1970 Volume 36 Issue 4 Pages 266-274
A virus diseaase of soybeans, characterized by a rugosity of leaves and a dwarfing of plants, has been found in Hokkaido District since about 1952. The disease causes a severe damage to soybean crops. This virus, designated as soybean dwarf virus (SDV), was transmitted by the aphid, Aulacorthum solani (Kaltenbach), but not by sap inoculation nor through seeds. Of 43 species of plants in 10 families, which were inoculated by the aphids, 13 leguminous species were found to be infected with the virus. All soybean varieties tested were susceptible, though they differed in their symptom expression. The aphid was able to acquire the virus by feeding on infected soybean plants for 30-60min, and viruliferous aphids reared on source plants could transmit the virus to healthy soybean seedlings during a period of 10-30min. The longer the periods of acquisition and inoculation feedings, the higher was the transmission rate. The minimum latent period in the aphid vector was between 15 and 27hr. In serial transmission tests, the aphids retained their infectivity through molting and for periods of up to 21 days, but most of them lost infectivity in the later transfers. Although the transmission pattern of SDV is quite similar to that of other circulative aphid-borne viruses, SDV differs from any previously described virus on the basis of host range, symptoms, and vector species.