Etiology of Phytophthora drechsleri and P. nicotianae (=P. parasitica) Diseases Affecting Floriculture Crops

Abstract

Phytophthora nicotianae and P. drechsleri isolates (n = 413) recovered from eight floricultural hosts at 11 different production sites were described according to compatibility type, resistance to mefenoxam, and amplified fragment length polymorphism (AFLP) profiles. Sample sizes ranged from 2 to 120. In all cases, isolates recovered from a single facility had the same compatibility type and resistance to mefenoxam. AFLP analysis indicated that six clonal lineages of P. nicotianae and two clonal lineages of P. drechsleri were responsible for the 11 epidemics and that isolates recovered from the same facility were identical. A single clone of P. nicotianae was recovered from snapdragons at two field production sites in the southeastern United States receiving seedlings from the same source. This clone persisted at one site from 2000 to 2001. Another clone was recovered from verbena at three separate greenhouse facilities where one facility was supplying verbena to the other two. These results suggest that asexual reproduction of these pathogens plays an important role in epidemics and spread may occur between distant facilities via movement of plants.

Genetic characterization of Phytophthora nicotianae by the analysis of polymorphic regions of the mitochondrial DNA

“…Clonal populations of P. nicotianae were identified as a component of field populations from the same tobacco field in four consecutive years (Sullivan et al 2010) and for isolates from different ornamental plants and production sites (Lamour et al 2003). It was suggested that isolates within the same ornamental nurseries spread by asexually generated propagules, such as hyphal fragments, sporangia, chlamydospores or zoospores (Lamour et al 2003). Furthermore, it was concluded that, at least in citrus orchards in Italy, P. nicotianae reproduced primarily asexually since in the majority of citrus orchards examined only the A1 mating type was found (Cacciola & Magnano di San Lio 1998).…”

“…The same technique was applied to differentiate isolates causing black shank (Zhang et al 2001) and to identify markers linked to the dominant black shank resistance gene (Johnson et al 2002). Amplified Fragment Length Polymorphism (AFLP), utilized by Lamour et al (2003) to study a population from different floricultural hosts and production sites, enabled the identification of six clonal lineages. Although RAPD-PCR and AFLP have proved valuable within a particular study, results obtained with such fingerprinting tools are not always easily reproducible in different laboratories (Cooke & Lees 2004).…”

Antifungal Effect of Plant Essential Oils on Controlling Phytophthora Species

“…Damping off and blight caused by the Phytophthora species, is one of the most devastating diseases affecting cucurbit and vegetables production in Iran (Etebarian, 2012). Some species such as P. capsici , P. drechsleri and P. melonis can cause strong pathogenicity on pepper, cucurbit, tomato, cantaloupe and ornamental plants that cause damping off disease and rot of crown and root (Lamour et al, 2003; Tabarrae et al, 2011). The genus Phytophthora is a soil borne pathogen and survives in the soils as oospores and mycelia for several years in plant debris (Jee et al, 2001).…”

Spatio‐temporal analysis of an invasive plant pathogen (Phytophthora ramorum) in England and Wales

“…In Oregon, most of infected trees were within 100 m of trees killed the previous year though occasional long-distance (up to 3 km) dispersal was possible (Rizzo et al 2005). Disease spread between production facilities via movement of plants was also previously reported for P. nicotianae and P. drechsleri (Lamour et al 2003). In the present study, the possible disease spread distance of up to 60 km found among GCN sites is probably specific to commercial trading characteristics during the survey period.…”