Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Diplodia africana causing twig death on Araucaria araucana, a new host and first record for Chile.

Abstract

Araucaria araucana (monkey puzzle tree) is an endemic conifer restricted to the temperate subantarctic forests of South America, with most of the world population concentrated in Chile, covering an area of 253,715 ha. As a native forest species, A. araucana has been the object of ongoing phytosanitary surveys by the Servicio Agrícola y Ganadero (SAG), the National Plant Protection Organization of Chile. During surveillance activities in 2018, a botryosphaeriaceous fungus was isolated from a sample of partially dead branches from a tree in Conguillio National Park, located in the Andes, Araucanía Region (38°39'00" S, 71°37'6" W). Pycnidia and conidia produced in vitro on pine needles on water agar after 14 days were identified as Diplodia sp., with conidia hyaline after discharge from pycnidia, non-septate, measuring (26-)31-34.5(-36) × (7-)9.5-12(-13.5) µm. The causal pathogen was further characterized as D. africana based on molecular and pathogenicity analyses. This is thought to be the first report of D. africana on A. araucana.