Tests conducted under greenhouse conditions at C.N.I. "Tibaitatá", showed that the potato varieties Picacho and Guantiva have resistance of the type antibiosis to the aphid Myzus persicae (an important vector of viruses PVY and PLRV); the variety Pastusa is susceptible and the varieties Capiro, Monserrate and San Jorge present an intermediate reaction.
"True migrants" alate forms of M. persicae perform short and frequent feeding probes on the resistant variety and as a consequence, the stylet-borne virus PVY spreads more rapidly on this type of variety. On the other hand, the persistant virus PLRV spreads more rapidly on the susceptible variety on which the aphid performed long enough feeding probes to transmit this virus.
In addition to the population growth rate of M. persicae colonies, it was found that the production of winged forms (date, proportion present at population peak, total formed), the probing behavior of winged forms and the degree of restlessness of the colonies, help defining the presence of potato resistance to this aphid.
