Abstract
Mycoplasmalike organisms (MLOs) transmitted by the leafhopper vector, Macrosteles orientalis Virbaste, were compared in host range and symptoms in test plants. Twelve MLO diseases from Japan, including Japanese honewort witches' broom, lettuce yellows, sickle hare's ear yellows, garland chrysanthemum witches' broom, water dropwort yellows, strawberry witches' broom, onion yellows, and carrot yellows were considered to be caused by the agents closely related each other. From the result of inoculation test with M. orientalis to the test plants including 20 species in 11 families, these MLO isolates were classified into three strains. Strain I infected Lactuca sativa, Callistephus chinensis, Chrysanthemum coronarium, Daucus carota, Apium graveolens, Spinacia oleracea, Allium cepa and others. Strain II infected Brassica rapa, Pisum sativum, Solanum melongena, Nicotiana glutinosa, and others, including the host plants of strain I. Strain III infected Lycopersion esculentum in addition to the host plants of strain II. Strain II and III did not infect Geranium nepalense which was a host plant of strain I.
