New correlations between aphid stylet paths and nonpersistent virus transmission

The electrical penetration graph technique was used to study probing behavior of the aphid Myzus persicae (Sulzer) during the transmission of potato virus Y (PVY) to pepper plants. Single aphids allowed a 5-min access to infected plants achieved 51.3% transmission efficiency. Aphids acquiring the virus probed the plant more frequently but these probes were shorter than the ones produced by the aphids that were unable to acquire PVY. Moreover, aphids that transmitted PVY produced more intracellular punctures (as measured by potential drops), but their mean duration did not differ significantly from that of the aphids unable to transmit the virus. The mean duration of none of the potential drop subphases could be associated with PVY transmission. Two of the 18 behavioral variables analyzed proved critical for virus acquisition according to a stepwise logistic regression model. The 1st variable was the total number (observed during the entire 5-min register) of typical pulses recorded during subphase II3 of the potential drops (positive correlation). Subphase II3 is the last true intracellular distinct phase of a potential drop. The 2nd variable was the time elapsed from the last potential drop to the end of the probe (negative correlation). The implication of these results an the transmission mechanisms of nonpersistently transmitted viruses is discussed.