Oryctes sp. is a key pest of date palms, where larval and adult feeding on different plant parts reduces tree vigor and yield. Although insects are recognized as potential vectors of plant pathogenic fungi, the role of Oryctes beetles in transmitting fungal pathogens to date palms remains unclear. This study aimed to identify Oryctes species in two major date-producing regions of Saudi Arabia-Al Kharj and Al Qassim-and to characterize the fungal communities associated with beetles, infested roots, and rhizosphere soils. Adult beetles were collected from date palms and identified using morphological characters and DNA barcoding of the mitochondrial cytochrome c oxidase I gene. Fungi were isolated from beetle exoskeletons, root tissues of infested palms, and rhizosphere soils; cultured on Czapek Dox Agar; grouped by colony and microscopic features; and identified using standard morphological keys. Morphological and molecular analyses of collected specimens revealed two species-Oryctes elegans and Oryctes agamemnon-in Al Kharj, while only O. agamemnon occurred in Al Qassim. In total, 72 fungal isolates representing 13 genera were recovered. From beetles, 27 isolates included common taxa such as Phytophthora parasitica, Fusarium sp., Aspergillus niger, Aspergillus flavus, Penicillium sp., Alternaria alternata, Helminthosporium sp., and Stemphylium verruculosum, with additional species unique to each Oryctes species and region. Similar overlapping and region-specific assemblages occurred in roots and rhizosphere soils. The frequent detection of phytopathogenic fungi on beetle exoskeletons, together with their presence in roots and rhizosphere soils, supports a role for Oryctes species as mechanical vectors that facilitate fungal entry through feeding wounds.
Alajmi et al. (Sun,) studied this question.