Alexander "Sandy" Purcell, professor of entomology at UC Berkeley's College of Natural Resources, retired July 1 after 35 years of research and teaching. Purcell was instrumental in first culturing Xylella fastidiosa and demonstrating the bacteria as the cause of Pierce's disease, whose devastating effects on grapevines gravely threaten California's vineyards.

Much of Purcell's work has focused on the understanding and mitigating the impacts of the glassy-winged sharpshooter, X. fastidiosa's most dangerous vector.

"Sandy wrote the book on understanding the process by which many important agricultural diseases operate," said UC Berkeley collaborator and microbial biology professor Steve Lindow. "His work has been unique and incredibly important because it looks at both the process of plant pathology via insect vectors, and also the epidemiology of disease, understanding how a disease moves around."

Purcell earned his Bachelor of Science degree from the U.S. Air Force Academy in Colorado and his Ph.D. in Entomology at UC Davis, in 1974. He began teaching at UC Berkeley in 1974 and served as chair of the department of Environmental Science, Policy and Management from 1993 to 1994 and as head of the Environmental Biology division the following year.

Rodrigo Almeida, an assistant professor of insect biology at UC Berkeley and Purcell's former graduate student, said that in addition to his research contributions, Purcell was also a great mentor. "Members of the lab group could always try their own ideas. He never said 'this is a bad idea,' but instead subtly directed people to where they would find their own success," Almeida said.

Most importantly, Almeida said, "Sandy always emphasized the importance of field work, and of linking basic research to real-world problems."

Purcell, who was granted emeritus status, plans to continue some of his research over the next two to three years.