Fusarium culmorum

Fusarium culmorum is the causal agent of seedling blight, foot rot, ear blight, stalk rot, and other diseases of cereals, grasses, and a wide variety of monocots and dicots.

Identification
Growth on PDA

Colonies grow rapidly. Aerial mycelium is whitish to yellow, tan or pale orange, but become brown to dark brown to red-brown with age. Under alternating conditions of light and temperature, rings of spore masses may be formed by some isolates.

Microconidia
 * Absent

Macroconidia Chlamydospores
 * Abundance: Usually abundant.
 * Sporodochia: Orange to bronw color and relatively common
 * Morphology: Thick and bluntly pointed at their apex. Conspicuously wider above the center of the spore. The dorsal side is somewhat curved, but the ventral side is almost straight. Distinguishing character from F. sambucinum is the broader macroconidia.
 * Size: Range from 4 to 7 μm wide and from 25 to 50 μm long.	Number of septa: Usually 3- or 5-septate
 * Development: Develop singly from phialides (5 x 15-20 μm). They are loose at first and are later aligned in sporodochia.
 * Abundance/Speed of formation: Usually abundant and form relatively quickly, requiring 3-5 weeks on CLA.
 * Location: In hyphae and macroconidia. Those found in the macroconidia persist longer than those found in the hyphae under field conditions.
 * Morphology: Thick-walled, globose.
 * Appearance: Found singly, in clumps or chains.
 * Size: 9-14 μ m in diameter.