Materials were locally sourced to formulate growth media for culturing of Phytophthora megakarya pathogen of black pod disease of cacao. This scarcity of canned V8 juice necessitates this study with the objective to develop an alternative medium locally formulated from vegetables, evaluate and compare them with other media in supporting the growth and sporulation of P. megakarya. Formulated medium was compared with Potato Dextrose Agar (PDA), Carrot Agar (CA), Cassava Dextrose Agar (CDA) and V8 juice agar by measuring their efficiency on growth and sporulation of P. megakarya. Growth of P. megakarya was poor on PDA with 28.83 mm, CA with 40.83 mm. CDA with 60.00 mm, while canned V8 juice agar and formulated V8 agar had 73.00 and 81.83 mm, respectively for all growth measured after five days of incubation. Sporulations were observed on both canned and formulated V8 agar on the 5th day, CDA on the 10th day, while PDA and CA cultures failed to sporulate. No significant difference in mycelia growth and sporulation of P. megakarya in canned and formulated V8 agar was observed but there was significant difference as compare to other media examined. The formulated V8 agar is thus an effective alternative to canned V8 juice agar for studies on growth and sporulation of P. megakarya for management of this pathogen in Nigeria.
Keywords: Phytophthora megakarya, V8 agar, mycelia growth, sporulation, black pod.