TRANSMISSION OF SPANISH PEPPER-PVY AND POTATO-PVY ISOLATES BY APHID (HOMOPTERA, APHIDIDAE) VECTORS - EPIDEMIOLOGIC IMPLICATIONS

Transmission of Potato Virus Y (PVY) by several aphid vectors was stud ied under laboratory and greenhouse conditions to determine vector pro pensity on sweet pepper (Capsicum annum L.) plants. Laboratory experim ents were conducted with three PVY strains: pepper-PVY pathotype phi ( PVY(phi)) and potato-PVY (ordinary strain, PVY(o), and necrotic-type s train, PVY(N)). Pepper ('Yolo Wonder'), tobacco (Nicotiana tabacum L., xhanthi nc'), and potato (Solanum tuberosum L., 'Bintje') were used a s virus sources or test plants, or both. Results showed that both pepp er-PVY and potato-PVY strains were transmissible by Myzus persicae Sul zer to pepper plants, although potato-PVY(o) and -PVY(N) are less effi ciently transmitted than PVY(phi). Transmission tests between differen t species of aphids using PVY(phi)-infected pepper and tobacco as sour ce plants indicated that M. persicae was the most efficient vector, fo llowed by Aphis gossypii Glover and Acyrthosiphon pisum Harris. Aphis fabae Scopoli also was capable of transmitting PVY(phi), but with much less efficiency. Greenhouse experiments designed to evaluate the disp ersion (secondary spread) of PVY by alatae aphids indicated that M. pe rsicae transmitted the virus at the highest rate. Aphis fabae and Aphi s gossypii also were able to spread PVY efficiently under test conditi ons. Previous works indicated that non-colonizer species, principally in the genus Aphis, have much higher alate activity in open field cond itions (higher landing rate) than M. persicae. Therefore, much of the natural spread of virus may be by species that are not commonly found feeding on pepper crops.