|HAVILAND, DAVID - University Of California - Cooperative Extension Service|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2021
Publication Date: 4/26/2021
Citation: Sisterson, M.S., Burbank, L.P., Krugner, R., Haviland, D., Stenger, D.C. 2021. Spread of Xylella fastidiosa by the glassy-winged sharpshooter in the San Joaquin Valley of California. Meeting Abstract. p. 51.
Technical Abstract: The glassy-winged sharpshooter is an invasive vector of Xylella fastidiosa that arrived in California in the late 1980’s. Pierce’s disease epidemics in the Temecula Valley in the late 1990’s and in the southern San Joaquin Valley in the early 2000’s were associated with high glassy-winged sharpshooter abundance. In response, an area-wide glassy-winged sharpshooter suppression program was initiated that successfully reduced glassy-winged sharpshooter populations for nearly a decade. However, beginning in 2009 glassy-winged sharpshooter populations in the southern San Joaquin Valley began increasing and as a result another epidemic occurred. A field study was conducted to provide quantitative estimates of the effects of time of year on prevalence of X. fastidiosa-positive sharpshooters and detection of X. fastidiosa in chronically infected grapevines. Vineyards were sampled to assess the abundance of glassy-winged sharpshooters, with all sharpshooters subjected to qPCR to determine if X. fastidiosa was present in insect mouthparts. In addition, petiole samples were collected from chronically infected grapevines throughout the summer to monitor pathogen populations present in grapevines.Chronically infected grapevines did not test positive for X. fastidiosa until July. Similarly, X. fastidiosa-positive-sharpshooters were rare in vineyards until vines began to test positive. Results suggest that secondary (vine-to-vine) spread of X. fastidiosa is most likely to occur during July, August, and September in vineyards in the southern San Joaquin Valley.