
Friendly Fungus With Dirty Name Takes on
Southern MenaceBy Jan Suszkiw May 25, 1999Wiping out smut is a campaign for some
folks. But in Louisianas bayou country, Rex Millhollon is actually trying
to encourage it--loose kernel smut, that is. The fungus, Sphacelotheca
holci, is the respected agronomists latest jab at halting
Johnsongrass, a loathsome southern weed that keeps popping up in the
regions sugarcane fields every year. Millhollon is exploring this biological approach to weed control at the
Sugarcane Research
Unit, operated in Houma, La., by the Agricultural Research Service, chief
scientific agency of the U.S. Department of
Agriculture. In the lower Mississippi Delta region of southern Louisiana, where
Millhollons research takes place, cane growers typically rely on chemical
herbicides to rid their fields of the pesky grass. One concern, however, is the
potential build-up of chemical residues in the environment. Another is cost:
Cane growers can spend up to $50 per acre applying chemical controls. Though a
good sugar crop can defray the expense, each new season is met by a fresh
contingent of the weed, necessitating another round of herbicide. To break the cycle, Millhollon has sought to develop the smut fungus into a
so-called mycoherbicide. The trick: getting the fungus to infect the whole
plant, weakening it and its prolific seed-producing machinery. In greenhouse experiments, Millhollon injected a smut spore solution
directly into the weeds tissues, causing infection rates of 75 to 85
percent and seedheads resembling a dark, crumbly mass. In a more practical
approach, Millhollon formulated the fungus into a mycoherbicide, spraying it
onto the weed in field plots. Though 50 to 80 percent became infected, the
treatment didnt protect the plots cane crop as well as conventional
herbicides. Now, Millhollon is eyeing ways to give the fungus a helping hand,
including breeding it with other Sphacelotheca that are more effective
at infecting Johnsongrass. A longer article about smut, the fungus, appears in the May issue of Agricultural Research magazine
at: http://www.ars.usda.gov/is/AR/archive/may99/smut0599.htm Scientific contact: Rex Millhollon, ARS Sugarcane
Research Unit, Houma, La., phone (504) 853-3174, fax (504) 868-8369,
[email protected]. Story contacts Sugarcane Research Jan R Suszkiw U.S. Department of Agriculture | |