Gibbago trianthemae, a Recently Described Hyphomycete with Bioherbicide Potential for Control of Horse Purslane (Trianthema portulacastrum). James K. Mitchell, Postdoctoral Research Associate, Department of Plant Pathology, University of Arkansas, Fayetteville 72701. . Plant Dis. 72:354-355. Accepted for publication 22 October 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0354.

Gibbago trianthemae, the causal agent of leaf spot on horse purslane, was isolated from diseased plants collected in Brazos County, TX, in 1984. Plants sprayed with conidia at 1 × 10⁵ spores/ml or more were killed within 9 days. In host-range studies, the fungus was pathogenic only to horse purslane and not to 18 other crop and weed species in 11 plant families. Results of both pathogenicity and host-range studies demonstrate that this fungus may be a useful agent for the biological control of horse purslane.

Keyword(s): mycoherbicide, weed control.