SUMMARY

A survey of potato leaf roll disease conducted in ma-jor potato growing regions of Kenya (Meru, Kiambu, Nyamira and Kisii districts) revealed the highest inci-dence in Kisima location, Timau division of Meru dis-trict and an absence of PLRV in leaf-rolled samples from Githongo location of the same district. The lowest incidence was recorded in Kisii district. The virus was detected in the phloem tissues of potato sprouts and leaves by tissue blot immunoassay (TBIA). The method was found to be simple, rapid and sensitive in detecting PLRV in infected potato plants. In Myzus persicae Sulz., the Acquisition Access Period (AAP), Inoculation Ac-cess Period (IAP) and the Latent Period of PLRV, iso-lated from potato variety ‘Pimpernel ’ collected from Tigoni location, Kiambu district, were typical of PLRV. It is suggested that virus control in potato in Kenya can be made more effective by planting virus-free seed-tu-bers and by early treatment with insecticides. Addition-ally, volunteer plants and alternative hosts should be rogued and destroyed because they serve as sources of virus for subsequent infections. Key words: potato, PLRV, tissue blot immunoassay, aphid transmission, control