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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Commodity Protection and Quality Research » Research » Publications at this Location » Publication #307573

Title: Distribution of olive fruit fly in California based on fruit infestations since the 1998 invasion

item Yokoyama, Victoria

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/25/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Olive fruit fly, Bactrocera oleae (Rossi), was first discovered in Los Angeles, California in 1998. Eradication and containment programs were immediately initiated, but within four years the olive pest was detected throughout the state. Olive fruit fly is not tolerated in canned fruit, and the insect has potential to destroy the annual table olive crop which is solely produced in California for domestic consumption. Pest abundance and distribution has been traditionally determined with yellow sticky traps with adult pheromone lures and female baits, but trap captures are not good indicators of fruit damage. To determine the extent of fruit infestations, olives were collected throughout the state and evaluated for olive fruit fly larval emergence. Olives were maintained in the laboratory in plastic containers, and mature larvae emerging from the fruit were collected as pupae. Larval age was evaluated by emergence date, and insect density was determined by numbers per fruit or fruit weight. Olive growing regions were delimitated by climate and county and classified as inland valley including the Sacramento and San Joaquin Valleys, or coastal including the northern, central, and southern coast. Infested fruit was collected primarily during the fall when olive fruit fly populations were prevalent. Collection sites were reported by coordinates and compared among the olive growing regions from 1999 to 2013. A large amount of infestation data was obtained during an intensive biological control program in which a parasitoid imported from Guatemala was released throughout the state from 2002-2011. Olive fruit fly adults were shown to be heat sensitive, and populations in table olives were limited in distribution by high summer temperatures. Fruit infestations were highest and as many as three adults were reared per fruit in olives grown along the humid Pacific coast where temperatures are mild throughout the year. Lowest infestations or < 1 per fruit were collected from olives grown in the hot and dry inland valleys. Fruit grown in the foothills at or above 125 m where temperatures were mild, also had infestations more typical of coastal populations. Olive fruit fly has not yet become an economic pest of new high density plantings of oil olives grown in the Central Valley of California. Although mature olive fruit grown for oil is smaller than fruit grown for canning, unripe table fruit 1 cm in length can produce one olive fruit fly adult, so the pest has potential to migrate to oil olives.