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Tephritid fruit flies are major economic pests for fruit production and are an impediment to international trade. Different host fruits are known to vary in their suitability for fruit flies to complete their life cycle. Currently, international regulatory standards that define the likely legal host status for tephritid fruit flies categorize fruits as a natural host, a conditional host, or a nonhost. For those fruits that are natural or conditional hosts, infestation rate can vary as a spectrum ranging from highly attractive fruits supporting large numbers of fruit flies to very poor hosts supporting low numbers. Here, we propose a Host Suitability Index (HSI), which divides the host status of natural and conditional hosts into five categories based on the log infestation rate (number of flies per kilogram of fruit) ranging from very poor (100). Infestation rates may be determined by field sampling or cage infestation studies. We illustrate the concept of this index using 21 papers that examine the host status of fruits in five species of polyphagous fruit flies in the Pacific region: Bactrocera tryoni Froggatt, Bactrocera dorsalis (Hendel), Bactrocera latifrons (Hendel), Zeugodacus cucurbitae (Coquillett), and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). This general-purpose index may be useful in developing systems approaches that rely on poor host status, for determining surveillance and detection protocols for potential incursions, and to guide the appropriate regulatory response during fruit fly outbreaks.

Fluorescent dust marking is widely used in tephritid sterile insect programs to differentiate mass reared sterile individuals from the wild individuals. While fluorescent dust marking is economical, it does not guarantee 100% marking success. In programs releasing millions of sterile flies, even a very low rate of misclassification of sterile individuals (due to a failure of dust marking) could greatly over-estimate the number of resident wild individuals. This could be an important outcome since, in some horticultural production areas, detection of as few as two wild individuals trigger suspension of exports. In this study, we sought to test the accuracy of fluorescent dust marking for the identification of sterile Bactrocera tryoni (Froggatt) during a sterile release technique (SIT) program in New South Wales, Australia. We used DNA microsatellite data to as an independent discriminator between wild from sterile flies. Our results confirm earlier suspicions that a small proportion of sterile flies remain unmarked during these releases. We also found that wild flies can be misclassified as sterile due to the presence of acquired dust grains on the body. These results indicate that any B. tryoni SIT program should not rely on fluorescent dust alone to unambiguously identify sterile released individuals. We show that additional methods, such as carbon isotope ratio measurements, are practical for use in B. tryoni SIT programs.

Tephritid fruit flies are among the most destructive horticultural pests posing risks to Australia's multi-billion-dollar horticulture industry. Currently, there are 11 pest fruit fly species of economic concern in Australia. Of these, nine are native to this continent (Bactrocera aquilonis, B. bryoniae, B. halfordiae, B. jarvisi, B. kraussi, B. musae, B. neohumeralis, B. tryoni and Zeugodacus cucumis), while B. frauenfeldi and Ceratitis capitata are introduced. To varying degrees these species are costly to Australia's horticulture through in-farm management, monitoring to demonstrate pest freedom, quarantine and trade restrictions, and crop losses. Here, we used a common species distribution model, Maxent, to assess climate suitability for these 11 species under baseline (1960-1990) and future climate scenarios for Australia. Projections indicate that the Wet Tropics is likely to be vulnerable to all 11 species until at least 2070, with the east coast of Australia also likely to remain vulnerable to multiple species. While the Cape York Peninsula and Northern Territory are projected to have suitable climate for numerous species, extrapolation to novel climates in these areas decreases confidence in model projections. The climate suitability of major horticulture areas currently in eastern Queensland, southern-central New South Wales and southern Victoria to these pests may increase as climate changes. By highlighting areas at risk of pest range expansion in the future our study may guide Australia's horticulture industry in developing effective monitoring and management strategies.

Radiation is a well understood and established technology which has been researched and reviewed extensively for over 100 years. The capability of irradiation to substantially improve the international bilateral trade of horticultural commodities has only just been gaining recognition, particularly over the last 10 years. The poor rate of adoption of irradiation as a method of disinfesting food can be attributed to the conservative attitude of some importing countries and consumer perception, particularly when it's associated with the word “nuclear”. The world's leading food health and safety bodies including the World Health Organisation, Food Standards Australia New Zealand and the United Nations Food and Agriculture Organizations have all reported that food irradiation is a safe and effective treatment to a wide range of insect pests and kills bacteria. Educating consumers about benefits and safety of irradiated food is considered the key to irradiation becoming accepted widely amongst Australia's international trading partners. Irradiated fresh fruit and vegetables are not accepted by several importing Asian countries or the European Union but there are several other countries that do use and accept phytosanitary irradiated treated fruits. As a technology, irradiation offers a range of benefits for fresh horticultural food producers, exporters and importers. Low-dose irradiation provides a rapid treatment that does not alter the temperature of the commodity, is free of residues, fruit remains nutritionally adequate, and can enhance shelf life and colouring of some fruits. Some research has reported that there is a reduction in vitamin A and C in treated fruits at higher dose rates. One of Australia's major phytosanitary pests of concern for international trade is the Queensland Fruit Fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae). Methyl bromide and cold treatment are treatment methods commonly used for international trade. However, methyl bromide is a greenhouse gas and has occupational health concerns. Cold treatment takes several weeks to complete and is unsuitable for air freight. Time frames for lemons, for instance, vary from fourteen to sixteen days (for Qfly) plus temperature ramp down and then ramp up after treatment; ramping often takes three days each. Given the limitations of other conventional post-harvest treatments, irradiation is well suited for fruit fly disinfestation of commodities to be airfreighted to countries demanding fresh fruit with no residues.

Bactrocera cucumis is a lesser known native fruit fly in Australia. There are 44 reported hosts including cucurbits, papaws and tomatoes with a strong preference for cucurbits. Adult flies are not attracted to the known male lures such as cuelure, methyl eugenol or zingerone. They are weakly attracted to protein lures and a recently discovered cucumber volatile. For this reason, surveillance for this fruit fly remains problematic. Its range is predominantly coastal and appears to be centred north of Rockhampton in Queensland. It is known in the Northern Territory, Queensland and in New South Wales north of 29 o S latitude. Internationally, it is not reported in any Pacific countries or other parts of the world.

Bactrocera cucumis is one of many fruit fly species of concern for Australia's international trade partners. This species is one of the lesser known native fruit flies in Australia and its distribution and hosts have been reviewed. Eggs are larger than in most other species with a short hatching period. The adults and larvae are also larger than most other Australian fruit flies. Adults are long lived and have a high rate of reproduction. Stridulation and pheromones appear not to be used in the mating process. Adults can be managed using a range of measures including chemosterilants, the sterile insect technique and chemical sprays. Produce can be disinfested using a range of post-harvest treatments. Current export protocols include hot air and chilling treatments, irradiation, methyl bromide fumigation and winter window.

Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), commonly called 'Queensland fruit fly' in Australia, and Mediterranean fruit fly (Ceratitis capitata Wiedemann) (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.

Anthropogenic climate change is a major factor driving shifts in the distributions of pests and invasive species. The Queensland fruit fly, Bactrocera tryoni (Froggatt) (Qfly), is the most economically damaging insect pest of Australia’s horticultural industry, and its management is a key priority for plant protection and biosecurity. Identifying the extent to which climate change may alter the distribution of suitable habitat for Qfly is important for the development and continuation of effective monitoring programs, phytosanitary measures, and management strategies. We used Maxent, a species distribution model, to map suitable habitat for Qfly under current climate, and six climate scenarios for 2030, 2050 and 2070. Our results highlight that south-western Australia, northern regions of the Northern Territory, eastern Queensland, and much of south-eastern Australia are currently suitable for Qfly. This includes southern Victoria and eastern Tasmania, which are currently free of breeding populations. There is substantial agreement across future climate scenarios that most areas currently suitable will remain so until at least 2070. Our projections provide an initial estimate of the potential exposure of Australia’s horticultural industry to Qfly as climate changes, highlighting the need for long-term vigilance across southern Australia to prevent further range expansion of this species.

The Queensland fruit fly (Qfly; Bactrocera tryoni Froggatt) is a major horticultural pest species in Australia and considered a serious quarantine concern, both domestically and internationally. When a Qfly outbreak is declared in the main horticultural regions of southeast Australia, a 15 km radius suspension zone is established (area of 707 km2) around the epicentre of the outbreak. This suspension radius was originally adopted in the early 1990s. Here, we analysed trapping data in New South Wales (Australia) from 2002 to 2010 to evaluate the suitability of the 15 km suspension radius. There were 439 Qfly incursions recorded in Qfly-free zones, but only 9.9% of these incursions resulted in a declared outbreak. For these outbreaks, we conducted two distinct analyses. First, we modelled the distribution of infestation radii from the outbreaks and predicted the suspension distance using multiple levels of risk protection (e.g. probit 8.7, probit 9). Second, we fitted various probability distributions to individual fly trapping data and then estimated upper confidence limits for suspension distances, based on dispersal patterns of Qfly. Overall, the predicted suspension radii were substantially smaller than the current 15 km radius. Our results concur with other studies suggesting that Qfly are relatively poor colonisers. We propose that the current 15 km could be reduced substantially to 3 or 4 km.

The sterile insect technique (SIT) has been used to suppress or eradicate fruit flies. It is critical to be able to identify sterile and wild flies so that informed decisions can be made during eradication activities. The current dye marking approach can be flawed on a small number of occasions, and a genetic method is needed to test suspect misidentified samples. As a proof of concept, a single multiplex PCR with nine microsatellite markers was used to study the genetic structure of Queensland fruit flies Bactrocera tryoni (Froggatt) in 11 locations in southern New South Wales. Cluster analysis demonstrated that one cluster was exclusive to the sterile mass-reared flies. A second distinct cluster was exclusive for one site in a wetter cooler area. The other sites were admixture of two main clusters. These nine microsatellite markers could be used to distinguish laboratory-reared flies from field flies. The mass-reared flies would need to be reanalysed after each introduction of wildness.

Early detection of Dacinae (Diptera: Tephritidae) incursions is vital for quick and effective management. A key method for early detection is the implementation of trapping networks in risk areas. Australia relies on the use of extensive trapping networks at, and surrounding, major ports and fruit production areas to identity any fruit fly incursions. Therefore, improvements to the trap efficiency of these networks may result in earlier detection of incursions and hence more rapid response times for management and/or eradication. The current Australian standard, the Lynfield trap, is expensive and does not stack readily for transport. Here, we test the effectiveness of a new trap type, the Probodelt cone trap, compared to the Lynfield trap. We ran three separate trials: an experimental trial in an inland orchard and two field trials using the Sydney trapping network. At the orchard site, Lynfield and Probodelt traps had similar capture rates (within 10%) for Bactrocera tryoni. For the Sydney trapping network, no significant differences were found in the number of species caught or trap rates for B. tryoni, Bactrocera cacuminata, Dacus absonifacies, and Dacus aequalis. Thus, the Probodelt cone trap was at least comparable to the Lynfield trap. Given the economic advantages of the Probodelt cone trap (e.g. reduced shipping and storage costs), the use of the Probodelt trap may be preferred over the Lynfield trap.

The sterile insect technique is used to manage or control fruit flies throughout the world. The technique relies on large scale production before delivery to release managers. As part of the mass production phase, there are many quality control tests to demonstrate and maintain high quality pupae and flies. One highly desirable characteristic is adults with a long life so that these adults can reach sexual maturity and sterile males mate with wild fertile flies in the field and thus produce no viable offspring. Originally longevity was assessed allowing adults to have unlimited access to food and water. As quality and longevity increased, this methodology added significantly to workload and space demands and many facilities moved to testing longevity under stress where no food or water was provided. Here we examined >27,000 Queensland fruit fly Bactrocera tryoni (Froggatt) from 160 weekly production batches from July 2004 to October 2009 where flies were not provided food or water. The mean longevity was 54.4 ± SE hours. Longevity was significantly shorter from August to March, and the longevity was significantly longer in June. Longevity was not related to pupal weight, contrary to expectations. Weights were significantly lower in June and highest in summer.

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 $US 0.1 million to $US 240 million and averaged about $US 12 million (normalised to $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. © 2014 Society of Chemical Industry Supporting information may be found in the online version of this article.

Fruit flies (Diptera: Tephritidae) are a major problem for Australia's $6.9 billion horticultural industry. Bactrocera tryoni (Froggatt) is the most significant fruit fly pest in the eastern states of Australia. Catches of male B. tryoni from cuelure-baited Lynfield surveillance traps in towns bordering the Fruit Fly Exclusion Zone in New South Wales, Australia, from November to May in 2001/2002–2007/2008 were analysed with respect to year, town, property type (urban/rural), and tree species/crop varieties in which the trap was placed (tree type). Average catches of all traps were highest in 2007/2008 and lowest in 2003/2004, and showed an overall positive correlation with rainfall (P

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 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.

The sterile insect technique has been in use for more than 50 years. Release techniques vary considerably from country to country. The release of sterile Queensland fruit fly in Australia continues to progress since its initial trials in the 1960’s. Three ground release methods (adult tub, adult chilled and pupal bucket) for sterile Queensland fruit fly were evaluated in the field. The recapture rate from the adult tub release method is significantly better than the other two methods. Adult chilled release had the lowest recapture rate but was not significantly different from the pupal bucket release. All methods could have been improved. 98.8% of recaptured flies were trapped within 600m of the release points. The dispersal distance was compared with other species.

The sterile insect technique has been used for more than 50 years to control a range of insects around the world. Sterile insect technique is rapidly becoming a major component of many area-wide fruit fly management programmes. Irradiation of immature life stages induces sterility in adults, which are then distributed over large areas to mate with wild flies, resulting in no viable offspring. However, irradiation in normal air results in declining adult quality. To optimize the quality of sterile adult flies, several techniques are available to lower the levels of oxygen in fruit fly tissues prior to irradiation. The simplest method is to seal pupae in plastic bags and allow the oxygen consumption of pupae to minimize oxygen in both the air and pupal tissue. Some fruit fly species have rapid decreases in eclosion as a result of low oxygen atmospheres. We tested the tolerance of Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), to low oxygen for the first time. In the first two experiments, unirradiated B. tryoni pupae were tested for different periods in sealed plastic bags at 17, 21, and 26 °C. Optimum eclosion occurred at 21 °C with the lowest eclosion at 26 °C. In general, mean full eclosion declined at ca. 0.1% eclosion per hour sealed in plastic bags during the first 96 h for all temperatures. In the third and fourth experiments at 17 °C, there was a decline in average eclosion for irradiated and unirradiated pupae of about 13.4% after they were sealed in plastic bags for 192 h. In general, B. tryoni eclosion declined at 0.1% per hour inside sealed plastic bags for periods up to 192 h at 17 °C. Queensland fruit flies can tolerate long periods of conditions found inside sealed plastic bags and current practices for sterile B. tryoni release programmes will result in minimum decrease in eclosion. The possible evolution of tolerance of these conditions is discussed.

The recognition of grapes as a host of Queensland fruit fly Bactrocera tryoni (Froggatt) (Qfly) has been inconsistent across Australian states due to the variable nature of reports. Here the current state of knowledge is reviewed. Grapes are not a preferred Qfly host and attacks are infrequent. Infestations were reported to be more common in coastal and subtropical areas or in periods of high rainfall associated with the low availability of preferred hosts. Egg survival appears to be low, although larval survival may be considerably higher. This review has identified a range of literature referring to grapes as a host of Qfly. A review of overseas literature also indicates that grapes are a host for several other fruit fly species.

Sterile Queensland fruit flies Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) are commonly marked with fluorescent dye to assist with subsequent identification after release and recapture. The impact of dye on adult eclosion and flight ability was tested using eight concentrations of dye (Swada, Fiesta Astral Pink) from 0 to 4.5 g/L of pupae. There was no significant difference in eclosion rates between undyed pupae (control) and pupae dyed at a concentration of 1.0 g/L. For dye concentrations of 1.5–4.5 g/L, adult eclosion rates declined from 85.7% to 77.4% and were significantly different from the control. Flight ability indices ranged from 92.1% to 83.3%. There was no significant difference in flight ability between control pupae and those dyed at 1.0 g/L and 3.5 g/L pupae, but other pupae from other dye concentrations were significantly different from the control. Pupal weight ranged from 8.3 to 10.2 mg and there was no significant relationship between pupal weight and adult eclosion or flight ability.

The Queensland fruit fly, Bactrocera tryoni (Froggatt), is the most significant pest of edible fruit in Australia. For the control of B. tryoni using sterile insect technique (SIT), either pupae or adults may be released. Using pupal release, this study tested the seasonal effect of different pupal loadings on eclosion and the flight of sterile B. tryoni. Pupal eclosion boxes were loaded with either 200, 350, 500, 650 or 800 g of pupae during five periods of the fruit fly season (August, October, December, February and April). Adult flies were allowed to emerge and the remaining pupal debris was sampled to determine the per cent emergence and per cent fliers. The duration of emergence, dye retention on the ptilinum of the flies, and temperature and relative humidity externally and internally of the eclosion boxes were recorded. The percentage of emergence was influenced by both pupal loading and the period of release. Overall, the percentage of emergence was lower for loadings of 200 and 350 g of pupae in August, October and April as compared with the 500 g or higher loadings. This difference was not apparent in December or February. The mean percentage of emergence for each pupal loading in December, February and April was well above 65%, the minimum required emergence parameter for successful sterile B. tryoni release. Across all pupal loadings, the percentage of fliers was greater than 99.3% in December, 87.8% in February and 80.8% in April. A high percentage of fliers (>92.7%) was recorded in October, but the percentage of emergence in August and October was below 65% for all pupal loadings; thus pupal release is a suboptimal SIT method during this period of time. Dye on the ptilinum was detected on every fruit fly sampled across all pupal loadings and release periods. Minimum temperature for optimal pupal emergence should not fall below 10°C, and the maximum should not exceed 35°C. Minimum temperature for successful flight should not fall below approximately 6°C while the maximum temperature should exceed 16°C. The described pupal release system is considered a possible option for use as part of an SIT program against B. tryoni under suitable environmental conditions in Australia.

BACKGROUND: McPhail traps, baited with protein food lure, are used worldwide for surveillance of many species of fruit flies. Queensland fruit fly (Qfly) Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) is a native Australian fruit fly and normally monitored using Lynfield traps baited with cuelure. On some occasions, McPhail traps with wet food lures are deployed to detect female flies or to find the incursion epicentre. This paper reviews field results on the merits of Lynfield and McPhail traps for detection of male and female Qfly. RESULTS: Following release of equal numbers of sterile males and females, Lynfield traps baited with cuelure captured more Qfly males than protein autolysate or orange concentrate in McPhail traps. Significantly more male than female Qfly were captured in McPhail traps baited with protein autolysate or orange. There was no significant difference between orange concentrate lure and protein autolysate lure in attracting either males or females. Another Australian native fruit fly, Dacus newmani (Perkins), was attracted to cuelure in Lynfield traps but not to either lure in McPhail traps. CONCLUSIONS: The data obtained run counter to the reputation of McPhail traps baited with protein autolysate or orange concentrate as a specialist lure/trap combination for female Qfly.

The sterile insect technique is used to manage or control fruit flies throughout the world. The technique relies on large scale production before delivery to release managers. As part of the mass production phase, there are many quality control tests to demonstrate and maintain high quality pupae and flies. One highly desirable characteristic is adults with a long life so that these adults can reach sexual maturity and sterile males mate with wild fertile flies in the field and thus produce no viable offspring. Originally longevity was assessed allowing adults to have unlimited access to food and water. As quality and longevity increased, this methodology added significantly to workload and space demands and many facilities moved to testing longevity under stress where no food or water was provided. Here we examined27,000 Queensland fruit fly Bactrocera tryoni (Froggatt) from 160 weekly production batches from July 2004 to October 2009 where flies were not provided food or water. The mean longevity was 54.4 ± SE hours. Longevity was significantly shorter from August to March, and the longevity was significantly longer in June. Longevity was not related to pupal weight, contrary to expectations. Weights were significantly lower in June and highest in summer.

Dispersion theory is applied to the distribution of two kinds of sterile insect, Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann), and Queensland fruit fly (Qfly), Bactrocera tryoni (Froggatt) (Diptera: Tephritidae). Dispersion theories are an essential basis of sampling theory and sampling plans, but this paper looks at them from another direction and uses data from arrays of sterile insect technique (SIT) monitoring traps to compare the utility of different measures such as coefficient of variation (CV), the exponent b of Taylor's power law, and exponent k of the negative binomial distribution and also derives predictions pertaining to the density (and hence release rate) of sterile insects that would be required to achieve effective coverage of the target area. This is far more useful than reliance on just the mean values of trap catches because such reliance takes no account of the fact that sterile flies distribute themselves unevenly with many patches inadequately covered despite the impression given by the mean. Data were used from recapture rates following either ‘roving releases’ of Medfly or releases from fixed points of Qfly. The relation of recapture rate to CV indicated that a doubling of release rate in order to double average recapture rate from 150 per trap per week to a value of 300 would have very little effect in terms of reducing CV and that there appears to be no practical prospect of reducing CV to below unity with the current methods of release without incurring a manifold increase in cost. Similarly, models derived from the negative binomial equation indicated that a law of diminishing returns applies in terms of the increase in the amount of adequate coverage (such as the percentage of traps catching >50 flies per week) that can be obtained by increasing release rates.

Queensland fruit fly, Bactrocera (Dacus) tryoni (QFF) is arguably the most costly horticultural insect pest in Australia. Despite this, no model is available to describe its population dynamics and aid in its management. This paper describes a cohort-based model of the population dynamics of the Queensland fruit fly. The model is primarily driven by weather variables, and so can be used at any location where appropriate meteorological data are available. In the model, the life cycle is divided into a number of discreet stages to allow physiological processes to be defined as accurately as possible. Eggs develop and hatch into larvae, which develop into pupae, which emerge as either teneral females or males. Both females and males can enter reproductive and over-wintering life stages, and there is a trapped male life stage to allow model predictions to be compared with trap catch data. All development rates are temperature-dependent. Daily mortality rates are temperature-dependent, but may also be influenced by moisture, density of larvae in fruit, fruit suitability, and age. Eggs, larvae and pupae all have constant establishment mortalities, causing a defined proportion of individuals to die upon entering that life stage. Transfer from one immature stage to the next is based on physiological age. In the adult life stages, transfer between stages may require additional and/or alternative functions. Maximum fecundity is 1400 eggs per female per day, and maximum daily oviposition rate is 80 eggs/female per day. The actual number of eggs laid by a female on any given day is restricted by temperature, density of larva in fruit, suitability of fruit for oviposition, and female activity. Activity of reproductive females and males, which affects reproduction and trapping, decreases with rainfall. Trapping of reproductive males is determined by activity, temperature and the proportion of males in the active population. Limitations of the model are discussed. Despite these, the model provides a useful agreement with trap catch data, and allows key areas for future research to be identified. These critical gaps in the current state of knowledge exist despite over 50 years of research on this key pest. By explicitly attempting to model the population dynamics of this pest we have clearly identified the research areas that must be addressed before progress can be made in developing the model into an operational tool for the management of Queensland fruit fly. (C) 2003 Published by Elsevier B.V.

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).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.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 $US 0.1 million to $US 240 million and averaged about $US 12 million (normalised to $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.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.

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.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.LAM offers a convenient, effective and economical assay to probe such changes.

Four releases of sterile Queensland fruit flies were used in Sydney to assess their flight and distribution characteristics. Flies were detected within 400 m of the release site but did not reach the 5 km trapping array. The distribution was more pronounced towards the north-east and it may have been linked with strong wind prevailing in that direction. CLIMEX was used to indicate that the distribution was not limited by adverse weather. The distribution tended to agree with the formula predicted by Meats (1998). Flies marked with orange dye resulted in the highest recapture rate compared with pink, green and blue dyes. The possible reduction in quarantine radius, following a declared outbreak, is discussed.

Seven small unquarantined towns in the central western district of New South Wales were used to compare variants of the sterile insect technique with respect to their suitability for suppression of populations of the Queensland fruit fly, Bactrocera tryoni (Froggatt). Two towns were treated with weekly releases of immature sterile flies at rates varying from 48 000 to 115 000 sterile males per km2. Evidence for suppression was poor (from comparison with 2� untreated towns) and the ratio of sterile to wild flies caught in monitoring traps never exceeded 80 : 1 in the last 4�weeks of any season or 40 : 1 during other parts of any season. However, the recapture rates of the sterile flies and estimates of their survival rates were often as good as the best that have been reported previously. Two other towns were treated with weekly releases of mature flies at rates of 5000–12 000 sterile males per km2. The recapture rates and estimates of survival rates of flies released when mature were unexpectedly low and the ratios of sterile to wild flies were often less than 1 : 1 and never exceeded 12 : 1. The results are discussed in terms of the relatively harsh climate of these towns (located in a region of average annual rainfall of 450–600 mm) and lack of quarantine.

Sterile Queensland fruit fly (QFF) Bactrocera tryoni (Froggatt) were released using a pupal-release technique in part of Wagga Wagga. Between August 1997 and May 1998, sterile flies were released using initially sand and later vermiculite mediums in the bed technique. A total of 234.16 million pupae were delivered, with an overall emergence rate of 41.4% and male recapture rate of 0.0365% based on emerged flies. A male recapture rate of 0.0141% was calculated from the male pupae deployed, not corrected for emergence. Released sterile flies were recaptured up to 74 days after release. Of the 16 563 males recaptured, 99.3% of sterile flies were trapped within 1�km of release sites. The CLIMEX model was used to rank the climate at Wagga Wagga to better understand emergence and recapture rates during this and earlier programs. CLIMEX indicated that the 1997–98 year was hotter and drier than both the 2 previous years and the long-term average. The Meats daily survival rate decrement formula was also used to compare quality of sterile flies. Results from previous suppression programs were compared using these parameters. In winter 1998 at Junee, pupae were deployed in foam eskies where emergence varied from 0 to 29%, with CLIMEX Cold Stress at an average of 481. Emergence occurred over a 4-week period. In the 1998–99 summer at Lake Cargelligo, sterile flies were deployed using the pupal-release technique. Foam containers replaced the metal trays from the previous season to afford better insulation from the heat. The average emergence rate was 64% for the program. A male recapture rate of 0.071% was calculated from the 9.12 million pupae deployed or 0.11% from the estimated emerged males. An overflooding ratio of 3.2 was achieved for the season, with some apparent suppression of wild fly populations. The last recaptured sterile fly was trapped 77 days after the final release. CLIMEX, with and without irrigation, was used to assess the suitability of Lake Cargelligo and surrounding rural areas for QFF survival.