Grapevine-propagating material from two vineyards and one nursery in Missouri and one
California nursery carry Agrobacterium tumefaciens latently in their vascular systems. A …

Materials and Methods Isolation of the pathogen was carried out using a slightly modified
technique of an earlier described method (LEHOCZKY 1968 a). To prevent the canes and …

Sap from hardwood stem pieces of 5 cultivars and 10 rootstock selections was collected by a
water-displacement procedure and plated on a medium selective for the A. tumefaciens …

Abstract Tumor-free root pieces, 13-16 mm in diameter, of 10-year-old naturally infected
vines cv. Olimpia on their own roots, were investigated. Non-pathogenic A. tumefaciens …

A. tumefaciens biovar 3 and (to a lesser extent) biovar 1 were detected in symptomless 1-yr-
old cane cuttings taken from crown gall-infected vines, thus indicating their systemic nature …

Higher populations of biovar 3 of A. tumefaciens and A. radiobacter were isolated from roots
of grapevines with crown gall than from roots of noninfected vines or from nonrhizosphere …

Agrobacterium tumefaciens was isolated from the bleeding sap of the xylem of chronically
infected vines cut at 15 and 80 cm. from the base of the cane. Tumours were produced …

Crown gall is the most important bacterial disease of grapevine and is primarily associated
with Agrobacterium tumefaciens biovar 3. The systemic distribution of the agrobacteria in …

RESULTS Isolations from sap. Although Agrobacterium spp. were recovered from sap on all
three media used, more strains were Isolations from galls. AT 3 was isolated from grapevine …

Ultrastructural observations of Agrobacterium tumefaciens during pathogenesis indicated
that the bacteria became pleomorphic and formed inclusions that migrated to polar positions …