California Department of Public Health: Vector Borne Diseases - The Vector-Borne Disease Section (VBDS) protects the health and well-being of Californians from diseases transmitted to people from insects and other animals. 

Pests of Home and Landscape - Pest Notes - The University of California's official guidelines for pest monitoring techniques, pesticides, and nonpesticide alternatives.

UC Intergrated Pest Management Website - Full of useful information. Pest Management Guidelines for many crops, also Weather Data, Pesticide Safety, Invasive Weeds and Pest Notes. Develops and promotes the use of integrated and ecologically sound pest management programs in California

California Department of Food and Agricultural - Animal Health and Food Safety Division - Division of animal and food safety for California agriculture. Updates regarding pests/diseases of livestock can be found.

California Department of Food and Agriculture- Invasive Pests and Diseases - Information on exotic invasive species in California. Includes information on active quarantines