Monday Ubogu
The rhizosphere and rhizoplane mycoflora of three rubber clones, PB 5/51, GT1 and PB28/59, were determined using the soil dilution plate method and serial washing of root lengths respectively. These were plated on PDA plates. Five genera of fungi, Aspergillus, Trichoderma, Penicillium, Botryodiplodia and Mucor, were isolated from the root zones of all three rubber clones. In both the rhizosphere and rhizoplane, the preponderance of Aspergillus among the various rubber clones was in the following order, PB 28/59 > GT1 > PB5/51. While for Penicillium, PB 5/51> GT1 > PB 28/59. The occurrence of Trichoderma in the rhizoplane was in the following order, PB 5/51 > GT1 > PB 28/59, while for the rhizosphere, GT1 > PB28/59 > PB 5/51. Botryodiplodia and Mucor were only isolated from the rhizoplane of all three rubber clones with relatively low level of occurrence. Isolates of A. niger, Trichoderma spp. and Penicillium spp. from the root zone of clone PB 5/51inhibited mycelia growth extension of R. lignosus by 17.4, 32.5 and 21.0 % respectively which were significantly higher than those from GT1 and PB28/59, which did not differ statistically (p = 0.05). Clear zone of inhibition against the pathogen were only produced by isolates of Penicillium spp. and A. niger in the range of 10.1 to 13.0mm, which did not differ significantly among the three rubber clones (p = 0.05).
