STUDIES ON THE HOST RANGES OF VIRUSES FROM THEOBROMA CACAO L.

Only plants in the natural order Tiliales were susceptible to experimental infection by viruses found infecting cacao. Of sixty-three species in the Tiliales colonized with infective mealybugs, twenty-eight became infected with the New Juaben virus. The ease with which different species contracted infection and the severity of symptoms varied considerably. The host ranges of seven other viruses were all contained in that of the New Juaben virus. The viruses could be divided into three groups according to their host ranges, and it is suggested that host ranges may prove helpful in attempts to classify cacao viruses. Four species of Corchorus were all rapidly killed by any of the eight viruses.