Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2005
Publication Date: 2/1/2006
Citation: Rosskopf, E.N., Ables, C.Y., Charudattan, R. 2006. Host range of phomopsis amaranthicola, a bioherbicide candidate, is confined to the genus amaranthus. Biocontrol Science and Technology. 16:27-35. Interpretive Summary: The safety of a weed biological control agent is often determined by the specificity of the agent. The potential for non-target effects can hinder the development of an agent, particularly if the agent is to be used in a cropping system or if the target weed has close relatives that are desirable and would be at risk. The biological control agent Phomopsis amaranthicola is currently under development for control of pigweeds (Amaranthus spp.). The fungus has been found to be highly specific to this group of weeds and does not infect any plants outside the genus Amaranthus.
Technical Abstract: Host-range testing was performed on the fungus Phomopsis amaranthicola, which is under development as a biological control agent for weeds belonging to the genus Amaranthus. Amaranthus hybridus served as the focal plant in a centrifugal phylogenetic scheme. Forty-five accessions of 21 species in the genus Amaranthus were tested for susceptiblity to infection by this fungus. Fifty-six plant species outside the genus Amaranthus were also tested. These latter included crops in which the fungus might be used as a bioherbicide, members of genera that are closely related to Amaranthus, and selections of species that have been reported as hosts of other species of the genera Phomopsis or Diaporthe. Phomopsis amaranthicola was highly pathogenic to several species in the genus Amaranthus. All Amaranthus species tested were infected to varying degrees by P. amaranthicola; the resulting mortality levels were variable. The fungus infected none of the plants from outside the genus Amaranthus. Thus, P. amaranthicola is highly host-specific to the genus Amaranthus.