ISHS Acta Horticulturae 455: V International Mango Symposium
SELECTIVE MEDIUM FOR ISOLATING NATTRASSIA MANGIFERAE |
| Authors: | W.C. Saaiman, Z. Smith |
| Keywords: | blossom blight, soft brown rot, mango diseases, endophytic colonization, benodanil, tannic acid, rose bengal |
| Abstract:
Nattrassia mangiferae is the causal organism of various mango diseases in South Africa. These include blossom blight and the postharvest diseases soft brown rot and stem end rot. In epidemiological studies it is necessary to make numerous isolations from tissue which may be infected by a specific organism. The isolation of N. mangiferae from branches, fruit and panicles by plating onto agar media is severely hampered by the presence of saprophytic fungi. The development of a selective medium was therefore necessary. Ten chemicals were screened for their effect on the radial growth of N. mangiferae. Growth of N. mangiferae was the least inhibited by bennodanil (100 ppm.), rose bengal (50 ppm.) and tannic acid (3000 ppm.). These three chemicals were then tested at different concentrations and combinations for their effect on the radial growth of N. mangiferae and seven other fungi commonly isolated from mango tissue. A selective medium consisting of tannic acid (4000 ppm.) and bennodanil (100 ppm) provided a superior tool for the detection of N. mangiferae in isolations made from mango branches, blossoms and fruit. | |
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