Abstract

Diaphorina citri (Hemipteran: Psyllidae), the Asian citrus psyllid, is a phloem-feeding, invasive species endemic to southern Asia that was first identified in the United States in Florida in 1998. Since introduction, D. citri has spread across the major citrus growing regions of the United States. This is of great concern to the citrus industry because D. citri is the primary vector of Candidatus Liberibacter asiaticus the causal agent of Haunglongbing (HLB). Haunglongbing is the most economically devastating disease of citrus causing an estimated 8.92 billion dollars lost in revenue and 4.62 billion dollars lost in gross domestic product between 2006-2007 in Florida alone (Hodges and Spreen, 2012). Current management strategies have had some effect on the spread of Candidatus Liberibacter asiaticus; however, due to concerns about insecticide resistance and the effect on non-target organisms, new pest management strategies need to be considered. Most of the current insecticides used to treat psyllids are neuromuscular toxins which affect the nervous system and muscles. Cyclaniliprole is an anthranilic diamide that acts on the endoplasmic reticulum’s ryanodine receptor in insects. When D. citri were exposed to citrus leaf substrate containing cyclaniliprole significant mortality was observed. Flonicamid is an antifeedent currently used on sap feeding insects like aphids. D. citri exposed to leaves treated with flonicamid had an alteration in feeding behavior. Flonicamid also has very low toxicity to humans. Possible biological management strategies were also considered. Paratransgenesis is a strategy that attempts to remove a pathogens transmission ability from a vector by transforming a symbiont of the vector that would produce a protein that is toxic to the pathogen. In this case, the paratransgeneic model would be to remove Candidatus Liberibacter asiaticus from D. citri using an alimentary associated bacterium isolated from D. citri an alimentary canal associated bacterium that was isolated from D. citri. This bacterium was identified as Enterobacter cloacae and the bacterium and associated plasmid were annotated for use in a future paratransgeneic management strategy for D. citri.

Date of publication

Summer 6-14-2016

Document Type

Thesis

Language

english

Persistent identifier

http://hdl.handle.net/10950/395

Committee members

Dr. Blake Bextine, Dr. Kate Hertweck, Dr. Dustin Patterson, Dr. Riqing Yu

Degree

Masters of Biology