Virulent Hessian Flies Renew Attack on U.S.
Wheat By Don
Comis January 24, 2007
Last year, the West Lafayette, Ind., area saw its first Hessian fly
(Mayetiola destructor) infestation in more than a decade. Over the last
two years, the flies have also shown up in Missouri for the first time ever,
signaling a westward expansion of the world's most destructive wheat pest.
Having mostly lurked outside of wheat fields for the past 45 years,
the flies have recently undergone genetic changes that enable them to make
major inroads into wheat fields once again.
It so happens that both the Agricultural Research Service's (ARS)
Production and Pest Control Research Unit and
Purdue Universitypart of a research
team that pioneered control of the Hessian flyare located in West
With this team's continuous help in breeding and updating genetic
resistance to the fly, wheat has been winning the battle against the pest since
1955, by which time the first three Hessian fly-resistant wheat genes had been
bred into wheat varieties.
But by 2000, the flies had overcome four of the latest primary wheat
resistance genes that had protected wheat successfully since 1986. This is the
fly's latest success in a 10,000-year-old, gene-for-gene battle with wheat. ARS
Williams and colleagues at West Lafayette discovered and mapped the newest
wheat genes, H31 and H32.
After a 45-year
hiatus, the Hessian fly is re-emerging as a threat to U.S. wheat.Click the
image for more information about it.
Aided by the latest genetic tools, the West Lafayette scientists are
hunting for fly genes as well. They now have enough gene markers to cover the
entire Hessian fly genome. With these, they have begun a search for all of the
fly genes that overcome resistance genes in wheat.
J. Schemerhorn is sampling Hessian flies across the United States to
determine their genetic variability. The greater the variability, the more
resistance genes will need to be bred into wheat varieties to counter the fly's
about the research in the January 2007 issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.