Impact of Feeding Time on PVYN and PVYNTN Transmission by Myzus Persicae (SULZ.)

In potato seed production, virus diseases especially Potato virus Y (PVY) are of great economic importance.This virus is transmitted by many aphid species in a non-persistent manner, while Myzus persicae (Sulz.) is its most important vector.The first aim of our research was to find out the dependence of the aphid feeding time, both in terms of acquisition feeding time and inoculation feeding time on PVY N W and PVY NTN transmission.The second aim was to compare the retention of both strains of the virus in the body of M. persicae.The research was carried out in a laboratory and in a glasshouse.It was found out that the dependence between feeding time and the effectiveness of PVY N W and PVY NTN transmission was similar.Along with the prolonging of the acquisition feeding time from up to 7 s, the effectiveness of the initial transmission of both strains increased.After transmission effectiveness reached the optimum, transmission clearly decreased, but within the extent of the applied feeding time (7 and 30 s; 2, 8, 32 and 60 min) it did not lower down to zero.The highest infection of test plants Physalis floriana Rydb.by both strains was recorded during a 2-minute-long feeding of aphids.The percentage of infected plants amounted to 50% with PVY NTN transmission, and 30% with PVY N W transmission.However, the prolonging the inoculation feeding time of aphids also initially increased the transmission effectiveness of both virus strains.Having reached the optimum, which took place as a result of a 30-second-long feeding (PVY NTN ) and a 30-second to 2-minutelong feeding (PVY N W), the share of plants infested by these strains was 30% and 15%, respectively.Continuous prolonging of the feeding time caused a slow decrease in the effectiveness of transmission.During a 60-minute-long feeding, the share of infested plants was 15% (PVY NTN ) and 10% (PVY N ).The retention of PVY N W and PVY NTN in aphids which were starved following the acquisition of the virus was similar and lasted less than 2 hours.However, in relation to aphids feeding after the acquisition of the virus, the retention of PVY NTN was much shorter (aphids could effectively transfer the virus as far as the 4th plant out of 10 consecutively inoculated) than that of PVY N W (in which the 7th plant was also infected).In total, PVY NTN was more effectively transmitted than PVY N W.