Phytophthora has been rebuilt to fix security-related problems and to restore GIS tools. These tools allow users to visualize the geospatial, temporal, and environmental contexts of Phytophthora discoveries. The next phase is to update species information and add data derived from large-scale surveys. If you have suggestions and requests to make the database better, please contact Seogchan Kang (sxk55@psu.edu).
Genus wide phylogeny for Phytophthora using four mitochondrial loci (cox2, nad9, rps10 and secY; 2,373 nucleotides). Maximum likelihood branch lengths shown. Numbers on nodes represent bootstrap support values for maximum likelihood (top), maximum parsimony (middle) and Bayesian posterior probabilities as percentages (bottom). Nodes receiving significant support (>95%) in all analysis are marked with an asterisk (*). Scale bar indicates number of substitutions per site.(Martin, Blair and Coffey, unpublished).
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Phytophthora phaseoli Thaxt. 1889 (Oomycetes, Pythiales)
Phytophthora infestans var. phaseoli (Thaxt.) Leonian 1925 Note: Listed by Tucker (1931).
Notes: The species concept was amended by Clinton in 1906.
Distribution: Africa (Congo, Zaire), Asia (Philippines, Sri Lanka, USSR), Europe (Italy, Romania), North America (Mexico, USA), Central America and Caribbean Islands, South America (Brazil).
Substrate: Pods. Also on shoots, leaves, petioles. Overwinters in soil or infected plant debris.
Disease Note: Downy mildew. At least 6 races have been identified. Races D, E, F have recently caused serious outbreaks in the eastern USA (DE, MD).
Host: Phaseolus lunatus (also reported as P. limensis) (lima beans, Fabaceae). Capable of infecting plants from other families after inoculation (Erwin & Ribeiro 1996). Also reported from Phaseolus vulgaris (common bean).
Supporting Literature:
C.M.I. 1983. Phytophthora phaseoli. C.M.I. Map 201: 1-2
Erwin, D.C., and Ribeiro, O.K. 1996. Phytophthora Diseases Worldwide. APS Press, St. Paul, Minnesota, 562 pages.
Kroon, L.P.N.M., Bakker, F.T., van den Bosch, G.B.M., Bonants, P.J.M., and Flier, W.G. 2004. Phylogenetic analysis of Phytophthora species based on mitochondrial and nuclear DNS sequences. Fungal Genet. Biol. 41: 766-782
Tucker, C.M. 1931. Taxonomy of the genus Phytophthora de Bary. Univ. Missouri Agric. Exp. Sta. Bull. 153: 1-208
Updated on Mar 20, 2006
P. phaseoli is classified in group IV (Stamps et al. 1990). Morphology is shown in Figure 1. See Tables 4.2 and 4.3 in Phytophthora Diseases Worldwide (Erwin and Ribeiro 1996) for tabular keys.
1. Sporangia
Sporangia are semipapillate, oval, or elliptical with a truncate base. The size varies with the substrate on which they are produced (Hyre and Cox 1953). Thaxter (1889) reports dimensions of 35 to 50 x 20 to 24 µm (average 28 x 19 µm). The length-breadth ratio averages 1.4:1. Sporangia are nonproliferating and caducous with short (5 to 20 µm) pedicels. Sporangiophores are sympodially branched and slightly swollen at the base.
2. Hyphal Swellings and Chlamydospores
Neither hyphal swellings nor chlamydospores are produced.
3. Sex Organs
P. phaseoli is homothallic and produces oospores abundantly on lima bean or host tissue. Antheridia are amphigynous and shaped like a flattened sphere; oogonia are subspherical, measuring 16.2 to 35.6 µm in diameter (average 23.7 µm); oospores measure 14.4 to 26.6 µm in diameter (average 19.2 to 22.5 µm) (Hyre and Cox 1953).
4. Growth Temperatures
The minimum temperature for growth is 5oC, optimum 15 to 20oC, and maximum 25 to 30oC. Incubation at 30oC for 2 weeks was lethal. Data on the effect of temperature on sporangia and zoospore germination (Hyre and Cox 1953) supported the prediction that disease forecasting could be based on expected temperature and rainfall parameters (Hyre 1957). P. phaseoli can be maintained for long periods on sterile lima bean seeds in water (Goth and Wester 1963).
Nomenclature information was provided by the the Systematic Botany and Mycology Laboratory in USDA-ARS.
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