The only economically important host of Phytophthora megakarya Brasier & Griffin is Theobroma cacao. The pathogen is one of several Phytophthora species causing black pod disease of cacao. Isolates of P. megakarya were grouped taxonomically with P. palmivora isolates until 1979, when it was recognized as a new species (Brasier and Griffin, 1979). Found only in Central and West Africa, losses due to black pod disease caused by P. megakarya can be 50-80% in nontreated areas (Despréaux, 2004).
Etymology: Derived from ‘large’ (mega) ‘karyotype’ (karya) due to the larger chromosomes compared to P. palmivora.
P. megakarya is heterothallic with amphigynous antheridia and distinctly pyriform oogonia. The caducous sporangia are papillate, varying in shape from limoniform, obpyriform, and ellipsoid. Terminal chlamydospores have an average diameter of 30 µm.