The Occurrence of Agrobacterium tumefaciens in Grapevine-Propagating Material and a Simplified Indexing System

Abstract

Grapevine-propagating material from two vineyards and one nursery in Missouri and one California nursery carry Agrobacterium tumefaciens latently in their vascular systems. A rapid yet simple procedure for detection of A. tumefaciens in grapevine-propagating material was developed. The process depends upon displacement of vascular fluids by sterile water in a low-pressure chamber. Expelled fluid is placed on a selective medium that readily permits discrimination of the pathogen from contaminants. Plants examined three times without revealing the presence of any bacteria in their xylem fluids are regarded as free of pathogen.