
New Bioherbicide Whacks Tomato
WeedsBy Tara
Weaver-Missick June 8, 2000Agricultural Research Service scientists
have found a new bioherbicide that shows promise as an alternative to methyl
bromide for controlling weeds in tomatoes. The bioherbicide, Myrothecium verrucaria, comes from the sicklepod
plant found primarily in the southeastern United States. ARS scientists
recently reported that the fungus controls kudzu, a problematic weed in the
South. Common purslane, horse purslane, ground spurge and spotted spurge are
serious weed pests in commercially grown tomatoes. Tomato crops have the
highest consumption of methyl bromide of all crop uses. Tomato crops account
for 23 percent of pre-plant methyl bromide use. About 3,773 tons are applied
annually to the crop to control nematodes (tiny worms), insects and weeds. Researchers C. Douglas Boyette and Hamed K. Abbas at the ARS
Southern Weed
Science Research Unit, Stoneville, Miss., treated plots with natural
infestations of these weeds with Myrothecium before planting Beefsteak
tomato seedlings. Myrothecium eliminated these weeds in several field
tests. Myrothecium was applied in place of methyl bromide. After 14 days, no
weeds were found and the tomatoes prospered. This research was part of an agency fast-track study to look for
alternatives to methyl bromide, a widely used fumigant and ozone-depletor.
Methyl bromide is scheduled to be banned in the United States in 2005, and
worldwide by 2015. Worldwide, 72,000 tons of methyl bromide are used in
preplant and postplant applications and fumigations. The researchers are also examining several other possible natural
alternatives to methyl bromide for controlling weeds, including Fusarium
solani and Colletotrichum truncatum. Boyette was scheduled to present these findings today at the Third
International Weed Science Conference, Foz do Iguassu, Brazil, June 6-11. ARS is the U.S. Department of
Agricultures chief research agency. Scientific contact: C. Douglas
Boyette, ARS Southern Weed Science Research Unit, Stoneville, Miss., phone
(662) 686-5222, fax (662) 686-5422, [email protected]. U.S. Department of Agriculture |