Robert J. Mullen, emeritus UC Cooperative Extension vegetable crops advisor, died on April 25, 2026. He was 83.

In 1970, Mullen joined UC ANR as a UC Cooperative Extension farm advisor, working first in San Diego and Contra Costa counties, before settling in San Joaquin County as a UCCE vegetable crops advisor specializing in tomato, asparagus and potato production with an expertise in weed science, 

Mick Canevari, UCCE farm advisor emeritus, recalled Mullen as a colleague, mentor and a friend during his tenure with UCCE in San Joaquin County. 

“As a mentor, he introduced me to the world of weed science and the many colleagues that we considered family,” said Canevari. 

“Conducting research trials with Bob was both an education and a marathon, completing in one day which took most of us three times as long. He would never say no when it meant helping his friends and growers,” Canevari said.

Over his UCCE career, Mullen conducted some 1,000 research trials and wrote 200 scientific reports and papers.

To illustrate Mullen’s prolific research, Canevari recalled a major grower cooperator at Mullen’s retirement party saying jokingly, “Bob, your energy level is amazing – you have so many research flags in my field, there’s no more room for me to farm. Suggest you place four flags in each corner of the field and take over the entire farm!”

Born and raised in San Francisco, Mullen attended UC Berkeley as a pre-dental major before taking a class in agriculture, which inspired him to pursue a different career. He transferred to UC Davis to earn a bachelor’s degree in horticulture in 1966. 

After college, Mullen attended U.S. Naval Officer Candidate School in Newport, Rhode Island, and was commissioned an ensign. He was appointed lieutenant junior in 1969. He served as a deck and weapons officer aboard the USS Stone County (LST 11412) and on the COMLANSHIPRON ONE staff, as well as a Naval Security Officer for a period of time in DeNang, South Vietnam. He became a lieutenant commander in 1982 and served in the Naval Reserves for 12 more years while working for UC ANR.

“Bob Mullen was a valued UC colleague,” said Gene Miyao, emeritus UCCE farm advisor in Yolo County. “Bob was an energetic advisor with an ambitious applied research program in grower fields. He evaluated many herbicides and fungicides for vegetable crops to improve crop production. Bob’s findings had impact locally, statewide and internationally.”

Mullen, who retired from UC ANR in 2004, received several achievement and distinguished service awards over his career, including being inducted into the Stockton Agricultural Hall of Fame in 2004.

“He is remembered for his love of agriculture and his passion for working closely with growers and industry to solve problems,” Canevari said. “His energy never waned, whether in the field following a tomato harvester all day, speaking at conferences or hiking a historical trail in the High Sierras. His daily pace, both physically and mentally, was a challenge for most humans.”

Mullen served as a board member and professional improvement chairman of the California Association of Farm Advisors and a member of the National Association of County Agricultural Agents. He was involved with the California Asparagus Growers Association, the California Tomato Growers Association, the American Society for Horticulture Science, Lodi Rotary Club, Micke Grove Zoological Society, and the San Joaquin County Agricultural History Museum.

In 2011, Mullen and his spouse, Maureen Mullen, moved to Anacortes, Washington.

“Bob’s legacy will be remembered by his work ethic, his knowledge and his pride in being a UC farm advisor; one who carried on the great legacy of Cooperative Extension’s mission to California agriculture, Canevari said.

Mullen is survived by Maureen, daughter Michelle Mullen, son Jerry Mullen (Carli) and granddaughter Macy Mullen-Racca.

A mass of celebration of Mullen’s life and reception is planned to be held at St. Luke Catholic Church in Stockton on June 11 at 11 a.m.

Read more about Mullen’s life at www.evanschapel.com/obituary/bob-mullen.