Microscopic observations revealed the uredinospore rust stage. Uredinia were hypophyllous, subepidermal, erumpent, dark yellowish, circular to irregular in shape. Urediniospores were light yellow in colour round to ovate in shape, echinulate and 25-35 µm x 15-20 µm include wall thickness. The pathogen was identified as Puccinia thaliae (HCIO. NO. 44.744). A reference sample has been deposited in the Herbarium of the Indian Agricultural Research Institute, New Delhi.
This is the first record of P. thaliae infecting C. edulis in India. Literature searches show that there are no previous records of this disease from India (Bilgrami et al, 1991; Butler, 1997). Bagyanarayana & Ramesh (1999) reported Puccinia cannacearum, another rust fungus on Canna indica from India. The only previous report of P. thaliae infecting canna is from Hawaii on Canna indica (Gardner & Hodges, 1989).