Latent Period Phenomena in Transmission of Sugar Beet Yellow-Net Virus by Green Peach Aphids

Abstract

Using the leaf cage technique in transmission tests of sugar beet yellow-net virus by green peach aphids, Myzus persicae (Sulz.), the following conclusions were reached: (1) A low percentage of the insects (1.1%) acquired virus if the cage was left in contact with a virus source leaf for 1 hour. Maximum acquisition (approximately 25% of the insects proving to be infective) occurred when the cage was left in place for a 48-hour period. (2) When leaf cages, containing two aphids which had been reared on virus source plants, were placed for 1 hour on healthy test plants, approximately 4% were infected, Increasing the test feeding access time increased the probability of transmission up to a maximum of approximately 25% with periods of 24 or 48 hours in duration. (3) Analysis of the results of serial transmission experiments with single aphids allowed a variable acquisition access period and subsequent sequential test feeding access periods each approximately 24 hours in length until death of the insects, lead to the conclusion that there was a measurable latent period averaging 3.5 days in length. In this analysis, the latent period was defined as the average time (in days) in excess of the acquisition threshold period required by the aphids to begin virus transmission.