Relationship of sunflower mosaic potyvirus (SMPV) with its aphid vector Aphis craccivora Koch.
Studies conducted on the relationship of sunflower mosaic potyvirus (SMV) with its aphid vector, Aphis craccivora indicated that the pre-acquisition starvation of the aphid vector was essential for the successful transmission of SMV in sunflower. The optimum pre-acquisition starvation period was found to be 90 minutes. The aphids acquired and transmitted the virus in a very short feeding period of 20 and 40 seconds, respectively. The optimum acquisition and inoculation feeding periods were found to be 10-20 and 15 minutes, respectively. Even a single viruliferous aphid was capable of transmitting the virus. However, the maximum transmission was obtained when 15 aphids per plant were employed. The infectivity of the aphid vector was lost when they were given post-acquisition fasting beyond 2 h. In serial transfers of single viruliferous aphids to healthy test plants, it was observed that when the interval of feeding on successive plants was 15 minutes and above, the aphids transmitted the virus to the first plant of the series only.