Special effects experts were unable to produce an authentic-looking locust plague. Just as they were about to abandon the scene, they received word that a real locust plague was taking place several states away. A camera crew was rushed to the scene to capture it on film.
According to Peter Hay's 1991 book "MGM: When the Lion Roars", when MGM studio boss Louis B. Mayer learned of production chief Irving Thalberg's desire to film Pearl S. Buck's novel about Chinese peasants, he told him, "The public won't buy pictures about American farmers, and you want to give them Chinese farmers?" Opposed by Mayer, Thalberg had to appeal to Nicholas Schenck, the chief executive of MGM parent Loew's Theaters Inc. and President of MGM, to make the film. Permission was given, but Thalberg never lived to see the film completed.
Because of conditions in China at the time due to the general political instability and wars throughout the country (i.e., The Nationalist government was fighting off a Japanese invasion while at the same time battling Communist rebels and various powerful local warlords.) precluded shooting location footage there, MGM turned a 500-acre farm in Chatsworth, CA into Chinese farmland and shot the "location" footage there.
Because the Sino-Japanese war was in progress, the Chinese government threatened not to approve the movie if any Japanese actors were cast in any role.
American-born Chinese actress Anna May Wong desperately wanted the role of O-Lan. Being a close friend of author Pearl S. Buck helped. She tested for the role, but producer Irving Thalberg was unsatisfied. Although sources say that the Hays Code prohibited actors of different races from playing husband/wife couples on film, by 1934 the Production Code of America clarified that the miscegenation clause forbid only relations between blacks and whites. Thalberg offered her the "vamp" role of Lotus, but a distraught Anna May turned it down.