STUDIES ON THE ECOLOGY AND EPIDEMIOLOGY OF BARLEY YELLOW DWARF VIRUS IN INDIANA (VIROLOGY)
Abstract
Barley yellow dwarf virus (BYDV) is recognized as a serious virus disease of cereals and grasses world-wide. Serological methods offer simple means of BYDV detection, and currently the most useful of these is the enzyme-linked immunosorbent assay (ELISA). ELISA-based studies were undertaken to investigate the incidence, ecology and epidemiology of BYDV in Indiana. The results indicated that a major source of BYDV for Indiana cereals is likely to be wind borne aphid populations moving from distant crops especially in the spring. Aphid populations in the fall probably include components both from distant crops and local sources such as grass or corn depending on the seasonal weather patterns. Overall, the predominant isolate of BYDV in Indiana and elsewhere in the Midwest is the PAV-type. Comparisons of intradermal and intramuscular procedures for BYDV antisera production showed intradermal injection produces high titer antisera to P-PAV for use in ELISA and is a valuable technique for immunogens that give low yields after purification. Comparisons of various buffers tested for virus extraction efficiency indicated that 0.1 M phosphate buffer at pH 7 gave optimum or near-optimum results with the P-PAV, MAV and RPV isolates of BYDV tested. Airmailing infected leaf samples to and from selected geographical locations world-wide indicated that ELISA activity remained adequate for BYDV diagnosis if the leaf was thoroughly air-dried prior to shipment. This would allow leaf samples to be shipped over long distances to diagnostic centers using ELISA based screening procedures.
Degree
Ph.D.
Subject Area
Plant pathology
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