Population genetic structure of Haplaxius crudus, the vector of palm lethal decline phytoplasmas, and planthopper diversity on coconut palms in Trinidad and Tobago (Hemiptera: Cixiidae, Delphacidae, Derbidae).

Planthoppers are a diverse and interesting group of insects. In the tropics, there are many undiscovered species and recent efforts have uncovered many new taxa associated with palms. One species of Cixiidae, Haplaxius crudus (Van Duzee), is economically important due to its ability to transmit palm lethal decline phytoplasmas, which has caused significant economic losses to palm producers across the Caribbean and the United States. A survey was conducted in Trinidad and Tobago to assess the potential threat that lethal yellowing and lethal bronzing pose to Trinidad and Tobago by evaluating the status of Haplaxius crudus (and other putative vectors) on the islands and genetically characterize populations in the islands to determine if H. crudus was a distinct haplotype. Populations of H. crudus were sampled and analyzed to assess genetic variability. Specimens of H. crudus were homogenous for the COI gene but represent a novel haplotype of the species. All specimens of H. crudus were negative for phytoplasma. Additionally, 8 species of Derbidae were documented, including one new species, Oropuna tobagoensissp. n., 5 species of Cixiidae and one species of Delphacidae on coconut palms. These data provide a valuable baseline to aid in the development of a long-term, robust monitoring program that will allow for rapid and early detection of palm phytoplasmas should they be introduced to the islands and ultimately help prevent the establishment of the disease and economic losses to the coconut industry.