Fusarium head blight in western Canada - Cultural characteristics

Cultural characteristics of the causal agents of Fusarium head blight in western Canada

Incubation conditions

Wheat seeds were surface disinfested by soaking in a 0.3% NaOCl solution for 1 minute. They were then dried in a laminar flow cabinet, placed onto cooled potato dextrose agar (Difco, Detroit MI) and incubated for 5 days under a cycle of 12 hours darkness at 20°C and 12 hours of mixed UV and fluorescent light at 25°C.

1. F. graminearum growing on wheat seed, above view in petri dish 2. F. graminearum growing on wheat seed, below view in petri dish
Plates 1 and 2. Fusarium graminearum
Fusarium graminearum growing from wheat seed as seen from above (left) and below (right).

2. Close-up of F. graminearum growing on a wheat seed
Plate 3. Close-up of Fusarium graminearum.
Typically red mycelia, sometimes with yellow tint. Sporodochia not always well developed, and predominantly or exclusively red.

4. F. culmorum growing on wheat seed, above view in petri dish 5. F. culmorum growing on wheat seed, below view in petri dish
Plates 4 and 5. Fusarium culmorum.

6. Close-up of F. culmorum growing on a wheat seed
Plate 6. Close-up of Fusarium culmorum.
Loose mycelium with abundant orange and red sporodochia. Fast growing.

7. F. avenaceum growing on wheat seed, above view in petri dish 8. F. avenaceum growing on wheat seed, below view in petri dish
Plates 7 and 8. Fusarium avenaceum.

9. Close-up of F. avenaceum growing on a wheat seed
Plate 9. Close-up of Fusarium avenaceum.
Dense white mycelium gives the culture the appearance of a cotton ball. From below it often has white border around the colony.

10. F. graminearum and F. culmorum growing on wheat seed
Plate 10.
One Fusarium graminearum and three Fusarium culmorum together on the same plate.

11. F. graminearum, F. culmorum, F. avenaceum growing on wheat seed (above) 12. F. graminearum, F. culmorum, F. avenaceum growing on wheat seed (below)
Plates 11 and 12.
Five Fusarium graminearum, one Fusarium culmorum (with multicoloured sporodochia), one Fusarium avenaceum (cotton ball appearance), and one Septoria nodorum on the same plate as seen from above and below. Septoria nodorum produces a small culture with ropy mycelium and a yellowish-orange undersurface.

13. F. graminearum, F. avenaceum, S. nodorum growing on wheat seed (above) 14. F. graminearum, F. avenaceum, S. nodorum growing on wheat seed (below)
Plates 13 and 14.
Three Fusarium graminearum, three Fusarium avenaceum, and one Septoria nodorum on the same plate as seen from above (left) and below (right).

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