeks for first-phase hardening at temper-
atures just above freezing. (K7425-14)


"Olien showed that these sugars
could provide a protective barrier,
minimizing or even preventing the
cell destruction."
Olien's work with barley and rye
led Livingston to similar studies with
oats. He found that when oats were
exposed to -30C for 48 hours, nearly
half the plant's glucose and 13
percent of its fructose were in the
apoplast. He also found that remov-


ing these sugars from the crown
halved its freezing tolerance.
It appears that the cells were
breaking down fructan-a stored
sugar that's a chain of fructose linked
to sucrose molecules-and moving it
into the space between the cells.
"It could be the sugars lower the
freezing point of the water in critical
regions of the crown or that they
alter the shape or size of the ice
crystals so they're less likely to
damage cells," Livingston says.
He spends a lot of time comparing
notes with other ARS researchers
who specialize in cold hardiness.
Sharing research gives them insights
not only into the various winter
crops, but also into the complemen-
tary biology of freeze resistance.
For example, Livingston, a
carbohydrate specialist, collaborates
with ARS plant physiologist Cynthia
Henson in Madison, Wisconsin, who
is an expert on enzymes used to
break down carbohydrates. Both
researchers keep in touch with Elliot
Herman, an ARS plant physiologist
in Beltsville, Maryland, who uses an
electron microscope to study how
proteins and other compounds
protect winter crops. And ARS plant
physiologist Kay Walker-Simmons
in Pullman, Washington, provides
information on how hormones are
involved in protecting plants from
freezing injury.
"Cold hardiness is the result of
several survival mechanisms working
together," says Livingston. "Without
scientific collaboration, it would be
easy to get so focused that you forget
that."-By Jill Lee, ARS.
David Livingston is in the USDA-
ARS Plant Science Research Unit,
North Carolina State University, Box
761, Raleigh, NC 27695-7614; phone
(919) 515-4324, fax (919) 515-2305,
e-mail dpl@unity.ncsu.edu *


Agricultural Research/December 1996























picture is said to be worth a
thousand words.
The picture of red clover here is
priceless to ARS plant geneticist
Richard R. Smith in Madison,
Wisconsin, because it represents his
30-year career as a plant breeder.
Thirty years ago, Smith was
assigned to work with and breed red
clover. His success is evident in the
breeding he performed to make red
clover plants resistant to root rots
such as Fusarium and to foliar
diseases such as anthracnose.
In 1973, Smith introduced farmers
to Arlington, a red clover variety
that soon became popular because of
its resistance to northern anthrac-
nose-a disease that causes plants to
lose their leaves, weaken, and die.
Over the years, in both green-
house and field work, Smith has
developed red clover germplasm
with even greater resistance to
Fusarium. Another bonus is that the


Compared with common red clover in left
test plot, newer varieties show
progressively higher forage yields.


Agricultural Research/December 1996


newer generations of red clover live
longer than common strains.
In the spring of 1992, Smith
planted red clover seeds that were
used by farmers in the 1950's,
1960's, 1970's, 1980's, and currently.
After 4 years, he took a photo. It
shows that, as the years progressed,
the clover got greener.
Today, because of Smith's selec-
tions and breeding, Midwestern
farmers can obtain red clover variet-
ies capable of surviving 3 to 4 years,
instead of only 2.
One such red clover variety is
Marathon, released in 1987 by ARS
and the Wisconsin Agricultural
Experiment Station.
"By planting \larathlii instead of
common strains of red clover, farm-
ers could save over $140 a year per
acre," says Smith. He points out that
common strains will grow for about 2
years, while Marathon lasts for 4. Per
year, Marathon can yield up to 3.5
tons of dry matter per acre, in
contrast to about 2 tons per acre
for the common red varieties.
Because it doesn't need to be
planted as often as the common
reds, Marathon has become so
popular that it makes up 50
percent of the red clover seed
sales in the Midwest.
"Today we have developed
new experimental strains that
exceed Marathon in yield and
persistence. But it will be another
2 years before these strains are
developed into commercial
varieties available to farmers,"
says Smith.


RICHARD SMITH

In the future, breeders like Smith
may experiment with transferring
underground stems, or rhizomes, from
wild clover species now found in
Eastern Europe. The rhizomes will
help the plants spread, as well as
resist root diseases. But Smith says
that before rhizomes can be trans-
ferred, much work has to be done.
For centuries, red clover has been
an important forage crop used as
silage, hay, and pasture to feed
livestock throughout the midwestern
United States. Not native to the
United States, however, red clover
originated in Europe and most likely
came to us via the New World settlers
in the 1500's.
Compared to other legumes, red
clover varieties are easier for farmers
to establish in pastures when planted
with grass.
Red clover usage as a livestock
feed declined when newer alfalfa
varieties, such as Vernal, came into
existence in the 1950's. But the
popularity of red clover picked up in
the mid-1980's when farmers again
began using it as a legume in pas-
tures. As silage for animals, red
clover is equal nutritionally to alfalfa
but is less difficult to grow, thanks to
Smith's improvements.-By Linda
Cooke, ARS.
Richard R. Smith is at the U.S.
Dairy Forage Research Center, 1925
Linden Lane, Madison, WI 53706;
phone (608) 264-5279, fax (608) 264-
5275, e-mail 1 id (i'h@fia tff
.wisc.edu *








Speck Trek Tracks Hard-To-Dye Cotton
Diverse researchers unite to identify source of textile flaw.


hat do you get when you
put cotton researchers
from the U.S. Depart-
ment of Agriculture together with key
contacts from industry, academia, and
agriculture?
You get Speck Trek, a multidisci-
pline, scientific task force focused on
reducing fabric dyeing flaws by im-
proving cotton quality.
"Simply put, Speck Trek is the pre-
diction of white specks and other tex-
tile processing flaws-from field to
fabric," says plant physiologist Judith
M. Bradow, who organized the infor-
mal collaborative group.
"It lets researchers from diverse
fields exchange knowledge on how
the environment affects cotton quali-
ty," she says. "Much like the televi-
sion and movie Star Trek crews, we
use our diverse backgrounds to solve
problems. It's just that our focus is on
what growers, ginners, and mills can
do when nature doesn't cooperate."


Technician Kevin Pratt collects data on
cotton samples and uses a small roller gin
to prepare the samples for fiber analysis.
(K7508-1)


Having more than one kind of
researcher address textile dyeing
problems makes sense, because
poorly dyeing fabric can come from a
number of sources. Poor growing
conditions, plant disease, and errors
in processing may all contribute. And
once a fabric has those tell-tale white
spots of undyed fiber, it must be
discounted or thrown out.
"Textile people must worry about
dye imperfections," says Bradow. "At
a 1991 conference they listed them as
the second most important problem in
textiles. But at the time, nobody was
looking into the physiological reasons
for a fabric not taking up dyes."
Bradow and her colleague, plant
physiologist Gayle H. Davidonis, de-
cided to explore the connection be-
tween dyeing quality and plant health.
The two scientists are stationed at the
ARS Southern Regional Research
Center in New Orleans, Louisiana.
The center is home to several textile
and fiber laboratories, including the
Cotton Fiber Quality Research Unit.
Cotton brought $482 million to
Louisiana's economy in 1995. That
made it the state's top-earning crop
by USDA estimates. The entire U.S.
domestic cotton crop-fiber and
seed-was valued at over $55 billion.
But cotton plants are not in it for
the money-they only want to repro-
duce. Their fruit, known as the boll,
contains the fiber and seed. Research-
ers speculate the plants first produced
fiber to scatter seed, either by wind or
by hitching rides on passing animals.
But self-preservation takes over
when it comes to bad growing condi-
tions. The plant may allow only a few
bolls-or even seeds-to ripen and
mature fully. Just a single dry day can
cause problems, for without water,
the plant doesn't produce the carbo-
hydrates needed to fill the fiber walls
with cellulose required for dyeing.
Electron microscopy done by other


researchers at New Orleans demon-
strated this problem.
When Bradow decided to explore
what growers could do to counter na-
ture's ill effects, she needed more than
the greenhouses at the center. So she
joined forces with agronomist Philip J.
Bauer in the ARS Cotton Production
Research Unit at Florence, South
Carolina, who had plenty of test fields.
When storms from Hurricane An-
drew drenched Bauer's cotton crop in
1992, he sent Bradow boll samples.
Together, they analyzed how cloudy
days and excess rain had damaged fi-
ber quality. They continue to research
the effects of irrigation and tempera-
ture on cotton and are to be joined by
a university soil scientist who can ex-
pand their work.
Soon other researchers were also
sending boll and fiber samples to ei-
ther Bradow or to her partner, depend-
ing on their experiments' require-
ments. While both analyze fiber,
Davidonis specializes in fiber devel-
opment and seed quality, and Brad-
ow's expertise is in boll maturity.
Having these scientific contacts
puts Bradow and Davidonis in a posi-
tion to link people with resources.
Speck Trek reaches a worldwide audi-
ence and Bradow says she expects
more farmers and crop consultants
will be participating in research pro-
jects, helping scientists develop real-
world cotton-growing databases that
can become part of computer models.
"We have software to help growers
enhance yield, and we have software
to help textile mills make fabric,"
Davidonis explains. "What we don't
have yet is the bridge between them.
Our databases will be the building
blocks for that bridge."
Another original member of the
team, biochemist Gretchen F. Sas-
senrath-Cole, became a trekker soon
after she joined the ARS Crop Simula-
tion Research Unit at Mississippi
State University. Her first interest was

Agricultural Research/December 1996





RrTr RTAI FR


to find out how much energy cotton
plants needed to produce flowers and
grow bolls. But she couldn't check fi-
ber quality until the bolls completely
formed, which stymied her research.
Through Bradow, Sassenrath-Cole
gained access to an AFIS (Advanced
Fiber Information System) that can
track developmental stages of fiber.
"It was really exciting the first time
we ran some of the immature fiber
samples through," she says. "The
bolls were only 24 days past floral an-
thesis, which is less than halfway
through the normal boll growth peri-
od. In the few minutes it took to run
the sample through AFIS, we had all
the information on fiber length, de-
gree of cell wall development, shape,
and maturity."
Now Sassenrath-Cole is research-
ing the ways that environment affects
fiber quality. To explore this, she will
rely on fiber analysis from Bradow.
"Previously, other researchers
found fiber walls that looked like an-


AFIS (Advanced Fiber Information
System) will automatically determine many
quality factors of cotton samples being
inserted by technician Katherine Pusateri.
(K7509-1)

Agricultural Research/December 1996


nual rings you see on
trees trunks. The cotton
fiber's cell wall would
be thick in some places
and thin in others, and
the rings would be
more pronounced with -. .
cooler night tempera-
tures," says Sassenrath-
Cole. "We want to see Plant physiol
if we can identify simi- science aide D
lar changes under field contribution t
S. quality. (K75(
growth conditions." quality. (K75
Sassenrath-Cole will
also be looking at the role leaves play
in maintaining an optimal growth
temperature. Some cotton varieties
have smaller leaves, which may result
in greater temperature variations
within the crop canopy.
Speck Trek also connected
Sassenrath-Cole and Bradow with bio-
chemist Allen K. Murray of Glyco-
zyme, Inc., in Irvine, California. Their
research helped him explore cotton
fiber and leaf biochemistry.
"What Gretchen provided me was
fully documented developmental
stages of cotton, says Murray. "I
had already done work linking water,
plant metabolism, and fiber develop-
ment. But without actual boll samples
at 21, 28, 42, and 56 days, I couldn't
demonstrate that the big changes were
happening with sugars in the plant."
He says that the samples came with
an extensive fiber analysis from
Bradow, making for consistency and
thoroughness.
"It's this unique treatment of the
same sample in three laboratories that
is so unusual-and outstanding," says
Murray. Through this cooperation, he
also got results suggesting there are
two genetic markers for sugar that oc-
cur mainly in drought stress.
"They actually appear before the
plant shows any outward signs of
drought stress and offer the possibility
of an early-warning system for grow-
ers," says Murray. "I had documented


-

)gist Gayle Davidonis (right) and biological
>eborah Wilson discuss plant mapping and its
.o understanding differences in cotton fiber
)7-1)


differences between irrigated and
drought-stressed cotton in California,
but I had no way to correlate the dif-
ferences until I received Gretchen's
developmental samples of normal and
temperature-stressed bolls."
"We also benefit from Murray's
impressive research facility and ex-
tensive biochemistry knowledge,"
says Bradow. "It's all part of the
Speck Trek mission. We build oppor-
tunities through cooperation."-By
Jill Lee, ARS.
Judith M. Bradow and Gayle Davi-
donis are in the USDA-ARS Cotton
Fiber Quality Research Unit, South-
ern Regional Research Center, 1100
Robert E. Lee Blvd., New Orleans, LA
70124; phone [Bradow] (504) 286-
4479, fax (504) 286-4419, e-mail
jbradow@nola.srrc.usda.gov; phone
[Davidonis] (504) 286-4273, fax
(504) 286-4419, e-mail davidon
@ nola.srrc.usda.gov
Philip J. Bauer is in the USDA-
ARS Cotton Production Research
Unit, 2611 W. Lucas St., Florence, SC
29501; phone (803) 669-5203, fax
(803) 662-3110, e-mail
bauer@sunbrn.florence.ars.usda.gov
Gretchen F. Sassenrath-Cole is in
the USDA-ARS Crop Simulation Re-
search Unit, P.O. Box 5367, Missis-
sippi State, MS 39762-5367; phone
(601) 324-4346, fax (601) 324-4371,
e-mail gfsc@marlin. csrumsu.ars.
ag.gov *








Mutant Corn Has Low Phytic Acid

KPCITH IAIC I CO


- AW
.J Pw


" .1


Biochemist Kevin Young (left) and David Ertl, a plant breeder with Pioneer Hi-Bred
International, Inc., analyze hybrid corn samples. High inorganic phosphorus in low-
phytic-acid kernels turns the test solution dark blue, while normal kernels show light
blue. (K7421-9)


W without enough phosphorus,
people and animals grow
too slowly and their bones
break easily. But this same essential
nutrient can turn a pristine lake into
an algae-covered grave for fish.
The problem starts when erosion
transports soil containing phosphorus
from agricultural fields into lakes and
streams. Algae thrive on the phos-
phorus in this runoff. In their expo-
nential growth and decomposition,
algae can use up the oxygen in the
water so there's not enough for fish
or other aquatic wildlife.
A significant source of phosphorus
is manure waste from commercial
livestock, poultry, and fish farms.
Producers apply the waste to crop-
lands as fertilizer.
In the United States, hogs and
poultry alone excrete enough waste
each year to fill a train of railroad
boxcars that would circle the Earth,
according to estimates by University
of Kentucky animal scientist Gary
Cromwell. These 30 million tons of
manure contain 460,000 tons of
phosphorus. It would take 150
million of the 50-pound bags of 12-
12-12 fertilizer you might use in your
garden to supply that amount of
phosphorus. Cromwell, based in
Lexington, is an expert on nutrient
use by livestock.
One way to reduce phosphorus
runoff is to give farm animals just the
amount of the mineral that they need
Sto grow, so they won't pass the
excess in their waste.
But nature has made achieving this
balance nearly impossible.
The mainstays of agricultural
feed-corn and soybeans--contain
plenty of phosphorus. But many
animals can use only about 15
percent of it. That's because the
plants bind up the mineral in a
compound known as phytic acid.
Cows, sheep, and other rumi-
nants-grazing animals with more


Agricultural Research/December 1996


"77- 4

*'
** r ''












than one stomach-have enzymes
that break down phytic acid into a
usable form. But in animals with one
stomach-hogs, poultry, fish, and
even people-phytic acid passes
through the digestive tract unused,
creating nutritional, economic, and
environmental problems. To give
their animals optimal nutrition,
farmers must add costly phosphorus
supplements to the feed.

Comes a Revolution
ARS geneticist Victor Raboy is
working with plant breeders to
develop a better solution.
"If hogs and other nonruminants
could make better use of the phos-
phorus found naturally in their diet,
producers could save money on
nutrient supplements and wouldn't
have to dispose of as much excreted
phosphorus," says Raboy. He works
at the ARS National Small Grains
Germplasm Research Facility in
Aberdeen, Idaho.
Raboy has found the first muta-
tions in corn to cause the plant to
store most of the nutrient as inorgan-
ic phosphorus-the form animals can
use-instead of as phytic acid. The
total amount of phosphorus in the
corn remains the same.
Swine producer Marlin Pankratz
says increasing phosphorus availabil-
ity could be a major benefit for the
industry. He and his brother produce
over 4 million pounds of pork
annually at their hog farm in Moun-
tain Lake, Minnesota.
"Feed is the most expensive part
of our operation, and phosphorus is
the most costly ingredient on a per-
ton basis," he says.
The same is true for the poultry
and aquaculture industries.
Some producers add an enzyme
known as phytase to their feed. In
experiments, phytase can increase
phosphorus use to around 42 percent.


Agricultural Research/December 1996


But Pankratz says that approach is
not cost effective for his swine
business. He concentrates on man-
agement techniques to reduce or
prevent soil erosion. That way, the
excreted phosphorus won't reach
lakes or streams.
Raboy's approach improves the
feed directly.
So far, he's isolated more than 20
mutations that shift the ratio of

KEITH WELLER


At me summer nursery in jonnston, iowa,
geneticist Victor Raboy prepares a low-
phytic-acid corn plant for self-pollination.
(K7418-16)

phytic acid to inorganic phosphorus
in favor of the usable form. He's
found similar mutations in barley and
rice, and other researchers are
working with soybeans. ARS has
applied for a patent on Raboy's
techniques.
"Some of the mutations reduce
phytic acid by up to 95 percent, but
at that level there can be problems
with seed germination or plant
yield," Raboy says. "Our most
promising mutant reduces phytic acid


by two-thirds, and the plants are
healthy and productive."
To create plants with the low-
phytic-acid trait, Raboy treats corn
pollen with chemicals that cause
random mutations in the genes.
"Today's corn evolved through
natural mutations. We just speed up
the process in the laboratory," he says.
Then Raboy uses the treated
pollen to fertilize ears of corn. He
and assistants test the resulting corn
kernels for inorganic phosphorus by
an easy, standard test.
The next step is to transfer the
new trait into a commercial product.

Trying It in the Real World
Under a cooperative research and
development agreement, Pioneer Hi-
Bred International in Johnston, Iowa,
is breeding the mutations into its own
commercially desirable corn lines to
develop low-phytic-acid corn.
Last summer, Pioneer grew 35
acres of hybrid corn with Raboy's
best mutant. They are testing the
experimental hybrid for yield and
quality. And they are using it in
animal studies to determine if the
new corn truly provides enough
phosphorus in an animal's diet.
Pioneer's preliminary data look
good. "So far, the seeds seem to
germinate well and in some cases
have yielded as well as our original
hybrid," says David Ertl, Pioneer's
research manager.
They've also started small feeding
tests with poultry. The researchers
compare normal commercial diets
that have a known amount of phos-
phorus to diets made with the low-
phytic-acid corn.
"Our results are very preliminary,
but the experimental hybrid corn
seems to be performing just as we
hoped it would," Ertl says. Chicks
fed on the new corn seem to get
adequate phosphorus for growth and







KEITH WELLER


development, and they appear to
excrete less phosphorus in the
manure, he says.
Next, the company will conduct
more precise tests with both poultry
and swine.
Pankratz sees benefits in both
aspects-reducing the excreted
phosphorus in his hog operation,
as well as optimizing nutrition for
his animals.
He says it costs up to a cent a
gallon to collect, transport, and apply
the hog waste as fertilizer. That adds
up, since each hog produces about
100 gallons of waste in the 120 days
it takes the animal to grow from 40
pounds to 240-pound market size.
His operation applies the waste to
1,100 acres of his own and neighbor-
ing fields.
The economics of disposal might
change as environmental concerns
increase the pressure to reduce the
phosphorus entering lakes and
streams. In the United States, the
amount of waste applied to cropland
as fertilizer is regulated based on its
nitrogen content, rather than phos-
phorus. Nitrogen, in the form of
nitrate, can pollute groundwater and
drinking water supplies. Other
countries use a standard based on
phosphorus, and farmers anticipate
similar requirements here.
"Phosphorus-based standards are
much stricter," says Pankratz.
"That's because crops use more
nitrogen than phosphorus, so more
manure can be applied if nitrates are
the determining factor.
"If application rates were based
on phosphorus, I would need about
4,000 acres of land instead of
1,100," notes Pankratz.
The poultry and aquaculture
industries are struggling with similar
nutritional and environmental issues.
Right now, both industries rely on
fish meal made from herring,
anchovies, mackerel, and menhaden '


Geneticist Victor Raboy and plant breeder David Ertl compare performance of the
cooperatively developed low-phytic-acid corn (right) with a normal hybrid growing in the
field on the left. (K7423-8)


to supply their animals with protein,
phosphorus, and other nutrients.
Phosphorus in fish meal is more
biologically available than in corn or
soybeans. Large quantities are still
excreted, though, because fish meal
contains more phosphorus than
carnivorous fish like trout and salmon
can use. And because producers
worry that there won't be enough fish
meal to go around in the future, the
industry is shifting to a more plant-
based diet.
"Worldwide, 600 million tons of
fish meal are produced annually, and
every bit is used by the global live-
stock industry," says Ronald Hardy
of the National Marine Fisheries
Service in Seattle, Washington.
Aquaculture uses about 15 percent
of this total, he notes. "If the aquacul-
ture industry doubles over the next 10
years, where is the protein going to
come from?" Hardy asks.
Perhaps from Raboy's low-phytic-
acid corn.
People might also benefit from the
improved corn, but advantages of
reducing phytic acid in human diets
are less clear. Meats, milk, and nuts
are rich in usable phosphorus, so
deficiency is rare.


But researchers around the world
have shown that the phytic acid form
of phosphorus has drawbacks, as well
as advantages.
For example, it can reduce the
body's ability to use other nutrients
like calcium, iron, and zinc. Iron
deficiency is a particular concern in
countries that rely almost entirely on
grains. UNICEF estimates that as
many as half the pregnant women
and children in the developing world
suffer from iron-deficient anemia.
Reducing phytic acid in their grain
foods might help them absorb iron
and other minerals better.
But phytic acid may also have
health benefits. Some research
indicates that it is a natural antioxi-
dant and may help prevent some
types of cancer.
"The technology will have to be
applied on a case-by-case basis,"
Raboy says.-By Kathryn Barry
Stelljes, ARS.
Victor Raboy is at the USDA-ARS
National Small Grains Germplasm
Research Facility, P.O. Box 307,
Aberdeen, ID 83210; phone (208)
397-4162, fax (208) 397-4165, e-mail
vraboy@uidaho.edu *


Agricultural Research/December 1996





DNA helps researchers sort subtle differences.


Yeast Collection on the Rise


I imagine matching a pair of socks
color-for-color, size-for-size all
of your life, then opening the
drawer one day to discover some
pairs really weren't similar even if
they looked alike, and other pairs
were a perfect match even though
they appeared to be a different color?
Agricultural Research Service
scientists in the Microbial Properties
Research Unit at the National Center
for Agricultural Utilization Research
(NCAUR) at Peoria, Illinois, have
expanded their knowledge of over
80,000 yeasts, molds, and bacteria
that are part of the largest publicly
accessible collection of such organ-
isms in the world.
Like sorting through a giant sock
drawer, they've found new categories
and discovered new matches through
DNA sequencing, a process that uses
specific sequences of nucleotides for
identification. The nucleotide se-
quence is unique to every organism
and reveals similarities and differenc-
es not apparent in other classification
systems, such as comparing outward
appearance or metabolism.
"We distribute about 4,000 strains
of molds, yeasts, bacteria, and actino-
mycetes annually to businesses,
domestic and foreign government
agencies, universities, and other
research facilities," says ARS micro-
biologist Cletus P. Kurtzman.
"Through our molecular genetic
studies we can make informed
recommendations for the exploitation
of these organisms for biotechnologi-
cal purposes."
Like detectives working to solve a
puzzle, the scientists use DNA se-
quencing to give them clues about a
particular organism-such as whether
it might be used for biocontrol, in
food processing, or to recognize a po-
tential pathogen of plants or humans.
Under the old system of classifica-
tion, scientists would group organisms
together by comparing their shape,

Agricultural Research/December 1996


size, and growth on specific nutrient
media. DNA sequencing allows scien-
tists to match specific nucleotides and
to identify separate species.
The scientists at NCAUR have
used this knowledge to create unique
databases that they access to quickly
and accurately identify yeasts, molds,
or bacteria that may pose a threat-or
afford an advantage-to humans or
agricultural crops.
For example, Kurtzman has
developed a special database to
identify yeasts of potential economic
importance to the fermentation
industry. These studies recently led
researchers to the discovery of a yeast
in the NCAUR collection that can be
used to ferment L-arabinose, a five-
carbon sugar found in agricultural
wastes such as the fibers left from
wet-milling of corn. (See "Improving
Ethanol Yield From Corn," Agricul-
tural Research, Oct. 1996, pp. 8-11.)
DNA sequencing also helps assess
biodiversity among species of organ-
isms. Stephen Peterson, an ARS
microbiologist, has used DNA
sequencing in his work with Aspergil-
lus and Penicillium, organisms used
in food processing and medicine. He
notes some species of Aspergillus are
useful in making food processing
preservatives such as the citric acid in
soft drinks, and some species of
Penicillium are useful in fermenting
cheeses like Brie, blue, and Stilton.
ARS microbiologist Kerry
O'Donnell has used DNA sequencing
to develop a one-of-a-kind database
to rapidly identify different species of
Fusarium, a mold that produces
toxins that can attack economically
important crops. Using information
gleaned from DNA sequencing,
O'Donnell has been able to success-
fully identify several species of the
fungus and trace them to the country
of their origin. This helps scientists
understand how the fungus traveled


and how it may attack economically
important crops.
"Species of the genus Fusarium
collectively represent one of the most
important toxin-producing molds
threatening agricultural crops and
commodities throughout the world,"
O'Donnell says.
Still other DNA-sequence data-
bases under development at NCAUR
include one for Bacillus bacteria and
another for agriculturally and indus-
trially important species of the
actinomycete Streptomyces.-By
Dawn Lyons Johnson, ARS.
Cletus P. Kurtzman is in the
USDA-ARS Microbial Properties
Research Unit, National Center for
Agricultural Utilization Research,
1815 N. University St., Peoria, IL
61604; phone (309) 681-6561, fax
(309) 681-6672, e-mail mpcpk@
ncaurl.ncaur.gov *



KEITH WELLER







_ I



_ _


Yeasts retrieved from the deep freeze by
microbiologist Cletus Kurtzman will be
used to develop molecular probes for
rapid identification of different strains.
(K7406-3)






JACK DYKINGA

"Eye-in-the-Sky" Made

More Useful to Farmers


.: information picked up by
airplanes and satellites will
someday help farm operators
maintain healthy, high-yielding
crops, with minimum use of irriga-
tion water, fertilizer, and pesticides.
An Agricultural Research Service
project now under way in Arizona is
aimed at demonstrating how remote
sensing can be used in farm manage-
ment. It's called MADMAC-
Multispectral Airborne Demonstra-
tion at Maricopa Agricultural Center.
The project's team is analyzing data
obtained from 15 airplane overflights
at 3,900 and 7,500 feet above fields
of cotton and other crops from mid-
April to the end of September 1994.
"Satellites have been beaming data
back to Earth for more than two
decades," says Thomas R. Clarke, a
physical scientist with the U.S. Water
Conservation Laboratory in Phoenix,
Arizona. "But most of that informa-
tion hasn't helped farmers because
no one could figure out how to
interpret it.
"One important
"One important Water Deficit Index
goal of the Arizona Maricopa Agricult
project is to develop
ways to turn those
numbers and read-
ings into reliable,
timely, and meaning-
ful information,"
Clarke says. "That
will one day enable
farmers to micro-
manage areas as
small as a few acres
within each of their
fields. It will guide
them to specific areas
that need more _
fertilizer, irrigation 0.0
water, or weed and Based on remot
satellite or airci
insect control." meteorological
Until recently, shows crops tha
adds Clarke, re- moisture (blue),
searchers have had irrigation yellowo
an overwhelming soil (orange). (k
an overwhelming


WDI
e s
raft
dat
t h
,cr
w),
i75


amount of data but no efficient way
to use it. For example, they might
obtain billions of bits of information
about a 1,000-acre farm over a
growing season. Their challenge was
to translate all that into recommenda-
tions for farmers and farm manage-
ment advisers.
Physical scientists M. Susan
Moran and Jiaguo Qi, biologist Paul
J. Pinter, Jr., and agricultural engi-
neer Edward M. Barnes are also
members of the ARS research team
now working on analysis of the
MADMAC data. They are in the
Environmental and Plant Dynamics
Research Unit at the Phoenix lab.
The airplane used in taking
measurements was equipped with a
frame holding four video cameras.
Three of the cameras were filtered to
allow each to receive only one kind
of light on the recording tape-near-
infrared, red, or yellow-green. The
fourth camera measured the far-
infrared energy that is related to
surface temperature.
The goal of
DI), 24 June 1994
Center, Arizona MADMAC is to
i combine these four
S measurements to
.4 create maps of crop
growth and crop
stress related to
irrigation schedules,
fertilizer applica-
S tions, and weed and
insect infestations.
To work, it is
necessary to convert
MADMAC digital
video data into values
S of surface reflectance
( m and temperature. So
1.0 researchers placed
sensing from specially coated 25-
along with foot-square tarps on
a, the WDI
ave ample the ground during
ops that need every aircraft over-
and bare, dry pass.
10-2)


After each "
flight, they :
retrieved the P A
digital numbers
associated with
the center of the
tarps and com- -

reading. Then the
scientists calcu-
lated a correction
factor from on-
site recordings to
use in calibrating
the hundreds of
reflectance and
temperature
measurements
taken by the
airborne sensor.
These airborne
measurements
eliminated the
need for ground
personnel to
physically record every overflight for
every field, each day.
On the ground, the team made up
to 875 separate observations of crop
and soil conditions during each
overflight at the University of
Arizona's Maricopa center, 20 miles
south of Phoenix. Those observa-
tions, which included crop type,
estimated plant height, growth stage,
percent crop cover, soil surface
texture and dampness, and presence
of insects and weeds, were matched
to the video images.
The advantages of video images
for farm management are the fine
spatial resolution-about 3 to 6
feet-and the potential availability of
data immediately after the flight. For
comparison, the spatial resolution of
data from currently orbiting satellites
is about 60 to 90 feet, and the data
are not available to researchers for
several days or weeks.
To provide timely, reliable maps
of crop conditions from video


Agricultural Research/December 1996
































ARS scientist Susan Moran adjusts a fixed position four-camera
monitoring device to take soil readings. Specially coated tarps in the
background enable scientists to obtain baseline digital readings
during aircraft or satellite observations. (K7510-1)


images, the MADMAC engineers
and scientists developed methods to
process video images and provide
information in a matter of hours after
the flight. This automated processing
included correction for effects of
atmospheric conditions, misalign-
ment of cameras, and aircraft motion.
Researchers noted that video
images can have as much as a 40
percent variance in brightness,
depending on the sun's position in
the sky and the camera's viewing
angle. The team developed a comput-
er model to correct this phenomenon
known as the bidirectional reflec-
tance factor. The model corrects
readings for all points in the picture
and allows a comparison between
pictures taken over the same fields at
different times.
Because of aircraft motion and vid-
eo camera optics, the horizontal lines
in the video images are often offset,
resulting in a zigzag pattern along
field edges. This geometric flaw is

Agricultural Research/December 1996


complicated further because the shift
is variable, and some shifts are re-
quired for less than a pixel-the
smallest measurement unit. The team
developed software to scan the images
and make corrections automatically.
Misalignment of cameras and
aircraft motion can cause band-to-
band image offsets that diminish the
accuracy and value of the video
images. The errors resulting from
these offsets are also corrected by
software the scientists developed.
From that, the team gets exceptional
band registration for all bands,
including the critical near-infrared
radiation, and the processing time is
only 15 minutes for 80 sets of the 3-
band images.
"The processing techniques and
farm management products resulting
from the MADMAC experiment are
useful for both aircraft-based cameras
and upcoming satellite sensors," says
Moran.


Major improvements in satellite-
based technology are planned. For
example, a new satellite system,
expected to be in operation within 3
years, will provide crop updates as
often as every 3 days. But cloudy
days will still hide many fields from
view, leaving those farmers who need
daily guidelines in a bind. The
Phoenix team is using computer
models to bridge the information gap
for the missed days.
The team also plans to merge the
remotely sensed data with a decision
support system that will help farmers
decide when to begin certain farming
operations, like insecticide or irriga-
tion applications.
"The work here in Arizona com-
plements work by our agency in
Weslaco, Texas," says Pinter. "There,
ARS' Remote Sensing Research Unit
plays a prominent role in developing
suitable equipment to record images
from remote."
The Texans have also established
spectral signatures of dozens of plant,
soil, and water conditions that can be
used to identify pest and nutrient
problems on range and croplands.
[See "Orbiting Eye Will See Where
Crops Need Help," Agricultural
Research, April 1996, pp. 12-14.]
"When we've succeeded, the
system will be what scientists only
dreamed of just 20 years ago," says
Moran.-By Dennis Senft, ARS.
Edward M. Barnes, Thomas R.
Clarke, M. Susan Moran, Paul J.
Pinter, Jr., and Jiaguo Qi are based
with the USDA-ARS Environmental
and Plant Dynamics Research Unit,
U.S. Water Conservation Laboratory,
4331 E. Broadway Rd., Phoenix, AZ
85040; phone (602) 379-4356, fax
(602) 379-4355, e-mail
ebarnes@uswcl.ars.ag.gov
tclarke @ uswcl.ars.ag.gov
moran @tucson.ars.ag.gov
ppinter@uswcl.ars.ag.gov
qi@tucson.ars.ag.gov *







Virus Zaps Pests,

Speeds Medical Research


virus that kills crop-eating
caterpillars may soon
power a new, environmen-
tally friendly insecticide.
The virus slays tobacco bud-
worms, one of the worst enemies of
cotton plants and a ravager of
tomatoes and other crops as well.
Field and laboratory tests suggest
that the microbe also fells dozens of
other worm pests. The list includes
the alfalfa looper caterpillar, Au-
tographa californica-the virus'
namesake-along with cabbage
looper and beet armyworm caterpil-
lars that feast on cabbage, broccoli,
and other vulnerable vegetables in
farms and gardens.


Entomologist Patrick Vail observes the internal
virus-infected cabbage looper larva magnified
on screen. (K7169-14)

Meanwhile, the virus has already
landed a starring role in biotechnol-
ogy labs around the world. It simpli-
fies and speeds the manufacture of
researchable quantities of intriguing
proteins and other compounds for
scientists in medical, veterinary, and
biological research.
The first experimental AIDS vac-
cine approved for tests on humans in
the United States, for example, was
created using the hardworking virus.


Produced by MicroGeneSys of Meri-
den, Connecticut, the vaccine has
been tested on more than 2,000 vol-
unteers. The company has also re-
cruited the alfalfa looper virus to
assist in producing proteins for exper-
imental vaccines to defend people-
and poultry-against influenza.
Entomologist Patrick V. Vail dis-
covered the virus in an alfalfa looper
caterpillar in 1967. Now at Fresno,
California, Vail was at the time work-
ing in an ARS laboratory at the Uni-
versity of California, Riverside.
The virus, known as AcAINPV, be-
longs to a group of microorganisms
called baculoviruses. Worldwide,
says Vail, scientists have found hun-
dreds of insect-kill-
ing baculoviruses.
University and
corporate research-
ers are working to
intensify the A.
californica virus'
strength as an
insecticide. An
example: American
Cyanamid, one of
^. this country's largest
manufacturers of
i agricultural chemi-
cals, is intent on
building a genetical-
ly engineered form
I tissues of a of the alfalfa looper
about 900 times virus as a safe, fast-
acting bioinsecti-
cide. To accelerate
the virus' normally slow rate of kill,
company scientists have given it a
gene borrowed from the North
African brown scorpion, Androctonus
australis.
Once inside a caterpillar, this
upgraded alfalfa looper virus com-
mandeers the insect's own cells so
that they carefully follow the scorpi-
on gene instructions, newly encoded
in the virus. The directions cue the
cells to churn out a new protein-a


toxin from the scorpion's venom-
that in turn paralyzes the insect.
The toxin targets only insects. A
pestiferous caterpillar that munches
on a leaf with the virus on it soon is
unable to chew or crawl. That means
the insect can't indulge in its usual
feeding frenzy. Normally, a healthy
caterpillar can eat many times its
weight in food every day as it pre-
pares to pupate-the final life stage
before becoming a moth.
The genetically engineered virus
takes about 2 to 3 days to kill a
caterpillar pest. During that time, the
virus replicates inside the hapless
insect. Soon the scorpion's paralytic
toxin causes the caterpillar to fold up
like a little accordion. Later, the
insect dies and tumbles from the
plant. American Cyanamid scientists
estimate that the bioengineered virus
may work as much as 60 percent
faster than the naturally occurring A.
californica virus.
The company's tests in the lab and
in cottonfields have shown that the
virus is harmless to beneficial in-
sects-honey bees, ladybugs, and
praying mantids, for example. Simi-
larly, the virus in its natural form or
enhanced with the borrowed toxin
won't affect people, pets, wildlife, or
other organisms-only specific cater-
pillars. That's according to American
Cyanamid's Thomas L. Merriam, di-
rector of the team responsible for de-
veloping new insecticides.
Besides increasing the virus' speed
by pairing it with the insect-specific
scorpion toxin, American Cyanamid
scientists want to boost production of
the virus in fermentation vats.
Traditionally, viruses such as A.
californica have been produced in
laboratory colonies of wiggly insects
such as cabbage loopers. As the
infection progresses, the virus prolif-
erates. Finally, when they have
become severely infected, the loopers
are popped into a blender. The new

Agricultural Research/December 1996
























supply of virus that was produced in
their bodies is then harvested by
extracting it from this puree.
However, this method can't be
scaled up to yield the copious
amounts of genetically engineered
virus needed for nationwide market-
ing. That's because the retooled
virus-enhanced with the scorpion
toxin gene-works faster than the
wild types that exist in nature. An
infected insect dies before the virus
has a chance to reproduce as profuse-
ly as it otherwise would.
Prolific production of the virus is
vital, if the bioengineered insecticide
is to complement or perhaps even
replace some of the synthetic insecti-
cides used today to combat caterpillar
pests of cotton and vegetable crops.
The hoped-for quantities would be far
larger than anything produced today


Left: Dead cabbage looper larva (shown
about 3 times actual size) was infected with
AcMNPV virus. Right: An insect cell
nucleus filled with AcMNPV polyhedrons
(magnified).



in research labs. The fermenter-based
strategy for keeping the virus alive
and rapidly reproducing relies on
cultures of insect cells, floating in a
nutrient-rich liquid.
Instead of multiplying inside
captive insects, the virus would live
and reproduce in these cultures of
disembodied cells of the fall army-
worm or other caterpillars. Inside
infected cells, the virus' genetic
material takes over the cells' func-
tions. The cells read-and follow-
the instructions carried in the virus'
genome, rather than their own.
In this case, cells are cued to make
more copies of the virus genes,
complete with the scorpion toxin
gene. The newly made virus would
then be separated from the insect cells
and the culture liquid.
The fermenter process would be
somewhat like the method already
used today in medical research to
produce new proteins. There are,
however, two key differences. First,


What's in a Name?
The Autographa californica virus' full name--"Autographa californica
multiply embedded nucleopolyhedrosis virus"-not only describes the
insect in which the virus was discovered, but also depicts the virus' distinc-
tive packaging.
Commonly abbreviated AcMNPV, the virus occurs in crystalline cases
that the alfalfa looper, A. californica, or other destructive caterpillars eat.
The cases are called polyhedrons because of their many sides.
"Polyhedrons seen through a microscope," says AcAfNPV discoverer
Patrick V. Vail, "look like little geodesic domes."
The term "nucleopolyhedrosis" refers to these polyhedrons and to the
fact that the virus infects the nuclei of insect cells. Each polyhedron typical-
ly contains a large number of separate bundles. A bundle encloses within its
own membrane one to eight stick-shaped virus particles, or rods. The terms
"multiply" and "embedded" refer to the many virus rods packaged in
distinct bundles inside a polyhedron.


the fermenters would produce the
virus in much larger quantities.
Second, in biomedical labs, the intent
is to have the virus exude the experi-
mental protein into the broth. But in
manufacturing a bioinsecticide, the
virus itself-with the new toxin gene
inside-is harvested.
Scientists at more than 500 labora-
tories around the globe have exploited
the virus to make more than 600
promising proteins. Those include
proteins to diagnose or prevent colon
cancer, breast cancer, and malaria in
humans and bluetongue, rabies, and
foot-and-mouth disease in animals.
Texas A&M University scientists
hold patents for this phenomenally
successful use of the virus. Lab
supply companies that market the
virus in kits offer the product as an
alternative to using cells of Escheri-
chia coli bacteria or mammalian cells.
Vail, director of the ARS Horticul-
tural Crops Research Laboratory in
Fresno since 1987, was recently
named the agency's top scientist. And
earlier this year, he won an honor
award from the U.S. Department of
Agriculture. These prizes acknowl-
edge not only his work with the
alfalfa looper virus, but also his
pioneering studies of other helpful
baculoviruses as well.-By Marcia
Wood, ARS.
Patrick V. Vail is at the USDA-ARS
Horticultural Crops Research Labo-
ratory, 2021 S. Peach Ave., Fresno,
CA 93727; phone (209) 453-3000, fax
(209) 453-3088. *


Agricultural Research/December 1996







Killing Psylla in Cold Blood
Commercial freeze-dried bacteria cause ice to form in these pear pests.


S scientists are exploring the
possible use of the
Pseudomonas syringae
bacterium, freeze-dried, to control
insects pests on pears.
Operators of ski resorts may have
more first-hand knowledge about
these critters than most entomolo-
gists. They use the commercially
available bacteria to make artificial
snow for their ski slopes. It's done
by dissolving the bacteria in water
and spraying the solution over ski
runs, prompting the formation of tiny
ice grains that closely match the
consistency of real snow.
Richard Lee, Jr., an internation-
ally known expert on insect cold
hardiness at Miami University in
Oxford, Ohio, has used the bacteria
to kill Colorado potato beetles and
insect pests in grain silos. Scientists
now hope the bacteria can also be
used against pear psylla, a major pest
of pears nationwide and the most
severe insect pest of pears in the
Pacific Northwest.
David R. Horton and Lisa G.
Neven, Agricultural Research
Service entomologists, have learned
when pear psylla are least cold hardy
and thus probably the most suscep-
tible to the bacteria's effects. Their
studies show that cold hardiness
parallels winter temperatures. The
psylla are most cold hardy in De-
cember and less so both earlier and
later than December.
Entomologists know that interior
ice formation is deadly for many
insects. To survive winter, these
insects must remain unfrozen, even
at subzero temperatures-a process
termed supercooling.
Several organisms, including
some bacteria, cause the supercooled
liquids inside insects and on their
body surfaces to freeze spontaneous-
ly. As at ski resorts, the microorgan-
isms act as catalysts. Ice forms


around the little particlelike bacteria
and proves fatal to insects.
"This is like the classical high
school science experiment," explains
Horton. "A small amount of pure,
distilled water can be cooled, without
freezing, to a lower temperature than
a similar volume of tap water.
Microparticles in the tap water serve
as nuclei around which ice can form,
speeding ice formation." Horton is at


the ARS Yakima Agricultural
Research Laboratory in Wapato,
Washington.
"Overwintering psylla spontane-
ously freeze when temperatures drop
to 9 below zero Fahrenheit. Dr. Lee
has shown that spraying psylla with
freeze-dried bacteria causes freezing
to occur at 10 above," says Horton.
"M) own studies show that mortality
in psylla actually begins at tempera-


To determine the effectiveness of the Pseudomonas syringae bacterium as a biocontrol,
entomologist David Horton samples the population density of pear psylla in a Bartlett pear
tree. (K7349-8)


Agricultural Research/December 1996












tures well above the point at which
the insects spontaneously freeze.
Many actually die at temperatures
above zero.
"The bacteria could make insects
in the Northwest more susceptible to
low winter temperatures."
They might get a double punch by
combining the freeze-dried bacteria
with solutions of soap and water. In
tests in the ARS lab, Horton and


Horton says the
tricky part will be to
get the spray on
insects at the right
time. Scientists
know that during a
normal season
about half of the
pear psylla leave
orchards in late fall
and take up resi-
dence in other
trees. They hide in
tiny cracks and
crevices in the bark.
Ideally, application
would precede this
exodus.


Neven noted that over 24
hours, pear psylla misted
with soapy water died
at temperatures
near 200F.
SoMany
.... nonmisted
insects were
able to survive
Temperatures as
low as zero.
"We assume the
surfactant, or soapy
water, increased the
welttability' of the insects
Slttficiently that the water
~ a:, able to) enter otherwise
t inmoisture-free openings in the
insects. As the water froze, ice
presumably had an easy and direct
route to the interior of the insects,
resulting in death," says Horton. "By
combining surfactants and the bacte-
ria, we may be able to get more of the
bacteria into openings in the insect."
Horton says the tricky part will be
to get the spray onto insects at the
right time. Scientists know that
during a normal season about half of
the pear psylla leave orchards in late
fall and take up residence in other
trees. They hide in tiny cracks and
crevices in the bark. Ideally, applica-
tion would be before this exodus.
Horton and Neven will continue
studies with Lee, and they will also
collaborate in field studies with
Everett Burts and John Dunley from
Washington State University at
Wenatchee. This research is partially
funded by growers through the Wash-
ington Tree Fruit Research Commis-
sion.-By Dennis Senft, ARS.
David R. Horton and Lisa G.
Neven are at the USDA-ARS Yakima
Agricultural Research Laboratory,
5230 Konnowac Pass Road, Wapato,
WA 98951; phone (509) 454-5639,
fax (509) 454-5646, e-mail
neven@yarl.gov +


Agricultural Research/December 1996


~r*;'"
""''









1996 Index


A
Aerial observations for farms, Dec-16
Aflatoxin
controlling in peanuts, Jul-14
keeping out of peanuts, Feb-22
varies in corn varieties, Oct-22
African swine fever, Aug-14
Agricultural commodities, new uses, new
markets, May-10
Alfalfa, for feed and fuel, Oct-18
Algae, blue-green Spirulina, Mar-23
Algae, monitoring in fishponds, Nov-21
Antioxidants and human health, Nov-4, 10
Apples, Asian germplasm, Feb-23
Aquaculture
monitoring pond algae, Nov-21
vaccines for catfish, Nov-20
Arboretum, U.S. National
IPM lowers chemicals use, Jan-12
new elms, Jul-6
Arthritis, from foodbome bacteria, Oct-16
B
Bacillus thuringiensis collection, Mar-16
Barley, heart benefits from, Feb-20
Bees, Africanized honey, Mar-4
Bees, bee-vac for sampling, Mar-10
Biocontrol against
brown spot, Mar-15
citrus root weevil, Nov-22
corn earworm, Jan-16
damping-off fungi, Jun-16
fall armyworm, Jan-16
golden nematodes, Apr-16
gypsy moth, Aug-23
Japanese beetles, Jan-16, Feb-12
medflies, Jan-20
mold on fruits, Jan-23
pear psylla, Dec-20
pink bollworm, Jan-16
plum pox virus, Mar-11
storage rot, Jan-16
tree fruit pests, Aug-20
water hyacinth, May-16
whiteflies, Jan-16, Jul-23
Biocontrol with
abamectin, curbs citrus pests, Jan-11
Autographa californica, Dec-18
Bacillus popilliae, Jan-16
Bacillus thuringiensis, Mar-16
Beauvaria bassiana, Jan-16
breeding, of rust-resistant oats, Feb-10
Calosoma sycophanta, Aug-23
Candida oliophila, Jan-16
caterpillar-killing proteins, May-23
controlled atmosphere, Nov-16
cotton that resists whiteflies, May-23
farm demos, Eastern Europe, Feb-23
Gliocladium virens GL-21, Jun-16
Paecilomyces fumosoroseus, Jan-16
Pseudomonas syringae, Mar-15, Dec-20,
Jan-16
red dye, Jan-20
resistant potato germplasm, Apr-16
Steinernema glaseri, Feb-12


Steinernema riobravis, Nov-22, Jan-16
transgenic fruits, Mar-11
Trichoderma harzanium, Jan-23
wild tobacco genes, Jul-23
Biodiversity, parasites help understanding of,
Dec-4
Biological processes in fungi, Feb-22
Bioremediation, cleaning wastewater, Jul-15
Breeding, precision, of corn, Aug-4
Brown spot, control, Mar-15
Brucellosis, producer-friendly vaccine, Oct-17
Buckskin disease, of cherries, Aug-20
C
Carbon, in soil, reduced by plowing, Mar-23
Carotenes, dietary, what they do, Nov-4, 10
Carrots, for seed, water needs, Jun-21
Catfish, vaccines, Nov-20
Cattle
biting flies, mites, ticks, Jun-10
dairy, BLAD disease, May-18
grazing helps range, Aug-22
haptoglobin shows health, May-22
Holstein, genetic link to mastitis, Aug-23
Line 1 valued in breeding, Aug-18
projecting producer profit/loss, Apr-4
Romosinuano embryos imported, Jun-23
Children's nutrition, body composition, Jun-18
Citrus
pests, biocontrol, Jan-11
pre-peeled with enzyme, May-8
suppressing weevil pest, Nov-22
variegated chlorosis, Jun-9
Clover, disease-resistant red, Dec-9
Computer
agricultural applications, Apr-4
algorithm spots jumping genes, Mar-23
TEKTRAN on-line, Oct-23
Computer models
EXNUT guides peanut irrigation, APR-7
MADMAC maps crop stresses, Dec-16
NLEAP spots nitrate leaching, Apr-11
STEERISK for cattle producers, Apr-4
Conservation tillage, field day demo, Jun-23
Corn
ethanol yield increased, Oct-8
individual plant pedigrees, Aug-23
more bioavailable phosphorus, Dec-12
precision breeding for yields, Aug-4
silk repels pests, Apr-23
Cotton
better grading, classification, May-4
fiber moisture sensor, Aug-23
fibers reject dye, Dec-10
foreign genes for domestic, Feb-14
naturally colored, Apr-20
resistant to whiteflies, May-23
textile enhancements, May-5
Cottonseed oil, isohexane solvent, Aug-7
CRADA (cooperative R & D agreement)
biological controls hit marketplace, Jan-16
breeding sweet corn, repel pests, Apr-23
combat BLAD in dairy cattle, May-18
detect larvae in stored grain, Jan-23
develop cytokinin plant defense, May-23
genetic markers for corn plants, Aug-23


harmless Aspergillus strains, Feb-23
in-shell poultry vaccinations, May-18
in-transit pest control for produce, Apr-23
test cotton fiber moisture sensor, Aug-23
test for coccidiosis drug, Jan-23
Cryptosporidium, in drinking water, Jun-4
Cucumber mosaic virus, curbing, Jul-16
D-E
Diagnostic test
DNA identifies Xanthomonas and Xylella
bacteria, Jun-9
ELISA for tree fruit viruses, Aug-20
for Campylobacterjejuni, Arcobacter,
Listeria, Feb-4
for elevated homocysteine, May-23
for salinomycin in feed, poultry, Jan-23
for soybean sudden death fungus, Jan-23
haptoglobin shows cattle health, May-22
quantifies aflatoxin in grain, Oct-22
Disney World, ARS research at, Jul-20
DNA fingerprinting
corn plant pedigrees, Aug-23
distinguishes microbes, Dec-15
sorts soybeans, Aug-12
Dust, reducing airborne particles, Mar-18
Elms, disease-resistant new Americans, Jul-4
Erosion
intercropping forage reduces, Mar-15
wind, PM-10 sources, Mar-18
Ethanol, improving yield from corn, Oct-8
F
Flowers, understanding color, Jul-12
Foodborne illness
minimizing, Feb-4
toxoplasmosis and cats/pigs, Feb-8
Foods, new, all-fruit confections, Nov-9
Foods, new, rice french fries, Feb-21
Forage
high-mass alfalfa, Oct-18
more with intercropping, Mar-15
rhizoma peanut, Apr-23
Forum
Pests Won't Concede: Here's How We
Deal, Jan-2
Curbing Foodborne Illnesses, Feb-2
Africanized Honey Bees-the March North
Has Slowed, Mar-2
Does Agriculture Compute?, Apr-2
The Research Commitment to Rural
Communities, May-2
ARS Science Serves Many Users, Jun-2
Horticultural Research Is No. 1, Jul-2
Today's Plant Breeders Increase
Tomorrow's Food Supply, Aug-2
A Summer Job Can Shape a Life, Sep-2
Agricultural Pests: No Shortage in the
Forecast, Oct-2
Pennies for Research Can Cut Dollars
From Health Care, Nov-2
Parasites: The Problems Persist, Dec-2
Fruits
apples from Kazakhstan, Feb-23
gelled puree in varied forms, Nov-9
IPM in orchards, Jan-18


Agricultural Research/December 1996









1996 Index


tree, important to rural economies, Aug-20
tree, preventing plum pox, Mar-11
Fungi
bacteria control damping off, Jun-16
Olpidium zoospore moves genes, Mar-23
sexual Trichoderma discovered, Feb-22
G-H-I
Genetic engineering
at Disney World lab, Jul-20
chromosome for cow mastitis
susceptibility, Aug-23
cytokinin-boosting plant gene, May-23
drawing chicken genome map, Jul-19
flower pigments, Jul-12
fungus transports genes, Mar-23
jumping genes, Mar-23
of Autographa californica, Dec-18
precision breeding possible, Aug-4
to control aflatoxin in peanuts, Jul-14
to control cucumber mosaic virus, Jul-16
to control plant aging, ripening, Aug-8
GPS/GIS, agricultural applications, Apr-4
Grain pests, microwaves zap, May-21
Grapefruit, controlled atmosphere, Nov-16
Grazing, helps range soil condition, Aug-22
Greenhouse, automated spray system, Jul-22
Health, human
arthritis from food poisoning, Oct-16
homocysteine and heart disease, May-23
Hi-tech mosquito barrier, Mar-12
Hormones, plant, muting effect of, Aug-8
Insects
Africanized honey bees arrive, Mar-4
ALFID detects in stored grain, Jan-23
corn earworms, biocontrol, Jan-16
fall armyworms, biocontrol, Jan-16
fire ants devour planted seeds, Oct-14
fruit flies, controlled atmosphere, Nov-16
grasshoppers, Jan-4, Jan-10
gypsy moth has beetle predator, Aug-23
Japanese beetles, Feb-12
managing livestock pests, Jun-10
Mediterranean fruit flies, Jan-20
microwaves subdue grain pests, May-21
mosquito repellents, Jun-4
mosquitoes, salt marsh, Mar-12
pink bollworms, biocontrol, Jan-16
tropical fruit flies, Apr-23
whiteflies, biocontrol, Jan-16, Jul-23
IPM (Integrated Pest Management)
at U.S. National Arboretum, Jan-12
grasshopper IPM User Handbook, Jan-8
of grasshoppers, Jan-4
orchard ecosystems tested, Jan-18
IRP-4, Interregional Research Project, Oct-4
Irrigation, computer-directed, Apr-4, May-18
K-L-M
Karnal bunt, genetic resistance to, Nov-23
Landscape plants, controlling pests, Jan-12
Legumes, pharmaceutical sources, Nov-12
Legumes, special-purpose collection, Nov-12
Leptospirosis, test identifies strains, Jun-4
Livestock Insects Research lab, Jun-10
Lyme disease, and ticks, Jun-4

Agricultural Research/December 1996


Melon, blight, Oct-20
Melon, cantaloupe for beta carotene, Oct-23
Mexico, cooperative bee research, Mar-4
Microbial collection, world's largest, Dec-15
Microwaves zap grain pests, May-21
Minor crops, pesticides research for, Oct-4
Mulch
pine needle straw, May-16
red plastic boosts yields, Jul-23
using construction waste, Jul-9
waste paper pellets, "peat" pots, Jul-9
N-O
NAPIAP, assesses pesticide impacts, Oct-5
Nematodes, golden, in potatoes, Apr-16
Nematodes, ridges distinguish types, Apr-18
NIR, spectroscopy to grade raisins, Jun-22
Nitrogen, soybeans use excess in soil, Apr-23
Nutrition, human,
algae nutritious, healthful, Mar-23
barley's benefits, Feb-20
beta carotene's benefits, Nov-10
children's body composition, Jun-18
fat-creep and aging, Jul-23
fruits and vegetables important, Nov-4
phosphorus' role, Dec-12
Oats, hardy, for cool climates, Dec-8
Oats, rust resistant, Feb-10
ORAC, measures antioxidant capacity, Nov-7
P
Parasites
Eimeria Coccidia in poultry, Oct-12
enzyme blocks whipworms, Jul-23
interleukin-4 expels, Nov-23
National Collection, Dec-4
ridge patterns identify nematodes, Apr-18
Peanut
aflatoxin-resistant, Jul-14
EXNUT guides irrigation, Apr-7
rhizoma is good forage, Apr-23
Phosphorus, in feed and food, Dec-12
Photosynthesis, slowed by cool nights, Oct-15
Pigments, plant, promote human health, Nov-4
Pigments, the basis of flowers' color, Jul-12
Pine needle mulch, May-16
Plum pox virus, preventing, Mar-11
Pollution
air, effects on crops, Oct-20
cleanup in water, Jul-15
NLEAP computes, Apr-11
Potatoes, golden nematode threat, Apr-16
Poultry
chicken genome map, Jul-19
in-shell vaccination, May-18
Salmonella in older hens, Nov-23
strategies against Coccidia, Oct-12
Precision farming, Apr-4
Preserving produce in transit, Apr-23
Prunus necrotic ringspot virus, Aug-20
Psylla, pear, bacteria control, Dec-20
R
Raisins, better grading, Jun-22
Range, improved by grazing, Aug-22
Range, restoring big sagebrush, Aug-11


Recycling, paper, farm, and yard waste, Jul-9
Remote sensing, data more useful, Dec-16
Remote sensing, spots crop needs, Apr-12
RESOURCE21, orbiting crop watching, Apr-12
Rice, for lower-fat french fries, Feb-21
Rural economies get boost, May 18
S
Safety, food, begins on farm, Feb-4
Sagebrush, big, restoring to range, Aug-11
Salmonella in older hens, Nov-23
Satellites, airborne crop surveillance, Apr-12
Sensors, wartime, find agricultural
applications, Oct-23
Sheep, hardy, for the midsouth, May-7
Soil
NLEAP, nitrogen applications, Apr-11
plowing lessens CO2, fertility, Mar-23
soybeans use excess nitrogen in, Apr-23
Soybean
enzyme for industrial uses, Jan-23
Sudden Death Syndrome fungus, Jan-23
remove excess soil nitrogen, Apr-23
sorting look-alikes, Aug-12
Soyoil, enzymes speed drying, Apr-22
Speck Trek, collaborators solve textile
problem, Dec-10
Starch, biodegradable wheat, Jul-23
Starch, superabsorbent polymer, May-10
Storage rot in fruits, biocontrol, Jan-16
Strawberries, angular leaf spot, Jun-9
Students, gain ARS research experience,
Sep-4-23
Sugarcane, for cooler climates, Feb-17
Super Slurper, starch polymer, May-10
Supercritical fluid extractor, multiuse, Jun-23
Swine, African swine fever, Aug-14
Synlophes, nematode ridge patterns, Apr-18
Systematics, naming and grouping living
things, Dec-4
T
TEKTRAN on World Wide Web, Oct-23
Temperature, cool hardiness in plants, Oct-15
Textiles, cotton fiber moisture sensor, Aug-23
Textiles, cotton specks resist dye, Dec-10
Tomatoes, cool nights limit growth, Oct-15
Toxoplasma gondii, in cats, pigs, Feb-8
w-z
Waste, recycling, Jul-9
Water hyacinth, biocontrol, May-14
Water
computer-aided irrigation, Apr-4, May-18
microbes clean polluted, Jul-15
probes signal need for irrigation, Nov-23
Weeds
aquatic, water hyacinth, May-14
smart sprayer detects, Apr-15
Wheat, resistant to karnal bunt, Nov-23
Zoonotic diseases, spread to humans, Jun-4







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*- Punched by a 4-year drought
and by insects that ravaged the
cotton crop in 1995, Texas
agriculture has been reeling.
But new conservation tillage
systems may help level the
playing field.


- Nucleic acid vaccines open a
dazzling array of possibilities for
preventing livestock diseases.


,- A mutant alfalfa that can't fix
nitrogen from the air finds a job
cleaning up soil after a train
derailment.




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