St. Paul, Minn. (June 5, 1997)—Sorghum, one of the oldest feed grain crops, is affected in several parts of the world by ergot disease. Plant scientists are taking the rapid spread of this fungus in South and North America over the past three years very seriously.
Sorghum ergot was found in the United States for the first time just three months ago in Texas's Lower Rio Grande Valley.
"This disease can significantly affect hybrid seed production. Its presence in Texas, the producer of 80 to 90 percent of the world's hybrid seed, could have significant repercussions on the state's economy," Dr. Tom Isakeit, Texas A&M University plant pathologist, said.
"Female parent plants used in hybrid seed production fields are generally the sorghums most heavily damaged by ergot. Forage sorghums are also at risk from ergot. By contrast, commercial grain sorghum hybrids have a negligible incidence of ergot during normal growing seasons," Dr. Gary Odvody, Texas A&M University plant pathologist, said.
A research and education response by plant doctors is underway in the United States and involves scientists from state and federal agencies. Conferences on ergot are being held this June in Brazil and Texas. The United States Conference on Ergot of Sorghum will be held in Amarillo, TX, on June 11, 1997.
The American Phytopathological Society (APS) is a professional scientific organization devoted to the study of plant diseases and their control.
Q & A: Sorghum Ergot
What is sorghum?
It is a grass and there are several varieties worldwide. In the United States, Mexico, Argentina, Australia and South Africa, sorghum is used for animal feed and silage. In Africa it is used as a source of syrup but also is ground into flour for use in pancakes and mush.
What causes sorghum ergot?
Ergot is caused by the fungus Claviceps africana that infects the ovary during flowering but prior to pollination.
How does ergot affect sorghum?
Ergot impacts seed production. Male-sterile (female parent) sorghums in hybrid seed production fields are most heavily damaged by ergot because they require an external pollen source for fertilization. Commercial grain sorghum hybrids have a negligible incidence of ergot during normal growing seasons.
What are the symptoms of ergot?
The most obvious symptom of ergot is a sugary exudation from infected flowers, called honeydew. It varies in color from clear to yellow-brown, pink or matte white. If environmental conditions are right saprophytes may grow on the honeydew giving it a black, matted appearance.
Where is the disease located?
Until recently, the disease was found only in India and Africa. In 1995, it was widespread in Brazil and has since spread to neighboring countries; it has been detected in Australia, Puerto Rico, the Dominican Republic, Jamaica, Honduras, and Mexico. In May, it was detected for the first time in the United States in Texas.
What's being done to fight the fungus?
A research and education response is already underway in the United States. University of Texas A&M scientists are working in cooperation with their Mexican counterparts in Rio Bravo, Tamaulipas and other plant scientists worldwide to research the problem and to educate seed breeders and growers.
What conferences on sorghum ergot are planned?
Plant doctors will meet this June in Texas and Brazil. The United States Great Plains conference on sorghum ergot is June 11, 1997 in Amarillo, TX. A global conference is in session now in Brazil.
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