Host range study of turmeric rhizome rot pathogen Pythium aphanidermatum on selected Zingiberaceae members

Abstract

Pythium aphanidermatum (Edson) Fitzp. belonging to Oomycetes is a well known devastating pathogen of many vegetables, fruits, grasses and ornamental crops in several parts of the world with a wide host range. It is also known to cause rhizome rot disease in turmeric. Disease management approaches like intercropping may not become a failure against pathogens with wide host range. The host range of P. aphanidermatum pathogenic to turmeric was studied on five members of Zingiberaceae viz., Curcuma zeodaria, C. amada, C. aromatica, C. cassie and Zingiber officinale which are crop rotated with turmeric in different turmeric growing tracts of Palakkad and Wayanad districts of Kerala. Among the crops tested, C. amada and C. cassie showed no symptoms till the end of the season by the most virulent isolate of P. aphanidermatum pathogenic to turmeric. C. zeodaria and Z. officinale were found to be more susceptible and showed symptoms within 7 days after inoculation. Cultivation of these two crops immediately after C. longa or vice versa may lead to crop loss in the upcoming season due to the survival of the pathogen in soil and its wide host range. Thus this information will be useful to take up the disease management with a non host crop.