Calumby R J N, Almeida L M, Eliziario J L L, Dornelas C B, Alvino V, Grillo L A M
Universidade Federal de Alagoas - UFAL, Instituto de Ciências Farmacêuticas - ICF, Maceió, AL, Brasil.
Braz J Biol. 2024 Feb 23;83:e275755. doi: 10.1590/1519-6984.275755. eCollection 2024.
Rhynchophorus palmarum (Coleoptera: Curculionidae) is a significant agricultural pest in palm plantations across tropical America, playing a critical role as a vector of the fungus Thielaviopsis paradoxa, which is the causative agent of stem bleeding disease in coconut palms. This disease has raised concerns due to its rapid spread and subsequent reduction in coconut production in northeastern Brazil. Additionally, this insect can establish mutualistic interactions with various fungi, including saprophytic, phytopathogenic, and entomopathogenic fungi, underscoring the importance of identifying its external mycobiota. The aim of this study was to assess the presence of T. paradoxa in the digestive tract and identify the cultivable mycobiota associated with the carapace of R. palmarum. To achieve this, a mycological study was conducted by culturing the external surface and digestive tract of field-caught adult insects (10 males and 10 females) on potato dextrose agar (PDA) in Maceió, Alagoas, Brazil. Fungal identification was performed by correlating microscopic features with the macroscopic characteristics of the obtained colonies. The results showed that T. paradoxa was detected in 15.0% of carapace isolates but was not found in the insects' intestinal tract. Additionally, nine fungal genera frequently associated with saprophytic or phytopathogenic behaviors were identified on the carapace. Eight of these genera belong to the Ascomycota phylum, while one is classified in the Basidiomycota phylum. The ubiquitous presence of Paecilomyces spp. and the occurrence of Trichosporon spp. in 95% of the assessed insects stand out. Furthermore, other potentially phytopathogenic fungi such as Penicillium spp., Fusarium spp., and Aspergillus spp., as well as fungi with entomopathogenic potential like Paecilomyces spp., Trichoderma spp., Metarhizium spp., and Beauveria bassiana, were detected. These findings enhance the understanding of the complex interactions between R. palmarum and its fungal hosts, providing insights for integrated pest management strategies.
棕榈象甲（鞘翅目：象甲科）是热带美洲棕榈种植园中的一种重要农业害虫，作为奇异根串珠霉的传播媒介发挥着关键作用，奇异根串珠霉是椰子树茎干流胶病的病原体。由于这种疾病在巴西东北部迅速传播并导致椰子产量下降，已引起人们的关注。此外，这种昆虫可以与各种真菌建立共生关系，包括腐生真菌、植物病原真菌和昆虫病原真菌，这凸显了识别其体表微生物群的重要性。本研究的目的是评估奇异根串珠霉在消化道中的存在情况，并识别与棕榈象甲外壳相关的可培养微生物群。为实现这一目标，在巴西阿拉戈斯州马塞约，对野外捕获的成年昆虫（10只雄性和10只雌性）的体表和消化道在马铃薯葡萄糖琼脂（PDA）上进行培养以开展真菌学研究。通过将显微镜下的特征与所获得菌落的宏观特征相关联来进行真菌鉴定。结果表明，在15.0%的外壳分离物中检测到了奇异根串珠霉，但在昆虫肠道中未发现。此外，在外壳上鉴定出了9个经常与腐生或植物病原行为相关的真菌属。其中8个属属于子囊菌门，而1个属归类于担子菌门。拟青霉属的普遍存在以及95%的评估昆虫中出现丝孢酵母属值得关注。此外，还检测到了其他潜在的植物病原真菌，如青霉属、镰刀菌属和曲霉属，以及具有昆虫病原潜力的真菌，如拟青霉属、木霉属、绿僵菌属和球孢白僵菌。这些发现增进了对棕榈象甲与其真菌宿主之间复杂相互作用的理解，为害虫综合管理策略提供了见解。
