RMA MONITORING SOYBEAN RUST DEVELOPMENTS
WASHINGTON, Jul 15, 2004 - The threat of soybean rust disease affecting U.S. soybean producers in the near future is of
concern to the Risk Management Agency (RMA). Some months ago, a soybean rust working group was
formed to prepare for the arrival of soybean rust by keeping State, commodity, and Federal
scientists informed of the recent activity related to soybean rust. RMA personnel are
participating in this work group.
Working group members include at least one extension
plant pathologist from each soybean state but also any other representatives from State,
Federal, and commodity organizations with an interest in soybean rust. The working group
meets by teleconference bimonthly or as needed to discuss items of concern to members.
Common topics are management options, information resources, range of soybean rust, and
recent research. The working group is hosted by the USDA Office of Pest Management Policy,
and past meeting summaries as well as other items of interest about soybean rust may be
Soybean rust disease is caused by two different rust fungi: Phakopsora meibomiae
(P. meibomiae) and Phakopsora pachyrhizi (P. pachyrhizi). P. pachyrhizi is the more
aggressive of the two species and causes more damage to soybeans. The two fungi cannot
be distinguished from each other without detailed laboratory tests. Soybean rust is native
to eastern Australia, eastern Asia, Japan, Taiwan, and the Philippines. The disease was
found in Africa in 1997 and has spread through most of the continent. Soybean rust was
found in Paraguay in 2001 and has spread to Argentina and Brazil. Entry of this disease
into North America now seems inevitable. The potential for the disease to spread in the
United States will likely depend on the climatic patterns in different regions.
Soybean rust is an airborne disease and can remain airborne throughout large sections of
soybean-growing areas, spreading from south to north on seasonal wind currents and persisting
on alternate host plants. The rust spores could over-winter on any number of host plant
species in the southeastern United States. Green beans, kidney beans, lima beans, and
cowpeas are also at risk. The fungi cause lesions on the bottom of leaves in mid to late
summer. The yield losses result when the rust lesions cover most of the leaf area, causing
premature defoliation. Yield losses associated with soybean rust have generally ranged from
10 to 80 percent if untreated. Once the disease invades a field, the window for effective
rescue treatments is only about seven days. After a week, the nearly completely defoliated
plants' yields are adversely affected.
Research is underway to determine the rust resistance and susceptibility of U.S. soybean
varieties and to develop rust resistant varieties. Crop rotation will not help because (1)
of the disease's ability to over-winter on other host plants, and (2) it is a wind-borne and not
a soil-borne disease.
Costly fungicide treatments currently represent the only option for containing soybean rust.
It may take three, four, or five applications to be effective and potential treatment costs
may vary widely.
Unavoidable loss of production due to plant disease (including soybean rust disease) is a
covered peril under the Coarse Grains Crop Provisions, provided it was due to natural causes
and not agroterrorism. Section 8 of the Coarse Grains Crop Provisions (7 C.F.R. 457.113)
states that, in accordance with the Basic Provisions, insurance is provided against loss of
production due to unavoidable causes of loss, including plant disease, but not damage due to
insufficient or improper application of disease control measures. Therefore, losses to
soybean production due to soybean rust disease is an insurable cause of loss provided the
insured can verify that the cause was natural and available control measures were properly
applied. If there are no effective control measures available or there are insufficient
amounts of chemicals available for effective control, resulting loss of production would
It will not be a covered loss if there are sufficient control measures available, but the
insured elects not to use them. Failure to purchase and apply recommended control measures
will result in uninsurable causes of loss being assessed. It will be critical for RMA and
insurance providers to monitor when outbreaks are detected in an area to determine if an
insured could have applied recommended fungicides in a timely manner and did not.
The current recognized good farming practices for soybeans generally should not be an issue
as soybean rust is not a soil borne disease and rotation of crops would not be effective
for control. It will be necessary to determine if adequate amounts of approved chemicals
were available at the time of an outbreak, and if adequate amounts were available, were
they applied in a timely manner to achieve optimum control regardless of the cost involved.