VIEW ARTICLE

Vector Relations

The Median Latent Periods for Three Isolates of Barley Yellow Dwarf Virus in Aphid Vectors. L. J. van der Broek, Graduate student, Department of Virology, State Agricultural University, Binnenhaven 11, 6709 PD Wageningen, The Netherlands; C. C. Gill, research scientist, Agriculture Canada, Research Station, Winnipeg, Manitoba, Canada, R3T 2M9. Phytopathology 70:644-646. Accepted for publication 28 December 1979. Copyright 1980 The American Phytopathological Society. DOI: 10.1094/Phyto-70-644.

The median latent periods (LP 50) were determined for three isolates of barley yellow dwarf virus in their specific vector or most efficient vector at two temperatures. The latent period per aphid was defined as the time lapse from the start of the acquisition feeding period to the middle of the inoculation day during which transmission of an infectious dose of virus first occurred. At 15 C and 20 C, the median latent periods for Sitobion avenae with S. avenae-specific isolate 6407 were 65.5 hr and 44.5 hr, for Rhopalosiphum padi with R. padi-specific isolate 6524 the values were 50.1 hr and 35.0 hr, and for R. padi with R. padi nonspecific isolate 7410 the values were 62.4 and 35.2 hr, respectively. A decrease equivalent to 50% in the median latent periods for a 10 C increase in temperature was found with the two aphid-specific isolates, but the decrease was more than 50% with the R. padi-nonspecific isolate.