Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Abstract Only
Publication Acceptance Date: August 20, 2004
Publication Date: December 7, 2004
Citation: Hunter, W.B., Albrecht, U., Achor, D. 2004. Glassy-winged sharpshooter iridovirus pathogen (Hemiptera: Cicadellidae: Homalodisca coagulata) [abstract]. CDFA Pierce's Disease Control Program Research Symposium. Technical Abstract: Pierce's Disease of grapes is caused by the bacterial pathogen Xylella fastidiosa. Other diseases also caused by these bacteria pose serious economic losses to U.S. agriculture, reducing production of grapes, almonds, fruits, oaks, and other woody crops. The glassy-winged sharpshooter, GWSS, Homalodisca coagulata, is the primary insect spreading these bacteria, thus reducing the ability of the U.S. to compete in world markets. Use of naturally occurring insect infecting viruses, or similar viruses introduced into an insect population can significantly reduce insect numbers by increasing mortality, or reducing population growth by reducing the number of eggs that are laid or survive. We demonstrate that several viruses may have a use in reducing the impact of GWSS in the spread of Pierce's Disease. Viral pathogens of leafhoppers are just now being examined as potential microbial control agents. We report on the pathogenicity of an iridovirus, which are the iridescent insect infecting viruses from the family Iridoviridae, and its effect on the GWSS. Adult GWSS were successfully infected with the iridovirus which was cultivated in lepidopteran larvae, Trichoplusia ni. Virus infection demonstrated a reduction in longevity and fecundity of GWSS. Adults were infected by microinjection and spray treatments. Infected individuals also transmitted the virus to 'healthy' GWSS's when caged together, suggesting an aerosol mode of transmission. Egg masses were tested and detection of virus positive eggs suggests that this iridovirus may be transovarially transmitted, from infected females into their eggs. Iridovirus infection of the GWSS had pathogenic effects. Further research on leafhopper viruses may lead to new, highly specific, microbial control agents against leafhopper vectors of Pierce's Disease such as the GWSS.