Asian Journal of Research in Botany

Cucumeropsis mannii is a herbaceous, perennial climbing vegetable crop in West Africa and parts of Central Africa belonging to the cucurbitacae family cultivated for it fruits and seeds. It is reported to play significant role in medicine and nutrition. Mosaic symptoms were observed on this crop during the 2021 planting season. The aim of this study was to investigate the use of Trichoderma harzianum as biocontrol agent against Papaya ringspot virus on C. mannii after characterising the virus from infected leave samples of C. mannii using RT-PCR and gene sequence analysis. The fungus Trichoderma harzianum was applied on the first set of polybag containing C. mannii followed by mechanical inoculation of the virus on leaves. Mechanical inoculation of virus was further carried out on the leaves of the second polybag containing C. mannii.   Result obtained from Gene sequence analysis revealed 91 % nucleotide sequence identity with Papaya ringspot virus. This is the first report of PRSV infecting C. mannii in Nigeria. The result further showed that plants inoculated with a combination Trichoderma harzianum and virus inocula showed no symptoms while plants inoculated with virus inocula only revealed symptoms of rugosity and mottling. This results is a confirmation that Trichoderma harzianum is very effective against virus pathogens.