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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 viewed at:


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 be covered.

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.