Transmission Efficiency of Papaya ringspot virus by Three Aphid Species

• Published in: Phytopathology Vol. 98; no. 5; pp. 541 - 546
• Main Authors: Kalleshwaraswamy, C.M, Krishna Kumar, N.K
• Format: Journal Article
• Language: English
• Published: St. Paul, MN American Phytopathological Society 01.05.2008
• Subjects: Animals; Aphididae; Aphids - virology; Aphis craccivora; Aphis gossypii; Biological and medical sciences; Carica papaya; crops; disease transmission; Fundamental and applied biological sciences. Psychology; Geography; host plants; host range; India; insect pests; insect vectors; Insect Vectors - virology; Myzus persicae; Papaya ringspot virus; papayas; Phytopathology. Animal pests. Plant and forest protection; plant pests; Plant viruses and viroids; Potyvirus - isolation & purification; Potyvirus - pathogenicity; vector competence; vectorial capacity; India; Asia; Aphidoidea; Aphis gossypii; Plant pathology; Microbiology; Plant pathogen; Insecta; Transmission; Myzus persicae; Virus; Plant; Pest; Papaya ringspot virus; Homoptera; Efficiency; Arthropoda; Aphididae; Potyvirus; Invertebrata; Vector; Potyviridae
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/PHYTO-98-5-0541

The transmission efficiency of Papaya ringspot virus (PRSV) by three aphid vectors (i.e., Aphis gossypii, A. craccivora, and Myzus persicae) was studied. Efficiency was measured by single-aphid inoculation, group inoculation (using five aphids), duration of virus retention, and the number of plants following a single acquisition access period (AAP) to which the aphids could successfully transmit the virus. Single-aphid inoculation studies indicated that M. persicae (56%) and A. gossypii (53%) were significantly more efficient in transmitting PRSV than A. craccivora (38%). Further, in the former two species, the time required for initiation of the first probe on the inoculation test plant was significantly shorter compared to A. craccivora. PRSV transmission efficiency was 100% in all three species when a group of five aphids were used per plant. There was a perceptible decline in transmission efficiency as the sequestration period increased, although M. persicae successfully transmitted PRSV after 30 min of sequestration. A simple leaf-disk assay technique was employed for evaluating the transmission efficiency of three species of aphids. The results of leaf-disk assays also indicated that A. gossypii (48%) and M. persicae (56%) were more efficient PRSV vectors than A. craccivora. Using leaf-disk assays, the ability of individual aphids to inoculate PRSV serially to a number of plants was studied. Following a single AAP on an infected leaf, M. persicae was more efficient than the other two species with 52.5% transmission after the first inoculation access period (IAP). However, its inoculation efficiency significantly decreased with the second and subsequent IAPs. A. gossypii was able to transmit PRSV sequentially up to four successive leaf disks, but with significantly declining efficiency. Since A. gossypii is reported to be the numerically dominant vector in south India in addition to being a more efficient vector capable of inoculating PRSV to multiple plants, it should be the target vector for control strategies.