Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 17, 2011
Publication Date: February 1, 2012
Citation: Yokoyama, V.Y. 2012. Olive fruit fly (Diptera: Tephritidae) in California: Longevity, oviposition, and development in canning olives in the laboratory and greenhouse. Journal of Economic Entomology. 105:186-195. Interpretive Summary: Olive fruit fly is a serious pest of olives in California and control methods are dependent on a complete understanding of the insect’s life cycle in its host. Greenhouse and laboratory research showed that olive fruit fly adults can live up to seven months in cool climates if a source of food and water is available. Females can lay eggs for three months, and larvae can develop to adults in fruit that is 3/8 of an inch in height. The larvae develop in three stages in fruit, and growth is slow in cooler temperatures and rapid in warmer temperatures. The pupal stage that exits the fruit is less likely to metamorphosis to adults when temperatures are high. The rapid increase in olive fruit fly numbers in cool coastal areas versus the warm interior valleys of the state is explained by these findings. Our results show that control tactics must be applied when the fruit is small and susceptible to prevent the adults from producing many generations during the growing season. This work helps protect the $90 million annual olive crop in California and the center of production of olives for the nation.
Technical Abstract: Olive fruit fly adults, Bactrocera oleae (Gmelin), lived 11 d without food and water, and 8 d with food and water in the warm side of a greenhouse; and, in the cool side, adults lived 10 d without food and water, and percentage survival with food and water was about 50, 25, 10, 1, and 0 at 26, 46, 80,124, and 203 d, respectively. A significantly higher number of adults survived during the 1st 10 d in the cool side with food and water than without, or than in the warm side. First and last eggs were oviposited in olive, Olea europaea L., fruit when females were 6 and 90 d-old, respectively. The highest numbers of eggs per day in 10 olive fruit (54.6 ± 24.4) were oviposited by 28 d-old females, and peak egg production occurred when females were between 13-37 d-old. Fruit height from the stem to the blossom end was significantly different among five sizes, and the calculated fruit volume was significantly different among three of six sizes of olive fruit. A significantly greater number of ovipositional sites occurred in all sizes of immature green fruit when exposed to adults in cages for 5 d versus 2 d. Adults emerged from fruit exposed to oviposition that had a height of greater than or equal to 1.0 cm or a volume of greater than or equal to 0.2 cm³. More than 7 adults per 15 fruit emerged from field infested fruit with a height of 1.1 cm and volume of 0.1 cm³. Mean duration of the egg stage was 6, 3, and 2 d; 1st instar was 18, 4, and 4 d; 2nd instar was 5, 3, and 1 d; and, 3rd instar was 3, 2, and 5 d at 15, 21, and 25ºC, respectively. Larval length was significantly different among the instars at 15ºC, 21ºC, and 25ºC. Mean larval length ranged from 0.7-1.6, 2.4-4.3, and 4.8-5.6 at 15ºC; 0.8-1.1, 1.9-2.9, and 3.9-4.4 at 21ºC, and 0.7-1.3, 2.4-2.9, and 4.4-4.8 at 25ºC for 1st, 2nd, and 3rd instars, respectively. Survival of pupae to the adult stage was significantly lower at 25°C and 35% than at 15°C and 65%, and 21°C and 60% RH. The period of adult emergence began at 38, 14, and 11 d over a period of 8, 5, and 1 d at 15, 21, and 25°C, respectively.