Aims: Piper nigrum L. (black pepper) is an economically important commodity plant in Malaysia, which generated RM 200.95 million from pepper export in the year of 2018. However, the increase in pepper production is restricted by diseases. Fusarium wilt is one of the major diseases of P. nigrum L. The objectives for this study were to isolate Fusarium spp. associated with Fusarium wilt of P. nigrum L. from selected pepper farms in the northwestern region of Sarawak and to characterize the Fusarium spp. isolated morphologically and molecularly. Methodology and results: Fusarium spp. were isolated from diseased root samples. The pathogen was grown on potato dextrose agar (PDA) under dark condition at circa (ca.) 25 °C for morphological characterisation. Molecular characterisation was done by using internal transcribed spacer (ITS). Phylogenetic tree was constructed to study the genetic relationship of the isolates. Fusarium solani, F. oxysporum, F. proliferatum were the three Fusarium species identified. There were variations in morphological characters observed between and among the species, including the colony form, margin, elevation, surface appearance and pigmentation. No distinctive morphological characteristic was specific to a location. In addition, growth rate, macroconidia sporulation rate, and microconidia sporulation rate of the isolates were not correlated. In molecular phylogeny, the three Fusarium species were separated into three distinct clades representing the three identified species. The genetic relatedness between isolates within each species was depicted in the tree. Conclusion, significance and impact of study Variations were observed among isolates in this study based on morphological and molecular characterization. This study would contribute information on the variations of Fusarium spp. associated with Fusarium wilt of P. nigrum L. from the northwestern region of Sarawak.
Fusarium ; Fusariosis ; Piper nigrum

Aims: Plant diseases caused by pathogens are threatening crop yield. Agrochemicals are used extensively to curb pathogens. Efforts to reduce the usage of agrochemicals are needed for sustainable agriculture. This study was aimed to screen medicinal plants possessing antifungal properties against crop pathogenic fungi. Methodology and results: Sequential extraction using absolute n-hexane, ethyl acetate and methanol was performed on nine selected medicinal plants to obtain crude extract. An antifungal assay using these crude extracts was performed on Fusarium solani, Collectotrichum musae and two isolates of Pyricularia oryzae. The assay showed that medicinal plant species with all three types of crude extract inhibited the growth of all three pathogenic fungal species tested. The inhibitory effects of crude extracts were not only fungal species dependent but also isolate dependent. Conclusion, significance and impact of study Antifungal effect of nine selected medicinal plant species was observed against the three tested fungal pathogens. These research findings suggest that the selected medicinal plant species may serve as a potential source for the development of new biofungicide products.
Plants, Medicinal