Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

First report of root rot of cocoyam caused by Pythium myriotylum in Sri Lanka.

Abstract

During September 1999, commercially grown cocoyam (cv. Ratu-kiri-ala) in Gampaha, Sri Lanka suffered from severe root rot. Initial symptoms were water-soaked lesions at the root tips that gradually enlarged to rot the entire root system and tuber. Wilting and yellowing of leaves were observed in advanced stages of the disease. A Pythium sp. was regularly isolated from the affected roots and an isolate, SC5, was identified as P. myriotylum based on the morphology and the internal transcribed spacer rDNA sequence. Upon conducting pathogenicity tests, P. myriotylum was reisolated from the diseased tissues and found to be morphologically identical to the original isolate SC5. This is thought to be the first report of P. myriotylum causing root rot of cocoyam in Sri Lanka.