The determining cause of the formation of the tubers is not certainly known, but Professor Bernard has suggested that it is the presence of a fungus, Fusarium solani, which, growing in the underground shoots, irritates them and causes the swelling; the result is that an efficient method of propagation is secured independently of the seed.
This form of fruit is succeeded by others which have received different names, and lastly by the mature Nectria which forms minute red flask-shaped perithecia on parts of the rotted potatoes that have dried up. The intermediate forms are known as Monosporium, Fusarium and Cephalosporium.
In Europe alone, fusarium head blight destroys a fifth of wheat harvests.
Fusarium rot, which usually causes the corm to disintegrate in the soil or during storage, shows itself as corrugated surface lesions.
The role of saprophytic microflora in the development of fusarium ear blight of winter wheat caused by Fusarium culmorum.