Spatiotemporal separation of groundnut rosette disease agents

Analysis by triple-antibody sandwich enzyme-linked immunosorbent assay of g roundnut samples from fields in two seasons from different regions of Malaw i showed the absence of groundnut rosette assistor virus (GRAV) from some p lants showing groundnut rosette disease symptoms and the presence of GRAV i n some symptomless plants. Viruliferous Aphis craccivora collected from fie lds transmitted either GRAV alone, groundnut rosette virus (GRV) with its s atellite RNA (sat RNA), or all three agents together, in different proporti ons. More plants became infected with all three agents when increasing numb ers of potentially viruliferous aphids were used per plant, suggesting a do sage response. Electrical pentration graph studies of aphid stylet activiti es indicated successful transmission of GRV and its sat RNA during both the "stylet pathway phase" and salivation into sieve elements, whereas GRAV wa s transmitted only during the latter phase. Aphids transmitted all three ag ents together only during the salivation phase. Reverse-transcriptase polym erase chain reaction testing of viruliferous aphids and of inoculated plant s revealed no correlation between the presence of all three agents in prosp ective aphid vectors and their simultaneous transmission to groundnut plant s. These results show that separation of the groundnut rosette disease agen ts occurs over time and space.