Association of Pythium coloratum and Pythium sulcatum with cavity spot disease of carrots in Western Australia |
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| Authors: | K. A. EL-TARABILY,G. E. ST. J. HARDY,& K. SIVASITHAMPARAM |
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| Affiliation: | School of Biological and Environmental Sciences, Murdoch University, Murdoch, WA 6150;, Department of Soil Science and Plant Nutrition, School of Agriculture, The University of Western Australia, Nedlands, WA 6009;Australia |
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| Abstract: | All 170 Pythium isolates from carrot cavity spot lesions from a field in Western Australia were found to belong to either P. coloratum or P. sulcatum . All isolates of P. coloratum produced large, brownish-black, water-soaked and depressed lesions on mature carrots inoculated with agar plugs colonized by the pathogen. In comparison, only a few isolates of P. sulcatum produced lesions and these were small. In glasshouse trials, P. coloratum produced substantial and numerous lesions at an inoculum density of 0.5% (weight of millet seed-based inoculum/weight of soil), whilst P. sulcatum produced few and small lesions at inoculum densities of 0.8 and 1% and none at 0.5%. This is the first record of P. coloratum as a causal agent of cavity spot of carrots. |
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