Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Proceedings
Publication Acceptance Date: 10/9/2009
Publication Date: 12/9/2009
Citation: Bextine, B., Hunter, W.B., Marshall, P., Hail, D. 2009. Identification and whole extraction of Homalodisca coagulata Virus 01 (HoCV-01) from Texas Glassy-winged sharpshooter populations. p. 9-12. In: Proceedings 2009 Pierce's Disease Control Program Research Symposium. Available: http://www.cdfa.ca.gov/pdcp/2009 Research Proceedings.html. Interpretive Summary: A leafhopper-infection virus, HoCV-1, shows promise as a tool for biological control. While the virus did not cause significant acute mortality, it reduced the fitness of the insects to a point where other control methods would be more effective, such as insecticides. The glassy-winged sharpshooter is the most economically important insect with respect to the spread of Xylella fastidiosa, the causal agent of Pierce’s Disease. Therefore control of this insect is of paramount importance to the management of the disease. While insecticides have been used successfully to reduce the economic impact of this disease system, alternate methods of population insect control are needed to continue management in the future. Biological control offers alternatives to chemical control that can be effective in negatively impacting insect population without harmful environmental effects or concern for insecticide resistance. We describe a virus that shows promise as a tool for biological control. We suggest that viral infection will make insects more sensitive to insecticide treatment. If so, lower insecticide rates could be used.
Technical Abstract: Viral infection makes insects more sensitive to insecticide treatment, resulting in lower LD50 rates needed to achieve significant control. The glassy-winged sharpshooter, GWSS, Homalodisca vitripennis (Hemiptera: Cicadellidae), is an invasive pest and important vector of Xylella fastidiosa, a xylem-limiting bacteria that causes Pierce’s Disease in grapes as well as other agricultural diseases. The primary method of managing the spread of Xylella is controlling its insect vector populations. Methods such as chemical control are not target specific and lead to problems such as residue contamination, injury to non-target organisms, and insecticide resistance. Identifying agents that can suppress H. vitripennis populations is the goal of this biological control strategy. In this study, we have identified and extracted whole virus [Homalodisca coagulata Virus-1 (HoCV-1)] from populations of H. vitripennis collected in Texas. HoCV-1 is a ssRNA virus that harbors pathogenic potential with regard to GWSS. Future plans for HoCV-1 include reintroduction into GWSS populations as a spray and through feeding. Increased amounts of HoCV-1 infection lead to weakened populations of GWSS that were more susceptible to current control methods such as insecticides. This would decrease the amount of insecticide needed to produce a desired mortality rate in GWSS populations, and reduce costs to growers.