Three New Fungi May Be Used as Biological ControlsBy
Three new species of fungi could give agriculture new tools to fill gaps in
pest control that may arise if methyl bromide is phased out in 2001 as
Agricultural Research Service
mycologist Gary Samuels identified and described the new fungi, which belong to
the genus Hypomyces. They are cousins of Trichoderma fungi
known to destroy "bad" fungi including Verticillium and
Pythium that cause wilts and other diseases.
Scientists are encouraged about Hypomyces' potential because efforts
to understand their biology--now underway--are crucial to exploiting them. Other
ARS scientists have preliminary evidence that different Hypomyces
species may have biocontrol potential.
The scientists don't yet know what diseases the new fungi might attack, but
alternatives to methyl bromide are needed. The chemical is widely used as a
soil fumigant and in postharvest and quarantine treatments to control rots and
other pests on many crops such as strawberries, stone fruits, grapes and nuts.
But it is scheduled to be phased out because it is thought to damage Earth's
ARS researchers discovered one of the new species, H. viridigriseus,
in Illinois. A USDA Forest Service
scientist found the other two, H. favoli and H. puertoricensis,
on rotting wood in Puerto Rico's rain forest.
According to Samuels, a world expert on Trichoderma, one obstacle to
using the new fungi as biocontrols is that they primarily reproduce asexually.
Thus, they can't be readily improved by sexual reproduction. However, the
scientists' discovery of a sexual state of Hypomyces in nature is a sign
the sexual state might be produced in lab cultures. Then the fungus could be
genetically improved as a disease fighter.
A story about the three fungi appears in the July issue of Agricultural
Research magazine. The story is also on the World Wide Web at:
Scientific contact: Amy Y. Rossman, Systematic Botany and Mycology
Laboratory, 10400 Baltimore Ave., Bldg. 011A, Rm. 304, Beltsville, phone (301)
504-5364, fax (301)504-5810, e-mail