Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2008
Publication Date: 4/1/2008
Citation: Dara, S.K., Mcguire, M.R., Ulloa, M., Kaya, H.K. 2008. Evaluation and Molecular Characterization of Beauveria bassiana for the Control of the Glassy-winged Sharpshooter (Homoptera: Cicadellidae) in California. J. Entomol. Sci. 43(2):241-246. Interpretive Summary: The glassy-winged sharpshooter (GWSS) is a relatively new pest in California which was introduced from southeastern United States. GWSS transmits the causal agent of diseases in grapes, almonds, citrus and other host plants and is a major agricultural pest. A few fungal pathogens that attack insects are known to infect GWSS in its native states of Texas, Mississippi and Florida. Such natural infections are not yet detected in California. This study was conducted to evaluate the fungal isolates obtained from natural infections of GWSS in southeastern states against California populations of GWSS and compare them with native fungal pathogens isolated from insect hosts other than GWSS and from soil collected in GWSS habitats. Two California isolates and a Texas isolate of the fungus Beauveria bassiana were identified as potential biocontrol agents. Since controlling GWSS with insect pathogenic fungi is not studied anywhere else in California, this research provides crucial information in this area of research. This research will be beneficial to pest control practitioners, researchers developing non-chemical pest control tactics, and commercial producers of insect pathogens.
Technical Abstract: The glassy-winged sharpshooter, Homalodisca coagulata (Say), is an important pest on grapes, citrus, almonds and other commercial crops in California as it is a vector of Xylella fastidiosa Wells, a bacterium that causes Pierce’s disease in grapes, citrus variegated chlorosis, almond leaf scorch and other plant diseases. Various entomopathogenic fungi isolated from natural infections of H. coagulata, its habitats and other insect hosts were evaluated for their potential for suppression of this insect vector. Assays were conducted using the hyphomycetous fungi, Beauveria bassiana (Balsamo) Vuillemin, Metarhizium anisopliae (Metschnikoff) Sorokin, Hirsutella sp. and an unidentified fungus against adult H. coagulata. In addition, three isolates of B. bassiana were selected for further evaluation. Two of these were California isolates, one each from the three-cornered alfalfa hopper, Spissistilus festinus (Say) and soil from H. coagulata habitat, and the third was a Texas isolate from natural infections of H. coagulata. All three isolates were similar in their virulence to H. coagulata under laboratory conditions. The genetic relatedness of the B. bassiana isolates was also compared using single sequence repeat (SSR) markers which showed genetic diversity of this species based on the source of the isolate. Some isolates were four times more infectious than others demonstrating that virulence of B. bassiana is not necessarily associated with their genetic relatedness.