In 1922, Christie began working with N. A. Cobb at the USDA Bureau of Plant Industry, where he remained for 31 years. In 1954, he joined the faculty at the University of Florida and established a nematology program. Christie worked with nematode parasites of insects and later focused on foliar and root-knot nematodes. He was a pioneering nematologist, developing nematicides and other nematode-management strategies. His greatest contributions included chemical nematode control work in the 1940s that led to the widespread use of ethylene dibromide and the discovery that ectoparasitic nematodes were of major economic importance. Christie was elected a fellow of APS in 1972.
(Submitted for publication in July 2008.)