Response of Fungal Contaminants of Egusi Kernels to selected Botanicals Treatments

Abstract

Egusi is an important crop used mainly for soups in Nigeria. Egusi is contaminated with many fungal pathogens, which reduce storability and quality of seeds in the store. Use of botanicals can be safe method to manage fungal contamination instead of chemicals which poses threat to human health. Therefore, effects of Piper guineense, Xylopia aethiopica and Ocimum gratissimum on fungi in egusi kernels (EK) were evaluated.One market in each of the six southwestern Nigerian states where egusi are sold was purposively selected in 2012 and 2013.Egusi kernels (½kg, n=162) were purchased from selected traders for fungi isolation, identification and incidence (%) determination. Clean EK treated with botanical powders (10, 20 and 40g/kg) were inoculated with fungi bi-weekly for 14 weeks storage period to evaluate growth reduction (%). Aspergillus flavus, A. niger, A. tamarii, Penicillium citrinum, P. aurantiogriseum, Fusarium solani and Rhizopus spp. Were frequently encountered in EK. Aspergillus (32.4±1.6%) was most predominant fungus followed by Rhizopus (21.5±2.0%) in all states. Fungi growths were progressively reduced by P. guineense (5.5-90.0%), X.aethiopica (6.7-100.0%) and O. gratissimum (7.4-66.7%) up to twelve weeks of storage.Egusi kernels were highly infected with postharvest fungi especially Aspergillus species.Xylopia aethiopica at 20g/kg, O. gratissimum (40.0%) and P. guineens e(40.0%) reduced fungi growth on egusi considerably and therefore could be used as a safe management option to mitigate storage fungi contamination in Egusi kernels.