California State Government Structure: https://en.wikipedia.org/wiki/Government_of_California
State Agencies: Comprehensive alphabetical list:
http://www.ca.gov/Apps/Agencies.aspx
The state government department that deals with agriculture and related matters is the California Department of Food and Agriculture (CDFA)
The CDFA is composed of a number of divisions, one of which focuses on plants, plant health and related matters. It is officially known as the Plant Health and Pest Prevention Services Division (PHPPS), also known as the Plant Health Division.
But in addition to the PHPPS Division, which covers all other plant diseases, the CDFA also has a special program outside the PHPPS called Pierce's Disease Control Program (Glassy-winged Sharpshooter). Pierce's disease is of such great concern, because it attacks and kills grape vines, and is a huge threat to the California wine industry. Pierces Disease is caused by the bacteria Xylella fastidiosa, and is carried by the insect pest, Glassy-winged Sharpshooter, which is also a plant pest itself. The Xylella fastidiosa bacteria is also responsible for the the disease Olive Qick Decline Syndrome (OQDS), which has killed millions of olive trees in Italy, since the outbreak began in 2013. And just in March, 2015, the European Commission proposed cutting down 11 million olive trees as a means of attempting to control this disease.