Identification of Weed Hosts of Cucumber Mosaic Virus in Maize Farms in Nasarawa State, North Central Nigeria

Cucumber Mosaic Virus (CMV), one of the most host-diverse plant viruses, is a persistent constraint across multiple vegetable and food crop production systems. In Nasarawa State, maize-growing communities have increasingly reported mosaic symptoms consistent with CMV infection in non-cucurbit crops, raising questions about the role of weeds as local virus reservoirs. This study was designed to identify weeds on or adjacent to maize farms in Nasarawa State that serve as hosts for CMV and to assess their potential as bridge hosts maintaining viruliferous aphid populations. Field surveys were conducted in 40 maize farms across four local government areas, with weed species inventoried systematically alongside disease symptom recording. Weed samples from species exhibiting mosaic, mottle, or chlorotic symptoms were tested using enzyme-linked immunosorbent assay and reverse transcription polymerase chain reaction. CMV was confirmed in ten weed species including Tridax procumbens, Commelina benghalensis, Euphorbia heterophylla, and Bidens pilosa. The highest CMV loads were detected in T. procumbens and C. benghalensis, both of which were abundant in surveyed farm borders. Aphis gossypii was the predominant aphid vector identified on infected weed hosts. The study recommends targeted weed management in buffer zones around maize farms as an integrated strategy for reducing CMV inoculum pressure. Keywords: Cucumber Mosaic Virus, weed hosts, maize, aphid vector, Nasarawa State.