First report of frosty pod rot (moniliasis disease) caused by Moniliophthora roreri on cacao in Belize

Moniliophthora roreri causes frosty pod rot (FPR), a highly destructive cacao disease, currently found in eleven countries in South and Central America. In Belize, the disease was first detected during a field visit to a small farm in the village of Maya Mopán, Stann Creek District in September 2004. Symptoms characteristic of typical FPR included pod deformation, premature ripening and chocolate-coloured pod lesions with creamy-coloured mycelium becoming darker as the spores mature. Internal pod tissues showed a typical necrotic compact mass, surrounded by a decayed watery substance. The presence of mummies (dehydrated, sporulated pods), the high disease incidence estimated at 60% of the pods affected and the extent of FPR within the plantation, all suggested that the disease had been present for at least six months. The fungus was grown in modified V8 medium and morphology of isolates examined. Colonies showed an initial whitish growth, later salmon-cream and finally dark brown due to the massive formation of spores. Spores were produced in chains and were thick-walled, pale yellow, brown en masse, heteromorphic, but most frequently globose/subglobose (59%) to ellipsoid (34%), with maximum dimensions 5-11 x 8-20 µm. These observations agree with the description of M. roreri given by Cifferi & Parodi (1933) and Evans (1981).

Further confirmation was obtained by amplifying and sequencing two regions of the nuclear ribosomal DNA repeatâ€"internal transcribed spacer region (ITS) and 28S large subunit (LSU) with fungal specific primers ITS1-F/ITS4 (ITS) and LSU4-B/LR6 (Aime & Phillips-Mora, 2005). The sequences obtained (GenBank accessions DQ222927 and DQ222928) were identical (100% homologous) to those of isolates from Panama, Costa Rica, Nicaragua and Honduras, that form a proposed Mesoamerican subgroup of the pathogen. The causal agent was deposited with the U.S. National Fungus Collection (BPI) as MCA2954. Following the initial discovery, FPR was detected in one additional farm in Maya Mopán in October 2004, and in three farms in the village of San Felipe (Toledo District) in April 2005. This is the first report of FPR disease in Belize.