Identification of Fusarium species is often difficult due to the variability between isolates (e.g. in shape and size of conidia and colony colour) and because not all features required are always well developed (e.g. the absence of macroconidia in some isolates after subculture). Note: Sporulation may need to be induced in some isolates and a good slide culture is essential. The important characters used in the identification of Fusarium species are as follows.
1. Colony growth diameters on potato dextrose agar and/or potato sucrose agar after incubation in the dark for four days at 25C.
2. Culture pigmentation on potato dextrose agar and/or potato sucrose agar after incubation for 10-14 days with daily exposure to light.
3. Microscopic morphology including shape of the macroconidia; presence or absence of microconidia; shape and mode of formation of microconidia; nature of the conidiogenous cell bearing microconidia; and presence or absence of chlamydospores.