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In view of the prevailing insecticide resistance and increasing safety and health concerns, there is an urgent need to develop effective and environmentally friendly methods to control stored-product pests. S-methoprene, a microbial volatile compound with insecticidal properties, has been identified as a potential candidate for this purpose. However, its efficacy against storage pests is not well understood. In this study, wheat was treated with S-methoprene at a rate of 5 mg/kg and stored in ambient conditions within a grain bin. Samples were collected after 90 and 365 days, and bioassays were conducted on 20 mixed-sex developmental stages of Tribolium castaneum and T. confusum. S-methoprene showed significant ovicidal, pupicidal, and adulticidal activity against T. castaneum and T. confusum. The efficacy of S-methoprene was found to be influenced by the developmental stage of the pests and the timing of its application. In the 90-day treatment group, the hatching rate of three T. castaneum strains was zero, while that of T. confusum strains from Guangdong and Beijing was (1.67±2.04)% and 0%, respectively. S-methoprene treatment in the 90-day group resulted in effective pupicidal activity against both T. castaneum and T. confusum, with the F1 generation of adults being unable to reproduce. However, in the 365-day treatment group, the pupicidal activity significantly decreased, and the F1 generation of adults were able to reproduce but their F1 generation pupae can not hatch. The adulticidal activity of both pests had some effects in both treatments, but the mortality rate significantly decreased in the 365-day treatment group. The F1 generation of T. castaneum only consisted of larvae, while some larvae of T. confusum were able to pupate but could not further develop into adults. T. castaneum was found to be more susceptible to S-methoprene than T. confusum. After S-methoprene induction, the activity of three detoxification enzymes in Tribolium species was affected in varying degrees and had different variation patterns. The activity was positively correlated with induction time.

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Mosquitoes are a threat worldwide since they are vectors of important pathogens and parasites such as malaria, dengue, yellow fever, and West Nile. The residual toxicity of several commercial mosquito larvicides was evaluated for the control of Culex pipiens pipiens under controlled laboratory and semi-field conditions during late spring and summer of 2013. The evaluation included six different active ingredient formulations, i.e., diflubenzuron Du-Dim), Bacillus thuringiensis var. israelensis (Bti) (Vectobac), spinosad (Mozkill), S-methoprene (Biopren), temephos (Abate), and polydimethylsiloxane (PDMS) (Aquatain), that are currently registered of and had been registered in the past for mosquito control. Under controlled laboratory conditions, the residual activity ranged from 1 week (S-methoprene) up to 2 months (spinosad, PDMS). Exposure of larvicides under semi-field conditions resulted in noticeable differences regarding their efficacy as compared to the laboratory bioassays. Exposure of S-methoprene, Bti, and spinosad, for up to 3 days, resulted in similar adult emergence to the controls. On the other hand, the residual efficacy of diflubenzuron, temephos, and PDMS ranged from 14 to 28 days, depending on the season of exposure. Longevity and fecundity of adults that had emerged from surviving larvae, in most of the cases tested, did not differ significantly from that of the controls. The results of the present study demonstrate the necessity of both field and laboratory studies to draw safe conclusions regarding the efficacy of larvicides against mosquitoes and the selection of the proper formulation for each application scenario. In addition, defining the seasonal variation in the residual toxicity of the tested formulations could be useful for improving mosquitos' management programs. [ABSTRACT FROM AUTHOR]

Mosquito larval control by biorational larvicides plays a crucial role in mosquito and mosquito-borne disease management. However, the availability of larvicides that meet the criteria of efficacy, safety, and quality is limited and conventional pesticides are no longer preferred for larval control. Although efforts are made to research new active ingredients (AIs), it is equally important to innovate new formulations based on currently available AIs such as microbial agents and insect growth regulators. Studies were therefore conducted to compare the laboratory activity and semi-field efficacy of OmniPrene® G and Altosid® Pellets with DR-tech, both containing 4.25% S-methoprene, at 2.8 kg/ha and 11.2 kg/ha against the yellow fever mosquito Aedes aegypti (L.) in outdoor microcosms. Both products performed equally in bioassays against the test species with comparable inhibition of emergence activities. In the semi-field study, the lower dose of Altosid Pellets at 2.8 kg/ha, showed lower efficacy than OmniPrene G during the initial 6 weeks; this difference became negligible on week 7, followed by higher efficacy in Altosid Pellets on weeks 8 and 9. More uniform efficacy was observed at the higher dose of 11.2 kg/ha. Equal performance was revealed during weeks 2 to 6, with the OmniPrene G outperforming the Altosid Pellets in week 1, but the opposite during weeks 7 to 9. Mortality patterns were similar in both products, i.e., majority of mortality occurred before emergence, although more incomplete emergence was noted in lower doses, particularly in Altosid Pellets. Overall, newly available OmniPrene G provided comparable activity and efficacy with Altosid Pellets against the test species, with the advantages of fast initial AI release and even coverage, particularly when applied at low doses., (Copyright © 2024 by The American Mosquito Control Association, Inc.)

Abstract Background The lesser grain borer, Rhyzopertha dominica is a serious pest of stored grains. Fumigation and contact insecticides play a major role in managing this pest globally. While insects are developing genetic resistance to chemicals, hormonal analogues such as s-methoprene play a key role in reducing general pest pressure as well as managing pest populations that are resistant to fumigants and neurotoxic contact insecticides. However, resistance to s-methoprene has been reported in R. dominica with some reports showing a remarkable high resistance, questioning the use of this compound and other related analogues in grain protection. The current study attempts to identify possible molecular mechanisms that contribute in resistance to s-methoprene in R. dominica. Results Transcriptome analysis of resistant and susceptible strains of this pest species identified a set of differentially expressed genes related to cytochrome P450s, indicating their potential role in resistance to s-methoprene. Laboratory bioassays were performed with s-methoprene treated wheat grains in presence and absence of piperonyl butoxide (PBO), a cytochrome P450 inhibitor. The results indicate that PBO, when applied alone, at least at the concentration tested here, had no effect on R. dominica adult emergence, but has a clear synergistic effect to s-methoprene. The number of produced progeny decreased in presence of the inhibitor, especially in the resistant strain. In addition, we also identified CYP complement (CYPome) of R. dominica, annotated and analysed phylogenetically, to understand the evolutionary relationships with other species. Conclusions The information generated in current study suggest that PBO can effectively be used to break resistance to s-methoprene in R. dominica.

Background: The lesser grain borer, Rhyzopertha dominica is a serious pest of stored grains. Fumigation and contact insecticides play a major role in managing this pest globally. While insects are developing genetic resistance to chemicals, hormonal analogues such as s-methoprene play a key role in reducing general pest pressure as well as managing pest populations that are resistant to fumigants and neurotoxic contact insecticides. However, resistance to s-methoprene has been reported in R. dominica with some reports showing a remarkable high resistance, questioning the use of this compound and other related analogues in grain protection. The current study attempts to identify possible molecular mechanisms that contribute in resistance to s-methoprene in R. dominica. Results: Transcriptome analysis of resistant and susceptible strains of this pest species identified a set of differentially expressed genes related to cytochrome P450s, indicating their potential role in resistance to s-methoprene. Laboratory bioassays were performed with s-methoprene treated wheat grains in presence and absence of piperonyl butoxide (PBO), a cytochrome P450 inhibitor. The results indicate that PBO, when applied alone, at least at the concentration tested here, had no effect on R. dominica adult emergence, but has a clear synergistic effect to s-methoprene. The number of produced progeny decreased in presence of the inhibitor, especially in the resistant strain. In addition, we also identified CYP complement (CYPome) of R. dominica, annotated and analysed phylogenetically, to understand the evolutionary relationships with other species. Conclusions: The information generated in current study suggest that PBO can effectively be used to break resistance to s-methoprene in R. dominica. [ABSTRACT FROM AUTHOR]

The insect growth regulator pyriproxyfen in two formulations (Sumilarv 90 CS and Sumilarv 5 GR) was evaluated in semi-field trials for the control of immature stages of Culex quinquefasciatus Say. In the first trial, the two formulations were compared with the industry standard Prolink 50 CS (50g/L s-methoprene) at the field application rate for Prolink (ie. 11gai/ha or 3.7 ppb) in 50 L tubs. All three products produced 100% emergence inhibition of a single generation. In the second trial, Sumilarv 5 GR was evaluated in two-litre buckets over various nominal concentrations from 500ppb down to 0.5 ppb for five successive generations over 60 days. When applied as a granule, Sumilarv 5 GR produced 100% emergence inhibition across 5 generations. However, where serial dilutions of Sumilarv 5 GR treated water were tested, efficacy was greatly reduced. To investigate this phenomenon, the dilution process was repeated and samples analysed for pyriproxyfen content. The dilution process generated just 6 ppm (against the nominal 500 ppb) indicating that the granules were very stable in water and the pyriproxyfen was not readily released. Further, the pyriproxyfen content of water over 10 weeks following application of granules (nominal 500 ppb) showed an erratic but gradual release of active ingredient and a peak concentration of just 8.5 ppb at 1 week declining to below 1 ppb at 10 weeks. Pyriproxyfen was very effective in inhibiting emergence of Cx. quinquefasciatus adults for multiple generations at less than 10 ppb, and probably much lower. Sumilarv 5 GR when applied directly to water at 0.1g/L (nominal 500ppb) provided emergence inhibition for at least five generations over 60 days. These results demonstrate that these products hold great potential to assist the management of mosquitoes of pest and public health concern. [ABSTRACT FROM AUTHOR]

A field study was carried out on the year-long residual activity of the insect growth regulator (IGR) pyriproxyfen (Nylar 0.5G) in comparison with methoprene (Altosid® XRP Pellets) against mosquito developmental stages in catch basins in northwestern Riverside County, southern California. Pyriproxyfen was applied at 75, 100, 125, 150, 175 g per catch basin and methoprene at 3.5 g per catch basin. A total of 80 catch basins (10 per each treatment and 20 for control) were used. Posttreatment observations of catch basins were carried out at weekly intervals, with all pupal collections reared to adults. Mosquito species composition in this study, consisting mostly of Culex species (693), was predominated by Cx. quinquefasciatus (92.8%), followed by Cx. erythrothorax (5.5%), Cx. tarsalis (1.2%), Cx. stigmatosoma (0.3%), and Cx. thriambus (0.2%). Activity of both IGRs was expressed as percent inhibition of adult emergence (% IAE). Data generated on % IAE showed that, like methoprene, pyriproxyfen provided complete control of mosquitoes at 75, 125, and 175 g per catch basin up to 50 wk posttreatment at the Riverside amusement park, whereas its activity against mosquitoes in catch basins treated with 100 g and 150 g at the Eastvale site was short-lived, up to 48 wk. Water samples, bioassayed against laboratory-reared, 4th-stage larvae of Cx. quinquefasciatus 1–2 wk after the 50-wk-long study, showed evidence of significant % IAE (∼50) by pyriproxyfen at the 2 higher rates (125 g, 175 g) used at the amusement park. In conclusion, pyriproxyfen can be used to effectively control mosquitoes in catch basins for 48–50 wk, depending on the rate of application. [ABSTRACT FROM AUTHOR]

Understanding the influence of salinity on the efficacy of mosquito larvicides in brackish water habitats is crucial for effective salt-marsh Aedes taeniorhynchus control. This study investigated the interactive effects of salinity on the toxicity of 3 commonly used mosquito larvicides: Bacillus thuringiensis israelensis (VectoBac® 12AS), spinosad (Natular® SC), and S-methoprene (Altosid® 12AS) against Ae. taeniorhynchus larvae. Four salinity levels (0 ppt [parts per thousand], 8 ppt, 16 ppt, and 32 ppt) were tested in laboratory bioassays. The results revealed distinct responses of these larvicides to varying salinity levels. VectoBac 12AS displayed consistent efficacy across all salinity levels, indicating its suitability for brackish water habitats. In contrast, Natular 2EC exhibited increased effectiveness with higher salinity, making it a preferable choice for saline environments. Altosid 12AS showed its highest efficacy in freshwater, with reduced effectiveness as salinity increased. These findings underscore the need to consider salinity levels when selecting and applying mosquito larvicides in diverse aquatic habitats. Understanding the complex interplay between salinity and larvicide performance is essential for optimizing mosquito control strategies and mitigating mosquito-borne diseases in various environments., (Copyright © 2024 by The American Mosquito Control Association, Inc.)

What Is Already Known About This Topic?: Anopheles sinensis ( An. sinensis ) is the predominant malaria vector in China. The impact of S-methoprene on the emergence process of mosquito larvae suggests its potential as a control method for vector mosquitoes. However, the efficacy of S-methoprene in controlling An. sinensis has not yet been demonstrated., What Is Added by This Report?: The effectiveness of S-methoprene against An. sinensis was assessed in laboratory and semi-field conditions in Yunnan Province., What Are the Implications for Public Health Practice?: These results offer valuable options and guidance for utilizing S-methoprene products in malaria reimportation prevention areas within Yunnan Province., Competing Interests: No conflicts of interest., (Copyright and License information: Editorial Office of CCDCW, Chinese Center for Disease Control and Prevention 2024.)

Aedes albopictus (Skuse) is a globally significant vector that complexifies management programs already contending with Aedes aegypti (L.). The Ae. albopictus mosquito is a daytime biting, container breeding, anthropophilic mosquito that is generally considered unresponsive to operational larviciding that does not also incorporate source reduction. S-methoprene is a readily available juvenile hormone mimic common to pest management. This 14-week study examines direct and indirect treatment efficacy using s-methoprene as an ultra-low volume (ULV) truck spray in area-wide operations against Ae. albopictus in the southeastern United States. An overall 63.3% reduction of Ae. albopictus adults and 47.8% reduction of deposited eggs in treatment areas were observed compared with control. Indirect plots saw reduction in Ae. albopictus adults by 32.7% and eggs by 32.3%. Using insect growth regulator bioassays, truck-mounted ULV application of s-methoprene was effective to an inhibition of emergence (IE) of ≥92% within directly treated (sprayed) areas and >65% IE among containers placed up to 90 m away. S-methoprene could still benefit urban vector management programs when applied at an operational scale. [ABSTRACT FROM AUTHOR]

Mosquitoes and mosquito-borne illnesses significantly impact public health and human well-being. To address this concern, environmentally compatible larvicides have become a critical component of integrated mosquito management. However, the number of available larvicides is at a historical low. Currently, larvicides that harness microbials and insect growth regulators account for most products. Screening of new active ingredients (AIs) or improvement of existing AIs is thus necessary to augment the capacity for mosquito control. S-methoprene possesses a similar molecular structure and identical function to mosquito juvenile hormone and has been one of the main targets for research and development. The efficacy and safety of S-methoprene have been well documented since the late 1960s, and numerous products have been commercialized to combat pests of economic importance. However, S-methoprene is vulnerable to environmental factors that lead to its degradation, which has created challenges in formulation development, particularly where extended efficacy is desired. A derivative of S-methoprene, namely S-methobutene, with molecular modification has become available. This derivative has demonstrated an enhanced activity of inhibition of emergence (IE) against species across the Aedes, Anopheles, and Culex genera at IE10, IE50, and IE90. Furthermore, S-methobutene consistently outperformed S-methoprene during a 120-day aging process against the southern house mosquito Cx. quinquefasciatus, where the IE% in S-methobutene was significantly higher than that in S-methoprene on most aging intervals. The former had significantly longer residual activity than the latter. The potential of S-methobutene for further development and application is discussed in consideration of its enhanced activity and stability., (© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Mosquito control plays a crucial role in the mitigation of mosquito-borne diseases. Larviciding that targets one of the aquatic stages is among the routine practices in mosquito control operations. One of the most extensive and challenging mosquito production sources in urban environments is underground storm drain systems. Along with the research and development of biorational larvicides in recent decades, numerous products based on microbial and insect growth regulators have become available. However, the performance of these products often varies because of product design and challenges associated with urban storm drain systems. This paper validates the comparative bioactivity and semifield efficacy of 2 control release products based on pyriproxyfen and S-methoprene. In laboratory bioassays, pyriproxyfen was significantly more active than S-methoprene against the test species, Culex quinquefasciatus Say and Aedes aegypti (L.). Culex quinquefasciatus was less susceptible than Ae. aegypti to both test materials. During a 26-wk-long semifield evaluation using the cast concrete simulated catch basins, the inhibition of emergence pretreatment and posttreatment in untreated control was negligible. The Sumilarv 0.5G applied at 75 g per catch basin provided 100% IE, whereas the Altosid XR briquet applied at 1 per catch basin yielded only partial control fluctuating from 12.7% to 82.7% (average 40.7%) of Cx. quinquefasciatus and 8.0% to 78.8% (average 37.4%) of Ae. aegypti. The Altosid XR briquet had an average residual weight of 59.9% at the end of semifield evaluation. Results are discussed in relation to field mosquito control operations in urban storm drain systems., (Copyright © 2023 by The American Mosquito Control Association, Inc.)

Floating emergence traps were used in 15 road gullies to determine the effectiveness and longevity of S-methoprene briquets over 124 days. Samples were taken monthly from October 2014 to March 2015. Two treatment methods were assessed: application of briquet using a float, and application without a float. These methods were compared with untreated control gullies. Mosquito emergence peaked in early November, and decreased by February. Effectiveness of the briquet was not impacted significantly by the presence or absence of a float ( P = 0.329). Gullies yielded a mean of 108 mosquitoes per day per gully over the season. Culex quinquefasciatus and Aedes notoscriptus were the most abundant species. The maximum number of Cx. quinquefasciatus emerging could exceed 1,600 per day per gully. Aedes notoscriptus numbers could exceed 70 adults per day per gully. Treatment with S-methoprene was highly effective against both species for at least 70 days and partially effective for up to 120 days. Treatment provided no control by day 124. S-methoprene provided 90% control over 124 days. Road gullies have been confirmed as a significant larval habitat and are likely to be increasing the potential for Ross River virus transmission in the area. [ABSTRACT FROM AUTHOR]

BACKGROUND The efficacy of methoprene can vary with surface substrates, application methods and environmental conditions. The objectives of the present study were to examine the effects of temperature and grain type on the long-term persistence and efficacy of methoprene in controlling Rhyzopertha dominica from Guangzhou, China. RESULTS Methoprene applied at 1 mg kg-1 caused >90% suppression of F1 adult progeny of R. dominica for 150-270 days. Temperature and grain type both influenced the long-term persistence of methoprene. Overall multivariate analysis of variance showed that the order of progeny reduction at different temperatures (°C) was: 24 > 28 > 32 > 36; the order of the progeny reduction on the different grains was: paddy > wheat and maize. CONCLUSION The results of our experiments show the maximum effect of methoprene for R. dominica control at 24 °C on paddy. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Mosquitoes and mosquito-borne diseases remain one of the major public health burdens. In most cases, vector control is the main or the only intervention to mitigate these problems. We are facing the challenges of traditional, emerging, or resurging vectors and diseases, yet the availability and affordability of safe and effective mosquito control products are at a historical low. Development of new active ingredients (AI) and novel formulations based on currently available AI are demanded by mosquito control operations. This paper validated the bioactivity in the laboratory and evaluated the semi-field efficacy for 2 newly registered controlled-release products based on juvenile hormone analog S-methoprene: OmniPrene™ water-soluble pouch (WSP) and extended water-soluble pouch (XWSP). Along with technical S-methoprene, these 2 formulations showed high inhibition of adult emergence in laboratory bioassays against Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus that are commonly found in catch basins. High initial and long-term residual efficacy were demonstrated in simulated catch basins against Cx. quinquefasciatus, where the OmniPrene WSP consistently provided over 90% control for 15 wk (105 days) and OmniPrene XWSP did the same for 38 wk (266 days). Considering the need for reliable mosquito control products, combined with commonly encountered product performance issues in catch basins, OmniPrene WSP and XWSP can be viable tools to combat mosquito species of public health concern that are associated with urban drainage systems., (Copyright © 2022 by The American Mosquito Control Association, Inc.)

We investigated the efficacy, fate, and potential for direct effects on salmonids of 4 common mosquito larvicides (Mosquito Dunks® and Bits® (AI: Bacillis thuringiensis var. israelensis, [Bti]), VectoLex® WSP (AI: Bacillus sphaericus [Bs], VectoLex CG [AI: Bs], and Altosid® Briquets [AI: s-methoprene]) in Seattle, WA, during 3 summers. During efficacy trials in 2006, all treatments resulted in a rapid reduction in number of mosquito pupae (Mosquito Dunks and Bits and VectoLex WSP) or emergence success (Altosid Briquets). VectoLex CG was chosen for city-wide application in 2007 and 2008. The average counts of pupae within round-top basins remained significantly below the control average for 11 wk in 2007, whereas efficacy in grated-top basins was short-lived. In 2008 the average counts of pupae within grated-top basins remained significantly below the control average for 10 wk. Altosid XR was also effective in reducing adult emergence within grated basins in 2008. In 2007 and 2008, frequent precipitation events made the evaluation of efficacy difficult due to reductions in pupae across control and treated basins. Four separate analyses of VectoLex products revealed that the product was a combination of Bs and Bti. Both Bs and Bti were detected in 3 urban creeks connected to treated basins in 2007 and 2008. Laboratory toxicity test results suggest that concentrations of Bs and Bti detected in each of the watersheds pose little direct hazard to juvenile salmonids. [ABSTRACT FROM AUTHOR]

Aerial applications of granular insecticides are preferable because they can effectively penetrate vegetation, there is less drift, and no loss of product due to evaporation. We aimed to 1) assess the field efficacy of VectoBac C to control Aedes vigilax (Skuse) in saltmarsh pools, 2) develop a stochastic-modeling procedure to monitor application quality, and 3) assess the distribution of VectoBac C after an aerial application. Because ground-based studies with Ae. vigilax immatures found that VectoBac C provided effective control below the recommended label rate of 7 kg/ha, we trialed a nominated aerial rate of 5 kg/ha as a case study. Our distribution pattern modeling method indicated that the variability in the number of VectoBac G particles captured in catch-trays was greater than expected for 5 kg/ha and that the widely accepted contour mapping approach to visualize the deposition pattern provided spurious results and therefore was not statistically appropriate. Based on the results of distribution pattern modeling, we calculated the catch tray size required to analyze the distribution of aerially applied granular formulations. The minimum catch tray size for products with large granules was 4 m² for Altosid pellets and 2 m² for VectoBac C. In contrast, the minimum catch-tray size for Altosid XRG, Aquabac C, and Altosand, with smaller granule sizes, was 1 m². Little gain in precision would be made by increasing the catch-tray size further, when the increased workload and infrastructure is considered. Our improved methods for monitoring the distribution pattern of aerially applied granular insecticides can be adapted for use by both public health and agricultural contractors. [ABSTRACT FROM AUTHOR]

A qualitative and quantitative population survey of immature and adult Chironomidae was conducted for 1 year in a country club wetlands in northeast Florida, USA. Glyptotendipes paripes and Goeldichironomus carus were the 2 predominant chironomid species in the wetlands. Adults of these 2 species emerged at nuisance levels from Apr through Jun, and in Aug and Sep. Polypedilum , Cryptochironomus , Tanytarsini, and Tanypodinae collected in low numbers during the survey were not identified to species. In laboratory bioassays, LC 90 values of technical grade temephos against G. paripes and G. carus were 0.01 and 0.009 ppm, respectively. For s-methoprene the LC 90 values were 0.082 and 0.055 ppm, and for Bacillus thuringiensis serovariety israelensis ( Bti ) 1.056 and 0.467 ppm, respectively. In experimental field plots in the wetlands, 5% AI Skeeter Abate® (temephos) pellets at 0.1 kg AI/ha reduced midge larvae by 52-86% and at 0.2 kg/ha by 74-92% during 4 weeks posttreatment. Sand formulated technical powder of Bti at 1,000,000 and 2,000,000 ITU (International Toxic Units) Bti /m 2 reduced midge larvae by 47-52% and 82-88%, respectively, during 6 to 20 days posttreatment. STRIKE® pellets (4.25% AI s -methoprene) at 0.14 kg AI/ha suppressed a maximum of 80% total chironomid adult emergence at 7 days posttreatment; this IGR at 0.28 kg AI/ha reduced adult emergence up to 92% during 15 days posttreatment. Temephos and Bti were more cost-effective and provided midge control for relatively longer period than s -methoprene in the field evaluations. [ABSTRACT FROM AUTHOR]

Our review outlines changes in insecticide usage for mosquito control against Australian mosquitoes, with a focus on biologically based insecticides. The most widely used microbial insecticide is Bacillus thuringiensis var. israelensis de Barjac ( Bti) and it is regularly used in estuaries and freshwater. In comparison, the use of Bacillus sphaericus (Neide) is limited to freshwater. The only insect growth regulator registered for mosquito control in Australia is s-methoprene, and it is used in both estuaries and freshwater. Although biologically based insecticides have been used for more than 10 years, there remains knowledge gaps surrounding the use of specific formulations in specific habitats: for example, VectoBac WG ( Bti) and VectoBac G ( Bti) in containers containing freshwater, or Altosid pellets ( s-methoprene) in ground-pool freshwater habitats. Where broad-scale mosquito control programs have been implemented in Australia, a reduction in the incidence of mosquito-borne disease, mainly Ross River virus, has been recorded. Therefore, the future application of these products is supported. The use of insecticides should be integrated with public education, biological control, physical habitat modification and coupled with spatial risk assessment. [ABSTRACT FROM AUTHOR]

Two juvenile hormone analogs (JHAs), pyriproxyfen and S-methoprene, were impregnated into dried tuna fish and fed to colonies of Monomorium pharaonis (L.) at very low concentrations (1.0, 2.0, 3.0, 4.0, and 5.0 μg/ml). Its effects on the production of sexuals and colonial growth were observed. Colonies treated with pyriproxyfen yielded sexuals with physical abnormalities. Both female and male sexuals developed bulbous wings, decreased melanization, and died shortly after emergence. Sexuals emerged from colonies treated with S-methoprene did not possess anomalous characteristics. Both pyriproxyfen and S-methoprene did not have significant effects on colonial growth because of the low concentrations of the baits. A commercial bait containing 0.3% S-methoprene (Bioprene-BM) also was evaluated for its efficacy on Pharaoh's ant colonies. Results showed that Pharaoh's ant colonies succumbed to the lethal effects of 5-methoprene. Colony members were reduced significantly. Production of queens also decreased significantly in treated colonies and treated queens were unable to lay eggs. JHAs are slow acting and eliminate ant colonies at a relatively slow rate. At low concentrations, pyriproxyfen recorded baffling results, i.e., bulbous wings and demelanized exoskeleton, and it is vital that further studies are initiated to solidify these findings. [ABSTRACT FROM AUTHOR]

The efficacy of pyriproxyfen against the Australian salt-marsh mosquito, Aedes vigilax, was examined in 2 laboratory and 1 semi-field study using both technical grade and formulated products. In a dose-response study, the median emergence inhibition (EI50) and EI95 values were determined to be 0.019 and 0.076 ppb, respectively, for pyriproxyfen technical grade, 0.021 and 0.092 ppb for a microencapsulated formulation (Sumilarv® 90CS), and 0.054 and 0.236 ppb for the formulated s-methoprene product, Altosid™ Liquid Larvicide. A further laboratory comparison of the microencapsulated formulation of pyriproxyfen and Altosid, at the nominal field rate for Altosid, showed that both products provided 100% emergence inhibition and this was confirmed in a semi-field study, which also included a granular formulation of pyriproxyfen (Sumilarv 0.5G). [ABSTRACT FROM AUTHOR]

The juvenile hormone analog S-methoprene is the only synthetic biopesticide that is registered with the United States Environmental Protection Agency to control arthropods of economic importance in public health, livestock, pets, urban, and stored products. The high activity, relative target specificity, and benign environmental profile of S-methoprene have been well documented. While the risk of resistance in mosquitoes to S-methoprene is generally low, there is a lack of information regarding cross resistance in S-methoprene-resistant mosquitoes to other pesticides. In this paper, a population of the southern house mosquito Culex quinquefasciatus Say from southern California acquired low levels of resistance to S-methoprene in the field, where the resistance ratios ranged 7.0- to 8.8-fold as compared with a laboratory reference colony. After 30 generations of laboratory selections by S-methoprene when resistance was elevated to 57.4- to 168.3-fold relative to an unselected population, various levels of cross resistance to other commonly used pesticides were revealed in the selected population. Cross resistance to the microbial mosquito larvicide Lysinibacillus sphaericus (Meyer & Neide) (Bacillales: Bacillaceae) was the most profound, amounting to 77.50- to 220.50-fold. The mechanism and potential management tactics toward cross resistance are discussed to preserve the unique value of this synthetic biopesticide., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: A spot-on formulation of fluralaner plus moxidectin has been designed to provide long-term protection against fleas and ticks, prevent heartworm disease and treat gastrointestinal nematode infections in cats. The objective of this study was to determine the efficacy of this product against fleas collected from a household with repeated fipronil failures following owner-administered treatments. Methods: Thirty cats were randomized to three equal groups: (A) untreated controls; (B) to receive a single application of fluralaner plus moxidectin (Bravecto® Plus) at 40 mg/kg and 2 mg/kg body weight, respectively; and (C) three applications at one month intervals with a spot-on formulation of fipronil and (S)-methoprene (Frontline® Plus) at 0.5 ml manufacturer recommended dose. Flea challenges were completed on Days −6 (for randomization), −1, 7, 14, 28, 42, 56, 70, 77, 84 and 91. Flea counts were completed 48 hours after initial treatment and 48 hours following each subsequent challenge. Results: Fleas were found on all control and all fipronil and (S)-methoprene treated cats at every assessment. From Day 2 to Day 93, all cats in the fluralaner plus moxidectin group were flea-free, with one exception (Day 58; three fleas counted on one cat); control group flea counts ranged between 34–109, and fipronil and (S)-methoprene group counts ranged between 1–79. At each assessment after Day 0, compared to the control group, geometric mean flea counts were significantly lower in the fipronil and (S)-methoprene group (P ≤ 0.04) and in the fluralaner plus moxidectin group (P < 0.001), and mean flea counts in the fluralaner plus moxidectin group were significantly lower than those of the fipronil and (S)-methoprene group (P < 0.001). The efficacy of fluralaner plus moxidectin, based on geometric means, was 100% at each assessment post-Day 0 except on Day 58 when efficacy was 99.7%. In the fipronil and (S)-methoprene group efficacy ranged between 30.6–65.6%. Conclusions: These findings demonstrate complete efficacy of fluralaner plus moxidectin against a flea isolate that was not controlled by fipronil and (S)-methoprene. This study provides confirmation of the consistent, sustained efficacy of topically applied fluralaner in the treatment and control of flea infestations in cats. [ABSTRACT FROM AUTHOR]