Isolation of Colletotrichum gloeosporioides (causal agent of yam anthracnos
e) from soil is difficult because of the presence of fast growing micro-org
anisms like Rhizoctonia spp., Rhizopus spp., Penicillium spp. and bacteria.
Therefore, a semi-selective medium consisting of antimicrobial agents such
as pencycuron 50 mg L-1, tolclofos-methyl 10 mg L-1, streptomycin sulphate
100 mg L-1, chloramphenicol 100 mg L-1 and chlortetracycline 100 mg L-1 wa
s developed using potato dextrose agar as the basal medium. The procedure i
nvolved screening of candidate fungicides, developing a suitable combinatio
n of antimicrobial agents, assessing the proposed semi-selective medium and
adjustment of pH of the medium to 5. The effectiveness of the medium is du
e to selective inhibition of micro-organisms by the antimicrobial agents an
d the development of distinct salmon-pink colonies of C. gloeosporioides.