Bernard C Dominiak

Eradication of tephritid fruit fly pest populations: Outcomes and prospects

BACKGROUND The number of insect eradication programmes is rising in response to globalisation. A database of arthropod and plant pathogen eradications covers 1050 incursion responses, with 928 eradication programmes on 299 pest and disease taxa in 104 countries (global eradication database b3.net.nz/gerda). METHODS A subset of the database was assembled with 211 eradication or response programmes against 17 species of fruit flies (Tephritidae) in 31 countries, in order to investigate factors affecting the outcome. RESULTS The failure rate for fruit fly eradication programmes was about 7%, with 0% for Ceratitis capitata (n = 85 programmes) and 0% for two Anastrepha species (n = 12 programmes), but 12% for 13 Bactrocera species (n = 108 programmes). A number of intended eradication programmes against long-established populations were not initiated because of cost and other considerations, or evolved during the planning phase into suppression programmes. Cost was dependent on area, ranged from

Review of Dispersal, Survival, and Establishment of Bactrocera tryoni (Diptera: Tephritidae) for Quarantine Purposes

US 0.1 million to

Evaluating Irradiation Dose for Sterility Induction and Quality Control of Mass-Produced Fruit Fly Bactrocera tryoni (Diptera: Tephritidae)

US 240 million and averaged about

Automated locomotor activity monitoring as a quality control assay for mass-reared tephritid flies

US 12 million (normalised to

Field Evaluation of Melolure, a Formate Analogue of Cuelure, and Reassessment of Fruit Fly Species Trapped in Sydney, New South Wales, Australia.

US in 2012). In addition to the routine use of surveillance networks, quarantine and fruit destruction, the key tactics used in eradication programmes were male annihilation, protein bait sprays (which can attract both sexes), fruit destruction and the sterile insect technique. CONCLUSIONS Eradication success generally required the combination of several tactics applied on an area-wide basis. Because the likelihood of eradication declines with an increase in the area infested, it pays to invest in effective surveillance networks that allow early detection and delimitation while invading populations are small, thereby greatly favouring eradication success.

Revised Distribution of Bactrocera tryoni in Eastern Australia and Effect on Possible Incursions of Mediterranean Fruit Fly: Development of Australia’s Eastern Trading Block

ABSTRACT The fruit fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) is a species of significant quarantine concern to many countries. Currently, B. tryoni is found in parts of Australia and on some Pacific islands. Understanding dispersal behavior is important for the development of scientifically justified trade restrictions or quarantine distances for B. tryoni. These distances ensure adequate protection for overseas markets while also ensuring that growers sufficiently distant from the affected area are able to retain unrestricted access to markets. This review considers scientific data on dispersal and uses this information to make recommendations for appropriate quarantine distances. Most studies conclude that the lifetime dispersal distance of this species rarely exceeds 1 km, although three studies indicate that longer dispersal distances of a small number of individuals may occasionally occur. These short dispersal distances are consistent with findings for other fruit fly species. Triggers for long-distance dispersal, the fate of these individual flies, nutritional requirements to support this dispersal, and reasons for discrepancies in the dispersal distances reported in different studies are reviewed. Reasons for the inability of B. tryoni to establish along southern parts of the east coast of Australia before European colonization are postulated. A proposed quarantine distance is based on the scientific basis of the mean and 3 SD, with a 3-fold level of protection based on distance. It is proposed that an area contained by a circle with a radius of 1.2 km is a reasonable quarantine area for B. tryoni outbreaks where flies are contained within 200 m of an epicenter. Where total trappings are contained within 400 m of the epicenter, a quarantine distance of 2.4 km is recommended. Three other quarantine distances are proposed based on the formula by using the mean.

Longevity of Mass-Produced Bactrocera tryoni (Diptera: Tephritidae) Held Without Food or Water.

ABSTRACT The sterile insect technique has been routinely used to eradicate fruit fly Bactrocera tryoni (Froggatt) incursions. This study considers whether fly quality in a mass-rearing facility can be improved by reducing irradiation doses, without sacrificing reproductive sterility. Pupae were exposed to one of five target irradiation dose ranges: 0, 40–45, 50–55, 60–65, and 70–75 Gy. Pupae were then assessed using routine quality control measures: flight ability, sex ratio, longevity under nutritional stress, emergence, and reproductive sterility. Irradiation did not have a significant effect on flight ability or sex ratio tests. Longevity under nutritional stress was significantly increased at 70–75 Gy, but no other doses differed from 0 Gy. Emergence was slightly reduced in the 50–55,60–65, and 70 -75 Gy treatments, but 40–45 Gy treatments did not differ from 0 Gy, though confounding temporal factors complicate interpretation. Reproductive sterility remained acceptable (>99.5%) for all doses—40–45 Gy (99.78%), 50–55 Gy (100%), 60–65 Gy (100%), and 70–75 Gy (99.99%). We recommend that B. tryoni used in sterile insect technique releases be irradiated at a target dose of 50–55 Gy, providing improved quality and undiminished sterility in comparison with the current 70–75 Gy standard while also providing a substantial buffer against risk of under dosing.

The Rise and demise of control options for fruit fly in Australia

BACKGROUND The Sterile Insect Technique (SIT) requires vast numbers of consistently high quality insects to be produced over long periods. Quality control (QC) procedures are critical to effective SIT, both providing quality assurance and warning of operational deficiencies. We here present a potential new QC assay for mass rearing of Queensland fruit flies (Bactrocera tryoni Froggatt) for SIT; locomotor activity monitoring. We investigated whether automated locomotor activity monitors (LAMs) that simply detect how often a fly passes an infrared sensor in a glass tube might provide similar insights but with much greater economy. RESULTS Activity levels were generally lower for females than for males, and declined over five days in the monitor for both sexes. Female activity levels were not affected by irradiation, but males irradiated at 60 or 70 Gy had reduced activity levels compared with unirradiated controls. We also found some evidence that mild heat shock of pupae results in adults with reduced activity. CONCLUSION LAM offers a convenient, effective and economical assay to probe such changes.

Review of the past and present distribution of Mediterranean fruit fly (Ceratitis capitata Wiedemann) and Queensland fruit fly (Bactrocera tryoni Froggatt) in Australia

ABSTRACT In Australia, tephritids are usually attracted to either cuelure or methyl eugenol. Methyl eugenol is a very effective lure, but cuelure is less effective likely due to low volatility. A new formate analogue of cuelure, melolure, has increased volatility, resulting in improved efficacy with the melon fruit fly, Bactrocera cucurbitae Coquillett. We tested the efficacy of melolure with fruit fly species in Sydney as part of the National Exotic Fruit Fly Monitoring programme. This monitoring programme has 71 trap sites across Sydney, with each trap site comprising separate Lynfield traps containing either cuelure, methyl eugenol, or capilure lure. In 2008, an additional Lynfield trap with melolure plugs was added to seven sites. In 2009 and 2010, an additional Lynfield trap with melolure wicks was added to 11 trap sites and traps were monitored fortnightly for 2 yr. Capture rates for melolure traps were similar to cuelure traps for Dacus absonifacies (May) and Dacus aequalis (Coquillet), but melolure traps consistently caught fewer Bactrocera tryoni (Froggatt) than cuelure traps. However, trap sites with both a cuelure and melolure traps had increased capture rates for D. absonifacies and D. aequalis, and a marginally significant increase for B. tryoni. Melolure plugs were less effective than melolure wicks, but this effect may be related to lure concentration. The broader Bactrocera group species were attracted more to cuelure than melolure while the Dacus group species were attracted more to melolure than cuelure. There is no benefit in switching from cuelure to melolure to monitor B. tryoni, the most important fruit fly pest in Australia.

Impact of marker dye on adult eclosion and flight ability of mass produced Queensland fruit fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae)

Abstract Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), commonly called ‘Queensland fruit fly’ in Australia, and Mediterranean fruit fly (Ceratitis capitataWiedemann) (Diptera:Tephritidae) are the two most economically important fruit fly in Australia with B. tryoni in the east and Mediterranean fruit fly in the west. The two species coexisted for several decades, but it is believed that B. tryoni displaced Mediterranean fruit fly. In southeastern Australia, this was deemed inadequate for export market access, and a large fruit fly free zone (fruit fly exclusion zone) was developed in 1996 where B. tryoni was eradicated by each state department in their portion of the zone. This zone caused an artificial restricted distribution of B. tryoni. When the fruit fly exclusion zone was withdrawn in Victoria and New South Wales in 2013, B. tryoni became endemic once again in this area and the national distribution of B. tryoni changed. For export markets, B. tryoni is now deemed endemic to all eastern Australian states, except for the Greater Sunraysia Pest-Free Area. All regulatory controls have been removed between eastern states, except for some small zones, subject to domestic market access requirements. The eastern Australian states now form a B. tryoni endemic trading group or block. All Australian states and territories maintain legislation to regulate the movement of potentially infested host fruit into their states. In particular, eastern states remain active and regulate the entry of commodities possibly infested with Mediterranean fruit fly. The combination of regulatory controls limits the chances of Mediterranean fruit fly entering eastern states, and if it did, Mediterranean fruit fly is unlikely to establish in the opposition to a well-established B. tryoni population.