Suitability of C alifornia bay laurel and other species as hosts for the non‐native redbay ambrosia beetle and granulate ambrosia beetle

The redbay ambrosia beetle Xyleborus glabratus E ichhoff is a non‐native vector of the pathogen that causes laurel wilt, a deadly disease of trees in the family L auraceae in the southeastern U.S.A. Concern exists that X. glabratus and its fungal symbiont could be transported to the western U.S.A . and cause damage to C alifornia bay laurel Umbellularia californica ( H ook. & A rn.) N utt. in C alifornia and W ashington. The present study evaluated in‐flight attraction, attack density and emergence of X. glabratus and another invasive ambrosia beetle Xylosandrus crassiusculus ( M otschulsky) on cut bolts of C alifornia bay laurel and eight related tree species in an infested forest in S outh C arolina. Xylosandrus crassiusculus is not a vector of the laurel wilt pathogen but is a pest of nursery and ornamental trees. Mean catch of X. glabratus on C alifornia bay laurel bolts was not significantly different from catches on bolts of known X. glabratus hosts sassafras Sassafras albidum ( N utt.) N ees and swampbay Persea palustris ( R af.) S arg. Mean attack density and adult emergence of both beetle species from C alifornia bay laurel was equal to or greater than all other tree species tested. Both beetle species readily produced brood in C alifornia bay laurel bolts. The results obtained in the present study suggest that C alifornia bay laurel may be negatively impacted by both of these invasive ambrosia beetles if they become established in the tree's native range.