
Research Counterattack Against New Sorghum
FungusBy Jim De
Quattro May 12, 1997Sorghum ergot (UR-get), an emerging
fungus disease, faces more scrutiny at the Agricultural Research Service. ARS has
released $100,000 in funds to expand research against the disease, found this
year in Puerto Rico and Texas. Grain sorghum is the nations number two feed grain. Sorghum ergot
mainly threatens hybrid sorghum seed crops. Texas is the worlds major
supplier of hybrid sorghum seed, and U.S. sorghum winter-nursery programs are
concentrated in Puerto Rico. First found in the western hemisphere in 1995,
sorghum ergot raced through South and Central America and the Caribbean.
Scientists found it in Puerto Rico in February and Texas in March. Ergot infects only unfertilized ovaries of female sorghum flowers, just
before the flowers are ready to accept pollen. The fungus multiplies rapidly,
and infected flowers cant make seed. Instead, they exude honeydew, sticky
droplets containing spores. Fungal structures are carried readily via harvested
seed, wind, insects, machinery and people. To combat the ergot, ARS will expand research at its
Tropical
Crops and Germplasm Research Laboratory, Mayaguez, P.R., and its
Foreign Disease-Weed Research
Laboratory, Frederick, Md. The research will be conducted in cooperation
with Texas A&M University. The
scientists will: - Continue evaluating fungicide treatments that were tested by ARS
scientists in Puerto Rico to kill ergot spores contaminating seed of breeding
lines shipped to North America.
- Identify resistant plants from ARS germplasm collection. Resistant
varieties would give growers long-term protection.
- Test a fungicide to suppress ergot infections on sorghum plants. Texas
A&M University plans tests on commercial seed farms in south Texas and
Mexico.
- Confirm the ergots identity. Principal sorghum ergot species are
Claviceps sorghi from India and C. africana, of African origin,
the species found so far in the western hemisphere. Evidence to date shows
C. africana makes no toxins, unlike a different ergot species, C.
purpurea.
ARS scientists in Puerto Rico operate a World Wide Web site as an ergot
resource for scientists, industry and growers. The site, which includes photos
of ergot on plants, is at: http://www.sorghumgrowers.com/Research/sorghum.html Scientific contacts: Morris Bonde, ARS
Foreign Disease-Weed Research Laboratory, Frederick, Md., phone (301) 619-2860,
fax 619-2880, [email protected]
Jeff Dahlberg, ARS Tropical Crops and Germplasm Research Laboratory, Mayaguez,
P.R., phone (787) 831-3435, fax 831-3386, [email protected]
Richard
Frederiksen, Texas A&M University, College Station, Texas, phone (409)
845-1227, fax 845-6483, [email protected]
Gary Odvody,
Texas A&M Research and Extension
Center, Corpus Christi, Texas, phone (512) 265-9205, fax 265-9434,
[email protected].
Story contacts Morris R Bonde U.S. Department of Agriculture | |