Screening and Identification of Fusarium sp. Associated with Wilt Disease in Shallot Plants (Allium cepa L. var. aggregatum)

Background: Allium cepa L. var. Aggregatum is an important horticultural commodity in Indonesia, particularly in East Java. However, shallot production is affected by Fusarium wilt, locally known as moler disease. Accurate identification of the associated Fusarium is important for supporting appropriate disease management. This study aimed to screen and characterize Fusarium sp. associated with wilt symptoms in shallot plants from Probolinggo and Nganjuk, East Java, through isolation, morphological characterization, and PCR amplification of the internal transcribed spacer (ITS) region. Methodology: Disease incidence was assessed based on symptomatic plants in five raised beds at each location. Three fungal isolates, P1 from Probolinggo and NG2 and NG3 from Nganjuk, were characterized morphologically and subjected to PCR using ITS1 and ITS4 primers. Findings: Disease incidence was 10.88% in Probolinggo and 0.45% in Nganjuk, with Probolinggo showing an approximately 24-fold higher incidence. All three isolates showed white to white-cream cottony colonies, hyaline and septate hyphae, and oval to ellipsoidal microconidia, consistent with Fusarium. PCR amplification produced a single band of approximately 750 bp in all isolates. Contribution: These findings provide baseline information on Fusarium associated with shallot wilt in Probolinggo and Nganjuk and support further sequencing-based identification.