Pierce's disease of grapevines, caused by a strain of the bacteria Xylella fastidiosa, threatens an industry with a farm value of production exceeding $3 billion per year. The grape industry incurs substantial costs from losses of vines to the disease and efforts to mitigate damage. Additional costs are borne by the public in providing programs that aim to contain the disease and develop longer-term solutions, and by the citrus, nursery and grape industries in complying with those programs. Aggregating the costs of vine losses, industry assessments, compliance costs, and expenditures by government entities, we estimate the cost of Pierce's disease in California is approximately $104.4 million per year. Of that, $48.3 million funds Pierce's disease activities undertaken by various government agencies, the nursery and citrus industries and the UC system, and $56.1 million is the cost of lost production and vine replacement borne by grape growers.