Abstract

---

Black rot is one of the most destructive diseases of African star apple fruits, caused by Aspergillus niger. This study aimed to explore the potential of using hot water (HW) in combating black rot on African star apple fruits. After harvest, the fruits were sorted and selected for maturity and uniform homogeneity and thereafter washed, disinfected in 10% NaOCl for 10 minutes and allowed to air dry at 26°C. All the fruits were inoculated with 1 ml of freshly prepared spore suspension (4.05×102 spores/ml) of the Aspergillus niger. After 12 hours of artificial inoculation, the fruits were later immersed separately in hot water bath at 500C for 5, 10, 15 and 20 minutes, while inoculated but untreated fruits served as control. Each treatment lot consisted of three fruits and both treated and control fruits were later stored in sterilized desiccators at 28 ± 2°C and 75 ± 5% relative humidity and observed daily for disease severity. Results obtained shows that both the control and all the HW treated fruits had same disease severity values (1.00 ± 0.00) for the first 10 days of storage, which implied non-diseased nature of the samples. However, as storage duration advanced to day 20, fruits treated at 50°C for 15 and 20 minutes still maintained their non-diseased status compared to the control fruits that already showed complete rottenness. Thus, HW treatments especially at 500C could probably be considered as effective non-chemical means that can be explored in fruits preservation.

Keywords: Black rot, Chrysophyllum albidum, hot water, storage