Asian Soybean Rust: Background and Issues
CRS Report for Congress
Asian Soybean Rust: Background and Issues
Updated January 12, 2005
Analyst in Agricultural Policy
Resources, Science, and Industry Division
Congressional Research Service ˜ The Library of Congress
Asian Soybean Rust: Background and Issues
On November 9, 2004, Asian soybean rust (ASR) was discovered in the United
States in an experimental field in Louisiana. In the following three weeks, it was
discovered in eight additional southern states — Alabama, Arkansas, Florida,
Georgia, Mississippi, Missouri, South Carolina, and Tennessee. Because ASR’s
arrival in the United States came late in the crop year, it is not thought to have had
any measurable effect on 2004 soybean production. Furthermore, its detection has
provided an early warning and has given the U.S. soybean sector time to prepare
strategies to guard against possible ASR damage to the 2005 soybean crop.
ASR is a harmful fungal disease that affects the growth of several commercial
plants, most notably soybeans. The rust spores, once windborne, can spread rapidly
and have been known to infect an entire region the same year the disease is first
detected. ASR has reduced soybean yields by 10% to 80% in infected areas. The
disease’s rapid transmission rate coupled with an abundance of host species suggests
that eradication would be unlikely once the fungus is established in the United States.
As a result, the most effective treatment is thought to be the development and use of
resistant plant varieties. However, no commercial U.S. soybean cultivar is resistant
to or tolerant of ASR. In the short term, the only effective responses are costly
fungicides and the use of early-maturing soybean cultivars.
Three chemicals are presently registered with the U.S. Environmental Protection
Agency (EPA) for treatment of rust on soybeans. In addition, EPA has approved
several temporary emergency exemptions (under Section 18 of the Federal
Insecticide, Fungicide, and Rodenticide Act) for additional fungicides. Estimates
suggest that the U.S. currently has fungicide capacity to treat up to 12 million acres.
During the past three years (2002-2004), U.S. soybean plantings have averaged 74.2
million acres. Thus, available fungicide appears sufficient to treat about 16% of
average plantings. A shortage of fungicides could lead to a constituent call for
The U.S. Department of Agriculture (USDA) is coordinating a plan to deal with
ASR that encompasses various USDA agencies, state land-grant universities, and
industry participants. Widespread ASR infection in the United States would likely
have significant regional and national effects on domestic and international
commodity markets. Timely fungicide applications can prevent national yields from
declining dramatically; however, the added cost of fungicides would likely lead to
a significant reduction in soybean production in lower-yielding southern states. A
2004 USDA study suggests that annual U.S. economic losses could range between
$240 million and $2 billion, depending on the severity and extent of any outbreaks.
The arrival of ASR has implications for several public policies including pest
control research (particularly the development of resistant varieties), pesticide
regulation, disaster assistance, and crop insurance. This report will be updated as
Current Status of Asian Soybean Rust (ASR) in the United States........1
Background on ASR...........................................2
Nature of the Disease.......................................2
Treatment and Control......................................3
Responding to ASR’s Arrival....................................4
What Is Being Done to Prepare?..............................4
Fungicide Registration Status in the United States................6
ASR-Related Market Issues......................................8
Potential Effects of ASR Entry into the United States..............9
For More Information.........................................11
List of Tables
Table 1. U.S. Regional Soybean Comparisons, 1996-2002 Averages........11
Asian Soybean Rust:
Background and Issues
Current Status of Asian Soybean Rust (ASR)
in the United States1
On November 9, 2004, ASR was discovered in the continental United States for2
the first time in an experimental field in Louisiana. In the following three weeks,
it was discovered in eight additional southern states — Alabama, Arkansas, Florida,3
Georgia, Mississippi, Missouri, South Carolina, and Tennessee. Most experts
expect the pathogen to spread into the more northerly U.S. soybean-growing areas
of the Corn Belt during the 2005 growing season (April-November), although there
remains considerable uncertainty about the likely timing, location, and degree of
infestation and its economic impact.
Experts suggest that ASR spores were carried to the southeastern United States
from South America on upper elevation winds during the 2004 hurricane season.
Because ASR arrived late in the crop year, it is not thought to have had any
measurable effect on 2004 U.S. soybean production — by November 9, 2004, nearly4
90% of the U.S. soybean crop had already been harvested. Furthermore, its
detection has provided an early warning and has given the U.S. soybean sector time5
to prepare strategies for establishing regional sentinel crops and distributing
information on methods for field scouting, detection, and treatment to guard against
possible ASR damage to the 2005 soybean crop.
1 For more information, see North Central Soybean Research Program (NCSRP), Plant
Health Initiative (PHI), Asian Soybean Rust, at [http://www.planthealth.info/rust/rust.htm].
2 A less harmful species of ASR, P. meibomiae, was first reported in Puerto Rico in 1976.
The more harmful species, P. pachyrhizi, was reported in Hawaii in 1994. U.S. Dept. of
Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS), Plant Protection
and Quarantine (PPQ), Strategic Plan to Minimize the Impact of the Introduction and
Establishment of Soybean Rust on Soybean Production in the United States, Nov. 2004, p.
3 USDA, APHIS, PPQ, Pest Alert: Soybean Rust, News and Information, “Soybean Rust
Updates,” available at [http://www.aphis.usda.gov/lpa/issues/sbr/sbr.html].
4 USDA, National Agricultural Statistics Service (NASS), Crop Progress, Nov. 14, 2004.
5 The sentinel crops are planted about one month prior to the commercial crops and scouted
daily by the cooperator. Because of their greater maturity, these sentinel crops become
infected first, giving area growers warning to start fungicide applications. Some of these
sentinel crops are then turned into fungicide demonstration plots.
Most experts anticipate the pathogen’s northward spread in 2005 into the Corn
Belt states for three primary reasons. First, conditions (e.g,. mild temperatures and
year-round presence of host species) in the southern United States, where the ASR
first appeared, tend to favor pathogen survival during the winter months. Second,
spring planting occurs in the Southeast and Delta several weeks ahead of planting in
the major soybean growing regions of the Corn Belt. This would give the pathogen
time to establish itself and be available for windborne transmission as the primary
soybean plantings of the Corn Belt reach vegetative stage. Third, rust spores are very
light and move easily on winds, sometimes traveling hundreds of miles in a single
day. A consolation to more northerly soybean producers is that, because ASR must
have a living host to survive the winter, ASR will only successfully over-winter in
the most southerly extremes of the United States and must be reintroduced each
successive year into more northerly soybean production areas.
Background on ASR
Nature of the Disease. Asian soybean rust (ASR) is a harmful disease —
caused by either of two fungal species Phakopsora pachyrhizi and Phakopsora
meibomiae — that affects the growth of several plant species of commercial
importance, most notably soybeans. P. pachyrhizi is a much more virulent pathogen
of soybeans than P. meibomiae. Environmental factors are critical to the incidence
and severity of ASR. Long periods of leaf wetness are needed for spore germination,
as well as temperatures between 60o and 85o Fahrenheit and a high relative humidity
of 75%-80%. As a result, ASR has been most destructive in the tropical and
subtropical regions of Asia, Africa, Australia, and more recently South America.
ASR is an obligate pathogen, which means it needs living host cells to survive.
The pathogen can infect and reproduce on 90 known plant species, 20 of which are
found in the United States and are most common in southern states — including dry
beans, kidney beans, peas, leguminous forage crops such as trefoil and sweet clover,
and weeds such as kudzu.6 The rust spores, once windborne, can be moved long
distances (reportedly up to 400 miles in a single day). Recent infestations in Africa
have been widespread in the same year that they were first detected. In contrast, in
South America, two to three years elapsed between detection and widespread onset.
Historical Expansion. Based on its recent history of geographic expansion,
ASR was expected to enter the mainland United States sometime within the 2004-
2007 period. The virulent form of ASR — P. pachyrhizi — was first discovered in
Japan in 1902. The next reports were in 1934 from Australia and India and again in
1940 in China. The pathogen then showed up in Africa in 1997. Spores are believed
to have crossed from Asia to Africa in wind currents of the upper atmosphere. It was
initially identified in Uganda, Kenya, and Rwanda in 1997, then in Zimbabwe in
1998. Zimbabwe suffered significant yield loss to the aggressive form of rust. Much
of what is known today about the effects and control of this pathogen has been
learned from scientists and farmers in Zimbabwe. The pathogen subsequently
showed up in South Africa in 2001. It is believed to have been spread throughout
Africa by prevailing winds.
6 USDA, APHIS, PPQ, ASR Strategic Plan (Nov. 2004).
The rust surfaced in Argentina in 2000, then a year later in Paraguay along the
border of Southern Brazil (although a major outbreak did not occur in either
Argentina or Paraguay). By 2002, the pathogen is believed to have moved
approximately 1,000 miles from the southern tip of Brazil to the heartland of soybean
production in central Brazil, causing significant yield losses. One of the reasons the
pathogen could have proliferated and spread so quickly in central Brazil is because
the region experiences very humid conditions — ideal for the proliferation of the
disease. Another potential factor is the discovery of rust reproduction on volunteer
soybeans. Unlike in the U.S. Corn Belt, where harsh winter conditions preclude
volunteer germination for several months, in Brazil’s tropical climate fallen soybeans
can germinate and grow into the vegetative stage shortly after harvest. This extends
the window of spore production and enables the pathogen to move more quickly via
prevalent winds. By September 2004, ASR spores had continued their northward
travel, appearing near Cali, Columbia, about 5 degrees north of the equator.7
Yield Loss. Once a soybean plant is infected, rust lesions tend to cover most
of the leaf, stem, and pods. The lesions cause premature defoliation, thereby
reducing photosynthesis and the number of days to maturity. Heavily infected plants
have fewer pods and lighter seeds. Marketable yields are further reduced by the
resulting poor seed quality.8 The pathogen has been shown to reduce soybean yield
as much as 80% when left untreated. Yield losses of 10% to 50% are quite common.
During the 2002/03 crop year, soybean producers in Mato Grosso and other Brazilian
states were caught unaware by ASR. In most cases, fungicides either were not
available or were applied too late. Brazil’s soybean crop losses in 2002/03 were
estimated at 3.4 million metric tons (mmt) out of a total crop of 52.6 mmt — a loss
of value of about $1.3 billion.9 The Brazilian government subsequently took
measures to alleviate the ASR problem — Brazil’s agricultural research network was
mobilized, and effective fungicides were identified and made available on the
marketplace. The following year, soybean yield damage in 2003/04 in Brazil due to
ASR was difficult to assess due to the simultaneous occurrence of drought and flood
across major soybean-growing areas; however, some analysts suggest that soybean
rust damage had grown to nearly 5 million metric tons.10
Treatment and Control. According to an expert at USDA’s Agricultural
Research Service (ARS), the disease’s rapid transmission rate coupled with an
abundance of host species suggests that eradication would be unlikely once the
fungus is established in the United States.11 As a result, the U.S. soybean industry
7 The Corn & Soybean Digest, Vol. 64, No. 8, “Soybean Rust Marches North,” by Greg
Lamp, Sept. 1, 2004.
8 Glen Hartman, USDA, ARS plant pathologist, quoted in Rob Wynstra, “Researchers
Prepare for Threat from New Soybean Disease,” Agriculture, Consumer and Environmental
Sciences (ACES) News, Univ. of Illinois, Apr. 22, 2002.
9 Reuters, “Big Asian Soy Rust Loss Ruled Out in Brazil Crop,” Jan. 20, 2004, reported by
@griculture Online, at [http://www.agriculture.com].
10 ProFarmer, “Lessons Learned Brazil,” by Editor Chip Flory, Nov. 20, 2004.
11 APHIS scientist Mary Palm, quoted in Bill Tomson, “Plans Made to Fight Soybean
and scientific community agree that the best long-run strategy for minimizing the
effects of ASR is the development of resistant varieties. However, current
commercial U.S. soybean cultivars are not resistant to or tolerant of ASR.
In the short run, industry participants and the scientific community suggest that
access to registered fungicides and the planting of early-maturing soybean cultivars
are the primary means of mitigating production losses due to ASR. Fungicides have
been used effectively in other countries to mitigate the impacts of ASR on soybean
production. In addition, the planting of early-maturing soybean cultivars has been
found to reduce ASR’s harmful effects by minimizing the extent of growing time
under warm-humid conditions when the disease proliferates.
Responding to ASR’s Arrival
What Is Being Done to Prepare? USDA has taken the lead in coordinating
activities to prepare for the introduction of ASR into the United States. Since May
2002, an ad hoc working group composed of USDA agencies — APHIS, ARS, and
the Cooperative State Research Extension and Education Service (CSREES) — and
the National Plant Board, as well as several major land-grant universities and
industry participants, has been working to develop and implement a four-pronged
approach to ASR that includes protection, detection, response, and recovery.12
Protection. Initially, this component involved identifying and protecting
possible pathogen entryways into the United States to slow or prevent the arrival of
ASR. In particular, APHIS sought to use its legislative authority under the Plant
Protection Act (Title IV of P.L. 106-224) to control the importation of commodities
that may serve as pathways for the introduction of foreign plant and animal pests andth
diseases. During the 108 Congress, legislation was proposed (H.R. 3775), with the
support of both the American Farm Bureau Federation and the American Soybean
Association, to ban soybean imports from countries known to harbor the pathogen.
However, no action was taken as the confirmed arrival of ASR into the United States
has refocused work to the remaining three components of the plan.
Detection. The detection plan is designed to ensure the early detection and
rapid identification of ASR once it reaches the United States. Specifics include the
distribution of information concerning field characteristics about the disease, details
on collection and submission of specimens, as well as diagnostics, and confirmation
procedures. According to USDA, accurate and timely identification is the key to
determining whether a response will be attempted and, if so, the extent, direction, and
magnitude of that response.
Sentinel soybean plantings (made about three weeks prior to commercial
plantings) throughout major soybean growing areas will be used to provide early
detection, thereby allowing time to control the pathogen in commercial plantings
Disease,” Wall Street Journal, Nov. 30, 2003.
12 USDA, APHIS, PPQ, ASR Strategic Plan (Nov. 2004).
before the disease becomes epidemic. APHIS has identified and is training key
participants throughout the soybean industry with respect to detection survey
procedures and best crop management practices to ensure effective ASR detection
and treatment methods. In addition, scouting and other detection information is
available through the North Central Soybean Research Program’s (NCSRP’s) Plant
Health Initiative (PHI) website.13
Response. To help minimize the potential impacts, APHIS has established
a communication network for facilitating a response once ASR has been detected in
a particular locality. Also, NCSRP’s PHI provides recommendations for rust
management and directs interested parties to other useful information sources.
Finally, APHIS’s Plant Protection and Quarantine (PPQ) is implementing a14
forecasting system to provide information about the probability of rust occurring
within a specific region based on current detection sites, weather patterns, crop
plantings and growth stage, and other information.
Recovery. The principal component of recovery involves the research and
development of improved, lower-cost fungicides and fungicide application practices,
as well as the research and development of disease-resistant soybean cultivars.
Personnel from USDA’s APHIS, ARS, and CSREES are collaborating with Iowa
State University and with USDA’s Foreign Disease-Weed Science Research Unit at
Fort Detrick, Maryland, to examine options for controlling the disease and
developing new sources of genetic resistance. ARS and CSREES also have been
working with seed companies to develop commercially acceptable rust-resistant or
-tolerant soybean varieties. This research has been supported by USDA and the
Homeland Security Department, as well as the state soybean checkoff boards
(represented by the North Central Soybean Research Program) and the United
Soybean Board.15 More recently, Congress appropriated $800,000 for research on
soybean rust and specifically included language encouraging USDA to accelerate
research on plant varieties that improve tolerance to soybean rust pathogens in the
Consolidated Appropriations Act, 2005 (P.L.108-447). The joint research objectives
!Determine resistance of U.S. commercial germ plasm to rust.
!Identify resistant germ plasm from international sources.
!Determine efficacy of fungicides against soybean rust, as well as the
optimum stage of disease development for applying a fungicide
treatment to maximize the effectiveness of treatments and to
minimize the costs and environmental risks associated with chemical
use. Tests are underway in countries with heavy rust infestations.
13 NCSRP, PHI, Asian Soybean Rust, at [http://www.planthealth.info].
14 For more information see, APHIS, PPQ, Pest Alert: Soybean Rust, “U.S. Soybean Rust
Detection and Aeriobiological Modeling, Nov. 2004; at [http://www.aphis.usda.gov/ppq/ep/
15 The Corn and Soybean Digest, “Fight Against Soybean Rust,” October 1, 2003.
!Develop Climate Prediction Models to identify the potential rust
pathway within the United States to determine which resistant
varieties should receive research emphasis.
!Develop an international network of collaborators and collect
soybean rust isolates.
According to the United Soybean Board, USDA scientists have already screened
more than 20,000 lines of U.S. and exotic germ plasm for resistance to rust.16 Of the
lines screened, 700 lines appear to show at least partial resistance to rust. Yet, the
availability of cultivars with good resistance and other characteristics desired in
soybeans for commercial production is still thought to be six to eight years away.17
Fungicide Registration Status in the United States. The sale of any
pesticide (including fungicides) is prohibited in the United States unless it is
registered and labeled in accordance with the regulations of the U.S. Environmental
Protection Agency (EPA).18 New uses (for example, on soybean rust) for pesticide
active ingredients previously registered with the EPA must also be reviewed and
registered. As of November 19, 2004, three chemicals were registered with the EPA19
for treatment of soybean rust. In addition, EPA had approved several emergency
exemptions for fungicides for the treatment of soybean rust under Section 18 of the
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Section 18
registrations grant temporary emergency use rights in specifically named states.
Chemical companies, university researchers, and the soybean industry are
searching for additional efficacious chemicals, formulations, and application rates
and methods. Selection, testing, and eventual registration with EPA of potential
fungicides for use in treating ASR can be a slow process that may take months or
years. Major chemical companies that already have fungicides on the market are
making efforts to get labeling changes approved through the EPA. However, labeling
changes can often require additional testing for residues and tolerance levels,
particularly if dosage rates and application methods for ASR vary greatly from
currently labeled uses.
EPA receives its authority to regulate pesticides under FIFRA, the Federal Food,
Drug, and Cosmetic Act (FFDCA), and the Food Quality Protection Act (FQPA).
Under FIFRA, EPA registration requires more than 100 different scientific studies
and tests from applicants to ensure that a pesticide, when used according to label
directions, can be used with a reasonable certainty of no harm to human health or the
16 Production Quarterly, “Soybean Checkoff Remains on the Front Lines in the Battle
Against Rust,” Dec. 2004; available at [http://www.unitedsoybean.org/f_public.htm].
17 NCSRP, PHI, Asian Soybean Rust.
18 For information on the registration of pesticide products, see CRS Report RL31921,
Pesticide Law: A Summary of the Statutes.
19 EPA, Pesticides, Pesticide News Stories, “EPA’s Pesticide Program Ready For Soybean
Rust Threat to Soybean Crop,” Nov. 19, 2004; available at [http://www.epa.gov/oppfead1/
environment.20 For pesticides that may be used on food or feed crops (as is the case
for soybeans), EPA is required by FFDCA and FQPA to set tolerances (maximum
pesticide residue levels) for the amount of the pesticide that can legally remain in or
on human foods or animal feed.21 However, under certain circumstances a state may
be granted an emergency exemption from the complete battery of testing necessary
for full pesticide registration. Under Section 18 of FIFRA (codified as 7 U.S.C.
136p), EPA can allow state and federal agencies to permit the unregistered use of a
pesticide in a specific geographic area for a limited time if emergency pest conditions
exist.22 Crisis exemptions are available if a need is more immediate, but allow for
unregistered use for only a 15-day period unless the applicant follows up with a
specific exemption request.
Fungicide Availability. One market watcher estimates that the United States
currently (as of November 13, 2004) has fungicide capacity to treat up to 12 million23
acres. During the past three years (2002-2004), U.S. soybean plantings have
averaged 74.2 million acres. Thus, sufficient fungicide is available to treat about
16% of average plantings. How widespread will ASR outbreaks be? How intense
will any infestation be (i.e., how may times will fungicides have to be applied to the
Fungicide producers confront these uncertainties when they make fungicide
production decisions well in advance of knowing what demand will be. Soybean
producers, on the other hand, are unlikely to purchase costly fungicides until they
learn of the appearance of ASR in their locality, at which point they will want to
purchase fungicide immediately. A shortage of fungicides or even the perception of
a fungicide shortage could lead to a constituent call for congressional action. The
response of local, state, and federal agencies is limited because the U.S. fungicide
market is in private hands. For a discussion of government response during the 2004
influenza shortage (an apparently analogous situation), see CRS Report RL32655,
Influenza Vaccine Shortages and Implications.
Crop Insurance. According to USDA’s Risk Management Agency (RMA)
— the agency charged with administering the federal crop insurance program —
unavoidable loss of production due to plant disease (including ASR) is a covered
peril under the crop insurance program, provided it was due to natural causes and the
producer followed recognized good farming practices in applying recommended,
available control measures (i.e., fungicides).24 Failure to purchase and apply
20 EPA, “Pesticides — Pesticide Registration Program: Evaluating Potential New Pesticides
and Uses,” retrieved on Feb. 5, 2004, from [http://www.epa.gov/pesticides/regulating/
22 EPA, “Pesticides: Regulating Pesticides — FIFRA Section 18 Emergency Exemptions,”
retrieved on Feb. 5, 2004, from [http://www.epa.gov/opprd001/section18/].
23 ProFarmer, “Asian Soybean Rust Makes its Way to U.S.,” by Chip Flory, Editor, Nov.
24 USDA, RMA, Risk Management Agency Remains Concerned About Soybean Rust,
recommended control measures will result in assessing uninsurable causes of losses.
If no effective control measures are available or there are insufficient amounts of
chemicals available for effective control, the resulting loss of production is covered.
However, producers are responsible to keep informed of soybean rust outbreaks in
Disaster Assistance. A widespread and severe loss of soybean production
due to ASR may encourage legislation to assist growers if a 2005 rust outbreak is
severe. There is substantial precedent for ad hoc disaster payments being made to
assist growers who suffer yield loss due to plant disease.25 Most recently, payments
were made to producers of any 2003 or 2004 crop with significant losses caused by
any natural disaster.26
ASR-Related Market Issues
Soybean production represents a vital economic activity in a large portion of the
United States. Soybeans rank second only to corn as the most important field crop
grown in the United States, both in terms of planted area and value. Soybean
harvested area has exceeded corn harvested area in every year since 1999. From
1999 to 2003, U.S. soybean planted area averaged nearly 74 million acres, while the
value of soybean production averaged nearly $14 billion.27 During that same period,
over half of the states derived important economic returns from soybean production
— the value of average annual soybean production was between $14 million and $90
million in 11 states (AL, DE, GA, MD, NJ, NY, OK, PA, SC, TX, VA); between
$100 million and $950 million in 14 states (AR, KS, KY, LA, MI, MO, MS, NC,
ND, NE, OH, SD, TN, WI); and greater than $1 billion in 4 states (IA, IL, IN, MN).
During the 1999 to 2003 period, the soybean processing sector annually
produced over $7 billion in soybean meal (nearly 98% of which was destined for use28
as animal feed) and $3.5 billion in soybean oil. In addition, soybeans, soybean oil,
and soybean meal averaged a combined $7.4 billion in exports during that same29
period, which was nearly 14% of all U.S. agricultural exports.
Given soybean production’s widespread economic significance, government
policy makers, commodity market participants, and the U.S. soybean industry are
concerned by the pathogen’s recent arrival in the United States, its tendency to
spread, and its detrimental effects on soybean yields. In addition to the potential
Dec. 30, 2004; available at [http://www.rma.usda.gov/news/2004/12/soybean-rust.html].
25 For more information, see CRS Report RL31095, Emergency Funding for Agriculture:
A Brief History of Supplemental Appropriations, FY1989-FY2005.
26 For details, see the section “Agricultural Disaster Assistance” in CRS Report RL32581.
27 USDA, National Agricultural Statistics Service (NASS), Crop Value, various issues.
28 Annual averages are for 1999 to 2003; USDA, ERS, Oil Crops Yearbook.
29 USDA, Foreign Agricultural Trade of the United States (FATUS), available online at
[ h t t p : / / www.f a s .us da .gov/ u s t r a de / ] .
economic harm, the arrival of a new pest of a major U.S. crop has implications for
several public policies, including pest control research, pesticide regulation, disaster
assistance, and crop insurance.30
Potential Effects of ASR Entry into the United States. ASR is
potentially devastating to temperate soybean producers because it easily adapts to
diverse environments, it is prolific under the right environmental conditions, and it
is very mobile. In April 2004, USDA’s Economic Research Service (ERS)
completed a simulation modeling exercise to project the potential economic losses
associated with various degrees of ASR infestation in the United States.31 According
to ERS, “The extent of economic impacts will depend on the timing, location, spread,
and severity of rust establishment and outbreaks, and on how soybean and crop
producers, livestock producers, and consumers of agricultural commodities
Early ASR detection combined with widespread fungicide availability can
greatly reduce yield losses and economic damage. However, the added cost of
fungicide application would lower soybean returns relative to other field crops such
as corn that are unaffected by the pathogen. As a result, it is likely that the presence
of ASR would lead to some acreage shifting away from soybeans and toward other
crops. These effects would vary regionally and would depend on relative expected
returns of different crops and alternate land-use activities. Corn would likely be the
primary beneficiary of displaced soybean acres, especially in the Corn Belt. In the
Plains states, wheat, other small grains, and possibly pastureland could gain some
area. In the Delta and Southeast, cotton probably would be the primary beneficiary
of soybean acreage shifts.
ERS medium-term results (which assume that ASR is already established and
endemic to the United States) suggest that annual economic losses could range
between $240 million and $2 billion, depending on the severity and extent of
subsequent outbreaks. The large range of damage estimates reflects the uncertainty
associated with the eventual effects of soybean rust in the United States. Under a
high-infestation scenario, ERS assumes national average yield losses of 9.5%. In
contrast, under a low-infestation scenario ERS actually assumes some yield gains due
to shifting of soybean area out of lower-yielding regions (such as the Southeast and
Delta states). The ERS simulation model suggests that soybean producers would
bear most (60% to 70%) of the costs of adjusting to soybean rust, while consumers
and livestock producers assume the remainder of the economic cost. Although not
specifically included in the ERS model, the U.S. oilseed-crushing industry would
also likely see its profit margins squeezed by high soybean prices relative to meal and
30 For more information, see USDA, ERS, Economic and Policy Implications of Wind-Borne
Entry of Asian Soybean Rust into the United States,” OCS-04D-02, by M. Livingston, R.
Johansson, S. Daberkow, M. Roberts, M. Ash, and V. Breneman, April 2004, p. 2; hereafter
referred to as USDA, ERS, ASR Study (April 2004).
32 Ibid., p. 2.
Market analysts suggest that the discovery of ASR in the United States is not
likely to have any impact on U.S. soybean exports because nearly every major
soybean producing country in the world also is infected by ASR.33
Regional Disparities. Under the ERS simulation model, the impact of an
ASR infestation falls heaviest on those regions that grow the most soybeans — the34
Corn Belt, the Delta, Appalachia, the Northern Plains, and the Southeast. When
soybean rust is assumed to infest a given region, soybean acres and soybean net
returns decline. Livestock producers in all regions suffer economic losses due to
higher feed costs.
USDA’s research suggests that, because of the potential severity of the disease
and fungicide costs needed to control field infections, a significant share of soybean
production in the southernmost states could become unprofitable. During the 1996
to 2002 period, soybean yields in Appalachia (AP), the Delta (DL), and the Southeast
(SE) averaged about 26% below the national average (see Table 1). Yet soybean
production has been a valuable agricultural activity for both regions. During that
same period, the AP, DL, and SE regions (combined) averaged more than 10 million
acres planted to soybeans, with annual production valued at $1.6 billion.35 The loss
of a significant share of soybean production in these regions likely would adversely
affect their growing pork and poultry sectors, due to the regions’ growing disparity
between feed production and demand.
Conclusion. Anticipatory work headed by USDA’s APHIS to mitigate the
adverse effects of ASR’s arrival in the United States is well underway. Until ASR-
resistant soybean varieties are developed, soybean producers will have to rely on
fungicides and early-maturing varieties to diminish potential yield losses. The
resultant higher production costs are expected to have important regional effects,
particularly in lower-yielding southern states, while livestock producers nationwide
are expected to suffer economic losses due to higher feed costs.
33 World Perspectives, Inc., “Asian Soybean Rust Arrives in the U.S.,” by John Baize,
Nov. 12, 2004.
34 Appalachia = KY, NC, TN, VA, WV; Corn Belt = IA, IL, IN, MO, OH; Delta = AR, LA,
MS; Northern Plains = KS, ND, NE, SD; and Southeast = AL, FL, GA, SC.
35 USDA, National Agricultural Statistics Service (NASS), Agricultural Statistics Database.
Table 1. U.S. Regional Soybean Comparisons,
Corn BeltNo. & So.Appalachian,
& LakePlainsNorth-Delta, &United
Ca te go r y States States east So ut he a s t States
Planted million ac.40.311.31.110.062.8
Harvested million ac.40.011.01.19.661.6
Production million bu.1,658386 392772,358
Source: USDA, NASS, Agricultural Statistical Database.
Note: Appalachia = KY, NC, TN, VA, WV; Corn Belt = IA, IL, IN, MO, OH; Delta = AR, LA, MS;
Northeast = PA, NY, MD, NJ, DE; Northern Plains = KS, ND, NE, SD; and Southeast = AL, FL, GA,
SC; and Southern Plains = OK, TX.
For More Information
North Central Soybean Research Program (NCSRP), Plant Health Initiative (PHI),
Asian Soybean Rust, at [http://www.planthealth.info/rust/rust.htm].
USDA, Animal and Plant Health Inspection Service (APHIS), Plant Protection and
Quarantine (PPQ), Pest Alert: Soybean Rust, News and Information, “Soybean
Rust Updates,” available at [http://www.aphis.usda.gov/lpa/issues/sbr/sbr.html].
USDA, Economic Research Service (ERS), Economic and Policy Implications of
Wind-Borne Entry of Asian Soybean Rust into the United States,” OCS-04D-02,
by M. Livingston, R. Johansson, S. Daberkow, M. Roberts, M. Ash, and V.
Breneman, April 2004; available at [http://www.ers.usda.gov/publications/OCS/
U.S. Environmental Protection Agency (EPA), Pesticides, Pesticide News Stories,
“EPA’s Pesticide Program Ready For Soybean Rust Threat to Soybean Crop,”
November 19, 2004; available at [http://www.epa.gov/oppfead1/cb/csb_page/
updates/soyb ean_rust.htm] .