This is the fist report on detailed aphid transnsmission studies of cruciferous virus in Korea, and experiments aimed to get basic informations for control of vectors. Aphid transmission of turnip mosaic virus prevalent on radish in the field was studied. Results obtained were as follows: 1. Myzus persicae, Lipaphis erysimi, Aphis gossypii and Aphis craccivora were found to transmit turnip mosaic virus. 2. The proper time for turnip mosaic virus transmission by Myzus persicae was 1 hour of fasting, 3 minutes for acquisition, and 1 minute for inoculation: Lipaphis erysimi was 2 hours for fasting, 5 minutes for acquisition, and 3 miuutes for inoculation: while Aphis gossypii needed 1hour for fasting, and 3 minutes for each of the acquisition and inoculation periods. 3. There was Po great difference in probing patterns between nonfasted and fasted aphids for 2 hours. All the fasted aphids began feeding after 4 minutes, 4. When Myzus persicae were transferred artificially at 1-2 minute intervals, the number of probes with aphids fasted for 2 hours was much greater than that of nonfasted aphids. Aphids fasted for 2 hours mainly transmitted the virus before 4 minutes, with an acquisition feeing period of less than 3 minutes