Phytopathogenic and antagonistic potentialities of fungi associated with pistachio bark beetle, Chaetoptelius vestitus (Coleoptera, Curculionidae), infesting pistachio ( Pistacia vera ) in Tunisia

Abstract

Aim This study investigated the biodiversity of fungi associated with the pistachio bark beetle, Chaetoptelius vestitus, in Tunisia. We evaluated the phytopathogenic activities and tested antagonistic potentialities with respect to phytopathogens. Methods and Results A total of 41 fungal isolates were randomly isolated from C. vestitus adults and galleries. We identified 28 species belonging to 13 genera using ITS sequences of the ribosomal RNA operons. Pathogenicity assays performed using the excised shoot method revealed that isolates Aal_io_1 (Alternaria alternata), Feq_io_1 (Fusarium equiseti), Fgra_io_1 (Fusarium graminearum), Fve_io_1 (Fusarium verticilloides), Tro_io_1 (Trichothecium roseum) and Nqu_io_1 (Nothophoma quercina) displayed a high pathogenic activity on pistachio stems. Estimation of the antagonistic potentialities of isolated fungi against several phytopathogenic isolates as tested using a dual‐culture method showed that isolates Tpi_io_1 (Talaromyces pinophilus), Pbi_io_2 (Penicillium bilaiae), Asc_io_1 (Aspergillus sclerotiorum) and Gla_io_1 (Geosmithia lavendula) displayed a broad range of antagonistic activities. Conclusion Fungi associated with C. vestitus had a variable range of pathogenic activity on pistachio stem. Phytopathogenic fungi were antagonized by different fungal isolates which could be promising in pistachio protection against phytopathogenic fungi. Significance and Impact of the Study This study is the first that investigated the diversity of fungi associated with C. vestitus and evaluated both their phytopathogenic activity and antagonistic potential against fungal phytopathogens.

Screening of biological activities of fungi associated with pistachio bark beetle, Chaetoptelius vestitus (Coleoptera, Curculionidae), infesting pistachio cultivations in Tunisia

“…In a previous study (Hadj Taieb et al ), we have reported the lack of phytopathogenic activity with respect to pistachio plants of isolates Ata_io_1 ( A. tamarii ), Pal_io_1 ( P. album ), Pbi_io_1 ( P. bilaiae ), Pch_io_1 ( P. chrysogenum ) and Tpi_io_1 ( T. pinophilus ) which presented a high entomopathogenic activity against C. vestitus . This group of isolates could be investigated for biocontrol of the cited beetle.…”

“…According to previous internal transcribed spacer (ITS)‐based molecular taxonomic characterization, these isolates were assigned to 27 different species belonging to the following 13 fungal genera: Alternaria , Aspergillus , Curvularia , Fusarium , Geosmithia , Nothophoma , Paecilomyces , Parengyodontium , Penicillium , Talaromyces , Thielavia , Trichothecium and Meyerozyma (yeast; Table ). In previous investigations, fungal isolates displayed variable degrees of phytopathogenicity on pistachio stem, ranging from absence to high activity (Hadj Taieb et al ).…”

Identification of fungi in Tunisian olive orchards: characterization and biological control potential

“…The susceptibility of Alternaria consortialis to 14 of the fungal isolates as, e.g., Penicillium chrysogenum, Penicillium crustosum, Penicillium pinophilum, and Penicillium polonicum tested in this study is consistent with previous studies reporting the antagonistic activity of antifungal compounds produced by Penicillium sp., (Macropherin A, Atrpinin A, Botryodiplodin and Brefeldin A) which allowed the inhibition of Alternaria sp. [3,47].…”

“…Biological control is an often effective and environmentally friendly method for controlling pests and phytopathogens by a natural enemy and/or formulation. Some of these biological control methods as, e.g., combating insect pest species by pathogens and plant diseases by antagonists, were found efficient [ 1 – 3 ]. However, effectiveness is strongly related to the biological control agent’s origin, with native ones being more efficient and often achieve better results [ 4 , 5 ].…”