DNA polymorphisms in 38 isolates of Colletotrichum gloeosporioides infecting avocado, banana, mango and papaya were examined using ribosomal DNA (rDNA) from Saccharomyces carlsbergensis and mitochondrial DNA (mtDNA) purified from C. gloeosporioides total DNA as probes. The average size of the rDNA repeat unit of the isolates was 9??2 kb, although there was considerable size variation.
Isolates obtained from different hosts never had the same rDNA or mtDNA RFLP patterns. With the exception of those from mango, isolates could not easily be grouped but could be distinguished in relation to their host source within geographical localities. There was no RFLP that could be used diagnostically on a worldwide basis to identify isolates from avocado, banana or papaya. In contrast, isolates obtained from mango fruits in the eastern and western hemisphere had the same rDNA and very similar mtDNA restriction fragment-banding patterns.