Occurrence of <i>Cucumber mosaic virus</i> (CMV) in vegetable crops in home gardens in southern Nigeria

Abstract

Vegetable crops in home gardens in eight states in Southern Nigeria were sampled in 1998, 1999 and 2004 to determine the occurrence of Cucumber mosaic virus (CMV). Leaf tissues of vegetable crops from 57 farms were indexed for CMV using dot blot immunoassay and enzyme-linked immunosorbent assay. In all, crop plants belonging to plant families Solanaceae, Lamiaceae, Dioscoreaceae, Cucurbitaceae, Leguminosae, Malvaceae and Asteriaceae were observed in the gardens. CMV was detected from four plants families namely Solanaceae, Lamiaceae, Dioscoreaceae, Cucurbitaceae. Of the 83 leaf samples collected, 51.8% were Capsicum sp, Dioscorea alata (20.5%), Solanum sp (9.6%), V. unguiculata (6.0%), Ipomea sp. and Occimum sp., 3.6% each and Telfairia occidentals, Cucumis melo, Albermuscus esculentus and Verononia amygdalina 1. 2% each respectively. C. annuum crops (43) were most frequently encountered with 81.4% CMV infection followed by D. alata (17) with 23.5% virus incidence. Other crops were Solanum sp (75.0%) and Cucumis melo (100.0%) and Occimum gratissimum 50.0% virus incidences respectively. However, the later crops accounted only for between 1.2 and 9.6% of the total crop plants. In screen house transmission experiments groups of 10 aphids each were able to transmit the virus to give at least 40% of the Vigna unguiculata test plants used. CMV occurred in vegetable crops in home gardens and the probability for spread within a mixed cropping system is high especially as CMV is transmissible by many aphid species.