Trichoderma Harzianum as Biocontrol Agent and Molecular Characterisation of Papaya ringspot virus(PRSV) on Cucumeropsis manniiin Calabar, Cross River State, Nigeria

Cucumeropsis manniiis a herbaceous, perennial climbing vegetable crop in West Africa and parts of Central Africa belonging to the cucurbitacaefamily 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 harzianumas biocontrol agent against Papaya ringspot viruson C. manniiafter characterising the virus from infected leave samples of C. manniiusing RT-PCR and gene sequence analysis. The fungus Trichoderma harzianum was applied on the first set of polybagcontaining 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. manniiin Nigeria. The result further showed that plants inoculated with a combinationTrichoderma harzianumand 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 harzianumis very effective against virus pathogens.