Biochemical and physiological characterisation of Erwinia species causing tip-over disease of banana

Abstract

Tip-over disease has become a serious threat to banana plantations in the past decade. The disease is reported to be caused by Erwinia carotovorasubsp. carotovora and Erwinia chrysanthemi. We compared nine Erwinia strains of diseased banana plants from different agroclimatic zones of Karnataka and Andhra Pradesh, Southern India by conventional means. On the basis of morphological, cultural, physiological and biochemical characteristics and pathogenicity tests, the seven isolates I₁ to I₆ and I₈ showed similarities to Erwinia carotovorasubsp. carotovora. Isolate I₉ from Andhra Pradesh expressed characteristics similar to that of Erwinia chrysanthemi and was identified as Erwinia chrysanthemi. The isolate I₇ which showed wider variation, neither confirmed to the characteristics of Erwinia carotovorasubsp. carotovora nor with that of Erwinia chrysanthemi, and possessed characteristics in between the two species. Further we studied the host range of the bacterium causing tip-over disease of banana.

Keywords:

• tip-over disease
• pathogenicity
• biochemical characterisation
• host range