Comparative studies of Phytophthora species
| MSI99P2054 | |
| Moutia, J-F. Y. | |
| Imperial College, Ascot, GB | |
| Comparative studies of Phytophthora species | |
| Thesis, MSc | |
| Thesis | |
| 1995 | |
| 171 p.: 31 tbls, 21 pl, 28 figs | |
| En | |
| En | |
| The 43 or more species in the genus Phytophthora cause a wide range of diseases on an ever increasing number of plants. The latter include major food crops, forest trees, subtropical and tropical fruit trees, berries, nut trees, many ornamental plants and valuable tropical export crops. The taxonomy of the genus is still unsettled and a "grey" area as to what a species in Phytophthora should be still persists. The identification of species in an important aspect of any work with the pathogen. Although variability is the key word, c ertain characters when studied together give a good clue as to the organism at hand. Morphological characteristics are still widely used to differentiate between species although with the recent advance in biotechnology, protein and DNA analysis are proving reliable and consistent. The aim of this study was to identify and to compare seven species of Phytophthora at the microscopic, macroscopic, behavioural and pathogenic levels. The species under study were P. drechsleri, P. citrophthora, P. capsici, P. palmivora, P. megakarya, P. cactorum and P. nicotianae. One of the main objectives of the study was to examine the host range of the cacao pathogen P. megakarya known until now to infect cacao only. Several fruits and vegetables were inoculated with mycelial discs. Results obtained indicate that the cacao pathogen may have other hosts. Indeed, in the present study, the pathogen has been found to infect apples and cucumber fruits with profuse sporulation at the fruit's surface. Inside tissues were also affected. Althouth artificial inoculation by wounding has been used, the potential threat to these two crops in the fields is certain. Glasshouse inoculation of seedling roots of Capsicum, melon, aubergine, tomato, peas and cucumber were also performed. Melon and cucumber were the most susceptible crops and suffered from damping off. At the behavioural level, important interactions between medium, light, temperature and isolate have been found to affect growth and sporulation of the Phytophthora species. | |
| PHYTOPHTHORA PHYTOPHTHORA DRECHSCLERI PHYTOPHTHORA CITROPHTHORA PHYTOPHTHORA CAPSICI PHYTOPHTHORA PALMIVORA PHYTOPHTHORA MEGAKARYA PHYTOPHTHORA CACTORUM PHYTOPHTHORA NICOTIANAE PLANT PATHOLOGY PLANT DISEASES | |
| Plant diseases | |
| Fungal diseases: Phytophthora | |
| 1995-12-13 | |
| En | |
| PATH |