Comparison between Traditional and PCR Methods for Identifying Fusarium oxysporum f. sp. Melonis, the Causal Agent of Watermelon Citrullus lanatus Wilt

Abstract

Fungal diseases have become a major threat to field crops, particularly watermelons, due to the escalating prevalence of Fusarium oxysporum. This soil-borne pathogen has been identified as a primary cause of significant yield losses in watermelon cultivation across various regions of eastern Libya, including Tobruk, Al Marj, and Tukrah. The study aimed to investigate the prevalence of F. oxysporum f. sp. melonis, the causal agent of Fusarium wilt in watermelons, and to establish a reliable and efficient diagnostic protocol.Visual symptoms such as leaf chlorosis, wilting, and root rot were observed in watermelon plants across the study sites. Fungal isolates were obtained from symptomatic tissues and subjected to morphological, microscopic, and molecular analyses. Morphological and microscopic characterization provided preliminary evidence of  Fusarium infection; however, molecular identification using polymerase chain reaction (PCR) with specific primers confirmed the presence of  F. oxysporum f. sp. melonis with a high degree of accuracy (99%).The study highlights the utility of PCR-based diagnostics in the rapid and accurate detection of  F. oxysporum f. sp. melonis in watermelons. This molecular approach offers significant advantages over traditional methods in terms of sensitivity, specificity, and time efficiency. The findings underscore the importance of implementing integrated disease management strategies, including the use of resistant cultivars, crop rotation, and appropriate cultural practices, to mitigate the impact of Fusarium wilt on watermelon production in eastern Libya.