SOME EFFECTS OF FORMALDEHYDE ON POTATO VIRUS Y IN VITRO, AND ABILITY OF APHIDS TO TRANSMIT THE VIRUS WHEN THEIR STYLETS ARE TREATED WITH FORMALDEHYDE

Abstract

Potato virus Y (PVY) was made noninfective by incubation with formaldehyde in vitro. Yet this noninfective virus reacted with PVY antiserum and caused antibodies to be produced in rabbits as readily as infective PVY. A method is described for baring the stylets of living aphids beyond the end of the labium, which normally encloses the stylets. Specimens of Myzus persicae (Sulz.) infective with PVY were made noninfective by treating the stylets for 30 sec. with concentrations of formaldehyde as low as 0.03%; and 0.25% formaldehyde caused the same effect in five seconds. Aphids were also made noninfective when the proboscis with the tip of the stylets bared was treated with formaldehyde, even after the stylets had been inserted a considerable distance into infected tobacco plants. By contrast, aphids usually remained infective when the proboscis with the stylets enclosed in the labium was treated with similar concentrations of formaldehyde. However, formaldehyde treatment of the stylets did not affect the ability of aphids immediately thereafter to acquire and transmit PVY. These results are compatible with the hypothesis that viruses transmitted like PVY are carried by the stylets of their aphid vectors.