EVALUATION OF THE POTENTIAL OF THIRTY TWO WEED SPECIES AS INFECTION SOURCES OF IMPATIENS NECROTIC SPOT VIRUS

The susceptibility of 32 weed species to Impatiens necrotic spot virus (INSV) infection was examined. Cerastium glomeratum, Cardamine scutata, Portulaca oleracea, Galium spurium var. echinospermon, Stellaria aquatica, S. media, Veronica arvensis, and V. persica showed systemic infections. Frankliniella occidentalis acquired INSV from all systemically infected plant species except for P. oleracea, and transmitted it to petunia leaf disks. The transmission efficiencies of all tested weed species were similar. Because none of the F. occidentalis individuals growing on P. oleracea survived, we could not derive the acquisition efficiency for P. oleracea. In a field survey, INSV was regularly detected in C. scutata, S. media, and C. glomeratum that spontaneously grew in an INSV-affected greenhouse. These results suggest that these three weed species are sources of INSV infection. This virus was also detected in one plant of P. oleracea, which may in fact not be a major reservoir of INSV because F. occidentalis individuals could not survive on this plant.