Influence of nutritional media, pH and temperature on mycelial growth and sporulation of Fusarium udum

Abstract

Effect of different culture media, pH and temperature on mycelial growth and sporulation of three culturally and pathogenically different isolates of Fusarium udum (F,, F, and F,,) was studied. Four liquid media viz, two synthetic media (Czapek's dox and Martin's media) and two semi synthetic media (potato dextrose and pigeonpea seed extract) were used. Mycelial growth and sporulation were studied at eight different temperatures ranging from 10-45°C and seven pH ranging from 5.0-8.0. Dry mycelial weight was maximum on pigeonpea seed extract medium by all the three isolates while in respect of sporulation (both micro and macro conidia production), potato dextrose broth was found the best. Isolate F, produced maximum mycelial growth while isolates F, and F,, produced comparatively less mycelial growth. Temperature range of 25 to 30°C was, in general, most suitable for all the three isolates. These isolates showed reasonable growth at pH regimes ranging from 5.0-8.0, optimum being 7.0-8.0. No differential response of the isolates to temperature and pH regime was recorded. It is indicated that slow growing isolates with appressed mycelium are more pathogenic than faster growing isolates with fluffy mycelium.