DOMESTIC, EXOTIC, AND EMERGING DISEASES OF CITRUS, VEGETABLES, AND ORNAMENTALS (DEED)
Location: Subtropical Plant Pathology Research
Title: Is the striped mealybug, Ferrisia virgata, a vector of huanglongbing bacterium ‘Candidatus Liberibacter asiaticus’
Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: March 17, 2011
Publication Date: N/A
This is the first report of ‘Ca. L. asiaticus’ (Las) present in striped mealybugs feeding on Las-infected periwinkle plants. In November 2010, specimens of a common greenhouse pest, the striped mealybug Ferrisia virgata (Cockerell) (Pseudococcidae; Hemiptera), were collected from Las-infected periwinkle plants in an U.S. Horticultural Research Laboratory greenhouse, Fort Pierce, Florida, and tested positive for the presence of Las bacteria using standard and quantitative Polymerase Chain Reaction (PCR) methods. The Las presence in mealybugs was further confirmed by conventional PCR with six additional primer sets LJ95f/LJ589f, LJ557f/LJ769r, LJ119f/LJ120r, LJ79f/LJ561f, LJ518r/LJ519f and LJ289f/LJ290r targeting different Las loci, followed by 100% sequence similarity of all seven PCR amplicons using Sanger sequencing. Additional F. virgata samples (25 ea.), taken from healthy guava plants located in an uninfected greenhouse, tested negative for Las.
The identity of Ferrisia virgata was determined by the presence of two longitudinal dark stripes on the dorsum and by micro-morphological characteristics of slide mounted females. Predominantly sap-feeding plant parasites, scale insects are an important pest of agriculture, horticulture, and forestry. Plant damage results from sap feeding, honeydew contamination, toxic salivary secretions, and viral transmission by some species. Ferrisia virgata is a documented vector for cocoa swollen shoot viral disease in West Africa and citrus tristeza virus in Ghana. Further investigations by the lab will elucidate the potential for striped mealybug to act as another vector of the Huanglongbing (HLB) bacteria and if so, the efficiency of Las transmission by the insect.