EUROPEAN COMMISSION Directorate-General for Research COST Action 830 Microbial inoculants for agriculture and environment COST 830 Working Group 4 IBMA Quality and Standards Working Group Proceedings of the joint meeting held in Seville (Spain) 25 to 28 October 2001 Edited by Quirico Migheli Dipartimento di Protezione delle Piante, Università di Sassari, Italy José Enrique Ruiz Sainz Departamento de Microbiologia, Universidad de Sevilla, Spain 2003 EUR 20444 EN Quality control and efficacy assessment of microbial inoculants: need for standard evaluation protocols