Abstract

Rotten fruits are known to cause major losses in post-harvest conservation. One of the causal pathogen of pineapple rot was investigated and the antifungal effects of selected plants extracts were evaluated in vitro against fungal pathogen; Pestalotiopsis microspora. The fruits samples were randomly collected from farms after harvest. The samples were collected in Awae; the experiment was conducted at Agricultural Research Institute for Development located in Yaounde, Cameroon. The fruits samples were inoculated on potato dextrose agar and pure culture of fungal pathogen responsible for pineapple rot obtained. The pathogen was isolated, and identified on the basis of morphological features. The pathogenicity test was conducted to determine that the fungus is responsible for the rot symptoms. The efficacies of three plant species, namely: Allium sativum, Syzygium aromaticum and Zingiber officinale were tested in vitro at concentrations 20, 40 and 80% on mycelial growth inhibition of the causal agent. Aqueous and ethanolic extracts for concentrations were used. Distilled water and the fungicide Mancozeb 80WP (800 g/kg) were used as negative and positive controls, respectively. The pathogenicity test confirmed that P. microspora fungus is responsible for pineapple fruit rotting. The non-inoculated controls showed no symptoms of fruit rot. Results of antifungal tests showed that after 08 days, aqueous and ethanolic extracts of A. sativum and S. aromaticum were the most effective. The mycelial growth inhibition was total with aqueous and ethanolic extracts of A. sativum for concentrations 20, 40 and 80%. Total inhibition was also recorded with ethanolic extracts of S. aromaticum for all the tested concentrations.  The overall result of this study reveals that aqueous and ethanolic extracts of A. sativum and S. aromaticum can be used to control P. microspora as they completely inhibited the growth of the pathogen that can contribute in post-harvest conservation of pineapple fruits.

Key words: Ananas comosus, antifungal activities, extracts, pathogenicity test, Pestalotiopsis microspora.