TRANSMISSION EXPERIMENTS ON THE VIRUS DISEASE DAPPLE APPLE

An alternation of apples, consisting mainly of numerous small vivid green isodiametric spots, has been repeatedly observed in several orchards in Italy. This disease occurs only in the fruit of plants which have been top-grafted. The symptoms are similar to those of the disease called dapple apple.

The reactions of woody indicators to infected plants are reported.

The results of indexing tests demonstrated that, besides the present known latent viruses, an agent causing fruit symptoms in Virginia Crab, similar to those described for the commercial varieties, was also present in all the infected trees. This lead us to the hypothesis that a new virus induced dapple symptoms.