VIEW ARTICLE

Ecology and Epidemiology

Field Variants of Barley Yellow Dwarf Virus: Detection and Fluctuation During Twenty Years. W. F. Rochow, Research plant pathologist, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, and professor of plant pathology, Cornell University, Ithaca, NY 14853; Phytopathology 69:655-660. Accepted for publication 4 January 1979. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1979. DOI: 10.1094/Phyto-69-655.

All 181 isolates of barley yellow dwarf virus (BYDV) that were recovered from field-collected oats, wheat, or barley during 1975 and 1976 resembled one of five characterized isolates found previously. Most of them resembled PAV, an isolate of BYDV which is transmitted nonspecifically by Rhopalosiphum padi, Macrosiphum avenae, and Schizaphis graminum. More than one variant of BYDV was recovered from nine of 57 winter grain plants. Only one mixed infection was detected among 114 spring oat samples. Since these tests complete 20 consecutive years of evaluation of BYDV isolates in New York, a compilation was made of the yearly results. Identification of 1,055 BYDV isolates from spring oats showed that isolates similar to four of five characterized ones were present almost every year. A gradual change in predominating isolate type has occurred in the 20 yr, from isolates similar to the vector-specific MAV (specifically transmitted by M. avenae) to those similar to PAV. A similar pattern was detected in tests of winter grains during the same period. Mixed infections by more than one isolate of BYDV were common in winter grains but rare in oats during most years. Further evaluations based upon two kinds of serological tests confirmed the identifications of 39 isolates of BYDV. One test was a neutralization of infectivity based on serological blocking of aphid transmission from treated virus preparations. The other was the enzyme-linked immunosorbent assay procedure, which has many advantages and shows promise for future work.