Fungi associated with Platypus cylindrus Fab. (Coleoptera: Curculionidae) from Quercus suber L. in North-Eastern Algeria

Abstract

The oak pinhole borer, Platypus cylindrus, is an ambrosia beetle capable of establishing symbiotic relationships with many fungi serve, among other things, as a feeding source and/or facilitate tree decline, which is the process of wood tissues decomposition. The aims of this study are to identify the diversity of fungi associated with the oak pinhole borer in cork oak forest of El Kala isolated from galleries, mycangia and intestinal contents of insects. Likewise, this investigation allows to acquire more information on the role of this interaction. A diversity of eleven fungi (Botryosphaeria sp., Penicillium sp., Aspergillus sp., Trichoderma sp., Mucor sp., three Ophiostoma sp., Raffaelea montetyi, Raffaelea canadensis-like and Biscogniauxia mediterranea) belonging to the six systematic orders and originating mainly from Ascomycota were isolated. Molecular characterization was performed based on amplification and sequencing of the D1/D2 domain of large subunit (LSU) ribosomal DNA (rDNA) to confirm the morphological identification of Ophiostoma sp. The sequences obtained revealed 86% similarity with Ophiostoma piliferum and 84% similarity with Ophiostoma sp. In this study, the presence of the species Raffaelea montetyi and Ophiostoma piliferum associated with P. cylindrus confirms its pathogenicity with respect to the health status of the cork oak.

Keywords:

Ambrosia beetle, fungi, ophiostomatales, cork oak, decline.