Journal ArticleDOI
Taxonomy of ‘Phytophthora palmivora’ on cocoa
Clive M. Brasier,M.J. Griffin +1 more
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Morphological and physiological studies-chromosome type, colony morphology and growth rate on carrot agar, cocoa pod lesion characteristics, morphology and size of sporangia, sporangial pedicels, chlamydospores and sex organs, compatibility type, growth on a synthetic medium, response to Trichoderma, and temperature relations-were made with c.Abstract:
Morphological and physiological studies-chromosome type, colony morphology and growth rate on carrot agar, cocoa pod lesion characteristics, morphology and size of sporangia, sporangial pedicels, chlamydospores and sex organs, compatibility type, growth on a synthetic medium, response to Trichoderma, and temperature relations-were made with c. 950 Phytophthora isolates from cocoa (Theobroma cacao L.) attributed to P. palmivora (Butl.) Butl. The survey covered isolates from all the major cocoa growing areas of the world, and included isolates studied by C. H. Gadd and S. F. Ashby in the 1920s. The majority of the isolates could be assigned to one of three distinct forms, termed S, L and MF4. The S-type is attributed here to P. palmivora, which is redefined. Both L and MF4 are considered to be distinct species of Phytophthora. The L-type could not be identified with any known species and is described here as P. megakarya sp.nov. P. palmivora occurred world-wide on cocoa, whereas P. megakarya was obtained only from West Africa and MF4 only from Central and South America and the West Indies. Isolates attributed to P. palmivora from other hosts were also examined. Some isolates from rubber, coconut and durian were P. palmivora (S-type). Isolates from pepper comprised a group closely resembling MF4. Isolates from coconut and rubber originally attributed to P. palmivora by S. F. Ashby, C. H. Gadd and E. M. Blackwell comprised a further group, and were also attributed here to P. palmivora, yet were somewhat different morphologically from the S-type on cocoa. It is not clear which of these two types is authentic P. palmivora. The significance of these results, and the value of the various diagnostic criteria used, is discussed.read more
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Phytophthora ramorum sp. nov., a new pathogen on Rhododendron and Viburnum
Sabine Werres,Rainer Marwitz,Willem A. Man In't veld,Arthur W. A. M. de Cock,Peter J. M. Bonants,Marjanne de Weerdt,Karin Themann,E. Ilieva,R. P. Baayen +8 more
TL;DR: It was concluded that a new Phytophthora species, described here as P. ramorum sp.
Journal ArticleDOI
Phytophthora capsici on Vegetable Crops: Research Progress and Management Challenges.
Mary K. Hausbeck,Kurt Lamour +1 more
TL;DR: Recent advances in the understanding of P. capsici’s biology are reviewed, in particular the role of sexual reproduction, and some of the management challenges presented by this information are provided.
Journal ArticleDOI
Phylogeny of five fungus-like protoctistan Phytophthora species, inferred from the internal transcribed spacers of ribosomal DNA.
Steven B. Lee,John W. Taylor +1 more
TL;DR: Ribosomal DNA variation was used to study evolutionary relationships among five fungal-like protoctistan Phytophthora species and both neighbor-joining and parsimony analysis of ITS variability support a close relationship between cacao isolates of P. capsici and P. megakarya.
Journal ArticleDOI
Phytophthora quercina sp. nov., causing root rot of European oaks
TL;DR: In a 3 year study of oak decline in Central and Southern Europe, a papillate homothallic Phytophthora species was isolated consistently from necrotic fine roots by direct plating on to selective agar medium and from rhizosphere soil samples by baiting with leaves of Quercus robur.
Journal ArticleDOI
Multiple new phenotypic taxa from trees and riparian ecosystems in Phytophthora gonapodyides-P. megasperma ITS Clade 6, which tend to be high-temperature tolerant and either inbreeding or sterile.
TL;DR: In contrast to most other Phytophthora clades, Clade 6 taxa are predominantly sterile or inbreeding in culture and show a strong association with forests and riparian ecosystems, only a limited association with agriculture and an ability to tolerate high temperatures.
References
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Journal Article
Homothallism, heterothallism, and interspecific hybridization in the genus .Phytophthora.
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Stimulation of sex organ formation in phytophthora by antagonistic species of trichoderma
TL;DR: The ability of Trichoderma isolates to induce a sexual response in Phytophthora was correlated with their ability to produce volatile antibiotics.
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Observations on the sexual mechanism in Phytophthora palmivora and related species
TL;DR: Twelve out of twenty-three isolates of Phytophthora palmivora (Butl.) Butl.