EFFECTS OF CALOTROPIS AND BITTERMELON LEAVES EXTRACTSONPOST HARVEST FRUIT ROT OF WATERMELON IN MAIDUGURI

Post-harvest fungal diseases are a major cause of spoilage and loss of watermelon (Citrullus lanatus ), especially in tropical markets. This studywas carried out to evaluate the effectiveness of Calotropis giganteaandbitter melon (Momordica charantia) powders as natural treatments for controlling post-harvest foot rot disease of watermelon. Diseasedwatermelon fruits showing symptoms of soft rot, mold growth, anddiscoloration were collected from Gamboru market, Maiduguri. Fungal pathogens were isolated using potato dextrose agar (PDA) and identifiedbased on their cultural and microscopic characteristics. Four fungi wereidentified as Aspergillus niger, Aspergillus flavus, Schizosaachromycespombe, and Zygosaccharomyces balii. The antifungal activity of Calotropis and bitter melon powders was testedusing the agar-amended method at concentrations of 5, 10, and15 g/100ml in a completely randomized design with three replications. Mycelial growthwas measured over a period of 216 hours. The results showed that bothplant powders significantly reduced fungal growth, and their effectivenessincreased with higher concentrations. However, Calotropis giganteapowder consistently showed stronger antifungal activity than bitter melonagainst all the tested fungi. The highest level of inhibition was recordedat15 g/100 ml, where fungal growth was greatly suppressed. The study concludes that Calotropis gigantea powder, particularly at aconcentration of 15%, is a cheap, readily available, and environmentallyfriendly alternative to chemical fungicides for the control of post-harvest 8 fungal diseases of watermelon. Its use can help reduce post-harvest lossesand improve the shelf life of watermelon fruits.