Mycelial Growth and Identification of Pathogenic Fungus Isolated from Basal Rot Disease of Onion and their Biological Control

Abstract

Onions (Allium cepa L.) are a major crop for spices in Bangladesh. The current study was conducted to assess the morphological traits, cultural effects, molecular identification, and environmentally friendly management of the pathogenic fungus isolated from onion basal rot disease. Fusarium verticillioides causes basal rot symptoms in onion at the early and mature stages. Mycelial growth of F. verticillioides was highest on the potato dextrose agar (PDA) medium (72 mm), followed by the potato sucrose agar (PSA) medium, and lowest on the yeast extract agar (YEA) medium (31 mm). F. verticillioides grew and developed mycelially best at 30°C and 6.5 pH, respectively. A blast search revealed 99% sequence match with the F. verticillioides species complex, and the internal transcribed spacer (ITS) region of the PCR products spanned 590 bp. Against the growth and development of F. verticillioides mycelium, Trichoderma harzianum exhibited the highest mycelial growth inhibition (75%), followed by T. erinaceum (64%), and T. asperellum (55%). According to the findings, T. harzianum, an antagonistic fungus, is a highly successful bio-control agent against F. verticillioides.

Plant Tissue Cult. & Biotech. 35(1): 93-104, 2025 (June)