PacBio sequencing of the fungal mutualists associated with Xylosandrus crassiusculus found on avocado

This study aimed to survey ambrosia beetle populations in South African avocado orchards to detect the polyphagous shot hole borer (PSHB) (Euwallacea fornicatus) and other potentially harmful ambrosia beetles that could potentially vector pathogens. This was followed by subsequent metabarcoding studies to identify potential pathogens associated with the most prevalent beetle species. Results from this study revealed that avocado in South Africa hosts seven Scolytine species with Xylosandrus crassiusculus being the most prevalent. Metabarcoding results identified 31 OTUs (operational taxonomic units) and revealed that X. crassiusculus hosts a functionally diverse fungal community including plant pathogens. The pathogenicity of Ambrosiella roeperi was investigated on commonly planted avocado cultivars including Hass, Fuerte and Pinkerton in a greenhouse trial and revealed that A. roeperi caused disease on this host.