Olive fruit fly (Bactrocera oleae) is believed to have originated in the Mediterranean region where there are records of infestations in fruit from the third century BC. It is also found in eastern and southern Africa where wild native olive trees are found and where there are more natural enemies. It was found for the first time in the US in October 1998 in Los Angeles, California. Since then it has spread to the rest of southern California in 1999 and the Central Valley starting in 2000. It was detected in Marin, Napa, Sonoma and Solano Counties in November of 2001, in Shasta in June of 2002, and in El Dorado and Lake Counties in July 2002.