THE EFFECT OF TEMPERATURE AND INOCULATION ACCESS PERIOD ON THE TRANSMISSION OF BARLEY YELLOW DWARF VIRUS BY RHOPALOSIPHUM-PADI (L) AND SITOBION-AVENAE (F)

Winged individuals of Rhopalosiphum padi and Sitobion avenae transmitt ed the PAV-like and MAV-like isolates of barley yellow dwarf virus res pectively. Success of transmission after inoculation access periods of 2, 6, 12, 24, 48 and 72 h were examined and survival, reproduction an d movement of the aphid vectors were recorded at these times. The expe riment was done at four different temperatures: 6 degrees C, 12 degree s C, 18 degrees C and 23 degrees C. For both isolates the inoculation efficacy did not increase after a 24 h inoculation access period and t here was no difference in inoculation efficiency at the three highest temperatures, that at 6 degrees C being significantly lower than at 12 degrees C to 23 degrees C. The results suggest that autumn temperatur e is a critical factor for BYDV epidemiology in Britain with a small i ncrease in autumn temperature leading to greatly increased infection r ates.