'Brotes grandes'(big bud)of potato:a new disease associated with a 16Srl-B subgroup phytopiasma in Bolivia

摘要

Potatoes are the main crop of smallholder farmers in the Valles Cruceflos,Santa Cruz Province,Bolivia.During surveys carried out from 2000 to 2003,a disease locally known as'brotes grandes'(BG,'big bud'),was prevalent on crops in the valleys of Chilon,Saipina,Pulquina and Comarapa,where up to 90% of plants were affected in some fields.Symptoms included tuber-like growths in leaf axils,varying in size and colour from red to purple or black and bearing terminal,adventitious leaves.Tubers often produced hair-like shoots,reducing their quality and yield.