Current News
	Biological Information about the Olive Fly
	Assessment of olive fly infestation
	Making control decisions
	Olive fly abatement methods
	Products available in California
	People involved in Olive Fly abatement in California
	Setting up a Pest Control District
	Olive Moth - Prays Oleae
	Pesticide use figures - Olive
	A Homeowner's Guide to the Olive Fruit Fly

From the Tree of Life

The Diptera Site - hosted by the U.S. Department of Agriculture - a site devoted to flies includes information on troublesome species such as the  fruit flies

Mediterranean basin, northern, eastern and southern Africa, Canary Islands, India, western Asia, and apparently wherever olives (the genus Olea) occurs in the Eastern Hemisphere. Has moved into the US via Mexico.  Not currently found in New Zealand and Australia olives.

The fly lives all of its life stages solely in the olive fruit and emerges as a winged adult in the early spring from unpicked or dropped fruit. There may be a sharp peak in flies caught in pheromone traps in March or April if fruit is available for egg-laying. By May there are no longer any acceptable host fruit so the fly becomes an asexual creature and is no longer interested or caught in pheromone traps. At this time and others, the fly can be found and trapped on plants other than the olive, although they do not molest them. When the new olive crop reaches a stage where the pit begins to harden it gives off chemicals which trigger the development of eggs in the female. The male flies are again attracted to pheromone attractants and mate with females. The ovipositor scar where the egg is laid is often the first evidence of infestation. The eggs hatch in 2 to 3 days and larvae will develop in 20 days during the peak season. The larvae create galleries in the fruit which is quickly infected with fungus. Between the mold and galleries, oxidative damage also occurs. Infestation of greater than 1% of olives in a grove render them unusable for table olives and if greater than 10% unusable for oil.  There may be time for several reproductive cycles in a single year. Temperatures greater than 104 degrees  for more than several hours and low relative humidity (less than 35%) will discourage the fly. Water stress resulting in shriveled fruit will impede fly infestation. Eventually lack of fruit or cold weather causes populations to decline in the late winter. A few of the insects find a home in unpicked or dropped fruit and over winter to start the cycle over.

Olive flies require a bacterial symbiont in their gut to break down the olive flesh.  The symbiont, Pseudomonas savastanoi, is the causal agent of olive knot disease.

Several investigations are ongoing to assess how far the flies spread.  A "flight mill" was used to determine how far a fly can go on a given amount of food.  The flies were glued to an outrigger and flew in circles till exhaustion.  Laps were counted and speed and distance calculated.  Females flew faster but males flew further.  Flies fed a protein rich diet tended to disperse less; energy may have gone into reproductive vs. flying organs.

A field test was also done to assess fly dispersal.  Flies marked with a fluorescent dye were released in a Fremont orchard.  Traps placed in a radial pattern were checked for wandering flies.  Interesting observations were that females left olive orchards for a nearby walnut orchard where presumably shade and cooler conditions prevailed. The adult flies may congregate in areas where sucrose is available from aphid infestations.  Adult olive flies have been collected in orange, lemon, grapefruit, tangerine, calomondin, cherry, plum, avocado, loquat, nectarine and Surinam cherry trees.

In Europe the fly prefers larger sizes of olives with a higher water content which describes most table olive varieties. The larger fruit produce greater numbers of fly larvae and increase larvae survival.  Preliminary studies by Zalom, Burrack and Kreuger show that the fly has definite variety preferences.  This could be important for oil producers who have multiple varieties to choose for planting.  Olives from different varieties were picked from an experimental grove (Wolfskill) near Winters which has 137 varieties of olives.  The olives were stored in nitrogen until sorted into ripe and unripe batches, then exposed for one week to lab reared flies.  Olives were dissected every two days to see the degree of infestation. Below is a table showing percent of olives infested

The female fly must puncture the fruit with her ovipositor.  It has been postulated that fruit which is easier to puncture will attract more flies.  Machines have been used to determine the force needed to puncture different varieties.  Manzanillo has been found to have the most fragile skin.

The adult female is approximately 5 mm long, and has a wing expanse of approximately 10 mm. The wings are mostly transparent and marked with brown, including a spot at the wing tips. The thorax is black, with a silvery pubescence dorsal surface stripped with three narrow parallel black lines. The abdomen is black, covered with a scattered gray pubescence. The basal segments are marked with pale transverse bands and an irregular parallel bar or blotch of reddish-brown occupying the center of the apical segments. The terminal segment is reddish-yellow. The sheath of the ovipositor is black, with the ovipositor reddish in color. from H.V. Weems, Florida Department of Agriculture and Consumer Services

Habitus male (dorsal), wing.

Habitus female (dorsal), wing.

Links: complete description

‘L.E. Carrol, I.M. White, A. Friedberg, A.L. Norrbom, M.J. Dallwitz and F.C. Thompson (2002 onwards). Pest Fruit Flies of the World: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 8th August 2002. http://www.sel.barc.usda.gov/Diptera/tephriti/pests/adults/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000)

In order to find out where the fly is and what it is doing and effectiveness of control measures, monitoring can be helpful.  Traps used for monitoring can be different from those used for control.  The simplest but least productive method of monitoring is visual inspection.  With heavy infestation the fly can be seen on the olive trees but even in orchards with 200% infestation (2 grubs/olive), the fly may not be noticed.  The fly is small, may not be active and can resemble similar species.  Pupa in the soil are difficult to detect. 

Visual inspection of fruit can yield information about the number of times eggs were laid, number of larvae which subsequently developed and number of flies which hatched. Not all ovipositor "stings" results in a grub.  Stings cause holes and a moon shaped blemish on the olive.  Other insects and mechanical damage can cause similar confusing marks.

Yellow panel sticky traps will incapacitate both females and males and are sometimes used in conjunction with a similar trap with pheromones to assess fly responsiveness to the pheromone. The trap is hung on the south side of the tree on the outside of the canopy. Flies caught per trap per day are noted. Some traps contain both a small pill of Spiroketal, a pheromone effective against the male and ammonia salt in plastic ampoules or sacs to attract both sexes. Generally speaking, relatively inexperienced workers can track fly loads by counting insects on the panel trap

McPhail traps are glass or plastic with a reservoir for liquid bait and a hole in the bottom the let the insect in. It drowns in the bait. Protein hydrolysates are effective baits but make identification of the insects difficult. Ammonia salt solutions will attract olive flies and is clear so enhances insect identification. Collection involves pouring the liquid and drowned flies through a sieve then pouring it back into the trap.  Flies are in better condition for examination that those glued to a sticky panel trap.  The McPhail trap attracts a greater percentage of females, the more revealing species for control studies, and fever beneficial species. The sex ratio and egg carrying condition of females can be noted daily from such traps. Studies at UC Davis show that the McPhail trap is superior to panel traps for monitoring purposes; attracting 10 times more flies in some comparisons.   

Fruit samples can be taken for examination under dissecting microscope for larvae and eggs. Stage of development, sex, mated status is noted. This takes a more sophisticated technician.

The timing of the first control measure of the year is crucial. Lure and kill traps last 5-6 months and sprays last only days or weeks. Considerations for first treatment for oil olives:


-. Olive crop is at risk - hardened pit stage
-. Flies are beginning to become sexually active as evidenced by preference to pheromone lure sticky traps vs. plain yellow traps.
-. Meteorological conditions amenable to control measures such as spraying.

The truth is that ALL growers in infested areas (pretty much the whole state of California) should be applying prophylactic spray even if they don't see a single fly starting around June 1.

Degree - Day Table

UC Davis Post graduate student Hannah Burrack with others is developing a degree-day table. By consulting such a table predictions can be made about fly behavior in the orchard and control measures can be timed. A degree day model for use in most parts of California should be developed by the end of  2004 and validated during 2005.

A word about lures; protein hydrolyzate is considered a cheap, effective but non-specific attractant. Ammonia is more specific to olive fly and pheromone is even more specific.

1. Yellow sticky panel trap alone. The fly is attracted to the yellow or green color and is mechanically trapped by glue or tape panel
        Advantages:
            Nontoxic
        Disadvantages: 
            Might require 3-4 traps per tree so not considered feasible for commercial orchards high labor cost to apply to every tree
            High trap costs
            Catches many non-target and possibly beneficial insects
            Traps become saturated with insects and debris

2. Yellow sticky panel trap with protein/phermone and/or ammonia salt attractant
        Advantages:
            Fewer traps needed - 1 per tree
        Disadvantages: 
            High labor cost to apply to every tree
            High trap costs
        Catch non-target beneficial insects
        Traps become saturated with insects and debris

3. McPhail type bottle traps with protein/phermone and/or ammonia bait
        Advantages:
            Can be used several years - just wash and replace bait periodically
            Good for light infestations
            Non-toxic
        Disadvantages: 
            High labor cost to apply to every tree
            High trap costs
            Male olive flies show little tendency to go into trpas

 

Lure and kill traps have an insecticide soaked panel of cardboard with attached or incorporated ammonia and pheromone attractant
        Advantages:
            Use on every other tree or as little as 80 - 100 per ha - lower costs
            Attracts fewer non-target insects
            contains the ingredients lambda-cyhalothrin (toxicant), ammonium bicarbonate (food lure) and spiroketalamine (pheromone)
            Insect contacts insecticide but goes elsewhere to die so doesn't saturate trap - longer trap life.
            Good for light to moderate fly levels
            Considered compatible with organic designation in EU
            Good as a barrier to flies migrating from home gardens or ornamental sources
            Can be used close to urban dwellings
            Good for small or non-contiguous plots
        Disadvantages:
            Traps must be monitored to see that they haven't been damaged or fall from canopy

 

GF-120 Naturalyte Fruit Fly Bait, a Spinosad bait made by Dow AgroSciences LLC, is the only spray-able material available at this time.  10 to 20 fl oz. are used per acre per application limited to every 7 days.  GF-120 is diluted from 1:1.5 to 1:4 with water then sprayed in large droplets once a week.

There are several spray scenarios:

1. Spot spraying of bait/insecticide mix: A mix of protein hydrolyzate or pheromone such as microencapsulated Spiroketal and insecticide is sprayed in a two square foot area of each tree on the south-facing side by a worker with a small inexpensive hand sprayer. One worker can cover 10 to 15 acres in a day and each application uses only about 1.5ml of spray. In Europe the insecticide used is demotoate-40, an organophosphate. In the U.S. it would be Spinosad or a prytherin based insecticide. Applications last days to weeks depending on exposure/weather.

2. Row spraying from ground sprayer
A lure/insecticide mix as above is sprayed on every 4th or 3rd row of trees.

3. Aerial spraying of bait/insecticide mix
A lure/insecticide mix as above is sprayed in 25 meter swaths with untreated 75 meter swaths in between. 

 

Combination mass trapping and spot or aerial spray
Considered by many to be the most effective combination. If populations are light to moderate the traps are effective, if populations surge the spray knocks them down where they can be controlled by the traps.

More on Pesticides and Olive trees

 

Natural predators

The olive fly has few natural enemies here and in Europe.  Researchers hope to find a predator in the fly's native habitat in Africa.

Sterile fly programs: The Olive Committee has invested $50k in a sterile fly breeding program. It is not anticipated that it will be as effective as other sterile fly programs such as the Med fly. A colony will be started and breeding methods investigated. Dr. George Haniotakis of the National Agricultural Research Foundation in Athens has had experience with the Greek program and says that problems encountered included mating of sterile males with sterile females instead of wild ones and fruit damage from laying of sterile eggs. 

Parasites: 

Some species of wasp lays its egg in an infested olive.  The wasp's grub must find and enter the olive fly larvae.  Other species of wasp actually penetrates the olive flesh with its ovipositor to deposit its egg within the larvae. Some Braconid wasps have been found to detect fly larvae by sound in the fruit.  They plunge their ovipositor through the fruit and into the moving larva.  Studies are ongoing to determine if the ovipositor in these wasps is long enough to reach larvae in the large fruit varieties common in California.  Other questions are whether the wasps can tolerate our climate and what are the best times to release the wasp for optimum fly control.  California native parasitic wasps (Pteromalus nr. sp. myopitae) have been found to parasitize the olive fruit fly but not in numbers adequate for control.

Preventive measures:
1. Thorough removal of fruit from trees to prevent over-wintering
2. Picking or treatment of ornamental, backyard, park reservoirs of olive trees. (In Tehama county it is estimated that there are 10,000 olive trees outside of managed orchards)

Post harvest Management

Bill Kreuger in Tehama has studied the effect of bare ground vs. winter cover crops on fly over wintering.  The olive fruit fly must leave ripe olives in the fall to avoid being consumed along with the ripe olive by birds and foragers.  The larvae exit dropped olives and burrow one inch into the soil to pupate and over winter. Cover crops seem to decrease fly levels, presumably by encouraging pupa predators.  Flaming, mowing, disking, flailing and fruit destruction will be also studied.

Horticultural methods:  In the Mediterranean resistant varietals are chosen, and trees are heavily pruned to let in light and air which discourages the fly.

Irrigation practices

Traps in sprinkler irrigated groves had ten times more flies caught than traps in non-irrigated groves. It is not know if the flies are attracted to the fruit on irrigated tress or whether cooler temperatures in irrigated groves offer a better refuge.   The observation that flies are often found in riparian areas where no olives are present would seem to support the latter. 

Effective Attractants are key to controlling the olive fly.  Attractants can summon the fly from hundreds of feet away to a sticky trap or poison bait.  Racemic 1,7-dioxaspiro[5.5]undecane, olean, 5, is the female produced sex pheromone of the olive fly, Bactrocera (Dacus) oleae. It is in a class of chemicals called spiroacetal and is the ingredient in the commercial product Spiroketal. Although not commonly used in this manner, at concentrations higher than those produced by olive fruit fly females the pheromone itself has insecticidal and ovicidal activity. 1,5,7-trioxaspiro[5.5]undecane, an analog of the major pheromone component, has been synthesized and tested, and under optimal conditions it was as attractive as the natural compound, but it did not last as long in traps as the natural material. Spiroacetals are common pheromones in wood boring beetles and other fruit flies. Spiroacetal will attract only the male olive fly.  Yellow colors attract both male and female flies. Ammonia and protein hydrolysate attract both male and female flies.

Ammonium bicarbonate or ammonium carbonate are effective attractants.  McPhail traps use Torula yeast tablets and borax in water.

        Product type: insecticide
        Producer:  Dow
        Mechanism of action: Spinosad is a mixture of spinosyn A and spinosyn D factors that are produced by the  actinomycete Saccharopolyspora spinosa under aerobic fermentation conditions. Spinosad causes rapid excitation of the insect nervous system and is fairly specific to dipterans.  "Spinosa" is usually sprayed with an attractant and/or bait such as protein hydrolysate.
        Cost: $5/acre
        Approval:  currently available under schedule 18 emergency registration in California.  It is approved for organically grown olives.
        Availability:  Widely available      
        More: http://www.dowagro.com/turf/insect%5Fmanagement/content/vl%5Fspinosad%5Ftech.htm

 

        Product type: pheromone attractant, mass trapping product
        Producer:  AgriSense BCS Limited 
        Mechanism of action: 1,7 dioxaspiro (5.5)undecane - a pheromone attractant used in a complete mass trapping product which includes a synthetic pyrethrin insecticide and ammonia salt lure. The cardboard sheet lure and kill trap is snapped around an inner tree limb.
        Cost: 80 cents per unit, about 40cents per tree
        Approval:  Submitted for EPA approval 2/2001
        Availability:  widely    
        More: 

Advanced Pheromone Technologies, Inc.
PO Box 417, Marylhurst, OR 97036-0417
toll free: 877-244-9610 , fax: 971-327-8407
e-mail: infoatapt@comcast.net

         Product type: pheromone attractant: IT 079B and IT079A
        Producer: ISCA Technologies, Inc.
        Mechanism of action:
        Cost: 
        Approval: 
        Availability: now  
        Use:  There are two different types of lure vials: red rubber septa and white plastic vials. The white plastic vials must be hung closed in place. The rubber lures may be pierced at the edges without hampering the potency of the lures.
 

Advanced Pheromone Technologies, Inc.
PO Box 417, Marylhurst, OR 97036-0417
toll free: 877-244-9610 , fax: 971-327-8407
e-mail: infoatapt@comcast.net

ISCA Technologies, Inc. – Pest Management Tools and Solutions
2060 Chicago Avenue, Suite C2
Riverside, CA 92507, U.S.A.
E-Mail: iscasales@iscatech.com
Phone (office): (951) 686 – 5008
Fax: 815 346 1722
www.iscatech.com 

        Product type: pheromone attractant and insecticide
        Producer:  Certis USA LLC
        Mechanism of action: a spiroketal attractant and lambda cyhalothrin, a synthetic pyrethroid insecticide
        Cost:  35 cents for product per tree, 10 cents for labor per tree
        Approval:  section 18
        Availability: now  
        Use:   Use 42 target devices per acre.  Apply 14 target devices which contain Active Ingredient A, and 28 target devices which contain Active Ingredient B.
        (All target devices contain lambda cyhalothrin insecticide.) Apply target devices only once. Traps are effective for 4 to 6 months. Do not exceed 42 target    devices per acre.  Hang each target device on an olive tree as follows:
    · Right after harvest
    · Hang the target devices in the tree on an inner branch that is not likely to break or be pruned before the end of the season. Hang the target devices in the tree as high as practical, at least out of the normal reach of children, pets, and animals of husbandry.
    · Hang the target devices by sliding it around the branch so that the branch is in the center of the device, and hook using the tab attachments. When attached properly, the target device will form a cone shape around the branch with the lures on the inner surface of the cone. Insure that the lures are on the inner side of the cone as attached to the tree branch.
 

 Certis USA LLC
 9145 Guilford Road  Suite 175
 Columbia, MD 21046

        Product type: pheromone attractant, mass trapping product
        Producer:  Vioryl S.A., of Greece
        Mechanism of action: a complete mass trapping product which includes an insecticide Deltamethrine 0.0187% and pheromone and Ammonium     Bicarbonate lures. The cardboard packet trap is hung from the inner branches of the tree and lasts up to 6 months.
        Cost:  35 cents for product per tree, 10 cents for labor per tree
        Approval:  Not yet submitted to EPA
        Availability:  pending    
        More: http://www.vioryl.gr/english/products_agroactive.html
                

.
        Product type: particle film
        Producer:  Engelhard corporation
        Mechanism of action:This material is a clay(kaolin) based oil that prevents oviposition and insect feeding on apples, walnuts and grapes.
        Cost:  This material is a clay(kaolin) based oil that prevents oviposition and insect feeding on apples, walnuts and grapes.
        Approval:  Surround® WP is the general-use formulation for most applications and is labeled in all 50 states. The Organic Materials Review Institute (OMRI) has listed Surround WP for use in organic production.
        Availability: widespread
        More:

Advanced Pheromone Technologies, Inc.
PO Box 417, Marylhurst, OR 97036-0417
toll free: 877-244-9610 , fax: 971-327-8407
e-mail: infoatapt@comcast.net

ISCA Technologies, Inc. – Pest Management Tools and Solutions
2060 Chicago Avenue, Suite C2 Riverside, CA 92507, U.S.A. * E-Mail: iscasales@iscatech.com
Phone (office): (951) 686 – 5008. Fax: 815 346 1722

Seabright Labs
4026 Harlan Street
P.O. Box 8647
Emeryville CA 94662
    Contact: Jim Wimberly
    510.665.3216 E-mail: stikem@seabrightlabs.com
    http://www.seabrightlabs.com/trap.htm

Scentry Biologicals
610 Central Ave.
Billings, MT 59102
406.248.5856

Simplot Soilbuilders
Orland
(530)865-9661
yellow sticky traps

Suterra
213 SW Columbia St.
Bend, OR 97702 (541)388-3688 www.suterra.com
yellow sticky traps (sold in cases of 100)

Trece, Incorporated
1031-C Industrial Street P.O. Box 6278 Salinas, CA 93912
Contact: Angel Parks 831.758.0204
E-mail: trece@trece.com

Wilbur Ellis Co.
Willows (530)934-7727
yellow sticky traps, NuLure by mail

There is a safer trap which can be make out of a plastic bottle.  Paul Vossen of the U.C. Davis agricultural extension office saw this being used in Spain .  The commercial version is filled with a liquid olive fly attractant.  Small holes near the top allow the fly to enter and get trapped.  The low cost plastic bottle variation was being used in some organic orchards, evidently with good results although unlike in Spain, this can only lower, not eliminate insect populations. Take a 1-2 liter plastic bottle and drill four to six  5mm sized holes into the neck with a drill or hot wire.  A hot paperclip bent over on the tip makes about the right sized hole or use a 1/4 inch drill bit.  Fill 3/4 full with a solution made from 3-4 Torula yeast tablets per liter of water.  Hang traps in tree canopy by wire or string on the south side of the tree at a rate of 20 per acre.  Hang on the South side of the tree in the Northern hemisphere.

 

MCPHAIL TRAPS

Better World Manufacturing, Inc.
5690 E. Dayton Fresno, CA 93727 (559)291-4276
email: bettertrap@aol.com
Multilure (McPhail-type) trap; torula yeast tablets (by the lb.)

Great Lakes IPM
10220 Church Road Vestaburg, MI 48891 (989)268-5693
www.greatlakesipm.com
Liquibator (McPhail-type) fruit fly trap; torula yeast tablets (sold individually);

Irv Boxer ERA International Ltd.
P. O. Box 7329 Freeport, NY 11520 (516) 379-5579
torula yeast tablets (50 lbs. drum)

John Taylor Fertilizers
Dixon, CA (707)678-2358
NuLure fruit fly bait (2 1/2 gal containers)

Milagros Olive Orchard Management
St. Helena CA  milagros@napanet.net (707)334-5194
McPhail traps

ISCA Technologies, Inc. – Pest Management Tools and Solutions
2060 Chicago Avenue, Suite C2 Riverside, CA 92507, U.S.A. * E-Mail: iscasales@iscatech.com
Phone (office): (951) 686 – 5008 Fax: 815 346 1722
www.iscatech.com
McPhail traps,  torula yeast tablets (by the lb.)

Baits for McPhail Traps:

TORULA YEAST

Available from Great Lakes IPM 1-800-235-0285
 

Better World Manufacturing  bettertrap@aol.com

Scentry Biologicals  www.scentry.com
 
ERA International Ltd. (516) 379-5579

Suterra  www.suterra.com

Great Lakes IPM  www.greatlakesipm.com

 John Taylor Fertilizers  (707) 678-2358

ISCA Technologies Inc. www.iscatech.com

Tréce´Inc.  www.trece.com

Wilber Elllis Co. (800) 426-3491

NULURE BAIT
Available from some John Taylor fertilizer stores or from Wilbur Ellis 1-800-426-3491

See county Agricultural commissioners:

Paul Vossen
University of California
Cooperative Extension
Sonoma and Marin Counties
133 Aviation Blvd.  Suite 109
Santa Rosa, CA  95403
(707) 565-2621 [Phone]
(707) 565-2623 [Fax]
(707) 477-4771 [Mobile]
pmvossen@ucdavis.edu [E-mail]
http://cesonoma.ucdavis.edu [Website]
 

Calaveras County Agricultural Commissioner
Contra Costa County Agricultural Commissioner
El Dorado County Agricultural Commissioner
Fresno County Agricultural Commissioner
Kern County Agricultural Commissioner
Kings County Agricultural Commissioner
Lassen County Agricultural Commissioner
Los Angeles County Agricultural Commissioner
Merced County Agricultural Commissioner
Monterey County Agricultural Commissioner
Napa County Agricultural Commissioner
Placer County Agricultural Commissioner
Sacramento County Agricultural Commissioner
San Diego County Agricultural Commissioner
San Francisco County Agricultural Commissioner
San Joaquin County Agricultural Commissioner
San Mateo County Agricultural Commissioner
Santa Barbara County Agricultural Commissioner
Santa Clara County Agricultural Commissioner
Siskiyou County Agricultural Commissioner
Sonoma County Agricultural Commissioner
Stanislaus County Agricultural Commissioner
Tulare County Agricultural Commissioner
Tulare County Rural Crime Task Force
Yolo County Agricultural Commissioner
 

See county U.C. extension experts

See county Farm Bureaus

Gary Agusta - California Department of Food and Agriculture
Hannah Burrack - Post Graduate Student, Dept. of Entomology UC Davis
Kent M. Daane UC Cooperative Extension Assistant Specialist in Biological Control
Robert Dowell primary state entomologist at the California Department of food and Agriculture
Louise Ferguson - Extension Specialist, University of California
Eric Fisher
Kim A. Hoelmer - USDA-ARS European Biocontrol Laboratory
Marshall Johnson - UC Kearney Agricultural Center
William Kreuger - UC Farm Advisor Glenn/Tehama Counties
Hanah Nadel - Research Entomologist University of California, Berkeley
Richard E. Rice U.C. Extension Kearney agricultural center in Parlier near Fresno
Mark Robertson - Research Entomologist, University of California, Riverside
Robert Wharton - Department of Entomology, Texas A & M University
Lynn Wunderlynch - Farm Advisor in El Dorado and Amador Counties
Robert Van Steenwyck, - cooperative extension entomologist at U.C. Berkeley
Frank Zalom - (UC Davis)  Department of Entomology,

Links:

UCCE Sonoma Olive Fly Handout for Growers
UCCE Sonoma Controlling Olive Fly at Home
Ern's Pest Control Ernie Simpson ernie.simpson@sbcglobal.net  Specializing in olive fruit fly control.  Licensed pest control operator.
UC Olive Fly catch data - updated weekly by county
UC Pest Management Guidelines updated 11/02
Bionomics of the Olive Fruit fly - from UC cooperative extension, Tulare county 
U.C. Plant Protection Quarterly with olive fly bionomics - July 2000
Developing an Ecologically Based Management System for Olive Fruit Fly  - good pictures of fly damage by UC  Davis researchers
Use of pheromones in control of the olive fly
Proposal for novel "organic" delivery system which creates a pseudo-epidemic in fly populations
http://fruitsandnuts.ucdavis.edu/Olive_Fruit_Fly_02.pdf
University of Florida olive fly review
The Diptera Site - hosted by the U.S. Department of Agriculture - a site devoted to flies such as the  fruit flies