Detection of Phytophthora ramorum in Nurseries and Forest Lands in California in 2004 to 2009.

From December 2004 through May 2009, samples were collected from California nurseries and wild lands to survey for Phytophthora ramorum and comply with federal regulations of nursery stock. Samples were prescreened by an enzyme-linked immunosorbent assay (ELISA) that detects Phytophthora spp. and tested by culture, P.

Incidence of Agrobacterium tumefaciens Biovar 1 in and on 'Paradox' (Juglans hindsii × Juglans regia) Walnut Seed Collected from Commercial Nurseries.

The walnut rootstock 'Paradox' (Juglans hindsii × J. regia) is susceptible to Agrobacterium tumefaciens, which often results in a high incidence of crown gall in nursery or walnut production orchards. Though A.

First Report of Leaf Spot Caused by Phytophthora taxon Pgchlamydo on Evergreen Nursery Stock in California.

As part of the Phytophthora ramorum testing program from 2005 through 2007, a Phytophthora sp. was isolated on PARP-CMA medium (4) at the CDFA lab in Sacramento, CA, from the margin of necrotic spots and tissue suffering from dieback on Arctostaphylos sp. (manzanita), Camellia spp.

Role of Systemic Agrobacterium tumefaciens Populations in Crown Gall Incidence on the Walnut Hybrid Rootstock 'Paradox'.

Greater than 75% of English walnut production in the United States occurs on the walnut rootstock Juglans hindsii × J. regia 'Paradox', which is highly susceptible to infection by Agrobacterium tumefaciens. When seed were germinated and grown in the presence of A.

Cationic Surfactants: Potential Surface Disinfectants to Manage Agrobacterium tumefaciens Biovar 1 Contamination of Grafting Tools.

Nursery production of walnut seedlings is a 2-year process, during which crown gall, caused by Agrobacterium tumefaciens, often develops at grafting wounds. In this study, the spread of crown gall via contaminated tools and the efficacy of several disinfectants against A. tumefaciens were demonstrated.