Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are wood-boring insects that have symbiotic associations with ambrosia fungi. In south Florida, several ambrosia beetles are associated with Raffaelea lauricola. This fungal pathogen is the causal agent of Laurel wilt, a deadly disease of avocado and other plants in the family Lauraceae. Ambrosia beetles are difficult to control using conventional methods because of their cryptic habits. Among the few organisms that inhabit the beetle’s galleries are phoretic mites. These organisms have been found in close association not only with the ambrosia beetles, but also with their fungal gardens. This work aims to identify the main phoretic mite species associated with ambrosia beetles in Florida and assess their potential use as biological control agents. A survey conducted in Miami-Dade County avocado groves revealed the presence of Histiogaster arborsignis (Astigmata: Acaridae), Proctolaelaps sp. (Mesostigmata: Melicharidae) and a potential new species in the Neopygmephoridae (Heterostigmata). The phoretic form (hypopi) of H. arborsignis was found associated with four ambrosia beetle species. Laboratory reared H. arborsignis were offered pure cultures of several ambrosia fungi and the entomopathogen, Beauveria bassiana. Feeding on Raffaellea spp. resulted in the highest H. arborsignis reproduction, followed by Fusarium sp. Feeding on B. bassiana resulted in poor H. arborsignis reproduction. Future research includes evaluating the ability of H. arborginsis and other phoretic mites to vector beneficial fungi into beetle galleries to disrupt the ambrosia beetle symbiosis and potentially target breeding sites of other wood-boring pests.
