When the 1:5 mixture was applied to naturally infested water containers in one village near Shaoxing, larval density fell by 100% at every monitored point under an every-two-weeks regimen and by 87.03% to 96.80% under a less frequent, higher-concentration regimen. Both treatment groups had significantly lower larval densities than untreated controls, although the difference between schedules was not statistically significant. The study addresses two practical limitations in mosquito larval control.

Temephos has been widely used for decades, but sustained use has contributed to resistance in Aedes populations, including populations in Zhejiang Province. Bti provides a biological alternative with target specificity, limited environmental persistence and low toxicity to non-target organisms, but its field efficacy can be lower against older larvae, particularly fourth-instar mosquitoes. Earlier compatibility research had identified temephos as a promising partner for Bti, but the optimal ratio for A. albopictus and the practical performance of the mixture in field containers had not been established.

The laboratory phase used early fourth-instar larvae from a susceptible laboratory colony maintained at the Zhejiang Provincial Center for Disease Control and Prevention and originally sourced from the Chinese Center for Disease Control and Prevention. Bioassays were conducted at 26 ± 1 °C and a relative humidity of 70 ± 5%. Each assay placed 30 larvae in 50 mL of water within a 150 mL test vessel.

Mortality was recorded after 24 hours, every concentration was tested in triplicate, and distilled water served as the control; control mortality was 0%. The researchers used log-probit analysis to estimate median lethal concentrations, or LC50 values, and then calculated a co-toxicity coefficient, or CTC, for each mixture. Under the study’s classification, a CTC above 120 indicated synergy, 80 to 120 indicated additive action and a value below 80 indicated antagonism.

The tested mixtures were formulation A at 1:1, formulation B at 1:3 and formulation C at 1:5 by mass. Temephos alone had an LC50 of 0.017 mg/L, with a 95% confidence interval of 0.010 to 0.022 mg/L, whereas Bti alone had an LC50 of 8.059 mg/L, with a 95% confidence interval of 6.901 to 9.249 mg/L. These values describe potency in this particular laboratory assay and do not establish equivalent operational doses.

Mixed formulation A produced an LC50 of 0.024 mg/L, formulation B an LC50 of 0.048 mg/L and formulation C an LC50 of 0.067 mg/L. Their CTC values were 141.477, 140.299 and 150.009, respectively. The lower limits of all three confidence intervals remained above 120.

Formulation C was selected for the field trial because it had the greatest measured synergistic potency, rather than because it had the lowest LC50 when evaluated as a complete mixture. The field experiment was conducted in Yingjia Village from early July to late September 2024. During the trial period, temperatures ranged from 26 to 31 °C and rainfall ranged from 147.7 to 264.6 mm.

Staff from local disease-control centers selected 150 permanent water containers naturally infested with A. albopictus larvae. These included flowerpots, earthenware jars and cisterns with capacities of 4 to 25 liters. Fifty containers received formulation C every two weeks at twice the laboratory-derived 99% lethal concentration, or 2 × LC99.

Another 50 received the formulation once a month at four times that concentration, or 4 × LC99, and 50 remained untreated. The groups were positioned close to one another because mosquito movement and oviposition patterns could affect comparisons. Water levels were standardized against marked graduation lines before dosing, although evaporation and rainfall later caused some variation in active-ingredient concentrations.

Larval counts were made before treatment and on days 1, 3, 7, 15 and 30 after each application, with larvae returned to their containers after counting. The trial comprised three consecutive one-month cycles. Baseline mean larval densities did not differ significantly among the control, every-two-weeks treatment and monthly treatment groups: 6.94 larvae per container in the control, 6.29 in the every-two-weeks group and 7.12 in the monthly group, with F = 0.069 and p = 0.933.

Generalized linear mixed models with negative-binomial regression compared larval densities over time, including group, average temperature and rainfall during the preceding week as fixed effects and date as a random effect. Mean larval densities over the three cycles were zero in the every-two-weeks group; 0.28, 0.58 and 0.30 in the monthly group; and 8.52, 4.36 and 9.11 in controls. Both treated groups had significantly lower larval densities than controls at p < 0.001, but there was no significant difference between the two application schedules at p = 0.804.

The every-two-weeks regimen achieved a 100% observed reduction and a control-adjusted standard reduction of 100% in each of the three months. Under the monthly regimen, observed reductions were 96.07%, 91.85% and 95.79%, while standard reductions adjusted for background mosquito fluctuations were 96.80%, 87.03% and 96.79%. Control-container density changed by −22.78%, 37.19% and −31.21% relative to baseline, showing that larval populations continued to fluctuate seasonally even without treatment.

Standardized reductions therefore provided a conservative estimate when control density increased, a contrast that was especially relevant during the first and third months. The measured persistence of the mixture was one of the study’s notable features. In earlier laboratory work, Bti applied at 2 × LC99 produced mortality below 99.8% after one week and below 66.0% after two weeks.

A separate field study reported that 50% of sewers treated with temephos granules were reinfested with larvae after two weeks. In the present trial, the 1:5 mixture remained effective at sampling points extending to 30 days under the monthly regimen. The researchers also calculated that temephos at the LC99 level in formulation C represented 65.97% of the amount used in pure temephos.

This supports the narrower observation that the combination used less of the chemical component in that comparison. It does not by itself demonstrate reduced environmental contamination, lower application costs or a measurable resistance-management benefit. Several limitations prevent the field results from demonstrating eradication or long-term control.

Only three ratios, from 1:1 to 1:5, were tested, so mixtures containing more Bti were not evaluated. Resistance in the local mosquito population was not measured during the experiment, although earlier monitoring had detected a 12-fold temephos resistance ratio in Shaoxing relative to a susceptible strain. The apparent 100% reductions could also reflect temporary suppression of larval development, mortality at another mosquito life stage, oviposition avoidance or insufficient sampling rather than complete elimination of breeding.

The trial covered one village, three months and 150 containers, limiting generalization to other mosquito populations, seasons and environmental settings. The researchers noted that the mixture may retain activity against temephos-resistant populations, but that possibility requires direct testing, as do its long-term effects on insecticide resistance and the environment.

Subject of Research: Laboratory and field evaluation of a temephos–Bti mixture against Aedes albopictus larvae

Article Title: Synergistic larvicidal effects of temephos and Bacillus thuringiensis israelensis against Aedes albopictus: a laboratory and field study

Article References: Wu, Y., Liu, Q., Sun, J., Hong, Y., Fu, Y., Zhou, D., Ling, F., & Jiang, G. (2026). Synergistic larvicidal effects of temephos and Bacillus thuringiensis israelensis against Aedes albopictus: a laboratory and field study. Frontiers in Veterinary Science, 13, Article 1930489. https://doi.org/10.3389/fvets.2026.1930489

Image Credits: AI Generated

DOI: 10.3389/fvets.2026.1930489

Keywords: Aedes albopictus, Bacillus thuringiensis israelensis, temephos, larvicidal synergy, mosquito bioassay, field vector control, insecticide resistance, arbovirus vectors, dengue, negative-binomial regression, Synergistic, larvicidal

The research team exposed laboratory populations of Anopheles coluzzii to three of the most important compounds used in vector control: the pyrethroids lambda-cyhalothrin at 0.05 percent and permethrin at 0.75 percent, and the organochlorine DDT at 4 percent. These are standard diagnostic concentrations used in World Health Organization-style susceptibility testing, which makes the results directly comparable with routine surveillance data collected across malaria-endemic regions. Male and female mosquitoes aged three to five days were tested in eight replicates, with 25 mosquitoes of each sex per insecticide per replicate, for a total of 2,000 mosquitoes in the susceptibility phase of the study. That scale matters, because behavioral ecology is notoriously variable, and small samples can easily generate artifacts that vanish on replication.

The experimental design was elegantly simple. Mosquitoes that survived exposure to the insecticides were classified as resistant cohorts, separated by sex into holding buckets, provided with sugar, and allowed an hour to acclimatize. The researchers then used a set of square-shaped containers connected by a pipe into an H-shaped apparatus. One chamber held insecticide-treated paper, abbreviated WITP, while the other held untreated paper, WOITP. Resistant mosquitoes, 15 per replicate in triplicate for each insecticide, were released into this arena and could choose where to fly, rest, land, and attempt to feed. The same assay was run with unexposed mosquitoes as a comparison. The team recorded flight efficiency, resting efficiency, repellency, landing, and biting behavior, translating each into quantitative scores across the observation period.

The behavioral results were strikingly asymmetric. Among resistant mosquitoes exposed to treated paper, flight efficiency rose dramatically, with mean scores climbing from 3.00 to 30.5 over the course of the assay. In the untreated chamber, by contrast, flight efficiency collapsed, with means falling from 2.00 to 0.50. Both trends were highly significant, with p-values below 0.0001. In plain terms, resistant mosquitoes that encountered the insecticide became hyperactive, darting around the treated environment rather than settling in it. This kind of locomotor stimulation is a well-documented consequence of sublethal pyrethroid and DDT exposure, but seeing it quantified against a matched untreated control makes the pattern unusually clear.

Resting behavior told the mirror-image story. In the treated chamber, resting efficiency plummeted from a mean of 12.50 to 0.00, while in the untreated chamber it climbed from 11.50 to 13.50, again with p-values below 0.0001. Repellency scores followed a similar trajectory in the treated environment, falling from 14.00 to 0.00, although responses in the untreated chamber did not follow a regular pattern. Landing and biting behavior likewise lacked a consistent trend across treatments. The overall picture is one of avoidance: resistant mosquitoes exposed to insecticide-treated surfaces abandon resting positions, take flight, and effectively vacate the treated zone. From an evolutionary standpoint, this is exactly what one would expect selection to favor. A mosquito that rests on a treated wall dies; a mosquito that detects the chemical and leaves survives to reproduce.

That adaptive logic, however, is precisely what makes the finding alarming for public health. Behavioral resistance of this kind can erode the effectiveness of insecticide-treated bed nets and indoor residual spraying without ever showing up in a standard susceptibility test. A net treated with a pyrethroid still kills susceptible mosquitoes that land on it, but a population that has evolved both physiological tolerance and irritant avoidance may simply feed outdoors, earlier in the evening, or on livestock, shifting the entire transmission dynamic. The study’s demonstration that resistance status predetermines these behavioral responses means that surveillance programs could, in principle, predict which populations are likely to evade control measures before those failures become visible as rising case numbers.

The reproductive findings add a second, less obvious layer of concern. The researchers crossed exposed and unexposed males and females in all combinations and assessed oviposition fitness, the ability of females to produce and lay eggs. Unexposed female mosquitoes took the largest blood meals, with a mean of 11.5, which matters because blood feeding drives both egg production and parasite transmission. The highest oviposition success was recorded in crosses between unexposed males and unexposed females, with a mean of 0.33. Every other cross, involving at least one insecticide-exposed parent, produced no eggs at all, with a mean of 0.00. Insecticide exposure, in other words, imposed a form of reproductive impairment that persisted even in mosquitoes that had survived the chemical encounter.

This sublethal reproductive cost has implications that cut in two directions. On one hand, it suggests that insecticide exposure carries a fitness penalty for resistant mosquitoes, which could theoretically slow the spread of resistance genes if exposed individuals contribute fewer offspring to the next generation. On the other hand, the complete absence of oviposition in crosses involving exposed parents hints at physiological damage, perhaps to sperm viability, egg maturation, or mating behavior, that standard resistance metrics never capture. If resistant females avoid treated surfaces and then fail to reproduce after incidental exposure, the population dynamics of resistance become far more complex than simple selection models assume. Understanding these trade-offs could inform strategies that deliberately exploit them, such as deploying compounds that maximize behavioral disruption and sterility in resistant populations rather than relying on outright kill.

The study also highlights a methodological gap in how the entomological community tracks resistance. Standard tube and cone bioassays measure knockdown and mortality over 24 hours, a binary outcome that says nothing about what a surviving mosquito does next. The H-tube behavioral arena used here, by contrast, converts flight, resting, repellency, landing, and biting into measurable endpoints that can be tracked alongside mortality. Incorporating such behavioral assays into routine monitoring would give control programs a leading indicator of operational failure, allowing them to rotate insecticide classes, deploy synergists like piperonyl butoxide, or introduce new-generation nets before avoidance behavior becomes entrenched. The authors argue explicitly that behavioral endpoints deserve a place in resistance monitoring programs, and the data they present make a strong case.

There are, of course, caveats worth keeping in mind. The work was conducted on a single vector species under controlled laboratory conditions, with relatively small cohorts of 15 mosquitoes per replicate in the behavioral assays, and the mechanisms linking exposure to oviposition failure remain to be identified. Field populations face a mosaic of insecticide pressures, environmental stresses, and parasite infections that no laboratory arena can fully reproduce. Yet the core message survives these limitations intact: resistance is a package deal, bundling physiological survival with altered behavior and diminished reproduction. As malaria vectors across Africa continue to evolve under intense chemical pressure, tools that reveal the full phenotype of a resistant mosquito, not just whether it dies on a treated paper, will be essential for keeping bed nets, sprays, and the decades of investment behind them effective.

Subject of Research: Behavioural responses and oviposition fitness of insecticide-resistant Anopheles coluzzii mosquitoes

Article Title: Insecticide resistance status predetermines behavioural responses and oviposition fitness in Anopheles coluzzii

Article References: Aghahowa, E., Enwemiwe, V. N., Esiwo, E., Edhebe, P. O., Ifeta, S. E., & Ojianwuna, C. C. (2026). Insecticide resistance status predetermines behavioural responses and oviposition fitness in Anopheles coluzzii. PLOS One, 21(10), e0360986. https://doi.org/10.1371/journal.pone.0360986

Image Credits: AI Generated

DOI: 10.1371/journal.pone.0360986

Keywords: Anopheles coluzzii, malaria, insecticide resistance, behavioural resistance, pyrethroids, DDT, lambda-cyhalothrin, permethrin, oviposition, vector control, mosquito behavior, resistance monitoring

Discriminating concentrations are the unsung heroes of resistance surveillance. These are standard doses of an insecticide used in bioassays to determine whether a wild mosquito population is susceptible or resistant to a given compound. Field programmes typically test their local mosquitoes annually, exposing them to a known concentration and measuring mortality after 24 hours. If susceptible mosquitoes die but a significant proportion of the local population survives, that is an early warning sign that resistance is emerging. The concept is elegantly simple: the discriminating concentration is traditionally defined as twice the LC99 value, the dose that kills 99 percent of individuals in a fully susceptible laboratory strain, as determined by a log-probit statistical model. The approach is cost-effective, efficient, and has been widely adopted for monitoring resistance in mosquitoes and other disease vectors worldwide.

The urgency of this study stems from the arrival of two entirely new modes of action in vector control. Broflanilide and isocycloseram both belong to class 30 of the Insecticide Resistance Action Committee classification, functioning as meta-diamides and GABA-gated chloride channel allosteric modulators. Their mode of action is fundamentally distinct from those of pyrethroids, carbamates, organophosphates, and organochlorines, the older classes that have dominated vector control for decades. This novelty is precisely their value: because they act on a target site different from established insecticide classes, limited cross-resistance with pyrethroids and other older compounds is expected, making them powerful tools for deployment against resistant mosquito populations. Both compounds are now incorporated into vector control products prequalified by the WHO for public health use, which means national programmes need reliable methods to track susceptibility as these products roll out.

The study followed a rigorous, three-step protocol formalized by the WHO as a generic approach for determining discriminating concentrations. In Step 1, preliminary bottle bioassays screened approximately 10 to 12 serial concentrations of each insecticide to establish a full range of mortality from 0 to 100 percent in susceptible mosquitoes. Step 2 involved multi-centre concentration-response testing, with each centre completing three validated replicates for each concentration of each compound against its assigned species. The validity criteria were strict: each test needed at least two concentrations producing less than 50 percent mortality, one producing approximately 50 percent, two producing more than 50 percent, and one producing approximately 100 percent mortality. Each bioassay used at least 100 mosquitoes per concentration, with different batches tested on different days, and impregnated bottles were used only once. Step 3 then validated the tentative discriminating concentrations across at least three independent laboratories against the same well-characterised susceptible strains.

The technical execution demanded careful attention to the chemical properties of the two compounds. Both broflanilide and isocycloseram are highly lipophilic, adhering to bottle surfaces and dissolving poorly without help. The solution was to add a surfactant, rapeseed oil methyl ester, at 1,500 parts per million for Aedes aegypti and 800 parts per million for Anopheles species, following the manufacturers’ recommendations and the WHO bottle bioassay standard operating procedure. Broflanilide was supplied by Mitsui Chemicals Crop and Life Solutions, and isocycloseram by Syngenta Crop Protection AG. Aliquots of each insecticide and of the surfactant were distributed centrally from Liverpool to all testing centres, ensuring a single source and identical concentrations across the entire study. Three- to five-day-old, non-blood-fed female mosquitoes were exposed to treated bottles for one hour, then held at 27 degrees Celsius with 75 percent relative humidity until the 24-hour mortality assessment.

The resulting discriminating concentrations, now recommended for adoption by the WHO, vary by species and compound in ways that reflect real biological differences in baseline sensitivity. For broflanilide, the recommended values are 10 micrograms per bottle for Anopheles gambiae and Aedes aegypti, 15 micrograms per bottle for Anopheles funestus, and 25 micrograms per bottle for Anopheles stephensi. For isocycloseram, the values are 15 micrograms per bottle for Aedes aegypti, 30 micrograms per bottle for Anopheles gambiae, 50 micrograms per bottle for Anopheles stephensi, and 60 micrograms per bottle for Anopheles funestus. Lethal concentrations were generally lower for Anopheles gambiae and Aedes aegypti than for Anopheles funestus and Anopheles stephensi, suggesting differences in body size, cuticular penetration, metabolic detoxification capacity, or target-site sensitivity between species. The study was not designed to attribute these differences to specific mechanisms, but the authors note that resolving their relative contributions would require dedicated biochemical and genetic characterisation in future work.

The statistical framework underpinning the analysis was equally sophisticated. Concentration-response data for each insecticide-species combination were analysed using a Bayesian binomial modelling approach, fitting a five-parameter logistic regression on square-root-transformed concentration scales. Models ran on four Markov chains for up to 10,000 iterations, with convergence assessed using the Gelman-Rubin statistic, requiring a value below 1.01 with zero divergent iterations. All models that met these criteria produced steep slopes with narrow confidence intervals at higher mortality levels, indicating consistent concentration-response relationships. Within-bioassay variability, measured as the mean absolute deviation of observed mortality from the model’s best-fit line, was remarkably low: the median was approximately 4 to 5 percent mortality, and 28 of 30 site-species-compound combinations fell below 10 percent, confirming that the WHO bottle bioassay is reproducible within sites.

Not everything went perfectly smoothly, and the study’s honest accounting of its challenges is itself instructive. The unforeseen withdrawal of one testing centre left only the Liverpool School of Tropical Medicine able to test Anopheles stephensi. The London School of Hygiene and Tropical Medicine held an independent colony of the same SDA500 strain and provided mosquitoes to Liverpool, allowing testing to proceed across three sites, but the lack of fully multi-centre data restricted inter-laboratory comparison and reduced the strength of evidence for validation. Seven rather than nine replicate tests were possible for this species. Some datasets, notably those from the Centre for Research in Infectious Diseases for Anopheles gambiae and Anopheles funestus, could not be fitted to the model because mortality was at or near 100 percent across all tested concentrations, meaning the dose-response curve could not be adequately resolved. In each case, however, the discriminating concentration was anchored on fitted curves from other centres and subsequently confirmed in Step 3 validation, where the proposed values produced 100 percent mortality.

One of the most valuable contributions of the study is the set of technical recommendations distilled from the experience of running it. The authors highlight that estimating an LC99 is inherently difficult because it depends on observations very close to, but not reaching, 100 percent mortality. A common misconception is that a full dose-response curve with a wide spread of mortality values is required; in fact, rich information near the target value matters far more than accurately defining the shape of the lower parts of the curve. The authors also question whether the traditional multiplier of two, applied to the LC99 to derive the discriminating concentration, is truly optimal, noting that the choice appears arbitrary and that a multiplier set too high risks missing early signs of resistance. They propose that a conservative approach would use the lower bound of the 95 percent confidence interval when defining the discriminating concentration, and that intermediate values such as LC80 or LC90 may offer a more realistic compromise between biological relevance and statistical confidence.

The implications for global health are immediate and profound. With these benchmarks now validated, national malaria and dengue programmes can integrate broflanilide and isocycloseram into their routine resistance monitoring activities, testing wild mosquito populations against standardized doses and detecting emerging resistance before it undermines control efforts. As field use of these new insecticides expands, monitoring with the discriminating concentrations established here will allow the expectation of limited cross-resistance with older classes to be tested in real-world conditions. The study also validates the WHO’s generic protocol for establishing discriminating concentrations, providing a template for future multi-centre studies as additional novel active ingredients enter the pipeline. In a field where resistance can emerge silently and spread rapidly, having reliable, internationally agreed benchmarks for the newest tools in the arsenal is nothing short of essential.

Subject of Research: Multi-centre laboratory study to determine discriminating concentrations for broflanilide and isocycloseram resistance monitoring in mosquitoes

Article Title: Multi-centre laboratory study to determine discriminating concentrations for broflanilide and isocycloseram resistance monitoring in mosquitoes

Article References: Praulins, G., Mechan, F., Harvey, G., Brooke, B. D., Corbel, V., Duchon, S., Kaiser, M. L., Moore, S., Mpelepele, A. B., Oliver, S. V., Singh, H., Stevenson, J., Toguem, Y. G. F., Verma, V., Wondji, C., & Lees, R. S. (2026). Multi-centre laboratory study to determine discriminating concentrations for broflanilide and isocycloseram resistance monitoring in mosquitoes. Frontiers in Malaria, 4, Article 1874255. https://doi.org/10.3389/fmala.2026.1874255

Image Credits: AI Generated

DOI: 10.3389/fmala.2026.1874255

Keywords: insecticide resistance, mosquito vectors, WHO bottle bioassay, discriminating concentration, broflanilide, isocycloseram, malaria, dengue, vector control, Multi-centre, laboratory, determine

The study, led by Fadhila Kihwele and Tegemeo Gavana of the Ifakara Health Institute together with collaborators from the Swiss Tropical and Public Health Institute, the University of Basel, and Tanzania’s National Malaria Control Programme, is part of a comprehensive evaluation of the Tanga pilot. Companion publications report on the program’s operations, entomological and epidemiological impacts, and costs. This particular investigation focused on the human dimension: how stakeholders at every level, from national officials down to village volunteers, perceived the intervention, what made it work, what got in its way, and whether it could endure beyond the pilot phase.

The scientific logic behind larviciding is straightforward. Malaria control has long depended on insecticide-treated nets and indoor residual spraying, both of which target adult mosquitoes inside homes. But malaria parasites still kill an estimated 597,000 people each year, and global progress has stalled since 2015, driven in part by mosquito behavioral adaptations and widespread pyrethroid resistance. Larval source management attacks the problem at a different stage of the mosquito life cycle, applying agents to aquatic breeding habitats to kill larvae before they ever take flight. The World Health Organization recommends larviciding as a supplementary measure, ideally where breeding sites are few, fixed, and findable. Historically, larviciding helped eradicate malaria vectors in Brazil, Egypt, and the Zambian copperbelt, but large-scale implementation in modern Africa has been rare, constrained by the difficulty of locating scattered breeding sites and questions of cost-effectiveness.

Tanzania’s pilot was distinctive in two respects. First, it used biological larvicides rather than conventional insecticides: Bactivec, containing spores of Bacillus thuringiensis var. israelensis (Bti), and Griselesf, containing spores of Bacillus sphaericus (Bs). These bacteria produce toxins that are lethal to mosquito larvae when ingested but are considered harmless to humans, livestock, fish, frogs, and the broader ecosystem. Because their mode of action differs completely from the pyrethroids used in nets and indoor spraying, they offer a way to diversify the vector control arsenal and manage insecticide resistance. Both products are manufactured in-country by Tanzania Biotech Products Limited, a government-owned enterprise created through a bilateral partnership between Tanzania and Cuba. Second, the program was delivered entirely through the existing government system, from the National Malaria Control Programme at the top down to village executive officers, using community-owned resource persons, or CORPs, selected by village leaders to identify breeding sites and apply larvicide weekly, the interval at which the products remain effective.

To capture perceptions of this ambitious undertaking, the researchers conducted a cross-sectional qualitative study in 2023, the second year of implementation. They carried out 31 in-depth interviews with government officials overseeing the project at village, ward, council, regional, and national levels, and held 13 focus group discussions with 156 community participants, including 72 CORPs and 84 other community members. The three intervention councils, Handeni District Council, Tanga City Council, and Lushoto District Council, were deliberately chosen to represent high, moderate, and low malaria risk strata and to span rural and urban settings. Interviews were conducted in Swahili, audio-recorded with consent, transcribed verbatim, and analyzed using framework analysis with NVivo software, with double coding and triangulation to reinforce rigor. Data collection continued until thematic saturation was reached.

The findings on acceptance were striking. Almost all stakeholders described the intervention as safe, and no adverse events were reported at village or ward offices across the study area. Yet the initial rollout tested community trust. When CORPs began spraying larvicide into water sources used for drinking and domestic purposes, some residents worried about their safety. The response was remarkably direct: CORPs sometimes tasted the biolarvicide or drank water from sprayed wells in front of community members to prove it was harmless. One CORP in Handeni told the researchers,

The willingness of CORPs to demonstrate the safety of the larvicide by drinking treated water illustrates a broader principle in community health programming: acceptability is not merely a passive attitude but something actively constructed through trust, demonstration, and repeated positive experience. In the Tanga pilot, this trust-building appears to have paid off. Community members across the three councils came to view the weekly applications as a routine and beneficial part of village life, and many participants in the focus group discussions linked the intervention to perceived reductions in mosquito densities and malaria episodes. Such perceptions matter for sustainability because community-based programs depend on voluntary cooperation, from granting CORPs access to private water sources to tolerating the logistical disruptions of weekly spraying campaigns.

The qualitative design of the study deserves attention for what it can and cannot reveal. Framework analysis, the method used to organize the interview and focus group data, allows researchers to systematically chart themes across stakeholder categories while preserving the context and nuance of individual accounts. By triangulating the perspectives of national officials, council health teams, ward and village officers, CORPs, and ordinary community members, the researchers could identify where perceptions converged and where they diverged. What emerges is a layered picture: national and regional officials emphasized feasibility and institutional fit, while community participants focused on tangible experiences such as the smell of the product, the reliability of CORP visits, and the visibility of results. This kind of multi-level perception mapping is increasingly recognized as essential for designing interventions that survive the transition from pilot to program.

The challenges identified in the study are not unique to larviciding, but they carry particular weight for this intervention model. The unpleasant odor of the larvicide, repeatedly mentioned by participants, is more than a cosmetic nuisance; in community-based programs, sensory characteristics of a product can shape rumors, resistance, and ultimately coverage. High turnover among CORPs poses a parallel threat, because these volunteers embody the institutional memory of the program. Each departure means retraining, re-mapping of breeding sites, and re-establishing relationships with village leaders and residents. The study’s finding that turnover was driven partly by irregular or inadequate incentives echoes a well-documented problem in community health worker programs across sub-Saharan Africa, where volunteer cadres are often asked to perform substantial labor without reliable compensation.

Discontinuous implementation emerged as another recurring concern. Larviciding, unlike bed net distribution, requires sustained, rhythmical application: the biological toxins in Bti and Bs products degrade in the environment within roughly a week, so any pause in the spraying cycle allows larvae in treated habitats to complete their development and replenish the adult mosquito population. Interruptions caused by funding delays, stockouts, or seasonal gaps in supervision therefore have direct entomological consequences. This characteristic makes larviciding operationally more demanding than some other vector control tools, and it underscores why the study’s participants stressed the importance of predictable financing and supply chains for any future scale-up.

The Tanga pilot also offers a case study in implementation through government structures rather than parallel project systems. Delivering the program through local government authorities, with the National Malaria Control Programme providing national supervision, was a deliberate choice intended to produce a model that could be replicated if the government decided to expand. This design has implications for sustainability: interventions embedded in existing administrative structures are generally better positioned to survive the withdrawal of external donors and technical partners. The involvement of the President’s Office–Regional Administration and Local Government signals that the program was conceived from the outset as a potential public service rather than a research demonstration, which may explain the strong institutional buy-in reported by officials at multiple levels.

The broader context of malaria control in Tanzania lends urgency to these findings. Sub-Saharan Africa carries roughly 95 percent of global malaria cases and deaths, and the continent faces mounting threats from insecticide resistance, invasive vector species such as Anopheles stephensi that thrive in urban environments, and changing mosquito behaviors that reduce the effectiveness of indoor tools. Biological larvicides, with their distinct mode of action, offer a way to relieve selection pressure on pyrethroids while targeting outdoor-biting and outdoor-breeding vectors. The renewed interest in larval source management across countries such as Rwanda, Kenya, Burkina Faso, and The Gambia reflects this strategic logic, and the Tanzanian experience provides one of the few large-scale, government-implemented evidence bases available to inform those efforts.

For policymakers weighing a national rollout, the qualitative findings suggest that the technical questions about larviciding are increasingly inseparable from social and organizational ones. The Tanga evidence indicates that communities will accept and even champion larviciding when it is delivered by trusted local actors and perceived as safe and effective. But it equally indicates that the same community-based model is fragile in the face of volunteer attrition, supply disruptions, and product characteristics that irritate the very people it protects. Addressing these operational vulnerabilities, through sustainable incentive structures for CORPs, reliable procurement of biolarvicide, improved product formulation or masking of odor, and continuous rather than episodic implementation, will likely determine whether the promise demonstrated in Tanga can be translated into durable malaria reduction across Tanzania and beyond.

Subject of Research: Stakeholder perceptions, acceptability, and sustainability of a community-based mosquito larviciding intervention for malaria control in Tanga Region, Tanzania

Article Title: Stakeholders’ perceptions, acceptability, and sustainability of a larviciding intervention in Tanga Region, Tanzania

Article References: Kihwele, F., Gavana, T., Kailembo, D., Kasagama, E., Mwalimu, C. D., Bernard, J., Yoram, B., Ndekuka, L., Kajange, S., Lazaro, S., Kisoka, N., Chaki, P., Lengeler, C., & Dillip, A. (2025). Stakeholders’ perceptions, acceptability, and sustainability of a larviciding intervention in Tanga Region, Tanzania. Frontiers in Malaria, 3, Article 1693543. https://doi.org/10.3389/fmala.2025.1693543

Image Credits: AI Generated

DOI: 10.3389/fmala.2025.1693543

Keywords: malaria, larviciding, Tanzania, vector control, biolarvicide, Bacillus thuringiensis israelensis, community health workers, Tanga Region, insecticide resistance, larval source management, public health, qualitative research

The socioeconomic dimension of malaria looms large in the editorial’s framing. Although profound knowledge exists in targeted prevention, treatment, and detection, people in endemic countries often have limited access to these services. In 2020, people in low- and middle-income countries spent 40 percent of their income on healthcare, a burden that risks pushing households deeper into poverty. Malaria is also shaped by social inequities such as low education, agricultural work, and unprotected housing, all of which increase human exposure to infected mosquitoes. The authors argue that these structural vulnerabilities demand coordinated global approaches rather than fragmented, country-by-country responses, particularly as climate change, wars, and economic decline continue to erode hard-won gains.

Accurate measurement of the disease burden underpins every elimination strategy, and several contributions in the Research Topic address this need directly. Drawing on data from the 2021 Global Burden of Disease database, Zhou and colleagues assessed malaria in the Comoros across indicators including incidence, prevalence, mortality, disability-adjusted life years, years of life lost, and years lived with disability. Their analysis showed that the malaria burden in the Comoros decreased between 1999 and 2021, driven mainly by epidemiological changes. Yet the study also revealed persistent hotspots of vulnerability: women under 40, school-aged children, and adults under 30 continue to carry a higher malaria burden than other groups, signaling where interventions should be concentrated.

In low-transmission settings, conventional case counts lose sensitivity, and serological surveillance offers a way forward. Lubis and colleagues conducted a cross-sectional study in 2019 in Langkat District, North Sumatra Province, Indonesia, where malaria incidence has declined significantly but low-level transmission persists. The team measured antibody responses to two blood-stage antigens of Plasmodium falciparum and Plasmodium vivax: merozoite surface protein-1 (MSP-1) and apical membrane antigen 1 (AMA-1). Seroprevalence for P. falciparum reached 10.6 percent for PfAMA-1 and 13 percent for PfMSP-1(19), while seroconversion rates were 18.6 percent for PvAMA-1 and 7.4 percent for PvMSP-1(19). The authors concluded that this serological assay is suitable for identifying epidemiological risk factors and supporting surveillance where elimination programs must be triggered by the earliest signals of residual transmission.

Blocking transmission from asymptomatic carriers is another critical frontier. Mmasi and colleagues used a direct membrane feeding assay (DMFA) with blood from gametocytemic participants to test how three variables influence infection of female Anopheles gambiae sensu stricto mosquitoes: artemether-lumefantrine (AL) treatment, mosquito feeding time during day versus night, and serum replacement. Infection rates in mosquitoes declined after AL treatment and were unaffected by whether mosquitoes fed during the day or at night, but rates increased after serum replacement. These findings, the authors note, will pave the way for optimizing the DMFA as a standardized tool for evaluating transmission-blocking interventions, a key step toward interrupting the silent chain of asymptomatic gametocytemia that sustains malaria in endemic regions.

Modeling studies in the Research Topic extend these insights to policy decisions. Seong and colleagues built a dynamic transmission model for P. vivax in the Republic of Korea and adapted it with demographic and climate data from the Democratic People’s Republic of Korea (DPRK), then evaluated the impact of tafenoquine administration and rapid diagnostic tests (RDTs) on malaria incidence from 2014 to 2018. The results are striking: a 1-day RDT would reduce malaria incidence by over 65 percent over the next decade, while a single-dose regimen of tafenoquine, compared with the standard 14-day regimen of primaquine, would prevent 77.5 percent of relapses and 11.3 percent of malaria cases. The combination of tafenoquine and RDTs, the authors conclude, appears to be a convincing strategy for eliminating P. vivax as a major public health problem in the DPRK, where the relapsing nature of the parasite makes diagnosis and radical cure especially challenging.

Imported cases pose a different kind of threat to elimination programs. Saudi Arabia established a malaria elimination program years ago, yet a study by Alghamdi and colleagues in Jeddah City between 2018 and 2023 documented 2,124 imported malaria cases, underscoring the need for novel antimalarial prevention protocols. Jeddah’s role as a global logistical hub for tourism through its air- and seaports makes it particularly exposed. Nearly 50 percent of the imported cases originated from Pakistan, and more than 30 percent came from African countries. Parasitologically, 38 percent of cases were caused by P. falciparum, the species responsible for most malaria deaths, while 57 percent were P. vivax infections. The findings illustrate how international travel and trade can reintroduce parasites into malaria-free areas, demanding vigilant screening at points of entry.

The COVID-19 pandemic’s disruption of malaria services in Africa between 2000 and 2022 provided the backdrop for another investigation. Amegatcher and colleagues implemented a community health education and medical screening (CHEMS) approach in Southern Ghana, conducting a cross-sectional survey in Accra and the Central regions that enrolled 953 people. Of these, 136 participants underwent both a malaria prick test and a COVID-19 nasal swab, with both samples analyzed by PCR. The results showed that 6 percent of participants were infected with malaria against a background of SARS-CoV-2 infection rates ranging from 12 to 37 percent, and notably, 2 percent were coinfected with both malaria and COVID-19. The study demonstrates how integrated community screening can simultaneously address two overlapping epidemics and maintain malaria surveillance during health system shocks.

Insecticide resistance emerged as the second major focus of the Research Topic, with at least four articles dedicated to the problem. Machange and colleagues evaluated a new combination net, ProNetDuo, which pairs bifenthrin, a fluorinated pyrethroid related to permethrin, with chlorfenapyr, an inhibitor of cellular energy production. In experimental hut trials at M’be in Cote d’Ivoire and Lupiro in Tanzania, using 18 huts with free-flying wild mosquitoes, the team compared ProNetDuo against Interceptor G2 nets, which contain alpha-cypermethrin and chlorfenapyr and have proven efficacy in malaria reduction. Using two endpoints, 72-hour mosquito mortality and the proportion of mosquitoes that successfully blood-fed, the researchers found that ProNetDuo showed inferior mortality but was superior in preventing blood feeding. The authors conclude that ProNetDuo, with its bifenthrin component, offers a valuable alternative against pyrethroid-resistant Anopheles gambiae populations.

Even the best nets fail if people do not use them. Savi and colleagues modeled urban malaria dynamics in Accra, Ghana, incorporating demographic and epidemiological factors, and identified limited living space and bed-net repurposing as critical barriers to reducing malaria prevalence. They recommend one-on-one sensitization campaigns to understand why adoption of insecticide-treated nets lags in urban and slum settings. In Ethiopia’s Shebella Bernata District, Minwuyelet and colleagues found that bed-net use among pregnant women was significantly associated with antenatal care attendance, educational status, and exposure to informative messages, yet only 45.1 percent of pregnant women used insecticide-treated bednets, well below WHO standards. A literature review by the same authors covering 61 research articles published between 2011 and 2015 confirmed severe resistance to pyrethroids and organochlorines in the principal African vectors, Anopheles gambiae sensu lato and the Anopheles funestus group, while highlighting three candidate insecticides with retained susceptibility: clothianidin, a neonicotinoid; chlorfenapyr, a pyrrole; and broflanilide, a meta-diamide.

The editorial closes with a sober warning. Beyond the scientific progress documented across the Research Topic, reductions in international donor funding from the US administration and other stakeholders since 2025 threaten to undermine all achievements, a scenario recently modeled for tuberculosis with substantial impacts on mortality and morbidity. The authors emphasize that modern scientific tools exist in abundance, but only careful observation, coordinated responses, strong quality assurance systems, and sustained investment, particularly for vulnerable groups such as children and pregnant women in rural areas, will convert these tools into elimination. One contribution also addresses the threat of invasive vector species, documenting the spread of a malaria-transmitting Anopheles mosquito into a previously malaria-free area west of Johannesburg, while six contributions illustrate the necessity of novel monitoring mechanisms to detect infections early in areas of low transmission. The message is clear: the tools are ready, but the funding and political will to deploy them remain the decisive variables.

Subject of Research: New tools and strategies for addressing contemporary threats to global malaria control, including insecticide resistance, invasive vectors, drug efficacy, and surveillance in low-transmission settings

Article Title: Editorial: Addressing contemporary threats to global malaria control: new tools and strategies

Article References: Kaiser, A. E., Messenger, L. A., Oxborough, R., & Matowo, N. S. (2026). Editorial: Addressing contemporary threats to global malaria control: new tools and strategies. Frontiers in Malaria, 4, Article 1776838. https://doi.org/10.3389/fmala.2026.1776838

Image Credits: AI Generated

DOI: 10.3389/fmala.2026.1776838

Keywords: malaria, insecticide resistance, Anopheles gambiae, insecticide-treated nets, tafenoquine, rapid diagnostic tests, Plasmodium vivax, Plasmodium falciparum, seroprevalence, transmission blocking, global malaria elimination, vector control

At the heart of the resistance problem lie four primary, universally recognized mechanisms. The first is target-site insensitivity, in which point mutations alter the molecular docking sites that insecticides must bind to be lethal. The best documented of these are the knockdown resistance mutations, known as kdr, in the voltage-gated sodium channel that pyrethroids and DDT attack. Mutations such as L1014F and L1014S, and the less common V1010L allele, change single amino acids in the channel pore, reducing the binding affinity of neurotoxic compounds by orders of magnitude without crippling the channel’s normal function. A parallel story unfolds at acetylcholinesterase, encoded by the ace-1 gene, where substitutions blunt the inhibition caused by organophosphates and carbamates, and at the GABA-gated chloride channel, where Rdl mutations confer resistance to cyclodiene insecticides.

The second major mechanism is metabolic detoxification, a strategy in which mosquitoes amplify the enzymatic machinery that degrades insecticides before they reach their targets. Three enzyme families dominate this landscape. Cytochrome P450 monooxygenases catalyze oxidative metabolism of pyrethroids and many other chemistries, and their overexpression, often driven by duplications and regulatory changes, is among the most widespread resistance signatures in Anopheles and Aedes populations. Carboxylesterases hydrolyze ester-containing compounds such as organophosphates, while glutathione S-transferases conjugate electrophilic insecticide metabolites and also buffer oxidative stress induced by chemical exposure. Because these enzymes are broad-spectrum, their amplification produces cross-resistance, meaning a mosquito selected by one insecticide class may simultaneously withstand several others, a phenomenon that has repeatedly compromised sequential rotation strategies.

The third mechanism is cuticular thickening. The insect cuticle is the first barrier an insecticide must cross, and mosquitoes subjected to prolonged selection can increase the thickness or alter the composition of their epicuticular hydrocarbons, slowing uptake and buying time for internal detoxification enzymes to act. Studies in both Anopheles funestus and Anopheles gambiae have linked cuticular hydrocarbon profiles and structural changes to reduced susceptibility, demonstrating that resistance is not confined to molecular targets inside the body but can be built into the mosquito’s outer armor.

The fourth mechanism is behavioral avoidance, an evolutionary response that operates before any chemical contact occurs. Mosquito populations under intense insecticide pressure have shifted their biting times from late night, when indoor residual spraying and insecticide-treated nets offer maximum protection, to earlier evening or dawn hours when humans are outdoors or unprotected. Others have moved from indoor to outdoor resting and biting, or shifted host preferences from humans to livestock. Because these behaviors reduce exposure without requiring any biochemical change, they are notoriously difficult to detect with standard susceptibility assays, yet they can substantially dilute the protective effect of indoor-based interventions.

Beyond these classical frameworks, the review highlights contemporary discoveries that are reshaping how scientists conceptualize resistance. Among the most striking is the functional role of the commensal midgut microbiota in escalating phenotypic pyrethroid resistance. Bacteria resident in the mosquito gut can metabolize insecticides or modulate host detoxification pathways, so that the resistance phenotype is not solely a property of the mosquito genome but of an integrated holobiont. This microbial dimension opens both diagnostic and intervention possibilities, since manipulating gut communities could in principle restore susceptibility. The review also underscores novel extracellular metabolic markers such as the CSDIR protein, which may serve as an early indicator of resistance before it becomes fixed in a population, offering surveillance programs a molecular early-warning system.

These adaptation networks have forced a paradigm shift in public health programming, away from traditional neurotoxic monotherapies and toward next-generation chemistries designed to circumvent legacy cross-resistance. The World Health Organization has prequalified several such interventions. Neonicotinoids such as clothianidin act on nicotinic acetylcholine receptors at sites distinct from those targeted by organophosphates, and have shown efficacy in indoor residual spraying against pyrethroid-resistant Anopheles. The pyrrole chlorfenapyr is a pro-insecticide that becomes activated inside the mosquito’s mitochondria, disrupting oxidative phosphorylation through a mechanism with no cross-resistance to neurotoxic compounds. Novel meta-diamides such as broflanilide act as allosteric modulators of GABA-gated chloride channels, binding at sites remote from the classical Rdl mutations. Biorational insect growth regulators, exemplified by pyriproxyfen, do not kill adult mosquitoes directly but sterilize females or disrupt larval development, attacking the population through reproduction rather than neurotoxicity.

The review grounds these global dynamics in the geographically and epidemiologically diverse landscape of India, where both rural and urban transmission systems coexist. Anopheles culicifacies, the primary rural vector, has developed mapped multi-insecticide resistance profiles spanning DDT, organophosphates, carbamates, and pyrethroids, complicating indoor residual spraying campaigns across large parts of the country. Meanwhile, Anopheles stephensi, historically an urban vector, has been expanding its footprint and presents its own resistance challenges, a concern amplified by its recent detection in African cities. India’s national sentinel networks, operated by the National Centre for Vector Borne Diseases Control and ICMR-National Institute of Malaria Research, have generated PCR-based target-site genotyping data documenting the distribution of L1014F, L1014S, and V1010L kdr alleles across vector populations, providing a molecular map that complements phenotypic bioassays. Localized evaluations of novel allosteric chemistries are also underway, testing whether broflanilide-class compounds and other next-generation tools can restore effective mortality in Indian field conditions.

The strategic significance of bridging India’s field surveillance data with international resistance management frameworks lies in the design of integrated strategies that delay the selection of multi-resistant phenotypes. Rotation of insecticide classes with unrelated modes of action, combination interventions that pair a pyrethroid with a second active ingredient on the same net or spray, and mosaic deployment across landscapes all aim to impose multiple, independent selection pressures that no single mutation or enzyme amplification can simultaneously overcome. Complementing chemical tactics, the review’s emphasis on microbiome-mediated resistance suggests that biological manipulations could one day be layered onto existing programs, while behavioral resistance underscores the need for tools that act outdoors or at novel times of exposure.

The stakes of this evolutionary contest could hardly be higher. Malaria alone still causes hundreds of thousands of deaths annually, and dengue and Zika continue to expand their geographic range as urbanization and climate change enlarge mosquito habitats. Every percentage point of susceptibility lost in a vector population translates into infections that prevention programs fail to avert. The review’s synthesis makes clear that resistance is not a single problem but a constellation of mechanisms, molecular, metabolic, structural, behavioral, and now microbial, each evolving under the selection pressure that control programs themselves apply. Sustaining progress toward vector elimination will depend on continuous surveillance, rapid deployment of prequalified next-generation tools, and the intellectual integration of field data from diverse epidemiological settings into a coherent global resistance management strategy. The mosquitoes, meanwhile, continue to adapt, making the race between chemical innovation and evolutionary response a permanent feature of infectious disease control.

Subject of Research: Mechanisms of insecticide resistance in mosquito vectors and their implications for malaria and arbovirus control

Article Title: Mechanisms of insecticide resistance in mosquitoes and their implications for disease control

Article References: Padhan, R., Kumar, J., Goyal, B., Das, R., Kumar, V., Pradhan, S., Pandey, K. C., Vats, T. K., & Dixit, B. (2026). Mechanisms of insecticide resistance in mosquitoes and their implications for disease control. Frontiers in Malaria, 4, Article 1890327. https://doi.org/10.3389/fmala.2026.1890327

Image Credits: AI Generated

DOI: 10.3389/fmala.2026.1890327

Keywords: insecticide resistance, mosquitoes, malaria, kdr mutations, metabolic detoxification, pyrethroids, Anopheles, vector control, microbiota, next-generation insecticides, India, public health

The study, published in Frontiers in Parasitology, examined ethyl acetate extracts prepared from Terminalia catappa (Indian almond) leaves and from the seeds and stems of Eucalyptus citriodora (lemon-scented gum). Researchers led by Eze Elijah Ajaegbu of David Umahi Federal University of Health Sciences set out to fill a notable gap in the botanical pesticide literature, which has historically favored leaf assays while largely ignoring other plant organs. Their comparative evaluation across three medically important mosquito species—Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus—provides one of the more comprehensive simultaneous bioassays reported to date.

The team collected plant material from two Nigerian locations: T. catappa foliage from Trans-Ekulu in Enugu State and E. citriodora stems and seeds from Lakokari Farm in Gombe State. After taxonomic authentication and voucher deposition, the dried materials were milled into fine powder and subjected to cold maceration with ethyl acetate for 48 hours. Extraction yields varied by organ: the seed extract (LEEE) produced the highest recovery at 4.7 percent by weight, the leaf extract (TLEE) yielded 3.3 percent, and the stem extract (LSEE) gave the lowest at 2.8 percent. Interestingly, yield did not predict potency—a theme that would recur throughout the study.

Larvicidal bioassays were conducted on fourth-instar larvae using a concentration gradient spanning 125 to 1000 parts per million, with mortality assessed at 24 and 48 hours. Groups of 25 larvae were exposed in quadruplicate, and results were corrected using Abbott’s equation. The findings were striking. Against Ae. aegypti, the dengue and Zika vector, the eucalyptus stem extract proved the most aggressive toxicant, achieving complete 100 percent mortality at 1000 ppm within 24 hours and posting an LC50 of 172.851 ppm. By 48 hours, its LC50 had dropped further to 144.393 ppm, with total population elimination persisting down to 500 ppm.

The malaria vector An. gambiae showed even greater vulnerability over longer exposure. After 48 hours, the T. catappa leaf extract recorded an extraordinary LC50 of just 13.271 ppm, killing 96 percent of larvae at a mere 125 ppm and wiping out entire cohorts at 250 ppm and above. The eucalyptus stem extract was nearly as potent, with an LC50 of 20.370 ppm and complete mortality from 250 ppm upward. The seed extract, while weaker, still reached an LC50 of 84.841 ppm at the same time point. These figures suggest that even modest concentrations of these botanical preparations could deliver lethal blows to malaria-transmitting larvae given sufficient contact time.

Culex quinquefasciatus, the filariasis vector, presented a different vulnerability hierarchy. The T. catappa leaf extract dominated here, eradicating entire cohorts at 1000 ppm within 24 hours and maintaining an LC50 of 20.370 ppm at 48 hours with complete mortality from 250 ppm onward. The eucalyptus seed extract consolidated its performance over time, reaching an LC50 of 49.090 ppm by 48 hours, while the stem extract lagged behind with an LC50 of 302.323 ppm. The species-specific differences likely reflect variations in larval detoxification enzymes, cuticular permeability, and receptor sensitivities—factors that underscore the importance of testing botanical larvicides against multiple vector species before field deployment.

Phytochemical screening revealed the chemical underpinnings of these effects. Tannins appeared uniformly across all three extracts, but the eucalyptus derivatives carried a richer metabolic load, concentrating flavonoids, resins, and steroids. Alkaloids were detected exclusively in the stem tissue, while saponins were absent from all samples. The researchers explain that these compound classes act through complementary mechanisms: alkaloids inhibit acetylcholinesterase, causing continuous nerve firing, muscle spasms, and paralysis; flavonoids and tannins bind digestive enzymes in the larval midgut, disrupting nutrient assimilation and inducing oxidative stress; and steroids and resins can compromise membrane integrity and arrest developmental processes.

Gas chromatography–mass spectrometry (GC-MS) profiling of the T. catappa leaf extract resolved 16 discrete volatile compounds, dominated by fatty acids and their methyl esters—including n-hexadecanoic acid, 9,12-octadecadienoic acid, and hexadecanoic acid methyl ester—alongside nitrogenous heterocycles such as 2-methyl-7-phenylindole and 7-methyl-7H-purin-6-amine. Prior research links these lipophilic fatty acid configurations to membrane disruption and energy production failure in insects. The authors argue that the broad-spectrum toxicity likely arises from synergistic interactions among multiple metabolites rather than the action of any single molecule, a hallmark of botanical insecticides that also complicates the evolution of resistance in target populations.

The study’s implications extend beyond the laboratory. With malaria claiming approximately 608,000 lives and causing 249 million cases in 2022 according to the World Health Organization, and dengue now endemic in over 100 countries, the search for sustainable alternatives to synthetic neurotoxicants has become urgent. Botanical larvicides degrade rapidly in the environment, pose reduced risks to non-target organisms, and employ multiple modes of action that delay resistance development. The U.S. Environmental Protection Agency has already classified lemon eucalyptus oil as a biopesticide candidate for integrated vector management, lending regulatory precedent to this approach.

Nevertheless, the authors caution that laboratory results do not automatically translate to field success. Sunlight, water chemistry, microbial degradation, and temperature fluctuations may all alter larvicidal performance under natural breeding conditions. Moreover, because the extracts were evaluated as complex mixtures, the individual contribution of each identified compound remains unknown. Future work, they note, should focus on bioassay-guided fractionation, purification of active constituents, elucidation of specific mechanisms of action, toxicity assessment toward non-target aquatic organisms, formulation studies to improve stability, and ultimately field evaluation. For now, the findings position Terminalia catappa and Eucalyptus citriodora as promising candidates in the ongoing quest for eco-friendly mosquito control tools.

Subject of Research: Larvicidal activity and GC-MS chemical profiling of Terminalia catappa leaf and Eucalyptus citriodora seed and stem extracts against Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus mosquitoes

Article Title: GCMS profiling and larvicidal potentials of the extracts of Terminalia catappa leaf, Eucalyptus citriodora seed and stem against malarial, dengue and filarial vector mosquitoes (Diptera: Culicidae)

Article References: Ajaegbu, E. E., Nwigwe, J. O., Chikezie, C. C., & Enyi, N. C. (2026). GCMS profiling and larvicidal potentials of the extracts of Terminalia catappa leaf, Eucalyptus citriodora seed and stem against malarial, dengue and filarial vector mosquitoes (Diptera: Culicidae). Frontiers in Parasitology, 5, Article 1934443. https://doi.org/10.3389/fpara.2026.1934443

Image Credits: AI Generated

DOI: 10.3389/fpara.2026.1934443

Keywords: mosquito larvae, botanical insecticides, Terminalia catappa, Eucalyptus citriodora, larvicidal activity, GC-MS analysis, vector control, malaria, dengue, lymphatic filariasis, phytochemicals, insecticide resistance

The framework’s central claim is that additive models, which simply sum the effects of warming, deforestation, and biodiversity loss, systematically underestimate risk. Instead, each axis modifies the marginal effect of the others. The impact of rising temperature on vector breeding depends on how fragmented the surrounding forest already is; the effect of deforestation on transmission depends on the biodiversity of remaining host communities; and the consequences of biodiversity loss are themselves modulated by climatic suitability for vector survival. The review substantiates this interaction-based formulation with quantitative evidence. In southern Venezuela, a spatiotemporal modeling study found that the same ENSO-linked climatic anomaly produced markedly larger increases in malaria incidence in environmentally degraded municipalities than in intact ones. In the Peruvian Amazon, an analysis of Plasmodium vivax malaria found that a model including an interaction between ENSO phase and county-level forest cover achieved a goodness of fit of R-squared 0.85, compared with just 0.26 for a model without the interaction term.

Temperature remains the most extensively studied climatic driver, and for good reason. Because mosquitoes, ticks, and sandflies are ectothermic, nearly every trait that governs transmission—larval development time, adult survival, biting frequency, and the extrinsic incubation period during which a pathogen matures inside the vector—varies with temperature in a unimodal, non-linear fashion. Malaria transmission by Anopheles mosquitoes peaks between roughly 25 and 30 degrees Celsius, with transmission ceasing above about 34 degrees. Dengue transmission by Aedes aegypti is optimal between 21 and 34 degrees, and models project a 35 percent rise in global dengue incidence by 2050 under moderate warming. West Nile virus transmission peaks in a narrower band of 23 to 26 degrees, and Lyme disease transmission intensity peaks within an even tighter window of 17.0 to 20.5 degrees Celsius—a thermal sweet spot that is shifting geographically as surface temperatures rise, causing risk to decline in regions that warm past the optimum while emerging in newly suitable cooler areas.

The review also highlights a frequently neglected dimension: the diurnal temperature range. Even when mean temperatures sit comfortably within a vector’s optimal range, large daily fluctuations can reduce mosquito survival and lengthen the extrinsic incubation period, while small fluctuations within an already optimal range can accelerate pathogen development. Climate models projecting a reduced diurnal temperature range under greenhouse warming may therefore have implications for transmission intensity that extend beyond mean temperature effects. The review is candid about the limitations of current thermal suitability models, noting that laboratory-derived thermal performance curves often diverge from field estimates because microclimatic heterogeneity, behavioral thermoregulation, and biotic interactions modulate vector ecology in ways controlled experiments cannot replicate.

Precipitation and humidity exert their own complex influence. Moderate rainfall creates and replenishes the standing water that mosquito larvae require, but intense flooding can flush larval habitats, temporarily suppressing vector populations before floodwaters recede and create abundant new pools. Drought produces a paradox of its own: as water sources shrink, humans, livestock, and wildlife cluster around them, intensifying contact between hosts and vectors. The El Niño–Southern Oscillation acts as a powerful multi-year modulator of these dynamics. In Bangladesh, dengue cases surged by 317 percent in 2023 compared with 2019, with observed links to ENSO and Indian Ocean Dipole dynamics, and recent research indicates that rising ENSO amplitude is intensifying dengue risk globally.

Sea level rise emerges as an underappreciated but consequential driver. Global mean sea level has risen approximately 0.20 meters between 1901 and 2018 and is projected to rise by 0.43 to 0.84 meters by 2100 under the highest emissions scenario. Saltwater intrusion pushes brackish water into coastal aquifers and wetlands, expanding habitat for mosquitoes such as Anopheles sundaicus that breed preferentially in saline conditions. In Bangladesh’s Ganges-Brahmaputra delta, salinity intrusion has already shifted the distribution of this malaria vector landward by 15 to 30 kilometers, correlating with a doubling of malaria incidence in affected coastal districts. In the Nile Delta, a modeling study predicted a 35 percent increase in the seasonal abundance of Culex pipiens under a 0.5-meter sea level rise scenario, with a corresponding 20 percent rise in filariasis transmission potential. Displacement adds another layer: sea level rise is projected to displace 13 to 40 million people in South and Southeast Asia by 2100, many of whom will relocate to informal settlements with poor sanitation and high vector exposure.

On the anthropogenic axis, deforestation stands out as one of the most powerful drivers of emerging and re-emerging vector-borne disease. A synthesis of 305 studies identified deforestation, forest fragmentation, and agricultural development as the most commonly reported drivers of transmission change in the scientific literature. A landmark study in Amazonian Brazil demonstrated that each 1 percent increase in deforestation was associated with a nearly 1 percent increase in malaria incidence, driven by the expansion of sun-exposed forest edges where vector density is highest. Urbanization compounds the problem: by 2050, 68 percent of the world’s population is projected to live in urban areas, and unplanned expansion creates ideal conditions for Aedes aegypti through water storage containers, discarded plastic waste, and blocked drains, while the urban heat island effect raises temperatures 2 to 5 degrees Celsius above surrounding rural areas, enabling year-round mosquito activity at latitudes where winters would otherwise interrupt transmission.

Globalization completes the anthropogenic triad. A comprehensive global analysis documented 697 first records of non-native mosquito vectors across 288 regions, with Aedes aegypti now present in 192 regions and Aedes albopictus in 189. The Asian tiger mosquito’s spread from Southeast Asia to Europe, the Americas, and Africa has been driven largely by the international trade in used tires and lucky bamboo plants, in which desiccation-resistant eggs survive long-distance transport. The explosive emergence of Zika virus in the Americas between 2015 and 2017 exemplifies the role of travel, with phylogenetic analyses tracing the introduction of the Asian lineage to Brazil through viremic travelers, after which the virus spread through existing Aedes aegypti populations across 35 countries within two years. Meanwhile, insecticide resistance—driven by metabolic detoxification, target-site mutations, and behavioral adaptations such as shifts to nighttime biting—continues to undermine chemical control programs, with warming temperatures accelerating the selection of resistance alleles by boosting detoxification enzyme activity in mosquitoes.

The ecological axis ties these threads together through the dilution effect hypothesis, which posits that diverse host communities reduce transmission by including incompetent hosts that dilute the proportion of bites taken on competent reservoirs. When biodiversity declines, communities become dominated by amplification hosts such as the white-footed mouse, a highly competent reservoir for the bacterium that causes Lyme disease, elevating tick infection rates in fragmented forest patches. A recent meta-analysis confirmed that global change drivers, including biodiversity loss, are significantly associated with elevated infectious disease risk across a broad range of pathogens. The review also documents three self-reinforcing feedback loops: deforestation releases stored carbon while creating warmer edge habitats favorable for vector breeding; urban growth generates heat islands that extend mosquito seasons while producing artificial breeding sites; and biodiversity loss attenuates the dilution effect, driving higher transmission that further degrades ecosystems through the socioeconomic consequences of endemic disease.

Against this sobering picture, the review documents interventions that work. In Niterói, Brazil, the release of Wolbachia-infected mosquitoes helped reduce dengue cases from 12,000 in 2013 to fewer than 330 in total between 2020 and 2023, with Wolbachia persisting in over 90 percent of the mosquito population even after releases stopped. A community-based program in Chiapas, Mexico, reduced dengue transmission by more than 80 percent through participatory elimination of Aedes breeding sites. The WHO’s recommendation of the R21/Matrix-M malaria vaccine alongside RTS,S represents a historic breakthrough, and Kenya’s Rift Valley fever early warning system correctly predicted the 2018–2019 outbreak three months in advance by linking satellite-derived vegetation indices with livestock serosurveillance. The review concludes that limiting warming to 1.5 degrees Celsius rather than 2.5 to 3 degrees would leave hundreds of millions fewer people exposed to novel vector-borne disease risk by 2100, but that adaptation must also address the health equity dimension: low-income tropical countries bear the greatest burden of these climate-sensitive diseases while contributing least to the emissions driving them. The next decade, the author argues, will be critical.

Subject of Research: How climatic, anthropogenic, and ecological changes interact to drive vector-borne disease transmission

Article Title: Influence of environmental, anthropogenic, and climatic changes on vector-borne disease transmission: a comprehensive framework and critical review

Article References: Bera, B. (2026). Influence of environmental, anthropogenic, and climatic changes on vector-borne disease transmission: a comprehensive framework and critical review. Frontiers in Tropical Diseases, 7, Article 1908060. https://doi.org/10.3389/fitd.2026.1908060

Image Credits: AI Generated

DOI: 10.3389/fitd.2026.1908060

Keywords: vector-borne diseases, climate change, deforestation, dengue, malaria, urbanization, biodiversity loss, El Niño-Southern Oscillation, sea level rise, insecticide resistance, One Health, Aedes aegypti

The evidence base for this argument comes from resistance data collected between 2022 and 2023 across seven Rwandan districts. At sentinel sites including Bukora in Kirehe district, Gahini in Kayonza, Gashora in Bugesera, Kajevuba in Rulindo, Mubuga in Karongi, Nyagasambu in Rwamagana, and Rwanza in Musanze, Anopheles gambiae mosquitoes were collected during both rainy and dry seasons and tested with World Health Organization tube assays. The mosquitoes were exposed to two widely used pyrethroids, permethrin and alphacypermethrin, both alone and in combination with piperonyl butoxide, or PBO, a synergist that inhibits the cytochrome P450 enzymes mosquitoes use to detoxify insecticides.

The results were striking. Mortality from the pyrethroids alone was consistently below 80 percent at every site, and in some locations fell to between 40 and 50 percent—well below the WHO threshold of 98 to 100 percent mortality that defines a susceptible population. When mosquitoes were pre-exposed to PBO before the pyrethroid challenge, mortality rose significantly, indicating that a large share of the resistance is metabolic in origin, driven by overactive detoxification enzymes. Yet mortality still did not reach the 98 to 100 percent benchmark, which tells researchers something important: P450-mediated metabolic resistance explains only part of the problem, and additional resistance mechanisms must be operating in these populations.

Those additional mechanisms are diverse and, crucially, invisible to the standard bioassay. The policy brief lists target-site resistance—knockdown resistance mutations such as L1014F and L1014S in the voltage-gated sodium channel gene, the Ace-1 G119S mutation, and the N1575Y mutation—as likely contributors in some areas. Cuticular resistance, in which a thicker or chemically altered insect cuticle slows insecticide penetration, and behavioral resistance, in which mosquitoes shift their biting to earlier hours, move outdoors, or avoid sprayed surfaces, may also be present. Phenotypic testing with the WHO tube assay can confirm that resistance exists at a given site, but it cannot identify which mechanism is responsible, nor can it predict how resistance will spread over time. That diagnostic blind spot is the central technical argument of the brief.

This is where genomics enters the picture. The authors recommend integrating molecular and genomic tools into routine national entomological surveillance by 2027, including polygenic risk scores and targeted amplicon sequencing panels such as AgVampIR, which can screen mosquito populations for multiple resistance markers simultaneously. Such tools would allow the Rwanda Biomedical Centre’s Division of Malaria and Other Parasitic Diseases to detect emerging resistance earlier, track how resistance alleles move across the landscape, and build the evidence base for site-specific intervention decisions. The WHO itself supports routine entomological and insecticide-resistance surveillance using molecular and biochemical assays, emphasizing that accurate species identification and detection of resistance mechanisms require advanced molecular analysis.

The geographic heterogeneity documented in the 2022–2023 data carries a direct policy implication: interventions should be stratified by village or district rather than applied uniformly. Resistance levels vary significantly by district and ecological zone, and WHO guidelines recommend that surveillance be context-specific, reflecting those ecological differences. In practice, this means using village-level resistance profiles—including both the intensity of resistance and its molecular mechanisms—to select and rotate insecticides for each next malaria control campaign. The Rwanda Biomedical Centre would coordinate this at district, sector, and village levels, replacing the current one-insecticide-everywhere approach with a mosaic of locally matched interventions.

One immediate, evidence-backed recommendation is the prioritization of PBO-treated bed nets, or dual active-ingredient nets, in locations where metabolic resistance is confirmed. Because PBO restores susceptibility by blocking the detoxification enzymes, nets treated with the synergist perform better where P450-mediated resistance dominates. The brief calls for scaling up PBO net deployment in high-resistance villages and rotating non-pyrethroid insecticides where susceptibility allows, within two years, in line with WHO recommendations. The Ministry of Health, through the Rwanda Biomedical Centre, would handle procurement and distribution and establish an insecticide rotation schedule in collaboration with partners. The authors are careful to note, however, that PBO nets are not a permanent solution, since the residual mortality gap points to non-metabolic mechanisms that PBO cannot address.

Timing matters as much as tooling. Rwanda has two major malaria transmission seasons—the long rains from March to May and the short rains from September to December—which shape mosquito breeding and transmission intensity. The brief recommends expanding insecticide resistance surveillance to twice yearly at sentinel sites, collecting mosquitoes before and after the main rainy seasons to capture seasonal variation in mosquito abundance, insecticide exposure, and resistance levels. This cadence aligns with WHO guidance published in 2022 for routine, longitudinal resistance monitoring using consistent methods across different parts of the country, and it would give the national program an early-warning system for emerging resistance markers rather than a retrospective record of failure.

The economic framing of the brief is equally pointed. Citing the vision articulated by President Paul Kagame as the African Union champion for domestic health financing at the 34th African Union Summit, the authors argue that health investments should be judged by their impact on service coverage and health outcomes rather than by the amount spent. Indoor residual spraying, for example, may cost approximately two million dollars annually in a single district, and up to 24 million dollars when all target districts are included. If the insecticide deployed is ineffective against a resistant local mosquito population, that investment buys little protection. Strengthening resistance monitoring and targeting effective nets to the right locations, the authors argue, directly improves the efficiency of existing spending, reduces waste on ineffective interventions, and supports evidence-based resource allocation.

Finally, the brief stresses that insecticide resistance is not solely a public health problem. The same compounds used to kill mosquitoes are widely used in agriculture, and cross-sectoral pesticide use accelerates selection for resistance. The authors propose co-designing pesticide regulations with communities, coordinated by the health and agriculture sectors, and establishing by 2027 a joint task force spanning the Rwanda Agriculture and Animal Resources Development Board, the Rwanda Inspectorate, Competition and Consumer Protection Authority, the Ministry of Agriculture and Animal Resources, the Rwanda Environment Management Authority, the Rwanda FDA, the Rwanda Revenue Authority, the Rwanda Standards Board, and the University of Rwanda. The underlying message is that malaria elimination will not be achieved by traditional vector control tools alone: insecticide selection and rotation must be informed by regular genomic surveillance of mosquitoes, and pesticide stewardship demands collaboration among public health, agricultural, regulatory, and community stakeholders alike.

Subject of Research: Genomic surveillance of insecticide resistance in Anopheles gambiae mosquitoes to inform malaria vector control policy in Rwanda

Article Title: Genomic surveillance of mosquito resistance to guide cost-effective insecticide policy in Rwanda

Article References: Lambert, N., Dyer, N. A., Diane, U., Sherrard-Smith, E., & Leon, M. (2026). Genomic surveillance of mosquito resistance to guide cost-effective insecticide policy in Rwanda. Frontiers in Tropical Diseases, 7, Article 1887818. https://doi.org/10.3389/fitd.2026.1887818

Image Credits: AI Generated

DOI: 10.3389/fitd.2026.1887818

Keywords: Anopheles gambiae, insecticide resistance, genomic surveillance, malaria, Rwanda, pyrethroids, piperonyl butoxide, bed nets, indoor residual spraying, WHO tube assay, vector control, cytochrome P450

The research began with a systematic bioprospecting exercise. Fifteen species were selected from the Qinling Mountains on the basis of local abundance and regional representativeness, ranging from familiar solanaceous herbs to Allium species, legumes and Asteraceae shrubs. Plant material was rinsed, air-dried, oven-dried at 45 degrees Celsius, ground and sieved before being extracted with ninety-five percent ethanol at a solid-to-liquid ratio of one to four for forty-eight hours, with the process repeated twice on the residue. The combined filtrates were concentrated on a rotary evaporator to yield crude extracts, which were then dissolved into stock solutions and diluted to test concentrations. This simple but rigorous pipeline allowed the team to compare all fifteen species on an equal footing before committing resources to any single candidate.

Laboratory bioassays were built around three complementary measures of pest suppression: direct larvicidal toxicity, antifeedant activity and oviposition repellency. For the toxicity screen, five-centimeter cabbage leaf discs were dipped in each extract at fifty milligrams per milliliter, air-dried, and offered to twenty starved third-instar larvae per dish, with mortality scored at twenty-four, forty-eight and seventy-two hours. The results revealed striking interspecific differences and a clear time-dependent pattern. At twenty-four hours, Atropa belladonna extract already led the field with a corrected mortality of 58.87 percent, well ahead of Asparagus dauricus, Allium ochotense, Tupistra wattii and Blumea riparia var. megacephala. By seventy-two hours, A. belladonna had reached 83.11 percent, the only extract to break the eighty percent barrier, while B. riparia var. megacephala climbed to 73.53 percent. Ten of the fifteen extracts never exceeded fifty percent mortality, and Solanum nigrum was barely distinguishable from the ethanol control.

The behavioral assays told an equally compelling story. In the leaf-disc antifeedant test, smaller treated and untreated discs were offered to larvae, and consumed leaf area was measured after forty-eight hours. B. riparia var. megacephala and A. belladonna again dominated, with antifeedant rates of 87.45 and 89.46 percent respectively, meaning larvae ate only a small fraction of the foliage consumed by untreated controls. Extracts of A. ochotense, A. dauricus and Bauhinia championi also held rates above eighty percent, while several others faded over time. The oviposition assay extended the effect beyond feeding: potted Chinese cabbage plants sprayed with extract and caged with twenty adult moths received far fewer eggs than ethanol-treated controls. B. riparia var. megacephala reduced egg-laying by 82.14 percent, leaving just 1.25 eggs per plant, and A. belladonna achieved 78.57 percent repellency. Together, the data suggested these two plants attack the moth at multiple points in its life cycle.

With two standouts identified, the researchers asked whether combining them would improve performance. Eleven treatments were prepared in a volumetric series spanning pure A. belladonna to pure B. riparia var. megacephala, and the median lethal concentration of each was determined by probit analysis. Alone, A. belladonna showed an LC50 of 76.69 milligrams per milliliter against the more toxic B. riparia var. megacephala at 95.53. The critical result came from the eight-to-two mixture, which lowered the LC50 to 65.76 milligrams per milliliter, better than either single extract. Using the co-toxicity coefficient framework of Chinese pesticide standards, where values at or above 120 indicate synergism, at or below 80 indicate antagonism and values between indicate additivity, the eight-to-two blend scored 110. The authors are careful to call this an additive effect rather than true synergism, but the absence of any antagonistic combination, even at ratios where the weaker extract dominated, is a meaningful signal that the two extracts are chemically compatible partners.

Why might these particular plants be so potent? The team draws on phytochemical literature to build plausible, though deliberately tentative, mechanistic hypotheses. Atropa belladonna, the infamous deadly nightshade, is rich in tropane alkaloids including hyoscyamine, scopolamine and norhyoscyamine, compounds known to interact with insect muscarinic acetylcholine receptors and thereby disrupt cholinergic signaling and neural transmission. Blumea species, by contrast, produce sesquiterpene-rich volatile oils and diverse flavonoids, compound classes associated elsewhere with feeding deterrence, digestive enzyme inhibition and interference with detoxification enzymes. Allium ochotense owes its activity, if the pattern holds, to sulfur-containing compounds and steroidal saponins that can induce oxidative stress and permeate cell membranes. Because the study did not perform chemical profiling of the extracts, these explanations remain literature-supported hypotheses rather than demonstrated mechanisms, and the authors are explicit about that limitation.

Translating laboratory promise into a sprayable product required formulation chemistry. The combined eight-to-two extract was tested against four organic solvents, and ethanol was chosen over dimethyl sulfoxide and methanol for its lower toxicity and favorable stability, while petroleum ether failed solubility requirements outright. Four surfactant systems were then screened. Formulations containing pesticide emulsifier 500# combined with NP-2 remained homogeneous and transparent through high-temperature storage at 54 degrees Celsius for fourteen days, low-temperature storage near freezing for a week, and dilution testing, whereas OP-10 and emulsifier 601# showed precipitation under stress. Concentration optimization settled on five percent emulsifier 500# and eight percent NP-2. The final emulsifiable concentrate contained ten percent active ingredients, seventy-seven percent ethanol and the two emulsifiers, and it passed the physicochemical stability benchmarks, though the authors caution that these accelerated tests are not a substitute for a full shelf-life evaluation.

The decisive test came in the field. In a randomized complete block trial on cruciferous vegetables in Jingyang County, the ten percent botanical formulation diluted one hundred times was compared with emamectin benzoate, a widely used macrocyclic lactone insecticide, and a water-sprayed control across twelve plots. The pattern of action differed sharply between treatments. Emamectin benzoate, which paralyzes insects by acting on glutamate-gated chloride channels, showed faster knockdown in the first day. The botanical spray started slowly, delivering only 10.86 percent control at day one, but its performance climbed steadily as its toxic, antifeedant and reproductive effects accumulated. By seven days after application, the botanical formulation had achieved 58.35 percent control, statistically indistinguishable from the 60.58 percent achieved by emamectin benzoate. Meanwhile, the untreated plots saw larval populations surge by more than thirty percent, underscoring how much pressure the pest exerts when left alone.

The researchers and outside observers alike stress that 58.35 percent is moderate efficacy, not commercial-grade knockout, and the trial covered a single site and one growing season. But the trajectory is what makes the study noteworthy: a crude plant combination, formulated without synthetic active ingredients, matching a leading chemical insecticide within a week of application suggests genuine development potential rather than a laboratory curiosity. The authors outline the road ahead with commendable candor. Chemical profiling by LC-MS or GC-MS and bioassay-guided fractionation are needed to identify the actual active constituents. Safety evaluation is not optional, because natural origin does not equal safety: A. belladonna’s tropane alkaloids can pose risks to humans, livestock and beneficial insects at sufficient exposure, so mammalian toxicity, non-target effects, residues and environmental fate all require dedicated study. Resistance management potential, multi-location trials and dosage optimization round out the agenda. If those hurdles are cleared, the Qinling Mountains may have supplied an unlikely gift to cabbage growers worldwide: a plant-based spray that the diamondback moth has not yet learned to beat.

Subject of Research: Botanical insecticide screening and field evaluation against the diamondback moth Plutella xylostella

Article Title: Bioactivity screening of plant ethanol extracts against Plutella xylostella and field evaluation of an optimized botanical combination formulation

Article References: Zhang, J., Wang, X., Xu, X., Gustave, W., & Zhang, X. (2026). Bioactivity screening of plant ethanol extracts against Plutella xylostella and field evaluation of an optimized botanical combination formulation. Acta Biochimica Polonica, 73, Article 16918. https://doi.org/10.3389/abp.2026.16918

Image Credits: AI Generated

DOI: 10.3389/abp.2026.16918

Keywords: Plutella xylostella, diamondback moth, botanical insecticide, Atropa belladonna, Blumea riparia, plant extracts, antifeedant activity, insecticide resistance, emulsifiable concentrate, integrated pest management, field trial, cruciferous vegetables