EFFECTS OF FEEDING SUBSTRATE ON RETENTION AND TRANSMISSION OF XYLELLA FASTIDIOSA STRAINS BY THE GLASSY-WINGED SHARPSHOOTER

• Author(s): Cooksey, Donald; Costa, Heather; Bextine, Blake;
• Abstract: In this project we are testing the effects of feeding substrate on the acquisition and retention of Xylella fastidiosa by the glassy-winged sharpshooter (GWSS), Homalodisca coagulata. We are using two strains of X. fastidiosa that are present in California: a Pierces disease (PD) strain that infects grape, and an oleander leaf scorch (OLS) strain that infects oleander. A series of experiments were conducted to compare the retention of PD or OLS strains after acquisition, when insects were subsequently maintained on a plant species that was either a host or non-host of that particular strain. In these studies, we found no significant difference in the mean proportion of insects testing positive for the PD or OLS strains, regardless of whether the insects were subsequently fed on either a host or a non-host of the PD or OLS strain. Thus, retention of a particular strain of the pathogen by an individual insect does not appear to be dependant on the xylem content of the plant host on which it is feeding. In a second study transmission efficiency of adult GWSS fed for 24 h on X. fastidiosa-infected plants was compared to those fed for 24 h on X. fastidiosa from pure media-grown cultures delivered through a cut stem system. In these experiments insects transmitted PD and OLS strains when they acquired the bacteria from a plant, but did not transmit either strain when media-grown bacteria were delivered through the cut-stem system.
• Publication Date: Dec 2004
• Journal: 2004 Pierce's Disease Research Symposium