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Background: The sterile insect technique (SIT) is emerging as a tool to supplement traditional pesticide-based control of Aedes aegypti, a prominent mosquito vector of microbes that has increased the global burden of human morbidity and mortality over the past 50 years. SIT relies on rearing, sterilizing and releasing large numbers of male mosquitoes that will mate with fertile wild females, thus reducing production of offspring from the target population. In this study, we investigated the effects of ionizing radiation (gamma) on male and female survival, longevity, mating behavior, and sterility of Ae. aegypti in a dose-response design. This work is a first step towards developing an operational SIT field suppression program against Ae. aegypti in St

Background Despite the use of numerous methods of control measures, mosquito populations and mosquito-borne diseases are still increasing globally. Evidence-based action thresholds to initiate or intensify control activities have been identified as essential in reducing mosquito populations to required levels at the correct/optimal time. This systematic review was conducted to identify different mosquito control action thresholds existing across the world and associated surveillance and implementation characteristics. Methodology/Principal findings Searches for literature published from 2010 up to 2021 were performed using two search engines, Google Scholar and PubMed Central, according to PRISMA guidelines. A set of inclusion/exclusion criteria were identified and of the 1,485 initial selections, only 87 were included in the final review. Thirty inclusions reported originally generated thresholds. Thirteen inclusions were with statistical models that seemed intended to be continuously utilized to test the exceedance of thresholds in a specific region. There was another set of 44 inclusions that solely mentioned previously generated thresholds. The inclusions with “epidemiological thresholds” outnumbered those with “entomological thresholds”. Most of the inclusions came from Asia and those thresholds were targeted toward Aedes and dengue control. Overall, mosquito counts (adult and larval) and climatic variables (temperature and rainfall) were the most used parameters in thresholds. The associated surveillance and implementation characteristics of the identified thresholds are discussed here. Conclusions/Significance The review identified 87 publications with different mosquito control thresholds developed across the world and published during the last decade. Associated surveillance and implementation characteristics will help organize surveillance systems targeting the development and implementation of action thresholds, as well as direct awareness towards already existing thresholds for those with programs lacking available resources for comprehensive surveillance systems. The findings of the review highlight data gaps and areas of focus to fill in the action threshold compartment of the IVM toolbox.

Current methods of broad area application of contact insecticides used in mosquito control are becoming less effective, primarily due to resistance within mosquito populations. New methods that can deliver ingestible insecticides are being investigated as a means to mitigate resistance. This study evaluated insecticide delivery through toxic sugar baits (TSB) and resulting mortality of susceptible and resistant strains of Aedes aegypti. Two Ae. aegypti strains were evaluated using a 1% boric acid TSB: the susceptible Orlando 1952 (ORL) strain and the resistant Puerto Rican (PR) strain. The TSB resulted in high mortality for both ORL and PR strain of Ae. aegypti. Average mortality of female mosquitoes given TSB was 90.8% for PR and 99.3% for ORL. Our study suggests that targeting resistant mosquitoes with ingestible insecticides through TSBs could be a viable alternative to current mosquito control strategies and should be considered when developing an integrated vector management program.

Thirteen botanical product repellent compounds such as 2-undecanone, capric, lauric, coconut fatty acids (and their methyl ester derivatives), and catnip oil were formulated in either Coppertone or Aroma Land lotions and evaluated against laboratory-reared Aedes aegypti L. (Diptera: Culicidae) mosquitoes. These formulations contained 7–15 wt/wt of the botanical repellent as the major active ingredient either pure or as mixtures. USDA standard repellent test cages were used to determine the complete protection time (CPT) of the different formulated repellents. Two of the evaluated formulations, a 7% capric acid in Coppertone (CPT 2.7 ± 0.6 h) and 7% coconut fatty acids containing carrylic acid, capric acid, and lauric acid in Coppertone (CPT 2.3 ± 2.0 h), provided strong repellency against mosquitoes up to 3 h, which was equivalent to the (N,N-diethyl-m-toluamide) DEET control (CPT 2.7 ± 0.6 h). This work suggests future potential for these botanical product-based repellents as alternatives to commercial DEET-containing products.

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Application of permethrin products by ultra-low volume (ULV) spraying against the container-inhabiting mosquito Aedes albopictus (Skuse) has been used for many years, but the impact of the insecticides on domesticated honey bees, Apis mellifera (Linnaeus) is still lacking. The present study was carried out to evaluate the impact of the permethrin product, Aqualuer® 20-20 (active ingredient: 20.6% permethrin+20.6% Piperonyl butoxide) ULV sprays on caged Ae. albopictus and A. mellifera in open semi-field conditions with cages spaced at 3 m, 22.8 m, and 45.7 m downwind of the spray-truck path. The results indicated that ULV spray of Aqualuer 20-20 is highly effective against Ae. albopictus achieving 94% mortality at 22.8 m and 82% mortality up to 45.7 m downwind distance. The highest mortality of A. mellifera was only 72% at 3 m downwind distance, but the spray killed 42% of the exposed bees up to 45.7 m down the spray path. This semi-field study conducted during the day time indicates the high effectiveness of the ULV spray of permethrin against Ae. albopictus and its comparatively low impact on the direct exposed non-target honey bee, A. mellifera. Further studies designed to be conducted in the natural environment during its real-time operations following label instructions of the insecticide will help establish spraying guidelines to minimize any unfavorable impact on domesticated A. mellifera while having expected mortality effects on Ae. albopictus.

Mosquito control programs are utilizing cost-effective long-term autocidal traps targeting the gravid population of container-inhabiting and other mosquito species, with the aim of reducing vector populations and disease transmission risk. In this field study we directly compared the efficacy of two autocidal trap types-the Autocidal Gravid Ovitrap (AGO) and SIRENIX mosquito trap in reducing mosquito abundances in St. Augustine, Florida to a control only site that had no autocidal traps deployed. Pre-treatment (wk1-4) and post-treatment (wk 5-14) adult mosquitoes were captured in all three sites using BG traps baited with BG lure and dry ice. Pre- and post-treatment trap counts of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and total mosquitoes (three species together) were compared to determine significant changes in abundance. Percent reduction in abundance of each species/group at the two trap sites were calculated to evaluate the trap efficacy at controlling Aedes and Culex container mosquitoes. Aedes albopictus populations were significantly reduced (86.6%) at the SIRENIX site compared to the populations at the AGO site (67.7% reduction). Ae. aegypti populations were reduced by 72.4% at the SIRENIX site compared to 25% at the AGO site. Culex quinquefasciatus population reduction at the SIRENIX site was 59.6% compared to 11.8% at the AGO site. The total mosquito group had only 45.1% and 10.3% reduction at the SIRENIX and AGO sites, respectively. Furthers studies conducted across the entire mosquito season would be required for full understanding of the effectiveness of these traps.