Fusarium Dry rot or Wilt

Fusarium spp.

•  Causal agents and transmission

Dry rots of tubers are caused by fungi of the genus Fusarium in particular Fusarium sambucinum = F. sulphureum and Fusarium solani var. cœruleum.

Occasionally this disease may be observed at the time of harvesting, although it usually appears during storage and eventually damages the entire tuber.

Infectious soil and tubers can be both the source of inoculum and the means of propagation.

These fungi, in their resting forms (chlamydospores), can also survive in storage areas and on equipment.

Fungi of the genus Fusarium especially F. solani, can multiply and live in the soil which is a primary inoculum source for this species of Fusarium. 

• Fusarium wilt

Other species of Fusarium present in the soil, e.g. F. oxysporum, can cause in dry conditions tuber rot in the soil and poor emergence but also later leaf dehydration and plant wilting due to the production of fungal toxins which are transported in the vascular system. Such disease is enhanced by short rotations and hot climates.

• Significance

Fusarium dry rot and wilt are present worldwide and their economic impact increases once potato production becomes mechanised and relies on machinery for harvesting, handling and grading.

For seed potato production, this fungi group may be a serious cause of quality degradation.