Characterisation of a Carlavirus of French Bean

Abstract

The carlavirus Cowpea mild mottle virus (CPMMV), has caused economic losses in Queensland’s $70 million green bean industry. The virus is efficiently spread from plant to plant by the silverleaf whitefly (SLW), with early inoculation time found to have a very significant effect on pod yield and quality. Symptoms include mottled leaves, discolouration and deformed pods. The disease has been most severe in autumn crops that are several weeks from harvest. Surveys in the Fassifern valley have indicated that bean crops grown during other windows over the spring-summer season are less likely to be affected by CPMMV. In addition to French bean, the virus has been found in soybean, mung bean, cowpea, Siratro and Glycine. Tests for seed transmission were negative. Project VG15073 has provided the bean industry with the essential information to implement management tools specifically targeting CPMMV. Strategic insecticide applications as whitefly populations are detected, release of biological control agents which attack whitefly, and selection of tolerant bean varieties are all expected to minimise losses from this virus.