Transmission of Plant Viruses by Insects

Abstract

Insects, as a general rule, play an essential part in the survival of the viruses that cause plant disease. It is true that a virus will pass from scion to stock, or the reverse, across a graft in those species of plants where organic union is possible. I t is also true that by vegetative reproduction of a diseased plant the virus is perpetuated in its progeny. But every living plant owes its origin ultimately to sexual reproduction; and the real problem, from a theoretical and a practical point of view, is how a virus can become established in a sexually produced plant.