Area-wide Integrated Pest Management Programmes Research Articles

Animal trypanosomosis eliminated in a major livestock production region in Senegal following the eradication of a tsetse population.

African animal trypanosomosis (AAT) was one of the main disease-related constraints to the development of intensive livestock production systems in the Niayes region of Senegal, a 30km wide strip of land along the coast between Dakar and Saint-Louis. To overcome this constraint, the Government of Senegal initiated an area-wide integrated pest management programme combining chemical control tactics with the sterile insect technique to eradicate a population of the tsetse fly Glossina palpalis gambiensis Vanderplank, 1949 (Diptera, Glossinidae) in this area. The project was implemented following a phased conditional approach, and the target area was divided into three blocks treated sequentially. This study aims to assess the temporal dynamics of the prevalence of Trypanosoma spp. during the implementation of this programme. Between 2009 and 2022, 4,359 blood samples were collected from cattle and screened for trypanosomes using both the buffy coat and ELISA techniques, and PCR tests since 2020. The seroprevalence decreased from 18.9% (95%CI: 11.2-26.5) in 2009 to 0% in 2017-2022 in block 1, and from 92.9% (95%CI: 88.2-97) in 2010 to 0% in 2021 in block 2. The parasitological and serological data confirm the entomological monitoring results, i.e., that there is a high probability that the population of G. p. gambiensis has been eradicated from the Niayes and that the transmission of AAT has been interrupted in the treated area. These results indicate the effectiveness of the adopted approach and show that AAT can be sustainably removed through the creation of a zone free of G. p. gambiensis.

Radiobiological studies on fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae)

Abstract The fall armyworm, Spodoptera frugiperda (JE Smith, 1797) is a notorious invasive pest causing significant economic damage to various crops. The extensive damage caused by this pest has created havoc in India and has become a nightmare for farmers. The management steps taken for controlling the pest have become futile. There are several instances depicting the failure of conventional management tactics, viz resistance against insecticides and transgenic maize lines paving the way for exploiting newer paradigms of pest management. Hence, a novel approach through the use of gamma irradiation against the pest was attempted. A dose-response trial encompassing doses from 50 to 200 Gy was employed to study the adverse effects of gamma irradiation on the biology of fall armyworm. The irradiated insects were crossed with their counterpart and the developmental profile of progeny was analysed. The obtained results were quite promising and showed a significant effect on the biology of the pest with progression of the irradiation dose. When females were exposed to irradiation and crossed with fertile counterparts, fecundity decreased with an increase in irradiation dose. A considerable increase in the egg, larval and pupal period was observed at 100 and 150 Gy. This decreased fecundity reduces the pest’s build-up in the field and the prolonged developmental period make the pest more prone to biotic and abiotic annihilation factors. Hence, the above-mentioned strategy has plausible applications in the near future and this tool can better be fitted into area-wide integrated pest management programmes.

Gamma-radiation of Glossina palpalis gambiensis revisited: effect on fertility and mating competitiveness

African animal trypanosomoses are vector-borne diseases that cause enormous livestock losses in sub-Saharan Africa, with drastic socio-economic impacts. Vector control in the context of an area-wide integrated pest management program with a sterile insect technique component requires the production of high-quality sterile male tsetse flies. In our study, we evaluated the effect of irradiation on the fecundity of Glossina palpalis gambiensis to identify the optimal dose that will induce maximum sterility while maintaining biological performance as much as possible. In addition, male mating performance was evaluated in semi-field cages. The irradiation doses used were 90, 100, 110, 120, 130, 140, and 150 Gy, and untreated males were used as the control. The results showed that pupal production and emergence rates were higher in batches of females that had mated with fertile males than in those that had mated with irradiated males with any experimental dose. A dose of 120 Gy administered to male flies induced 97-99% sterility after mating with virgin females. For the semi-field cage experiments, males irradiated with 120 Gy showed good sexual competitiveness as compared to fertile males and those irradiated with 140 Gy, considering the level of filling of spermatheca and the number of pairs formed. The optimal radiation dose of 120 Gy found in this study is slightly different from the traditional dose of 110 Gy that has been used in several eradication programmes in the past. The potential reasons for this difference are discussed, and an argument is made for the inclusion of reliable dosimetry systems in these types of studies.

Impact of invasive insects on native insect communities

Several biophysical factors are leading to the loss of biodiversity, among them the dominance of exotic invasive species on native communities is important. Their dominance can lead to changes in the structure of insect communities, by competing and displacing native species to other crops or habitats. These changes can impact the herbivore's natural enemies in invaded areas by diverging them from suitable herbivores and altering their biological control process. The development of edible insects and derived products at an industrial scale can also have an impact on the local fauna by the risks of spillover and accidental release in nature. Several area-wide integrated pest management programs are also using the sterile insect technique to control insect pests and disease' vectors. This technique is becoming largely used; however, its application as 'non-intrusive to the environment' is controversial particularly when eradication is concerning species that are at the basis of food webs.

Evaluation of Areawide Forecasts of Wind-borne Crop Pests: Sugarcane Aphid (Hemiptera: Aphididae) Infestations of Sorghum in the Great Plains of North America.

Airborne pests pose a major challenge in agriculture. Integrated pest management programs have been considered a viable response to this challenge, and pest forecasting can aid in strategic management decisions. Annually recurrent areawide sugarcane aphid [Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae)] infestations of sorghum [Sorghum bicolor (L.) Moench (Poales: Poaceae)] in the Great Plains of North America is one of such challenges. As part of the response, a spatially-explicit individual-based model was developed that simulates sugarcane aphid infestations over the southern-to-central part of the region. In this work, we evaluated model forecasts using 2015-2018 field data. The ranges of forecasted days of first infestation significantly overlapped with those observed in the field. The average days of first infestation observed in the field were approximated by the model with differences of less than 28 days in Texas and southern Oklahoma (2015-2018), and in northern Oklahoma (2016-2017). In half of these cases the difference was less than 14 days. In general, the modeled average day of first infestation was earlier than the observed one. As conceptual modeling decisions may impact model forecasts and as various socio-environmental factors may impact spatio-temporal patterns of field data collection, agreement between the forecasts and the observed estimates may vary between locations and seasons. Predictive modeling has the potential to occupy a central position within areawide integrated pest management programs. More detailed consideration of local agricultural practices and local environmental conditions could improve forecasting accuracy, as could broader participation of producers in field monitoring efforts.

Predicting the Invasion Risk by Anastrepha sororcula (Diptera: Tephritidae) in Distinct Geographic Regions.

The movement of endemic fruit flies to new habitats represents a major biological and economic threat. Anastrepha sororcula Zucchi, 1979 is widely distributed in Brazil and also in Colombia, Ecuador, and Paraguay. Here, we present the potential distribution of A. sororcula in endemic areas and project this model into other regions such as part of sub-Saharan Africa, Central America, and Asia to show areas around the world that this species can potentially establish. We combined geographic coordinates with climate data. The models were built using the maximum entropy (MaxEnt) algorithm. Many mango- and guava-producing countries exhibited climatic suitability for A. sororcula in the regions studied including the nine largest world producers: India, Brazil, Malawi, Kenya, Haiti, Cuba, Colombia, Madagascar, and the Democratic Republic of the Congo. Many of these countries showed ideal host plant availability and climatic conditions for the entry and establishment of A. sororcula. This study is a pioneer in the identification of representative areas in the world with climatic suitability for A. sororcula, which shows the importance of predicting areas at risk of invasion to monitor the movement and establishment of fruit fly species in new regions, which is fundamental to area-wide integrated pest management programs.

Operational Parameters for the Aerial Release of Sterile Codling Moths Using an Uncrewed Aircraft System.

Simple SummaryPest management through the release of sterile codling moths from drones or uncrewed aerial vehicles (UAVs) represents an efficient method for distribution over orchards. In this study, moths released from greater altitudes were more broadly distributed and drifted more in strong winds compared to those released from lower altitudes. Most of the released insects were recaptured in a 50 m wide swath under the release route. Recapture rates from aerially released insects were 40–70% higher compared to those released from the ground. We found that an uncrewed aircraft system (UAS) releasing insects from 35 m above the ground in release routes 50 m apart outperformed standard ground release methods. UASs provide a promising alternative to ground release and conventional aircraft for the release of sterile codling moths.The codling moth is a serious pest of apples in most regions of the world where this fruit is produced. The sterile insect technique is one strategy used to control this pest and is employed as part of an area-wide integrated pest management program for the codling moth in British Columbia, Canada. Modified fixed wing aircraft are the most common method for the release of sterile insects in large area-wide pest management programs. However, aerial release with a full-size aircraft can be prohibitively expensive. We evaluated the use of small, uncrewed aircraft systems (UASs) for the release of sterile codling moths. Sterile codling moths released from greater altitudes were more broadly distributed and drifted more in strong winds, compared to those released from lower altitudes. Most of the released insects were recaptured in a 50 m wide swath under the release route. Recapture rates for aerially released insects were 40–70% higher compared to those released from the ground. UASs provide a promising alternative to ground release and conventional aircraft for the release of sterile codling moths.

Low-oxygen hormetic conditioning improves field performance of sterile insects by inducing beneficial plasticity.

As part of sterile insect technique (SIT) programs, irradiation can effectively induce sterility in insects by damaging germline genomic DNA. However, irradiation also induces other off‐target side effects that reduce the quality and performance of sterilized males, including the formation of damaging free radicals that can reduce sterile male performance. Thus, treatments that reduce off‐target effects of irradiation on male performance while maintaining sterility can improve the feasibility and economy of SIT programs. We previously found that inducing a form of rapid, beneficial plasticity with a 1‐hr anoxic‐conditioning period (physiological conditioning hormesis) prior to and during irradiation improves male field performance in the laboratory while maintaining sterility in males of the cactus moth, Cactoblastis cactorum. Here, we extend this work by testing the extent to which this beneficial plasticity may improve male field performance and longevity in the field. Based on capture rates after a series of mark release–recapture experiments, we found that anoxia‐conditioned irradiated moths were active in the field longer than their irradiated counterparts. In addition, anoxia‐conditioned moths were captured in traps that were farther away from the release site than unconditioned moths, suggesting greater dispersal. These data confirmed that beneficial plasticity induced by anoxia hormesis prior to irradiation led to lower postirradiation damage and increased flight performance and recapture duration under field conditions. We recommend greater consideration of beneficial plasticity responses in biological control programs and specifically the implementation of anoxia‐conditioning treatments applied prior to irradiation in area‐wide integrated pest management programs that use SIT.

Combining sterile and incompatible insect techniques for the population suppression of Drosophila suzukii

The spotted wing Drosophila, Drosophila suzukii, has recently invaded Europe and the Americas, and it is a major threat for a wide variety of commercial soft fruits both in open field and greenhouse production systems. D. suzukii infests a wide range of ripening fruits, leading to substantial yield and revenue losses. As the application of insecticides close to the harvest period poses great concerns, the development of an efficient environment-friendly control approach to fight D. suzukii is necessary. In this study, we exploited the sterile insect technique (SIT) in combination with Wolbachia symbiosis as a population suppression approach that can constitute a potential component of an area-wide integrated pest management program. We aimed to establish a combined SIT/incompatible insect technique (IIT) protocol that would require lower irradiation doses as a complementary tool for D. suzukii management. Two D. suzukii lines trans-infected with the Wolbachia wHa and wTei strains were irradiated at doses four times less than usual (e.g., 45 Gy), and the egg hatching and adult emergence were determined. Our results indicated that wHa and wTei females as well as wHa males were sterile at this low dose. The longevity, adult emergence and flight ability of adults were evaluated, and no major effect caused by irradiation was detected. Our data indicate that a SIT/IIT protocol can be a competent approach for D. suzukii management.

Using machine learning to identify the geographical drivers of Ceratitis capitata trap catch in an agricultural landscape

The spatial distribution of Ceratitis capitata Wiedemann (Diptera: Tephritidae) trap catch was classified and related to a set of geographic variables to identify its main geographical drivers. Trap catch data were sourced from an area-wide integrated pest management (AW-IPM)1The integrated use of a combination of available management methods against a target pest including biological, chemical, and cultural management methods on an area-wide scale.1 programme and classified into statistically significant hot- and cold spots (HCSs)2Statistically significant spatial clusters of high values (hot spots) and low values (cold spots).2. Trap data of four consecutive fruiting seasons were combined to identify monthly and seasonal long-term HCSs. The main geographic drivers of the HCSs were identified using variable importance lists produced by the random forest (RF) machine learning (ML) algorithm. Long-term climate, topography, landscape and fruit fly management variables were used as predictor variables in RF to classify HCSs. The resulting RF models produced classification accuracies of up to 80%. In most cases, the most important variable was long-term rainfall, suggesting that this was the most prominent driver of C. capitata HCSs in our study region. The result of this study highlights the value of long-term pest monitoring data and long-term environmental data in understanding the spatial distribution of C. capitata trap catch in complex agricultural systems. This study sets out a framework to spatially quantify C. capitata trap catch into HCSs using monitoring data from AW-IPM programmes, enabling the investigation of complex ecological relationships through the use of ML algorithms. The results of these analyses could improve area-wide integrated fruit fly management programmes through more precise spatial planning of management actions, such as the sterile insect technique (SIT)3Biological environmentally-friendly insect pest control method.3, leading to better programme performance and reduced costs.

Impact of Glossina pallidipes salivary gland hypertrophy virus (GpSGHV) on a heterologous tsetse fly host, Glossina fuscipes fuscipes

BackgroundTsetse flies (Diptera: Glossinidae) are the vectors of African trypanosomosis, the causal agent of sleeping sickness in humans and nagana in animals. Glossina fuscipes fuscipes is one of the most important tsetse vectors of sleeping sickness, particularly in Central Africa. Due to the development of resistance of the trypanosomes to the commonly used trypanocidal drugs and the lack of effective vaccines, vector control approaches remain the most effective strategies for sustainable management of those diseases. The Sterile Insect Technique (SIT) is an effective, environment-friendly method for the management of tsetse flies in the context of area-wide integrated pest management programs (AW-IPM). This technique relies on the mass-production of the target insect, its sterilization with ionizing radiation and the release of sterile males in the target area where they will mate with wild females and induce sterility in the native population. It has been shown that Glossina pallidipes salivary gland hypertrophy virus (GpSGHV) infection causes a decrease in fecundity and fertility hampering the maintenance of colonies of the tsetse fly G. pallidipes. This virus has also been detected in different species of tsetse files. In this study, we evaluated the impact of GpSGHV on the performance of a colony of the heterologous host G. f. fuscipes, including the flies’ productivity, mortality, survival, flight propensity and mating ability and insemination rates.ResultsEven though GpSGHV infection did not induce SGH symptoms, it significantly reduced all examined parameters, except adult flight propensity and insemination rate.ConclusionThese results emphasize the important role of GpSGHV management strategy in the maintenance of G. f. fuscipes colonies and the urgent need to implement measures to avoid virus infection, to ensure the optimal mass production of this tsetse species for use in AW-IPM programs with an SIT component.

Is sterile insect technique’s efficiency affected by pomegranate variety in mixed cultivars? New insights from a case study on the carob moth, Apomyelois ceratoniae Zeller (Lepidoptera: Pyralidae) in Iran

Carob moth, Apomyelois ceratoniae Zeller (Lepidoptera: Pyralidae), is the most important pest of pomegranates in Iran. In this research, performance of the sterile insect technique (SIT) in the management of this pest was evaluated considering crop variety resistance. Rearing of the moth is carried out under constant environmental conditions and 3–4-day-old pupae were gamma-irradiated at 165 Gy. After cyclic releasing of the sterile moths, carob moth infestation decreased under SIT treatment (F1,81 = 32.48, p < 0.0001) in both susceptible (Aalak) and non-susceptible (Malas) pomegranate varieties. Our results indicated satisfying different declines in the pest infestation as 2.97 and 2.07 times on Malas and Aalak varieties, respectively (F1,81 = 6.56, p = 0.012). However, SIT was 1.43 times more successful on non-susceptible pomegranate variety than susceptible one in terms of crop injury. SIT efficiency is not only density dependent, but also dependent on crop variety and this finding leads us to consider crop resistance to insects in planning area-wide integrated pest management programmes based on sterile insect technique in future.

Drosophila suzukii in Southern Neotropical Region: Current Status and Future Perspectives.

Non-native insect pests are often responsible for important damage to native and agricultural plant hosts. Since Drosophila suzukii Matsumura (Diptera: Drosophilidae) has become an important pest in North America and Europe (i.e., in 2008), the global production of soft thin-skinned fruits has faced severe production losses. In the southern Neotropical region, however, the first record of D. suzukii occurred in 2013 in the south of Brazil. It has also been recorded in Uruguay, Argentina, and Chile. Despite its recent occurrence in the southern Neotropical region, the fast dispersion of D. suzukii has inspired local research efforts in an attempt to mitigate the consequences of this insect pest invasion. In this forum, we explore the current status of D. suzukii in southern Neotropical regions, discussing its future perspectives. Additionally, we attempt to draft activities and a research agenda that may help to mitigate the losses caused by D. suzukii in native and commercial soft-skinned fruits produced in this region. Currently, D. suzukii appears to be well established in the south of Brazil, but considering the entire southern Neotropical region, the invasion panorama is still underinvestigated. The lack of studies and regulatory actions against D. suzukii has contributed to the invasion success of this species in this region. Considering several peculiarities of both the pest biology and the environmental of this region, the authors advocate for the need of intensive and integrative studies toward the development and implementation of area-wide integrated pest management programs against D. suzukii in the southern Neotropical region.

Performance of a Genetically Modified Strain of the Mediterranean Fruit Fly (Diptera: Tephritidae) for Area-Wide Integrated Pest Management With the Sterile Insect Technique.

The genetically modified strain of Ceratitis capitata (Wiedemann) VIENNA 8 1260 has two morphological markers that exhibit fluorescence in body and sperm. To assess the feasibility of its use in area-wide integrated pest management (AW-IPM) programs using the sterile insect technique, its rearing performance and quality control profile under small, medium, and large scales was evaluated, as well as in field cages. The VIENNA 8 1260 strain had a lower yield than the control strains, VIENNA 8 with D53 inversion (VIENNA 8) and without D53 inversion (VIENNA 8 D53-). At mass-rearing scale, yield gradually increased in three generations without reaching the control strain values. The VIENNA 8 1260 strain was stable in the genetic sexing mechanism (>99.9%) and expression of fluorescence (100%). In field cages, the VIENNA 8 1260 males reduced the mating potential of wild males in the same magnitude as the VIENNA 8, when evaluated in independent cage tests. However, the relative sterility index and the strain male relative performance index of VIENNA 8 1260 males were significantly lower than those of the VIENNA 8. There were no significant differences in longevity of these strains. The potential application of the VIENNA 8 1260 in AW-IPM programs is further discussed.

Validation of a geographic weighted regression analysis as a tool for area-wide integrated pest management programs for Ceratitis capitata Wiedemann (Diptera: Tephritidae) on Terceira Island, Azores

ABSTRACTExtrapolation from quantitative sampling to the surrounding areas is an essential feature of many aspects of real world applications in pest management decision-making. However, these decisions are only as good as the accuracy of the methods that provided the information. The problem of estimating Mediterranean fruit fly population densities from trap grids is a specific case. The efficiency of three methods to estimate fruit flies trapped per day values for non-sampled areas in Terceira Island is evaluated, the inverse distance weighted, ordinary Kriging and the geographic weighted regression (GWR). Each method has its own specificities and merits. The results demonstrate that the GWR method is capable of estimating hotspots for the next season and can be used to identify ecological corridors over a non-sampled area. The high spatial heterogeneity and topographical conditions present on Terceira Island may explain why a more mathematically complex method is more reliable than simpler methods for use in possible future wide-area control program for medfly.

Influence of temperature and relative humidity on survival and fecundity of three tsetse strains.

BackgroundTsetse flies occur in much of sub-Saharan Africa where they are vectors of trypanosomes that cause human and animal African trypanosomosis. The sterile insect technique (SIT) is currently used to eliminate tsetse fly populations in an area-wide integrated pest management (AW-IPM) context in Senegal and Ethiopia. Three Glossina palpalis gambiensis strains [originating from Burkina Faso (BKF), Senegal (SEN) and an introgressed strain (SENbkf)] were established and are now available for use in future AW-IPM programmes against trypanosomes in West Africa. For each strain, knowledge of the environmental survival thresholds is essential to determine which of these strains is best suited to a particular environment or ecosystem, and can therefore be used effectively in SIT programmes.MethodsIn this paper, we investigated the survival and fecundity of three G. p. gambiensis strains maintained under various conditions: 25 °C and 40, 50, 60, and 75 % relative humidity (rH), 30 °C and 60 % rH and 35 °C and 60 % rH.ResultsThe survival of the three strains was dependent on temperature only, and it was unaffected by changing humidity within the tested range. The BKF strain survived temperatures above its optimum better than the SEN strain. The SENbkf showed intermediate resistance to high temperatures. A temperature of about 32 °C was the limit for survival for all strains. A rH ranging from 40 to 76 % had no effect on fecundity at 25–26 °C.ConclusionsWe discuss the implications of these results on tsetse SIT-based control programmes.

Radiation Biology ofEldana saccharina(Lepidoptera: Pyralidae)

Laboratory-reared male and female Eldana saccharina Walker (Lepidoptera: Pyralidae: Gallerinae)—a major pest of sugarcane (Saccharum spp.; Poales: Poaceae) in South Africa—were exposed to increasing doses of γ-radiation to assess this species' suitability for the sterile insect technique as part of an area-wide integrated pest management (AW-IPM) program. Irradiated male and female moths were crossed with non-irradiated counterparts and irradiated counterparts at the same radiation dose. Male and female moths were treated with radiation doses of 150, 200, 250, 300 and 350 Gy, and the following crosses were made: irradiated males (T♂) mated with untreated females (U♀) and irradiated females (T♀) mated with untreated males (U♂). Males and females of the T♀ × T♂ cross were exposed to the same radiation doses except in the 350 Gy treatment. Fertility (egg hatch) declined significantly with increasing doses of radiation in all crosses. Female progeny from the T♀ × U♂ and T♀ × T♂ crosses were more sensitive to irradiation than female progeny from the U♀ × U♂ and U♀ × T♂ crosses and were completely sterile when treated with either 200 Gy or 150 Gy. Treated males mated with untreated females still had a residual fertility of 0.19% when exposed to 350 Gy of radiation. The fertility of E. saccharina is therefore sensitive to increasing doses of ionizing radiation and this species is a suitable candidate for further development of the SIT as a component of an AW-IPM program. The fecundity of untreated E. saccharina females mated with irradiated males was not affected by radiation. The availability of a great number of infertile eggs can be regarded as a benefit in a program where natural enemies are combined with the SIT because non-fertile eggs can provide additional hosts for egg parasitoids and be a food source for predators.

LARVAL X‐RAY IRRADIATION INFLUENCES PROTEIN EXPRESSION IN PUPAE OF THE ORIENTAL FRUIT FLY, BACTROCERA DORSALIS

The sterile insect technique (SIT) was developed to eradicate the new world screwworm from the southern United States and Mexico, and became a component of many area-wide integrated pest management programs, particularly useful in managing tephritid fruit flies. SIT is based on the idea of rearing and sterilizing male pests, originally by ionizing radiation, and then releasing into field, where they compete for and mate with wild females. Mating with sterile males leads to reduced fecundity to lower pest populations. There are concerns with the use and distribution of radioisotopes for SIT programs, which have led to developing X-ray irradiation protocols to sterilize insects. We considered the possibility that X-ray irradiation exerts sublethal impacts aside form sterilizing insects. Such effects may not be directly observable, which led us to the hypothesis that X-ray irradiation in one life stage creates alterations in biological fitness and protein expression in the subsequent stage. We tested our hypothesis by irradiating larvae of Bactrocera dorsalis. There are two major points. One, exposing larvae to X-ray treatments led to reduced adult emergence, fecundity, fertility, and flight capacity from the corresponding pupae and emerged adults. Two, the X-ray treatments led to substantial expression changes in 27 pupal proteins. We assorted the 67 spots representing these proteins into three groups, metabolism, development, and structure. Our interpretation is these X-ray induced changes in biological performance and protein expression indicate their adult counterparts may be disabled in their abilities to successfully compete for and mate wild females in native habitats.

Determination of the optimal mating age of colonised Glossina brevipalpis and Glossina austeni using walk-in field cages in South Africa.

BackgroundFor the control of Glossina brevipalpis and Glossina austeni that occur in South Africa an area-wide integrated pest management (AW-IPM) program with a sterile insect technique (SIT) component has been proposed. The quality of the released sterile male tsetse flies will greatly determine the success of the SIT component of the programme. Sterile males need to be able to compete with wild males immediately after their release in the affected area. The mating competitiveness can be affected by many factors including the optimal mating age of the fly which can have an impact on the timing of the release.MethodsTo assess the optimal mating age for G. brevipalpis and G. austeni, mating competitiveness studies were carried out in a walk-in field cage. First, the time of peak fly activity was determined by performing the experiment in the morning and then again in the afternoon. Thereafter, 3, 6 and 9-day-old male flies competed for 3-day-old virgin females.ResultsThere were no significant differences in mating performance when the field cage experiments were done in the morning or in the afternoon. However, the mating latency was shorter in the afternoon than in the morning. For both species 9-day-old males mated significantly more often than 6 or 3-day-old males. Age did not affect the males’ ability to transfer sperm, mating duration or the mating latency. All females that mated were inseminated.ConclusionsAge did influence the mating competitiveness of G. brevipalpis and G. austeni and it is recommended that sterile males are not released before the age of 9 days. Keeping the male flies in the rearing facility for 8 days will have economic and logistic consequences for AW-IPM programmes that have a SIT component.

Economic evaluation of an area-wide integrated pest management program to control the Asian tiger mosquito in New Jersey.

Aedes albopictus is the most invasive mosquito in the world, an important disease vector, and a biting nuisance that limits outdoor activities. Area-wide integrated pest management (AW-IPM) is the recommended control strategy. We conducted an economic evaluation of the AW-IPM project in Mercer and Monmouth Counties, New Jersey with a controlled design (AW-IPM vs. control) from 2009 through 2011. The study analyzed financial documents and staff time for AW-IPM and surveyed an average of 415 randomly chosen households in AW-IPM and control areas each fall from 2008 through 2011. Hours lost from yard and porch activities were calculated as differences between actual and potential hours of these activities in an average summer week if there had been no mosquito concerns. Net estimated benefits of AW-IPM were based on cross-over and difference-in-difference analyses. Reductions in hours lost were valued based on respondents' willingness to pay for a hypothetical extra hour free of mosquitoes spent on yard or porch activities and literature on valuation of a quality adjusted life year (QALY). The incremental cost of AW-IPM per adult was $41.18 per year. Number of hours lost due to mosquitoes in AW-IPM areas between the base year (2008) and the intervention years (2009-2011) declined by 3.30 hours per summer week in AW-IPM areas compared to control areas. Survey respondents valued this improvement at $27.37 per adult per summer week. Over the 13-week summer, an average adult resident gained 42.96 hours of yard and porch time, worth $355.82. The net benefit over the summer was $314.63. With an average of 0.0027 QALYs gained per adult per year, AW-IPM was cost effective at $15,300 per QALY gained. The benefit-cost ratio from hours gained was 8.64, indicating that each $1 spent on AW-IPM gave adults additional porch and yard time worth over $8.