▁October ▁through ▁November ; ▁for ▁oil ▁production , ▁they ▁are ▁har v ested ▁between ▁mid - Dec ember ▁and ▁February . ▁They ▁are ▁sus cept ible ▁to ▁pe ac ock ▁spot , ▁a ▁disease ▁caused ▁by ▁the ▁fung us ▁Cy clo con ium ▁o le agin um , ▁and ▁o live ▁kn ot , ▁a ▁disease ▁caused ▁by ▁the ▁b acter ium ▁Pseud omon as ▁sav ast ano i . ▁ ▁Us es ▁Mission ▁ol ives ▁are ▁one ▁of ▁five ▁cultiv ars ▁( al ong ▁with ▁As col ano , ▁Bar ou ni , ▁Man zan illa , ▁and ▁Se v ill ana ) ▁commer cially ▁vi able ▁in ▁California ▁for ▁production ▁as ▁table ▁ol ives . ▁They ▁have ▁also ▁been ▁used ▁in ▁the ▁production ▁of ▁o live ▁oil ▁since ▁the ▁days ▁of ▁the ▁Spanish ▁miss ions . ▁ ▁Pre val ence ▁In ▁ 1 9 9 2 , ▁the ▁Mission ▁cultiv ar ▁represented ▁just ▁over ▁eight ▁percent ▁of ▁California ' s ▁overall ▁o live ▁a cre age . ▁Mission ▁ol ives ▁were ▁dominant ▁until ▁ 1 8 7 5 , ▁when ▁And alus ian ▁imm igr ants ▁introduced ▁the ▁Man zan illa ▁cultiv ar ; ▁subsequent ▁introdu ctions ▁further ▁reduced ▁the ▁percentage ▁of ▁Mission ▁trees ▁in ▁California . ▁After ▁Man zan illa ▁and ▁Se v ill ana , ▁however , ▁it ▁remains ▁one ▁of ▁the ▁more ▁common ▁cultiv ars ▁in ▁the ▁state . ▁The ▁O ro ville ▁district ▁in ▁But te ▁County ▁is ▁a ▁major ▁Mission ▁producer . ▁ ▁Origin ▁O live