Distribution of barley yellow dwarf virus isolates in Pennsylvania and the effect of the PAV isolate on yield of oats
1990
Gildow, F.E. | Frank, J.A. (Pennsylvania State University, University Park, PA (USA))
From 1984 to 1986 isolates of barley yellow dwarf virus (BYDV) were identified in small grains collected from three cereals management regions of Pennsylvania. Of 300 plants, 82, 19, 9 and 4 were infected with isolates resembling PAV, RPV, MAV, and RMV, respectively, based on enzyme immunoassays and aphid transmission bioassay tests. Of these plants, 16 % were infected with two isolates, suggesting that infection resulted from inoculation by two aphid species, or by dependent virus transmission from doubly infected source plants. Only 5 % of 329 alate Rhopalosiphum padi (L.) and Sitobion avenae (Fabricius) collected in the field from asymptomatic oats (Avena sativa L.) were viruliferous for BYDV. Field inoculations of oats at 4 or 6 weeks after planting with a PAV isolate significantly reduced the number of panicles/m, seed/m, and seed/panicle. The 1000-kernel weight was not affected. Yields in plots infected with viruliferous aphids at 4 or 6 weeks after planting were reduced by 86 and 28 %, respectively, compared to uninfested controls. Significant differences were observed between 1985 and 1986 relative to annual fluctuations in environmental parameters influencing aphid vector biology.
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