Advanced Research Journal of Microbiology ISSN: 1718-3499, Vol. 5 (3), pp. 114-119. April, 2018.  © Advanced Scholars Journals

Full length Research paper

Effect of storage on the antimicrobial potencies of some botanicals against Phytophthora megakarya, causal pathogen of black pod disease of cocoa in Nigeria

^*1B. A. Ogundeji, ²E. A. Babalola, ¹S. O. Adio, ²S. T. Balogun, ³R. T. Olorunmota, ⁴F. O. Ogundeji

¹Plant Pathology Section, Cocoa Research Institute of Nigeria, P. M. B. 5244, Ibadan, Nigeria

²Plant Breeding Section, Cocoa Research Institute of Nigeria, P. M. B. 5244, Ibadan, Nigeria

³Plantation Management Department, Cocoa Research Institute of Nigeria, P. M. B. 5244, Ibadan, Nigeria

⁴Federal University of Technology, P. M. B. 704, Akure, Nigeria

*Corresponding author E-mail: [email protected]

Accepted 31 January,2018

Abstract

Varying concentrations of Piper guineense, Ocimum gratissimum, and Cymbopogon citratus leaf extracts, at different periods of storage were tested against moderately aggressive strain of cocoa pod rot pathogen- Phytophthora megakarya. Percentage inhibitions exhibited by the extracts and chemical fungicide used as standard were calculated and recorded with respect to their storage time. Percentage mycelia inhibitions exhibited by the freshly prepared extracts against the pathogen ranged between 27.73-51.58% (P. guineense), 26.99-34.77% (C. citratus) and 24.49-48.46% (O. gratissimum), while the synthetic fungicide (standard) gave 44.25%. The inhibitions exhibited after seven days of storage dropped to 5.12-15.67%, 4.41-20.72%, 11.23-24.38% and 20.58% for P. guineense, C. citratus,O. gratissimum and fungicide respectively. Percentage inhibitions of the pathogen after 14 day storage partly followed a similar trend. The antimicrobial potencies of plant extracts and fungicide used in this study clearly decreased with storage time and as such, could be best applied when freshly prepared to control black pod disease of cocoa.

Keywords: Phytophthora, extracts, inhibitions, Piper, Ocimum,Cymbopogon, cocoa, potency, storage time.