Identification of new hosts for Ralstonia solanacearum (Smith) race 2 from Colombia

Abstract

Ralstonia solanacearum Smith induces the Moko disease on banana, plantain and heliconia
flowers. The objectives of this work were: I) to identify R. solanacearum hosts in weeds or cultivated hosts
and II) to determine its pathogenicity on the susceptible host plantain cv. Dominico-Hartón. A survey in search
of natural hosts of R. solanacearum race 2 was performed in selected Colombian regions. Sixty bacterial
colonies showing R. solanacearum characteristics in a semi-selective medium were used in further pathogenicity
tests in the susceptible plantain plants. Twenty six isolates induced Moko disease symptoms in plantain during
the 60 days of evaluation. Twelve new hosts were found for R. solanacearum at the worldwide level: nine of
them were weeds (Euphorbia graminea Jacq., Blechum piramidatum Lam., Oxalis latifolia Kunth, Cuphea
micrantha Kunth, Eleusine indica L., Gliricidia sepium Kunth ex Steud., Lobelalia xalapensis Kunth,
Stachys lamioides Benth., Salvia aff. lasiocephala Hook. & Arn.) and three cultivated crops (Colocasia
esculenta L., Cucurbita maxima Duchesne and Psidium guajava L.). The presence of R. solanacearum
race 2 in weeds and cultivated crops should be managed as an important component of an integrated Moko
disease control program.