EFFECTS OF DEPTH OF STYLET PENETRATION ON APHID TRANSMISSION OF POTATO VIRUS Y

Abstract

The aphid Myzus persicae (Sulz.) most often became infective with potato virus Y on inserting the stylets only superficially into infected tobacco plants after a period without food; the further the stylets penetrated into the plant, the less likely the aphid was to be infective. When epidermis was removed from infected plants, aphids acquired virus Y as readily from the exposed mesophyll as from the piece of removed epidermis. M. persicae can feed by inserting its stylets through a membrane and into tobacco plants. But aphids rarely became infective with virus Y when they inserted their stylets through a membrane and into infected plants; and infective aphids rarely transmitted the virus when they inserted their stylets through a membrane into susceptible plants. Yet infective aphids that penetrated a membrane could afterwards infect a plant not covered with a membrane. Also, aphids did not become infective when they penetrated the deeper tissues of infected plants that had had the virus in the superficial tissues inactivated by ultraviolet radiations. The main conclusion is that M. persicae rarely becomes infective with virus Y or transmits it after the stylets penetrate beyond the first layer of plant cells.