A survey of auchenorrhynchan insects for identification of potential vectors of the 16SrIV-D phytoplasma in Florida

  • De-Fen Mou University of Florida, Department of Entomology and Nematology, Fort Lauderdale Research and Education Center, 3205 College Avenue, Davie, Florida 33314, USA
  • Alessandra R. Humphries University of Florida, Department of Entomology and Nematology, Fort Lauderdale Research and Education Center, 3205 College Avenue, Davie, Florida 33314, USA
  • Noemi Soto University of Florida, Department of Entomology and Nematology, Fort Lauderdale Research and Education Center, 3205 College Avenue, Davie, Florida 33314, USA
  • Ericka E. Helmick University of Florida, Department of Entomology and Nematology, Fort Lauderdale Research and Education Center, 3205 College Avenue, Davie, Florida 33314, USA
  • Marina S. Ascunce University of Florida, Department of Plant Pathology and Emerging Pathogens Institute, Gainesville, Florida 32611, USA
  • Erica M. Goss University of Florida, Department of Plant Pathology and Emerging Pathogens Institute, Gainesville, Florida 32611, USA
  • Brian W. Bahder University of Florida, Department of Entomology and Nematology, Fort Lauderdale Research and Education Center, 3205 College Avenue, Davie, Florida 33314, USA

Abstract

Lethal bronzing disease is caused by the 16SrIV-D phytoplasma and is fatal to many palm species. This disease has caused significant economic losses to nursery and landscaping industries in Florida. As is the phloem-limited nature of phytoplasmas, the lethal bronzing disease phytoplasma is transmitted only by phloem-feeding insect vectors. However, the vector remains unconfirmed and this impedes the development of Integrated Pest Management programs that target vector populations. The primary objective of this study was to identify potential vectors of the 16SrIV-D phytoplasma in Florida by surveying auchenorrhynchans using sticky traps at the area where the disease is actively spreading, and screening the specimens for the presence of the phytoplasma. Cixiidae, Cicadellidae, Derbidae, and Membracidae insects were collected consistently during the 1-yr survey. The total number of a cixiid planthopper, Haplaxius crudus (Van Duzee) (Hemiptera: Cixiidae), was significantly higher than other insects that were collected on the traps. Of 3,734 specimens tested by nested polymerase chain reaction, approximately 0.672% of the H. crudus specimens and 1 unidentified leafhopper (Cicadellidae sp.) tested positive for the16SrIV-D phytoplasma. The 16S sequences amplified from the positive specimens were confirmed by sequencing and phylogenetic analysis. Based on the population survey and the polymerase chain reaction assay results, we suggest that H. crudus is the potential vector of the 16SrIV-D phytoplasma. However, the vector competency of H. crudus needs to be further investigated due to the possibility of feeding residue being detected. The study has important implication for current lethal bronzing disease management by monitoring and controlling vector candidates in disease areas.

 

Resumen

La enfermedad del bronceado letal es causada por el fitoplasma 16SrIV-D y es fatal para muchas especies de palmeras. Esta enfermedad ha causado pérdidas económicas importantes a las industrias de viveros y paisajismo en Florida. Como la naturaleza de los fitoplasmas se limita al floema, el fitoplasma la enfermedad del bronceado letal solo puede ser transmitido por insectos vectores que se alimentan del floema. Sin embargo, el vector responsable permanece sin confirmar y esto impide el desarrollo de programas de manejo integrado de plagas enfocados a las poblaciones del vector o vectores. El objetivo principal de este estudio fue identificar los posibles vectores del fitoplasma 16SrIV-D en Florida mediante el muestreo de auchenorrhynchans utilizando trampas adhesivas en el área donde la enfermedad se está propagando activamente y examinando las muestras para detectar la presencia del fitoplasma. Los insectos pertenecientes a las familias Cixiidae, Cicadellidae, Derbidae y Membracidae fueron recolectados consistentemente durante el muestreo de un año. El número total de chicharritas cixíidos, Haplaxius crudus (Van Duzee) (Hemiptera: Cixiidae), fue significativamente mayor que otros insectos que fueron recolectados en las trampas. De 3,734 muestras analizadas por reacción en cadena de la polimerasa anidada, aproximadamente el 0.672% de las muestras de H. crudus y 1 chicharrita no identificada (Cicadellidae sp.) dieron positivo para el fitoplasma 16SrIV-D. Las secuencias 16S amplificadas de las muestras positivas se confirmaron mediante secuenciación y análisis filogenético. Según el estudio de la población y los resultados de reacción en cadena de la polimerasa, sugerimos que H. crudus es el vector potencial del fitoplasma 16SrIV-D. Sin embargo, la habilidad de H. crudus como vector responsable debe de investigarse más a fondo debido a la posibilidad de detectar residuos de alimentación. Este estudio tiene implicaciones importantes en el manejo actual de la enfermedad del bronceado letal al monitorear y controlar los candidatos a vectores en áreas donde la enfermedad esté presente.

Key Words: lethal bronzing disease; Texas Phoenix Palm Decline; phytoplasma vector; palm disease; Cixiidae; Cicadellidae

View this article in BioOne

Published
2020-09-25
Section
Research Papers