VIEW ARTICLE

Vector Relations

Aphid Transmission of Barley Yellow Dwarf Virus: Inoculation Access Periods and Epidemiological Implications. Alison G. Power, Section of Ecology and Systematics, Cornell University, Ithaca, NY 14853; Abby J. Seaman(2), and Stewart M. Gray(3). (2)Section of Ecology and Systematics, Cornell University, Ithaca, NY 14853; (3)USDA-ARS and Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Phytopathology 81:545-548. Accepted for publication 7 January 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/Phyto-81-545.

In this study, we examined the efficiency of transmission of three isolates of barley yellow dwarf virus (BYDV) from New York by two aphid species for the purpose of assessing the relative importance of these species as vectors. The influence of the duration of the aphid inoculation access period (IAP) on transmission was investigated for RPV and PAV isolates of BYDV transmitted by Rhopalosiphum padi and for MAV and PAV isolates transmitted by Sitobion avenae. For each aphid–isolate combination, 15 IAPs, ranging from 30 min to 72 hr, were tested. R. padi was equally effective at transmitting the RPV and PAV isolates; 33.3 and 24.6% of individual aphids transmitted RPV and PAV, respectively, given a 30-min IAP. For both isolates, 50% transmission required an IAP of approximately 2 hr. In contrast, S. avenae was less efficient in transmitting PAV and MAV. Given a 30-min IAP, 1.8% of individual aphids of S. avenae transmitted PAV, while 10.0% transmitted MAV. Fifty percent transmission required an IAP of 4-6 hr for MAV and approximately 72 hr for PAV. After a 72-hr IAP, 86.7% of individual aphids of R. padi transmitted PAV, but only 53.3% of individual aphids of S. avenae had done so. These results suggest that S. avenae is likely to play a secondary role in the spread of BYDV when it co-occurs with R. padi and when PAV-like isolates predominate. Moreover, these data may help to explain the coincident increase of PAV and decline of MAV in upstate New York during the past several decades.