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April 15, 2004
Assessment
of the potential year-round establishment of soybean rust
throughout the world.
S. Pivonia and X. B. Yang, Iowa State University,
Department of Plant Pathology, Ames 50011. Plant Dis.
D-2004-0301-03R, 2004 (online).
Accepted for publication 2 January 2004.
Soybean rust has occurred in eastern Asia and Australia for
decades. During the past few years, the fungus had spread into
new areas in Africa and South America. A modeling approach,
taking into account the fungus temperature and moisture
constraints for reproduction, was applied to study the
potential year-round persistence of soybean rust. The data is
important to assess (i) the potential threat of soybean rust in
new regions and (ii) the potential dissemination into soybean
production regions from an overwintering area. Our study shows
that, globally, soybean production regions can be divided into
two types: type 1 areas, where the disease can survive
year-round on suitable hosts, and type 2 areas, where disease
occurrence depends on an external source of inoculum after
long-distance dispersal from a source area. Most regions where
soybean rust is known to occur are in areas of type 1. After
soybean rust enters the United States, the fungus is likely to
overwinter in parts of Florida and southern Texas. Major soybean
production regions in the United States and central Argentina
are, like Central China, type 2 areas. Further study is needed
to determine the potential build-up of soybean rust in the south
and the establishment of a northward spore pathway during a
soybean growing season.
The current issue of
APSNet, Volume 88, Number 5,
May 2004, is at
http://www.apsnet.org/pd/current/top.asp |
