Assessment and In Vitro Control of Pomegranate Fruit Rot Disease in Gilgit District, Pakistan

Abstract

The pomegranate fruit rot disease, referred to as "heart rot" or "black heart," stands as a significant issue among pomegranate diseases in Gilgit Baltistan (GB). This condition is defined by the presence of black rot within the fruit core, which extends from the calyx area. Importantly, the outer peel and tough rind maintain their healthy appearance. Several varieties of pomegranate fruit such as Sweet, Doom, Sour, and Kandhari are found in different localities of GB. Among these varieties, the sweet type locally known as isakolii is widely affected by fruit rot. The objective of this study was to determine the primary causal agent responsible for the occurrence of fruit rot disease in pomegranates in the Gilgit district. Additionally, the study aimed to develop effective management strategies for the disease under laboratory conditions. Although many fungal species belonging to genera, Penicillium, Aspergillus, Botrytis, and Rhizopus, have been isolated from pomegranate fruits, however, Aspergillus niger was the primary causal agent of fruit rot. In this study, two methods were carried out to manage fruit rot: biological control using Trichoderma harzanium in dual culture technique, resulting in a 60% inhibition of the fungus after seven days, and chemical control using food poisoning technique in culture method. The growth inhibition % on day seven was calculated as 27 ± 4.05, indicating the effectiveness of Tebuconazole 25.9 WP, which showed a decrease over time to inhibit the Aspergillus niger. The growth inhibition % for the Thiophanate Methyl treatment was calculated as 15.923 ± 3.27 after seven days. The study provides primary information regarding the prevalence of fungal disease infections in Gilgit and can help guide future studies toward mitigating fungal disease epidemics.