James F. Bonner, 86, a Caltech molecular biologist who improved methods of harvesting oranges and other citrus crops. Bonner was co-inventor of the mechanical method now used by most Florida citrus growers to harvest orange groves. He also found ways to improve the collection of natural rubber, which helped Malaysia double its rubber production and was an international advocate of population control. Bonner, a former president of the American Society of Plant Physiologists, was also co-author of a number of textbooks, including "Principles of Plant Physiology" in 1952 and "The Molecular Biology of Development" in 1965. He was an amateur photographer, an avid traveler and a ski patrolman for the National Ski Patrol System. On Sept. 13 in Pasadena.