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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Publications at this Location » Publication #224937

Title: Use of GIS maps in assessing the role of alfalfa in the epidemiology of xylellae diseases in California

item Sisterson, Mark

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/21/2008
Publication Date: 4/23/2008
Citation: Sisterson, M.S., Lynn-Patterson, K., Thammiraju,, S.R., Daane,, K., Groves,, R.L. 2008. Use of GIS maps in assessing the role of alfalfa in the epidemiology of xylellae diseases in California. California Geographic Information Systems (CalGIS) Annual Conference. Available:

Interpretive Summary:

Technical Abstract: Grape and almond are planted throughout much of California. Both crops are susceptible to diseases caused by Xylella fastidiosa. Within California’s Central Valley, the green sharpshooter (Draeculacephala minerva) is a key vector. This insect is often found in large numbers in cultivated alfalfa fields and alfalfa is a known host of X. fastidiosa. We are currently conducting studies to assess the role of alfalfa as a source of vectors and/or X. fastidiosa inoculum. GIS maps have significantly assisted in this analysis. Specifically, we used GIS maps, generated by pesticide use reports in California, to determine which counties in California have the greatest overlap of grape and almond with alfalfa. We found that the degree of overlap of grape and almond with alfalfa was greatest in Kern, Fresno, and Tulare counties. In addition, we are mapping field sites to visualize the spatial relationships between areas of high vector abundance and diseased plants.