Fusarium oxysporum f. sp. nicotianae

W.C. Snyder & H.N. Hansen
 
Fusarium wilt

Studies have been conducted in the USA to determine the variability of strains of Fusarium oxysporum infecting tobacco. It was found that the pathogenicity of the strains is very diverse. Some strains of this species would attack sweet potato (Fusarium oxysporum f. sp. batatas), while others would attack cotton (Fusarium oxysporum  f. sp. vasinfectum), (Snyder and Hansen, 1940). In addition, strains were not always pathogenic to different types of tobacco. Some authors have proposed four different races of  Fusarium oxysporum  f. sp. nicotianae

This soilborne pathogen is present in many tobacco-producing countries. It causes severe losses in warmer areas of the world. In Africa, the disease  is particularly severe in Malawi and to a lesser extent in Zimbabwe and South Africa. It seems to be present in all countries of the American continent. It is also widespread in Asia and Oceania.

Its' occurrence is more limited in Europe where it causes losses in Spain, but it has never been observed in France.

U.S. situation

Fusarium wilt, although not destructive, occurs in certain areas. It occurs in southeast U.S. most frequently in fields where sweet potatoes were planted the previous season.

(Mina Mila - North Carolina State University)