Influence of Cultural Media, Temperature and pH on the Growth Characteristics of Fusarium oxysporum f. sp. dianthi Isolated from Carnation

Fusarium is a large genus of filamentous, soil-dwelling ascomycetous fungi. While most species are harmless saprobes and commonly found in soil, some cause diseases in a variety of crops, including cereals, pulses, fruits, ornamentals, and vegetables. The fungi block the vascular bundles in plants, hindering water flow, which results in wilting and drying. Specifically, Fusarium oxysporum f. sp. dianthi causes wilting and plant death in carnations. Fusarium wilt symptoms include yellowing and stunted growth in older plants, initially affecting one side, which eventually leads to the wilting of the entire plant. The xylem tissue dries up and turns brown, causing the plant to die. The present investigation was conducted at the Department of Plant Pathology, VCSG UUHF, Bharsar, Pauri Garhwal, Uttarakhand to assess the influence of various culture media, temperature regimes, and pH levels on the growth of Fusarium oxysporum f. sp. dianthi. Maximum mycelial growth of the pathogen (89.59 mm) was observed on Potato Dextrose Agar (PDA) medium after seven days of incubation. Among the temperature treatments, 30 °C supported the highest mycelial growth (79.10 mm), while pH 6.0 favoured optimum growth (69.90 mm) under in-vitro conditions.