2008 Annual Report 1a.Objectives (from AD-416) The objective of this cooperative research is to determine the host specificity and genetic diversity of floriculture isolates of Phytophthora cryptogea and P. nicotianae. 1b.Approach (from AD-416) A recent collection of isolates of P. cryptogea and P. nicotianae will be tested for pathogenicity on a range of floriculture hosts to determine host specificity and fitness while rDNA of isolates will be analyzed for genetic diversity. 3.Progress Report This project is related to Objective 1 of this in-house project: Characterize ecology, biology, epidemiology, genetics and host interactions of domestic, exotic, newly emergent and re-emerging pathogens. In 2007-2008, 23 greenhouse establishments in North Carolina were surveyed for Phytophthora spp. Seventeen of these establishments were follow up surveys from 2001-2002 to determine if the Phytophthora population has changed at individual establishments. Phytophthora was isolated in 2001-2002 and 2007-2008 at five greenhouse facilities. A total of 164 Phytophthora isolates were collected from 14 host plants at 11 facilities. The 2007 isolates have been identified as P. nicotianae (28), P. drechsleri (29), P. cryptogea (2), and P. tropicalis (2) using morphology and sequencing of the recombinant deoxyribonucleic acid (rDNA) ITS region. The 2007 isolates were tested for mefenoxam sensitivity using growth on media amended with 0, 1, or 100 ppm of mefenoxam. Two isolates of P. nicotianae were sensitive at 1 ppm mefenoxam; whereas, the remaining isolates were insensitive at 100 ppm. Isolates of P. cryptogea and P. tropicalis were sensitive to mefenoxam at 1 ppm. In contrast, P. drechsleri isolates from the same greenhouse establishment were completely insensitive at 100 ppm. Authorized Departmental Officer's Designated Representative monitoring occurred through repeated phone calls, emails and face-to-face meetings to discuss and evaluate progress and fulfillment of project objectives.