Link to home

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

July 2003 , Volume 87 , Number  7
Pages  854 - 858

K. H. Lamour , Department of Entomology and Plant Pathology, The University of Tennessee, Knoxville 37996-4560 ; M. L. Daughtrey , Long Island Horticulture Research and Extension Center, Cornell University, Riverhead, NY 11901-1115 ; D. M. Benson and J. Hwang , Department of Plant Pathology, North Carolina State University, Raleigh 27695-7629 ; and M. K. Hausbeck , Department of Plant Pathology, Michigan State University, East Lansing 48824-1312



Go to article:
Accepted for publication 27 February 2003.
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.



© 2003 The American Phytopathological Society