KARAKTERISASI ISOLAT Pestalotiopsis sp. DARI BEBERAPA INANG DAN PATOGENISITASNYA PADA TANAMAN KARET (Hevea brasiliensis)

The variety of hosts of Pestalotiopsis sp. raises the question of whether Pestalotiopsis sp. originating from various hosts share the same characteristics as Pestalotiopsis sp. from rubber plants and have the potential to become pathogens on rubber plants. Therefore, this study was conducted to identify the morphological characteristics of Pestalotiopsis sp. from various hosts and to assess the pathogenic potential of Pestalotiopsis sp. from various hosts on rubber plants. The research was conducted at the Sungei Putih Research Unit, Rubber Research Center, Galang District, Deli Serdang Regency, North Sumatra. The study was carried out from February to June 2023. The research consisted of two main activities: the characterization of Pestalotiopsis sp. isolates and the testing of the pathogenicity of these isolates on rubber plants at the laboratory scale. The research employed a completely randomized design (CRD) non-factorial. The colony diameter characteristics of Pestalotiopsis sp. continued to increase. Colonies with nearly identical characteristics were white, had a smooth texture, resembled flowers forming patterns on their mycelium, and had conidiomata shaped like small black spots in the middle and irregularly scattered. Microscopic identification of Pestalotiopsis sp. fungi from various hosts showed similar characteristics, including being five-celled, having fusiform and oval conidia with four brown septa, and having two hyaline sentulae with a basal pedicel. Pathogenicity testing of Pestalotiopsis sp. isolates from various hosts indicated that rubber plant hosts had the highest lesion diameter compared to other hosts.