The occurrence of Peanut Mottle virus in Queensland

Abstract

A disease causing a mottle in the leaves of peanuts (Arachis hypogaea L.) in the Mingaroy district of Queensland has been shown to be caused by a virus which appears to be indistinguishable from peanut mottle virus. This virus has not previously been reported in Australia. The virus was sap-transmissible to a range of plants, all but one of which were in the Leguminosae, but the only hosts in the field were peanut and garden pea (Pisum sativum L.). It was shown to be transmitted in a stylet-borne manner by five aphid species including Aphis craccirora Koch, which is the most common species found infesting peanuts. The virus was also seed-transmitted and probably spread to Australia in infected seed. The virus had a thermal inactivation point between 55 and 60¦C and a dilution end-point between 10-3 and 10-4, and infectivity was lost within 48 hr of storage at 25¦C. Partially purified virus preparations were obtained by clarification of sap by freezing and thawing and :he addition of activated charcoal followed by differential centrifugation An antiserum with an homologous> title of 1 : 64 was prepared but no serological relationships could be demonstrated between this virus and common bean mosaic or bean yellow mosaic viruses Flexuous rod-shaped particles with a normal length of 704 nm were seen in electron micrographs of virus preparations.