Susceptibility of various accessions of Convolvulus arvensis to Phomopsis convolvulus

The susceptibility of Convolvulus arvensis L. accessions from different geo graphic locations to disease caused by the fungal pathogen, Phomopsis convo lvulus Ormeno, was evaluated. In a postemergence application experiment, si ngle excised plant shoots of C. arvensis collected from 11 different region s in North America and Europe were inoculated with P. convolvulus conidia. All C. arvensis accessions showed similar disease reactions. However, plant s originating in Canada (Quebec) and Spain showed significantly greater dis ease development than plants from a USA accession (Montana). In a separate preemergence application experiment, plants from two selected accessions or iginating in Greece and the USA (Montana) were grown from root stock and su bjected to a granular formulation of P. conuolvulus applied to the soil sur face. The emerging shoots of both accessions showed severe disease developm ent and the fungal application on Greek and Montana accessions reduced abov eground biomass 83 to 100% and 65 to 86%, respectively. Results of this stu dy indicate that control of C. arvensis using P. convolvulus might be achie ved in various geographic regions. (C) 1999 Academie Press.