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Provides strategies and topics of study designed to enhance student interest in botany using both familiar and exotic plant material to illustrate genetics, plant propagation, disease, germination, hybrid vigor, anatomy, natural insecticides, and tropisms. The relationship between plants and society is also used to develop several topics. (JM)

Contains a discussion of insects' ability to survive, of the development of pesticides and the introduction of DDT, of the problems of pesticide use and resistance to insecticides, and of the advantages of integrated pest control. (BB)

Provides a brief review of the use of pheromones and other behavior-controlling chemicals in pest control. Topics include control of moths, butterflies, beetles, aphids, nematodes, and slugs. (BB)

Explores the relationship between invention/innovation in pest control practices, food supply, and hunger in the United States from 1920-1970. Includes discussions of the nature, development, and use of insecticides, control of specific pests, and public arguments over the safety of residues leading to search for nonchemical methods of control. (JN)

A "colloqution module" (an instructional unit/strategy used in a conversation) consists of a reading assignment and a series of questions/activities. The strategy is suggested as an alternative to the lecture method. A sample module on insecticides (together with design information and advantages/disadvantages) is included. (DH)

Presents a brief review of pesticide use. Included topics are: biological activity, formulation, application, uptake, metabolism, residues, and tolerance. (BB)

Describes a high school chemistry student's research project in which limonene was isolated from the oil of lemons and oranges. Outlines the students' tests on the use of this chemical as an insecticide. Discusses possible extensions of the exercises based on questions generated by the students. (TW)

Drosophila suzukii lay eggs in soft-skinned, ripening fruits, making this insect a serious threat to berry production. Since its 2008 introduction into North America, growers have used insecticides, such as pyrethroids and spinosads, as the primary approach for D. suzukii management, resulting in development of insecticide resistance in this pest. This study sought to identify the molecular mechanisms conferring insecticide resistance in these populations. We sequenced the transcriptomes of two pyrethroid- and two spinosad-resistant isofemale lines. In both pyrethroid-resistant lines and one spinosad-resistant line, we identified overexpression of metabolic genes that are implicated in resistance in other insect pests. In the other spinosad-resistant line, we observed an overexpression of cuticular genes that have been linked to resistance. Our findings enabled the development of molecular diagnostics that we used to confirm persistence of insecticide resistance in California, U.S.A. To validate these findings, we leveraged D. melanogaster mutants with reduced expression of metabolic or cuticular genes that were found to be upregulated in resistant D. suzukii to demonstrate that these genes are involved in promoting resistance. This study is the first to characterize the molecular mechanisms of insecticide resistance in D. suzukii and provides insights into how current management practices can be optimized.

BACKGROUND: Aedes albopictus is an important vector for pathogens such as dengue, Zika, and chikungunya viruses. While insecticides is the mainstay for mosquito control, their widespread and excessive use has led to the increased resistance in Ae. albopictus globally. Gut symbiotic bacteria are believed to play a potential role in insect physiology, potentially linking to mosquitoes metabolic resistance against insecticides. METHODS: We investigated the role of symbiotic bacteria in the development of resistance in Ae. albopictus by comparing gut symbiotic bacteria between deltamethrin-sensitive and deltamethrin-resistant populations. Adults were reared from field-collected larvae. Sensitive and resistant mosquitoes were screened using 0.03% and 0.09% deltamethrin, respectively, on the basis of the World Health Organization (WHO) tube bioassay. Sensitive and resistant field-collected larvae were screened using 5 × LC50 (lethal concentration at 50% mortality) and 20 × LC50 concentration of deltamethrin, respectively. Laboratory strain deltamethrin-sensitive adults and larvae were used as controls. The DNA of gut samples from these mosquitoes were extracted using the magnetic bead method. Bacterial 16S rDNA was sequenced using BGISEQ method. We isolated and cultured gut microorganisms from adult and larvae mosquitoes using four different media: Luria Bertani (LB), brain heart infusion (BHI), nutrient agar (NA), and salmonella shigella (SS). RESULTS: Sequencing revealed significantly higher gut microbial diversity in field-resistant larvae compared with field-sensitive and laboratory-sensitive larvae (P

The appropriate use of human biomonitoring data to model population chemical exposures is challenging, especially for rapidly metabolized chemicals, such as agricultural chemicals. The objective of this study is to demonstrate a novel approach integrating model predicted dietary exposures and biomonitoring data to potentially inform regulatory risk assessments. We use lambda-cyhalothrin as a case study, and for the same representative U.S. population in the National Health and Nutrition Examination Survey (NHANES), an integrated exposure and pharmacokinetic model predicted exposures are calibrated to measurements of the urinary metabolite 3-phenoxybenzoic acid (3PBA), using an approximate Bayesian computing (ABC) methodology. We demonstrate that the correlation between modeled urinary 3PBA and the NHANES 3PBA measurements more than doubled as ABC thresholding narrowed the acceptable tolerance range for predicted versus observed urinary measurements. The median predicted urinary concentrations were closer to the median measured value using ABC than using current regulatory Monte Carlo methods.

Plant-systemic neonicotinoid (NN) insecticides can exert non-target impacts on organisms like beneficial insects and soil microbes. NNs can affect plant microbiomes, but we know little about their effects on microbial communities that mediate plant-insect interactions, including nectar-inhabiting microbes (NIMs). Here we employed two approaches to assess the impacts of NN exposure on several NIM taxa. First, we assayed the in vitro effects of six NN compounds on NIM growth using plate assays. Second, we inoculated a standardised NIM community into the nectar of NN-treated canola (Brassica napus) and assessed microbial survival and growth after 24 h. With few exceptions, in vitro NN exposure tended to decrease bacterial growth metrics. However, the magnitude of the decrease and the NN concentrations at which effects were observed varied substantially across bacteria. Yeasts showed no consistent in vitro response to NNs. In nectar, we saw no effects of NN treatment on NIM community metrics. Rather, NIM abundance and diversity responded to inherent plant qualities like nectar volume. In conclusion, we found no evidence that NIMs respond to field-relevant NN levels in nectar within 24 h, but our study suggests that context, specifically assay methods, time and plant traits, is important in assaying the effects of NNs on microbial communities.

Neonicotinoid insecticides are among the most used insecticides and their residues are frequently found in surface water due to their persistence and mobility. Neonicotinoid insecticides exhibit toxicity to a wide range of aquatic invertebrates at environmentally relevant levels, and therefore their contamination in surface water is of significant concern. In this study, we investigated the spatiotemporal distribution of six neonicotinoids in a large wetland system, the Prado Wetlands, in Southern California, and further evaluated the wetlands' efficiency at removing these insecticides. Total neonicotinoid concentrations in water ranged from 3.17 to 46.9 ng L-1 at different locations within the wetlands, with imidacloprid and dinotefuran among the most detected. Removal was calculated based on concentrations as well as mass flux. The concentration-based removal values for a shallow pond (vegetation-free), moderately vegetated cells, densely vegetated cells, and the entire wetland train were 16.9%, 34.2%, 90.2%, and 61.3%, respectively. Principal component analysis revealed that pH and temperature were the primary factors affecting neonicotinoids removal. Results from this study demonstrated the ubiquitous presence of neonicotinoids in surface water impacted by urban runoff and wastewater effluent and highlighted the efficiency of wetlands in removing these trace contaminants due to concerted effects of uptake by wetland plants, photolysis, and microbial degradation.

Mosquito-borne illnesses represent a significant global health peril, resulting in approximately one million fatalities annually. West Nile, dengue, Zika, and malaria are continuously expanding their global reach, driven by factors that escalate mosquito populations and pathogen transmission. Innovative control measures are imperative to combat these catastrophic ailments. Conventional approaches, such as eliminating breeding sites and using insecticides, have been helpful, but they face challenges such as insecticide resistance and environmental harm. Given the mounting severity of mosquito-borne diseases, there is promise in exploring innovative approaches using synthetic biology to bolster mosquitoes' resistance to pathogens, or even eliminate the mosquito vectors, as a means of control. This review outlines current strategies, future goals, and the importance of gene editing for global health defenses against mosquito-borne diseases.

ABSTRACT Silverleaf whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is a destructive insect pest damaging to diverse crops by vectoring several plant pathogenic viruses, which consequently causes economic losses in crop production. As the resistance of whiteflies to chemical insecticides is increasing, this study aimed to investigate the potential of entomopathogenic fungi as an alternative. A total of 72 entomopathogenic fungal isolates, collected from soils using Tenebrio molitor larvae as an insect baiting method, were assessed for their virulence against 2nd nymphs of whitefly. Their virulence was assayed by dipping whitefly‐infested tomato leaves in fungal conidia suspensions at 1.0 × 107 conidia/mL. Among the tested isolates, two isolates of Beauveria bassiana JEF‐462 and JEF‐507 showed high virulence. In the assessment of virulence depending on conidia concentrations, the estimated LC50 values for JEF‐462 and JEF‐507 were similarly 8.7–14.0 × 107 conidia/mL. However, B. bassiana JEF‐507 showed higher conidial productivity and thermotolerance on most of tested 12 grain substrates than B. bassiana JEF‐462, and millet was the most suitable grain substrate. Additionally, siloxane as a surfactant was able to sufficiently exhibit the insecticidal activity of JEF‐507 against whitefly nymphs compared with other surfactants. In a pot‐based greenhouse trial, JEF‐507 showed higher control efficacy than chemical insecticides, dinotefuran and spinetoram. This work suggests that B. bassiana JEF‐507 could be competitively used as a biopesticide to control silverleaf whiteflies while overcoming current resistance issues. The JEF‐507 isolate has been registered in Korea, 2022 and successfully commercialised as the name of Chongchae‐Stop in this local market to control whitefly and thrips. [ABSTRACT FROM AUTHOR]

Developmental exposure to carbamates, organophosphates, and pyrethroids has been associated with impaired neurodevelopmental outcomes. Sex-specific differences following chronic insecticide exposure are rather common in vivo. Therefore, we assessed the chronic effects of in vitro exposure to different carbamates (carbaryl, methomyl and aldicarb), organophosphates [chlorpyrifos (CPF), chlorpyrifos-oxon (CPO), and 3,5,6,trichloropyridinol (TCP)], and pyrethroids [permethrin, alpha-cypermethrin and 3-phenoxy benzoic acid (3-PBA)] on neuronal network development in sex-separated rat primary cortical cultures using micro-electrode array (MEA) recordings. Our results indicate that exposure for 1 week to carbaryl inhibited neurodevelopment in male cultures, while a hyperexcitation was observed in female cultures. Methomyl and aldicarb evoked a hyperexcitation after 2 weeks of exposure, which was more pronounced in female cultures. In contrast to acute MEA results, exposure to ≥ 10 µM CPF caused hyperexcitation in both sexes after 10 days. Interestingly, exposure to 10 µM CPO induced a clear hyperexcitation after 10 days of exposure in male but not female cultures. Exposure to 100 µM CPO strongly inhibited neuronal development. Exposure to the type I pyrethroid permethrin resulted in a hyperexcitation at 10 µM and a decrease in neuronal development at 100 µM. In comparison, exposure to ≥ 10 µM of the type II pyrethroid alpha-cypermethrin decreased neuronal development. In female but not in male cultures, exposure to 1 and 10 µM permethrin changed (network) burst patterns, with female cultures having shorter (network) bursts with fewer spikes per (network) burst. Together, these results show that MEA recordings are suitable for measuring sex-specific developmental neurotoxicity in vitro. Additionally, pyrethroid exposure induced effects on neuronal network development at human-relevant concentrations. Finally, chronic exposure has different effects on neuronal functioning compared to acute exposure, highlighting the value of both exposure paradigms. [ABSTRACT FROM AUTHOR]

Over the past decades, concern has been increasing over reported declines in aboveground biodiversity on farmland. In many regions, data on the toxicity of pesticides to honeybees (Apis mellifera), but not wider nontarget arthropod (NTA) data, are required for pesticide registration. In Europe, the effects of pesticides on NTAs and honeybees have been the subject of regulatory risk assessment for more than 30 years, resulting in a large database. Although insecticides may be expected to affect NTA populations, solely identifying insecticidal modes of action for further NTA testing would result in redundancy among low‐risk testing products and may also exclude other modes of action with potential effects in the field. This study assessed whether the honeybee acute risk assessment could provide any indication of the potential impact and recovery time of NTAs in cropped areas at the field scale and, if so, how it might be used in a tiered testing approach. The hazard quotients (HQs; foliar application rate/LR50) were derived for 151 active substances (32% insecticides, 28% fungicides, 38% herbicides, 2% plant growth regulators) for which toxicity data for established EU Tier 1 NTA indicator species (Typhlodromus pyri, Aphidius rhopalosiphi) and application rate data were available. These HQs were compared with published NTA HQ thresholds indicating the time to recovery of NTA populations and communities in field studies (>1 to >12 months). Using the same application rate data, honeybee acute risk quotient (RQ) and HQ were also determined and compared with NTA HQs and honeybee regulatory thresholds. These comparisons demonstrated that, where required, the current regulatory honeybee acute RQ of 0.4 or honeybee HQ of 50 can provide an efficient screening tier to target NTA testing at those products and uses with potential effects in the field where recovery may exceed 12 months. Integr Environ Assess Manag 2024;20:2326–2333. © 2024 SETAC Key Points: Comparison of the 151 nontarget arthropod (NTA) hazard quotients (HQs) with the honeybee acute risk quotients (RQs) and HQs revealed that the current honeybee thresholds (RQ 0.4 or HQ 50) can provide an efficient screening tier to target any NTA testing at those product and use rates with potential effects in the field where recovery may exceed 12 months.Such an approach is also applicable with mixture products and off‐crop, with the relevance of the NTA HQ thresholds potentially being more widely addressed by assessing whether taxa identified in EU field studies encompass the traits of taxa within a region or of a particular species of interest. [ABSTRACT FROM AUTHOR]

Pyriproxyfen (PPF) is an insecticide used in agriculture, which is approved for use in drinking water tanks for human consumption. However, some studies indicate that it may act as an endocrine disruptor and affect nontarget organisms. This study aimed to evaluate the effects of PPF on reproduction and general health status in female mice exposed from pre‐puberty to adulthood. In the first experiment, females were treated by gavage from postnatal day (PND) 23 to (PND) 75 and were distributed into three experimental groups: control (vehicle), PPF 0.1 mg/kg, and PPF 1 mg/kg. Female mice were assessed for the age of puberty onset, body mass, water and food consumption, and the estrous cycle. On PDN 75, a subgroup was euthanized, when vital and reproductive organs were collected and weighed. The thyroid, ovary, and uterus were evaluated for histomorphometry. The other subgroup was assessed in relation to reproductive performance and fetal parameters. In a second experiment, the uterotrophic assay was performed with juvenile females (PND 18) using doses of 0.01, 0.1, or 1 mg/kg of PPF. PPF treatment reduced thyroid mass and increased liver mass. Furthermore, there was an increase in ovarian interstitial tissue and, in the uterus, a decrease in the thickness of the endometrial stroma with reduced content of collagen fibers. There was also a reduction of 30% in pregnancy rate in the treated groups and an increase in the frequency of fetal death. This study suggests that, based on this experimental model, the insecticide may pose a reproductive risk for females chronically exposed to the substance from the pre‐pubertal period until adulthood. These results raise concerns about prolonged exposure of women to the same compound. [ABSTRACT FROM AUTHOR]

BACKGROUND: Elucidating fitness cost associated with field‐evolved insect resistance to insecticide is of particular importance to current sustainable pest control. The global pest whitefly Bemisia tabaci has developed resistance to many members of neonicotinoids, but little is known about whitefly resistance to neonicotinoid nitenpyram and its associated fitness cost. Using insecticide bioassay and life‐table approach, this study aims to investigate nitenpyram resistance status in field‐collected whitefly populations, and to explore whether such resistance is accompanied by a fitness cost. RESULTS: The bioassay results revealed that 14 of 29 whitefly populations displayed moderate to extremely high resistance to nitenpyram, demonstrating a widespread field‐evolved resistance to nitenpyram. This field‐evolved resistance in the whitefly has increased gradually over the past 3 years from 2021 to 2023. Further life‐table study showed that two resistant whitefly populations exhibited longer developmental time, shorter lifespans of adult, and lower fecundity compared with the most susceptible population. The relative fitness cost of the two resistant populations was calculated as 0.69 and 0.56 by using net productive rate R0, which suggests that nitenpyram resistance comes with fitness cost in the whitefly, especially on reproduction. CONCLUSION: Overall, these results represent field‐evolved high resistance to nitenpyram in the whitefly. The existing fitness costs associated with nitenpyram resistance are helpful to propose a suitable strategy for sustainable control of whiteflies by rotation or mixture of insecticide with different modes of action. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Stomoxyine biting flies play a pivotal role as mechanical vectors of Animal African Trypanosomosis (AAT), inducing painful bites and significant disturbances in cattle, thereby affecting productivity. This study delves into the dynamics of cypermethrin persistence on cattle, a key measure aimed at mitigating stomoxyine populations and the associated transmission of trypanosomes. Conducted within a cattle settlement in Ido, Ibadan, southwest Nigeria, data collection occurred biennially from 2016 to 2022. Cypermethrin application followed a restricted protocol triggered by high fly density. Stomoxyine flies were systematically trapped every three months over a five-day period, employing four Nzi traps per collection cycle. The flies were taxonomically categorised, and their relative abundance assessed. Additionally, engorged flies underwent ITS-PCR analysis to detect T. vivax presence in their mouthparts. The investigation unveiled a noteworthy decline in cypermethrin persistence from 10.7 to 4.9 days over the six-year span, significantly influencing stomoxyine population dynamics and T. vivax infection rates. Despite escalated cypermethrin utilisation, stomoxyine abundance exhibited stability, hinting at potential insecticidal resistance. Notably, cypermethrin persistence was at its highest during July-September, aligning with heightened rainfall and humidity conducive to stomoxyine larval development. The heightened probability of detecting T. vivax DNA in stomoxyine flies as cypermethrin persistence dwindled underscores the intricate interplay between reduced insecticide efficacy and heightened pathogen dissemination. This underscores the imperative for integrated, enhanced control strategies considering the prevailing T. vivax resistance to trypanocides and diminishing cypermethrin efficacy. [ABSTRACT FROM AUTHOR]

Habrobracon hebetor Say (Hymenoptera: Braconidae) is one of the most important parasitoids of many pyralid moths, including the olive leaf moth, Palpita unionalis Hubner (Lepidoptera: Pyralidae). The widespread use of insecticides threatens natural enemies. Assessing the side effects of insecticides on nontarget organisms supports the rational use of insecticides during field application. The present study evaluates the lethal and sublethal effects of three insect growth regulators (IGRs), novaluron, methoxyfenozide, and pyriproxyfen, on P. unionalis and the demographic toxicology of these IGRs on its parasitoid H. hebetor. The LC50 values of these IGRs on P. unionalis were 0.97, 0.176, and 0.00009 ppm, respectively, indicating that pyriproxyfen was the most toxic. When H. hebetor adults were exposed to these LC50 levels under laboratory conditions to determine possible side effects. The IGRs did not affect the paralysis and parasitism rates of the parasitoid nor the sex ratio of its offspring. IGR treatments slightly reduced hatching rates and immature survival by 15–25%, indicating moderate effects on the early developmental stages of H. hebetor. The longevity and fecundity of treated females were each reduced to < 50% of their respective values in untreated females. Additionally, some demographic parameters of the parasitoid were significantly affected by the IGRs. Nevertheless, despite these observed effects, the positive net reproductive rate (R0 > 0) and intrinsic rate of increase (rm > 1) of H. hebetor indicated an exponential population increase that reflects the compatibility of the IGRs with the parasitoid. Our results demonstrated that the tested IGRs could be categorized as relatively harmless compounds to the parasitoid. Following these laboratory assessments, field studies will be required to confirm the effects of the tested IGRs on H. hebetor as well as other nontarget organisms. [ABSTRACT FROM AUTHOR]

An important defense against the deadly diseases that mosquitoes transmit is the application of insecticides that reduce mosquito populations. Unfortunately, the evolution and subsequent spread of insecticide resistance has decreased their efficacy. Therefore, new mosquito control strategies are needed. One class of larvicides, known as photosensitive insecticides, or PSIs, kills larvae via light-activated oxidative damage. PSIs are promising larvicides because of their high larvicidal efficacy, rapid photodegradation, inexpensive cost, and mechanism that is dissimilar to other insecticide classes. We explored a novel delivery strategy for increasing both the larvicidal efficiency and environmental biocompatibility of PSIs, known as yeast encapsulation. Using the PSIs, curcumin and methylene blue, we measured the survival of Anopheles gambiae larvae and Escherichia coli following exposure to either non-encapsulated or yeast-encapsulated PSIs and a photoperiod. Yeast encapsulation increased the phototoxicity of both curcumin and methylene blue against mosquito larvae, likely by increasing ingestion. Furthermore, yeast encapsulation protected E. coli from the phototoxicity of yeast-encapsulated curcumin, but not yeast-encapsulated methylene blue. Yeast encapsulation increases the larvicidal efficacy of a PSI while also increasing biocompatibility. Therefore, yeast encapsulation of PSIs is a promising insecticide delivery strategy for mosquito control. [ABSTRACT FROM AUTHOR]

Insect biomass is declining globally, likely driven by climate change and pesticide use, yet systematic studies on the effects of various chemicals remain limited. In this work, we used a chemical library of 1024 molecules--covering insecticides, herbicides, fungicides, and plant growth inhibitors--to assess the impact of sublethal pesticide doses on insects. In Drosophila melanogaster, 57% of chemicals affected larval behavior, and a higher proportion compromised long-term survivability. Exposure to sublethal doses also induced widespread changes in the phosphoproteome and changes in development and reproduction. The negative effects of agrochemicals were amplified when the temperature was increased. We observed similar behavioral changes across multiple insect species, including mosquitoes and butterflies. These findings suggest that widespread sublethal pesticide exposure can alter insect behavior and physiology, threatening long-term population survival. [ABSTRACT FROM AUTHOR]

Pest Management (PM) has its 1959 origin in Integrated Control, a combination of a reduced dose of insecticide with biological control. At the time, it was not recognised that the interaction between these two control methods was more than additive. This ‘superadditivity’ can also be achieved with the full dose of insecticide, for example, by localising its application in space. There is also likely to be superadditivity in the interaction between partial plant resistance and biological control. Pests on resistant hosts are usually smaller and the same mortality can often be obtained with just two‐thirds or one‐half of the dose of insecticide needed on susceptible plants, giving superadditivity between partial plant resistance and chemical control. These positive interactions between biological control, chemical control and partial host plant resistance form a ‘Pest Management Triad’, though legislation and risk‐aversion may limit the practicability of protocols based on the Triad. [ABSTRACT FROM AUTHOR]

Codling moth (CM), Cydia pomonella, is a significant pest of apple (Malus domestica) and other orchard crops worldwide, posing challenges due to the decrease in registered insecticides, rising resistance, and a changing climate. The pest exhibits a strong resistance capacity to both synthetic and natural insecticides, while shifting seasonal temperatures disrupt the reliability of phenology-temperature models for predicting targeted control strategies. Alternative control strategies are necessary to future-proof control of this pest. Current control methods primarily rely on chemical insecticide sprays or granulosis virus applications during egg hatching. This review focuses explicitly on semiochemical-based manipulation of CM adults and larvae for control in orchards. Topics covered include the role of semiochemicals in integrated pest management, area-wide control, mating disruption, female attractants, larval kairomones, and incorporation into monitoring and control strategies. The potential of CM repellents in a push-pull strategy is also discussed. Primary sources for identifying relevant literature included GoogleScholar and ResearchGate, with a focus on papers published since 2013 but also include relevant papers from 2003. Nine review papers and 119 papers were reviewed. The review emphasizes that effective control necessitates an area-wide approach targeting all life stages (eggs, larvae, pupae, and adults). Comprehensive monitoring is crucial for identifying CM "hot-spots" and enhancing targeted interventions. Growers must consider landscape context when designing control programs. Lastly, recommendations are provided for future research and CM management strategies. There are opportunities to explore and exploit female kairomone attractants and repellents in control strategies and modify monitoring traps to be more attractive and autonomous. [ABSTRACT FROM AUTHOR]

Human biomonitoring (HBM) data indicate that exposure to pyrethroids is widespread in Europe, with significantly higher exposure observed in children compared to adults. Epidemiological, toxicological, and mechanistic studies raise concerns for potential human health effects, particularly, behavioral effects such as attention deficit hyperactivity disorder (ADHD) in children at low levels of exposure. Based on an exposure-response function from a single European study and on available quality-assured and harmonized HBM data collected in France, Germany, Iceland, Switzerland, and Israel, a preliminary estimate of the environmental burden of disease for ADHD associated with pyrethroid exposure was made for individuals aged 0–19 years. The estimated annual number of prevalence-based disability-adjusted life years (DALYs) per million inhabitants were 27 DALYs for Israel, 21 DALYs for France, 12 DALYs for both Switzerland and Iceland, and 3 DALYs for Germany; while the annual ADHD cases per million inhabitants attributable to pyrethroids were 2189 for Israel, 1710 for France, 969 for Iceland, 944 for Switzerland, and 209 for Germany. Direct health costs related to ADHD ranged between 0.3 and 2.5 million EUR yearly per million inhabitants for the five countries. Additionally, a substantial number of ADHD cases, on average 18%, were associated with pyrethroid exposure. Yet, these figures should be interpreted with caution given the uncertainty of the estimation. A sensitivity analysis showed that by applying a different exposure-response function from outside the EU, the population attributable fraction decreased from an average of 18 to 7%. To ensure more robust disease burden estimates and adequate follow-up of policy measures, more HBM studies are needed, along with increased efforts to harmonize the design of epidemiological studies upfront to guarantee meta-analysis of exposure-response functions. This is particularly important for pyrethroids as evidence of potential adverse health effects is continuously emerging. [ABSTRACT FROM AUTHOR]

The resistance of pests to common insecticides is a global issue that threatens food production worldwide. Diamide insecticides target insect ryanodine receptors (RyRs), causing uncontrolled calcium release from the sarcoplasmic and endoplasmic reticulum. Despite their high potency and species selectivity, several resistance mutations have emerged. Using a chimeric RyR (chiRyR) approach and cryo-electron microscopy (cryo-EM), we investigate how insect RyRs engage two different diamide insecticides from separate families: flubendiamide, a phthalic acid derivative, and tetraniliprole, an anthranilic compound. Both compounds target the same site in the transmembrane region of the RyR, albeit with different poses, and promote channel opening through coupling with the pore-forming domain. To explore the resistance mechanisms, we also solve two cryo-EM structures of chiRyR carrying the two most common resistance mutations, I4790M and G4946E, both alone and in complex with the diamide insecticide chlorantraniliprole. The resistance mutations perturb the local structure, directly reducing the binding affinity and altering the binding pose. Our findings elucidate the mode of action of different diamide insecticides, reveal the molecular mechanism of resistance mutations, and provide important clues for the development of novel pesticides that can bypass the resistance mutations. Pesticide resistance poses a serious threat to global food security. In this study, the authors show the mode of action of various diamide insecticides and elucidate the molecular mechanisms underlying resistance mutations. [ABSTRACT FROM AUTHOR]

As a result of its high reactivity, furan-2(3H)-one derivative 2 can be selected as a versatile and suitable candidate for building of novel nitrogen heterocyclic compounds. Consequently, furan-2(3H)-one derivative 2 and some nitrogen nucleophiles were utilized as starting materials for the formation of new pyridazinone and pyrrolone derivatives bearing naphthalene moiety. The continuous buildup of insecticide resistance is the main obstacle facing pest control measures. Pyrrole-based insecticides are a favourable choice due to their unique mode of action and no cross-resistance with traditional neurotoxic insecticides. The larvicidal activities of pyrrolone derivatives were assessed against field and laboratory strains of Culex pipiens larvae in comparison with chlorfenapyr (pyrrole insecticide). Compounds 17 (21.05 µg/mL) > 9 (22.81 µg/mL) > 15 (24.39 µg/mL) > 10 (26.76 µg/mL) > 16 (32.09 µg/mL) were most effective against lab strain of C. pipiens larvae relative to chlorfenapyr (25.43 µg/mL). While in field strain, 17 and 15 were the most toxic compounds followed by 9 > 10 > 16 > 2 with LC50 of 9.87, 10.76, 11.52, 12.68, 15.32 and 18.37 µg/mL, respectively, compared with chlorfenapyr with 14.03 µg/mL. The cytochrome P-450 monooxygenase activities were significantly increased in treated larvae of lab and field strains relative to untreated. The great variations in toxicity of the synthesized compounds were interpreted by structure-activity relationship study. The pyrrolone derivatives are effective against field and insecticide-resistant strains. Therefore, they are considered promising compounds to be integrated into pest management programs. [ABSTRACT FROM AUTHOR]

Serpentine leaf miner, Liriomyza huidobrensis, invaded New South Wales and Queensland late 2020. Overseas, L. huidobrensis has a history of developing insecticide resistance and, since its Australian discovery, has caused significant control issues in Australian horticultural industries. Here, we developed bioassay methods to test the response of L. huidobrensis larvae to spirotetramat and L. huidobrensis adults to dimethoate, imidacloprid and chlorantraniliprole. Against two New South Wales and one Queensland collected strains, we found a 33‐fold elevated response against dimethoate and 200‐fold more against imidacloprid than the field‐recommended field rates. Furthermore, we found that a maximum rate of 64‐fold the field‐recommended rate of chlorantraniliprole controlled only 94% of one tested population. Similarly, the maximum rate of spirotetramat tested (64‐fold the field‐recommended rate) only achieved 84%–94% mortality for the same populations. Prior to our study, the efficacy of chlorantraniliprole and spirotetramat against Liriomyza was poorly studied, with only a few reports with chlorantraniliprole against Liriomyza trifolii. Consequently, none of the tested insecticides in this study will likely control Australian invasive L. huidobrensis at the field‐recommended rates. Our results presented here highlight the need to identify and study alternative chemical and biological products and natural enemies for the control of L. huidobrensis in Australian horticulture. [ABSTRACT FROM AUTHOR]

ABSTRACT As an egg parasitoid, Trichogramma ostriniae (T. ostriniae) exhibits a broad host range and plays a crucial role in controlling various lepidopteran agricultural pests. However, the application of chemical pesticides negatively impacts its development and survival. Therefore, it is essential to assess the toxicity of commonly used insecticides against T. ostriniae and evaluate their compatibility. This study aims to determine the toxic effects of five common insecticides (dinotefuran, abamectin, imidacloprid, beta‐cypermethrin, and chlorantraniliprole) on the development, reproduction, and enzymatic activity of T. ostriniae. The contact, lethal, and developmental toxicities were evaluated. Activities of detoxification enzymes, including cytochrome P450 (CYP450), carboxylesterase (CarE), and glutathione S‐transferase (GST), and protective enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) as well as malondialdehyde (MDA) and reactive oxygen species (ROS), mitochondrial respiratory chain complex I (MRCC I), adenosine triphosphate (ATP) of T. ostriniae were examined after being treated with the five insecticides. The results showed that the order of lethal toxicity in adult T. ostriniae was beta‐cypermethrin > dinotefuran > imidacloprid > abamectin > chlorantraniliprole. The emergence rates of adult T. ostriniae exposed to insecticides during the egg and larval stages were higher than those exposed to insecticides during the prepupal and pupal stages. The activities of CYP450, GST, and SOD were increased, but CarE activity and ROS content were decreased in T. ostriniae treated with the five insecticides compared with the control. Beta‐cypermethrin increased the POD and CAT activities. Chlorantraniliprole decreased CAT activity and increased MDA content. The MRCCI of T. ostriniae was not significantly affected by any of the five insecticides tested. The ATP content of T. ostriniae was not significantly affected by chlorantraniliprole but was significantly decreased by the other four insecticides. In conclusion, the toxicities of the five insecticides to T. ostriniae were different, among which imidacloprid, dinotefuran, abamectin, and beta‐cypermethrin had a high risk of toxicity to T. ostriniae, and chlorantraniliprole had a low risk to T. ostriniae. [ABSTRACT FROM AUTHOR]

Benzyl alcohol (E1519) is an aromatic alcohol used in the pharmaceutical and food industry. It is used to protect food products against microorganisms during storage, as a flavoring in the production of chocolate and confectionery products, as an important ingredient in fragrance, and as a preservative in medical products. However, little is known of its effect on insects. The main aim of this study was to determine the influence of benzyl alcohol on the defense systems of the wax moth Galleria mellonella, i.e., its cuticular lipid composition and critical elements of its immune system. A gas chromatography/mass spectrometry (GC/MS) analysis found benzyl alcohol treatment to elicit significant quantitative and qualitative differences in cuticular free fatty acid (FFA) profiles. Our findings indicate that benzyl alcohol treatment increased the levels of HSP70 and HSP90 and decreased those of HSF1, histamine, and cysteinyl leukotriene. Benzyl alcohol application also increased dismutase level in the hemolymph and lowered those of catalase and 8-OHdG. The treatment also had negative effects on G. mellonella hemocytes and a Sf9 cell line in vitro: 48-h treatment resulted in morphological changes, with the remaining cells being clearly spindle-shaped with numerous granules. The high insecticidal activity of compound and its lack of toxicity towards vertebrates suggest it could be an effective insecticide. [ABSTRACT FROM AUTHOR]

Background: Studies evaluating the attrition, physical and insecticidal durability of dual active ingredient (AI) insecticide-treated nets (ITNs) are essential for making programmatic decisions regarding their deployment. We performed a prospective study embedded in a cluster randomised controlled trial (cRCT) to evaluate the attrition, fabric integrity and insecticidal durability of Interceptor® G2 (alpha-cypermethrin-chlorfenapyr) and Royal Guard® (alpha-cypermethrin–pyriproxyfen), compared to Interceptor® (alpha-cypermethrin) in Benin. Methods: A total of 2428 study nets in 1093 randomly selected households in five clusters per arm of the cRCT were monitored for ITN attrition and fabric integrity every 6–12 months post-distribution. Householders were further surveyed to investigate non-study net use and their preference for ITN fabric types used in the study nets. A second cohort of 120 nets per ITN type were withdrawn every 12 months and assessed for chemical content and insecticidal activity in laboratory bioassays. Alpha-cypermethrin bioefficacy was investigated using the susceptible Anopheles gambiae Kisumu strain, and chlorfenapyr and pyriproxyfen bioefficacy were investigated using the pyrethroid-resistant Anopheles coluzzii Akron strain. Net pieces were tested in WHO cone bioassays and tunnel tests for alpha-cypermethrin and in tunnel tests for chlorfenapyr; pyriproxyfen activity was assessed in cone bioassays as the reduction in fertility of blood-fed survivors using ovary dissection. Bioefficacy was expressed as the proportion of ITNs passing predetermined WHO criteria, namely knock-down ≥ 95% or 24/72 h mortality ≥ 80% or reduction in fertility ≥ 50%. Results: Overall ITN survivorship was 52% at 24 months and fell to 15% at 36 months. Median ITN survival time was lower with Royal Guard® relative to Interceptor® [1.6 vs 2.3 years; hazard ratio (HR) 1.49, 95% confidence interval (CI) 1.36–1.66; p < 0.001] and Interceptor® G2 (1.6 vs 2.1 years; HR 1.33, 95% CI 1.20–1.47; p < 0.001). Householders overwhelmingly preferred polyester nets over polyethylene nets (96%), and more Royal Guard® nets were replaced with spare polyester nets from previous campaigns. All Royal Guard® nets passed efficacy criteria for alpha-cypermethrin at all time points (100%) while ITN pass rates after 24 months had fallen to < 40% for pyriproxyfen and chlorfenapyr. The chemical content analysis showed a higher loss rate of the non-pyrethroid insecticides relative to the pyrethroids in each dual ingredient AI ITN; 74% vs 47% for Royal Guard® and 85% vs 63% for Interceptor® G2 at 36 months. Conclusions: The median ITN survival time for Interceptor® G2 (2.1 years) and Royal Guard® (1.6 years) in Benin is substantially lower than 3 years. Royal Guard® nets were discarded more quickly by householders, partly due to their low preference for polyethylene nets. The insecticidal activity of the non-pyrethroid insecticides in both dual AI ITNs was short-lived compared to alpha-cypermethrin. The results corroborate the findings from the cRCT conducted in Benin. [ABSTRACT FROM AUTHOR]

The population density of the domesticated bee, Apis mellifera is affected on a large scale by pesticide application and climate changes. Furthermore, contamination of bee flora with insecticide residue is another cause of honeybee mortality. The current study assessed the toxicity of five insecticides, namely bifenthrin (Talstar®10EC), endosulfan (Thiodon®35EC), imidacloprid (Confidor®200SL), ethofenprox (Trebon®30EC) and diafenthiuron (Polo®500SC) against haemocytes of the honeybee, A. mellifera under standard laboratory conditions. Analysis for counts of total haemocytes, differential haemocytes, and abnormalities was determined for larvae, pupae, and adult worker bees of A. mellifera. The haemolymph samples were assessed soon after, 30 and 60 min for selected insecticides applied at a concentration of recommended field doses. The total count of haemocytes was found to be significantly maximum in larval and pupal stages (35818 cells/mm3, 3387 cells/mm3) while lowest (5493 cells/mm3) in adult workers, but differential counts of haemocytes remained somewhat insignificant for all insecticides applied. Variation of total haemocytes count of honeybee resulted for all tested insecticides. Results revealed an increase in haemocytes count (6662 cells/mm3, 7237 cells/mm3, 7081 cells/mm3) of adult honeybees exposed to diafenthiuron, ethofenprox, and imidacloprid soon after application; however, these counts dropped (4506 cells/mm3, 4262 cells/mm3, 3481 cells/mm3, 4325 cells/mm3) after sixty minutes of application for all tested insecticides except for bifenthrin when compared with the untreated adult honeybee. While for differential count, granulocytes and plasmatocyte numbers increased in adult worker A. mellifera after the application of insecticides. Haemocytes immune response to insecticides exhibited abnormalities of various degrees, such as denucleation, cell shape distortion and agglutination. The findings indicate that insecticides influence the immunity of A. mellifera by altering of total and differential count of haemocytes, possibly leading to increased mortality and loss of the colony. [ABSTRACT FROM AUTHOR]

Soil and plant contamination with pesticides and heavy metals have significant effects on human health. There may be an interaction effect (synergistic or antagonistic) between them that can increase the risk of their presence in certain amounts. A pot experiment was conducted using four pesticides (acetamiprid, emamectin benzoate, imidacloprid, and thiamethoxam) applied on Lew mallow (Chorcoruis olitorus) plants grown on contaminated and uncontaminated soils. Some heavy metals and pesticide residues were determined. Treating plants with different pesticides increased the soil content of pesticide residues, and the increases were much higher in previously contaminated soils compared with the uncontaminated ones. Soil content of pesticide residues in contaminated soil can be arranged in descending order as follows: acetamiprid > thiamethoxam > imidacloprid > emamectin benzoate with increases by 707, 373, 287, and 124%, respectively, compared to the control. The highest antagonism was found between Acetamiprid and soil Zn, Emamectin benzoate and soil Pb, Imidacloprid and Mn in soil and plant, Thiamethoxam and plant Zn. The highest synergistic relationships were found between Acetamiprid with Pb and Ni in plant, emamectin benzoate with Mn and Cd, in soil and plant’s Mn, imidacloprid and plant Zn, thiamethoxam and Pb in soil and Cd in plant. [ABSTRACT FROM AUTHOR]

The functional and structural features of microbial load in soil are influenced by the presence of insecticides. This study examined the impact of two organophosphorus insecticides, dimethoate and parathion on the microbial load of soil. The colony count of fungi, actinomycetes, bacteria, and nitrogen fixing bacteria was reduced after insecticides application at 7 and 14 days, but at 28 days the colony count began to increase. The growth of two white rot fungi including Pleurotus sajor-caju and Phanerochaete chrysosporium was affected by parathion, which was reflected by a decrease in colony radius to 1.85±0.05 and 0.75±0.06 cm, respectively, and by dimethoate, reflected by a decrease in colony radius to 3.33±0.12 and 1.85±0.05 cm, respectively at 40 mg/L compared to colony radius at control 7.90±0.12 and 7.50±0.06 cm, respectively. The applied low concentration (10 mg/L) encouraged P. sajor-caju and P. chrysosporium to remove up to 87.7% and 81.8% of dimethoate, respectively, and 69.20 and 68.30% of parathion, respectively compared with the decomposition at high dose (40 mg/L) at 28 days. The presence of insecticides induced the production of ligninolytic enzymes lignin peroxidase, laccase, and manganase peroxidase. [ABSTRACT FROM AUTHOR]

The agronomic benefits of pesticides combined with amino acid application to increase rice production have been recognized, but they are still not well-known for greenhouse gas (GHG) emissions and mitigation in irrigated paddy fields. Thus, this study was conducted to investigate the combined effects of pesticide and amino acid application on rice yield and methane (CH4) emissions in a Korean rice paddy. A field experiment was conducted with five levels: none (no pesticide application, T1), different conventional practices (combined application of insecticides and fungicide, T2 and T3), and GroMore® programs (combined application of insecticides, fungicides, and amino acids, T4 and T5). Rice grain yield and yield components were obtained using agronomic measurements. To determine the greenhouse gas intensity (GHGI) of each treatment, CH4 emissions were measured throughout the rice growing period. Results showed that the chemical applications in combination with amino acids in T4 obtained a higher grain yield and number of panicles per plant compared to T1, T2, and T3, while T4 and T5 showed no difference on filled spikelets except for T2. T3 and T5 showed lower respective cumulative CH4 emissions by 30% and 32% during the entire rice growing season, compared to no chemical application (T1). Meanwhile, N2O emissions were negligible in all treatments because the paddy field was flooded most of the growing season. The results of the impact of GroMore® programs on relatively higher grain yield and lower GHG emissions are presented. In conclusion, the application of pesticides combined with amino acids obtained lower GHGI values. [ABSTRACT FROM AUTHOR]

Simple Summary: As a promising substitute for chemical insecticides, β-asarone has a broad application prospect in the field of crop protection. In order to improve the insecticidal activity of β-asarone, a series of derivatives were prepared by active substructure splicing strategy, and their insecticidal activities were evaluated. Compound 10, containing the 2-chloropyridine functional group, had the strongest insecticidal activity against the small brown planthopper (SBPH), Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae), which was 8.31 times higher than that of β-asarone. The ABC transporter gene MDR49 might be a candidate insecticidal target of compound 10. Furthermore, compound 10 showed excellent efficacy against Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and Tetranychus cinnabarinus (Boisduval) (Acarina: Tetranychidae). The small brown planthopper (SBPH), Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae), is an increasing threat to Gramineae crops, posing significant risks to both the environment and food safety. β-asarone, as a promising green alternative to chemical insecticides, possesses wide application prospects in the crop protection field. To enhance the insecticidal activity of β-asarone, a series of derivatives were prepared through an active substructure splicing strategy, and their insecticidal activities against SBPH were evaluated. Among the 7 commercial compounds with chemical structures similar to β-asarone and 12 structural derivatives of β-asarone, compound 10, which incorporates the 2-chloropyridine functional group from flupyrimin, exhibited the most potent insecticidal activity against SBPH, with an 8.31-fold increase in insecticidal activity compared to β-asarone. Furthermore, transcriptome analysis showed that among the selected genes that may play important roles in insecticidal activity, an ABC transporter gene, MDR49, was most significantly down-regulated. MDR49 was highly expressed in the 4th-instar nymphs, with the highest expression level in the fat body, midgut, and abdomen. RNA interference (RNAi) against MDR49 significantly reduced susceptibility to compound 10 in SBPH, which revealed that MDR49 may be the candidate insecticidal target of compound 10. Additionally, the insecticidal spectrum revealed that compound 10 showed excellent efficacy against Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and Tetranychus cinnabarinus (Boisduval) (Acarina: Tetranychidae). This study indicates that compound 10 could be further developed as a novel eco-friendly pesticide. [ABSTRACT FROM AUTHOR]

Simple Summary: The widespread use of broad-spectrum insecticides reduces the capabilities of ecological self-regulation of phytophages in agrocoenoses and in the adjacent natural territories. Those ecosystems suffer disruption of trophic relations that have been forming over long periods of time. At the same time, the numbers of non-target invertebrates affected by pesticides are declining. Pirimiphos-methyl is one of the cheapest, most effective, and widely used insecticides in the world. Its effect on invertebrate species is useful for agriculture; however, its effect on arthropods that improve soil fertility remains virtually unstudied. This article establishes that this insecticide can have a strong effect on some species useful for plant growing and a weak effect on others. As a result of such an effect of pirimiphos-methyl, the taxonomic structure of invertebrate communities in agrocenoses should change dramatically. The use of this insecticide in fields gives an advantage to species that are relatively more resistant to it and causes a faster disappearance of sensitive invertebrate species. The effects of pirimiphos-methyl have previously been assessed on blood-sucking insect species, pollinating insects, and target crop pest species. The sensitivity of non-target zoophagous and saprophage species to this insecticide remains largely unstudied. In laboratory conditions, we assessed the susceptibility of 43 species of invertebrates to pirimiphos-methyl. The most tolerant species to this insecticide were Pyrrhocoris apterus (LC50 measured over 60 mg/m2), Cylindroiulus truncorum, Pterostichus niger, Harpalus rufipes, Lithobius forficatus, and Carabus hortensis (LC50 ranged from 25 to 50 mg/m2). Average tolerance to pirimiphos-methyl was displayed by Ophonus rufibarbis, Teuchestes fossor, Silpha carinata, Badister sodalis, Rugilus rufipes, Phosphuga atrata, Porcellio laevis, Pterostichus oblongopunctatus, Aphodius foetens, Lasius fuliginosus, Oxypselaphus obscurus, Platydracus fulvipes, Myrmica ruginodis, Xantholinus tricolor, and Megaphyllum sp. (LC50 for those species ranged from 12 to 24 mg/m2). Higher sensitivity to this insecticide was seen for Amara nitida, Leistus ferrugineus, Harpalus xanthopus winkleri, Philonthus nitidus, Pterostichus melanarius, Harpalus latus, Limodromus assimilis, Philonthus decorus, Tachinus signatus, Ponera coarctata, Carabus convexus, Philonthus coprophilus, Philonthus laevicollis, Platydracus latebricola, Labia minor, and Carabus granulatus (LC50 for those species ranged from 6 to 12 mg/m2). The greatest sensitivity to pirimiphos-methyl was observed in Hister fenestus, Drusilla canaliculata, Bisnius fimetarius, Oxytelus sculptus, Lasius niger, and Lasius flavus (LC50 ranged from 0.4 to 6 mg/m2). We found a relationship between the parameters of bodies of invertebrates (the average body length and dry body mass) and sensitivity to pirimiphos-methyl. With an increase in body sizes of invertebrates, the tolerance to the insecticide increased (per each mm of body length, LC50 increased by 0.82 mg/m2 on average). We identified no relationship between the trophic specialization and sensitivity to the insecticide. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigated the behavioral asymmetries and mating success of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) under sublethal exposures to α-cypermethrin. Control males exhibited a right-side bias, which increased the likelihood of successful copulation, especially when head butts preceded mounting. A similar pattern was observed for LC10-exposed males, though their success rate slightly declined. In females, the right-side approach also enhanced copulation success. The direction of approach and mounting influenced the time required for key mating behaviors like mate detection and mounting. Males exposed to LC30 of α-cypermethrin needed a longer time for mate detection compared to control and LC10, especially when approaching from the back or front side. Females of the LC30 group were also influenced, with shorter copulation times when approaching from the right. These findings demonstrate that α-cypermethrin affects both mating success and the duration of related behaviors. Sublethal exposure to insecticides can adversely impact various biological and behavioral characteristics of insects. Although α-cypermethrin has been previously tested for its effects on control of Alphitobius diaperinus, there is no knowledge about the effect of this insecticide on its behavioral asymmetries and mating success. Μales at all exposures (control, LC10, and LC30), that first approached their mate, showed right-biased tendency (approached their mate from their right side) in mate recognition. Females, however, showed variation in this behavior between the three exposures. Right-biased tendency of males in all treatment scenarios led to a higher percentage of successful copulations compared to the three other directions. For males that first approached their mate, the insecticide did not affect their lateralization of the first approach but did affect their copulation success. The duration of copulation time was reduced after the exposure to the insecticide, with the longest duration noted in the control females (63.0 s) and the lowest in the α-cypermethrin LC30 females (46.9 s). Moreover, at the α-cypermethrin LC10 exposure, mate recognition time was reduced, as opposed to α-cypermethrin LC30 exposure where mate recognition time was increased. These results can be further utilized to uncover the behavioral impacts of insecticides, enhancing the effectiveness of pest management in warehouses and poultry production facilities. [ABSTRACT FROM AUTHOR]

Botanical insecticides are the origin of all insecticidal compounds. They have been widely used to control pests in crops for a long time. Currently, the commercial production of botanical insecticides extracted from plants is limited because of insufficient raw material supply. Synthetic biology is a promising and effective approach for addressing the current problems of the production of botanical insecticides. It is an emerging biological research hotspot in the field of botanical insecticides. However, the biosynthetic pathways of many botanical insecticides are not completely elucidated. On the other hand, the cytotoxicity of botanical pesticides and low efficiency of these biosynthetic enzymes in new hosts make it still challenging for their heterologous production. In the present review, we summarized the recent developments in the heterologous production of botanical insecticides, analyzed the current challenges, and discussed the feasible production strategies, focusing on elucidating biosynthetic pathways, enzyme engineering, host engineering, and cytotoxicity engineering. Looking to the future, synthetic biology promises to further advance heterologous production of more botanical pesticides. [ABSTRACT FROM AUTHOR]

We report a convergent synthesis of heteroaryl/aryl-annulated pyridine and quinoline derivatives by a metal-free Povarov reaction. para -Toluene sulfonic acid was used as the catalyst in this reaction, which produced the products in good yields from the corresponding aromatic amines and ethyl vinyl ether. A pyridocoumarin and a pyridopyrimidine product were evaluated for their mosquito larvicidal activity against the third instar larvae of the dengue vector mosquito Aedes aegypti. Examination of morphological changes in the larvae showed damage to the target body part after treatment with both the pyridocoumarin and pyridopyrimidine products at the LC50 concentrations. [ABSTRACT FROM AUTHOR]

In this paper, we formulate and analyze a compartmental model of visceral leishmaniasis (VL). We validate our model by calibrating it to the yearly VL incidence data for India and Bangladesh. The proposed model's basic reproduction number ( R 0 ) has been derived and estimated. We have proved the existence of backward bifurcation in our system. The phenomenon of backward bifurcation has public health implications because the classical requirement of R 0 < 1 , while necessary, is no longer sufficient for effective disease control (or elimination). In such a (backward bifurcation) situation, the initial sizes of the model's subpopulations (state variables) would determine the effectiveness of disease control or elimination. As a result, it is the first attempt to represent and study VL disease dynamics using active case detection (ACD) as a control strategy, although a few experimental studies have been conducted to evaluate ACD in disease transmission. We use sensitivity analysis to investigate the effects of the model's controllable parameters for the basic reproduction number. We found that σ 1 , σ 2 , σ 3 (monitoring rate to infected individuals) have negative impacts on R 0 . The numerical result suggests that the ACD strategy can be useful for the VL elimination program. Due to a small increment in the monitoring rate, the dynamic behavior of infected individuals dramatically decreased. Successful employment of ACD strategy may reduce more than 60–80% symptomatic and post kala-azar dermal leishmaniasis (PKDL) individuals. We found that healthcare organizations should prioritize ACD in symptomatic and PKDL individuals over asymptomatic individuals. We also observed that the use of only culling effect to the reservoirs is not beneficial to society in the control of VL, but spraying of insecticides and the use of treated bednets can be effective control strategies to curtail the outbreak of the disease. [ABSTRACT FROM AUTHOR]

A collection of ring distorted analogue of Nootkatone including 6 CTD (Complex to Diversity) compounds and 9 SAR (Structure Activity Relationship) compounds were synthesized utilizing the carbonyl group as a starting reaction point. [ABSTRACT FROM AUTHOR]

In the scientific toxicity evaluations of insecticides against larvae of Tuta absoluta (Tomato pinworm), a leaf coverage rate of 100 % or very close to this value is sought to guarantee the contact of the insect with the chemical product. However, deposition can change according to the different pesticide application methods used in field productions; consequently, interfering with pest control. From this perspective, this study evaluated the mortality of Tuta absoluta and the deposited volume dispersion on tomato leaflets as a function of droplet sizes and the method of chemical treatment with abamectin. For that purpose, an experiment was conducted in a randomized block design with five treatments and five replications. The treatments consisted of different chemical treatment methods: immersion, hydraulic spraying with three droplet sizes, and pneumatic spraying, in which the following parameters were evaluated: larval mortality, volume retained (deposition), surface density of active ingredient, droplet density, and coverage percentage. The different chemical treatments with abamectin provided larval mortality rates above 90%. Furthermore, the highest mortality values (98% and 95.9%) were associated; respectively, with the sprayings that provided the highest droplet densities: hydraulic spraying with average droplets (181 droplets cm-2) and pneumatic spraying with very fine droplets (256 droplets cm-2), the latter using an application volume 84% lower (80 L ha-1) than the lowest volume recommended by the manufacturer (500 L ha-1). [ABSTRACT FROM AUTHOR]

Insecticide resistance is widespread in global bed bug populations. Both common bed bugs and tropical bed bugs are pyrethroid-resistant among most field populations. Plant-based products and nonconventional pesticides offer minimal-risk strategies for managing bed bug resistance, but this strategy has yet to be formally evaluated in Cimex hemipterus (F.) (Hemiptera: Cimicidae). Here, several commercial plant-based formulations (Cedarcide, EcoRaider (also known as EcoVenger), EcoSMART, and Bio-D), a novel product, Provecta, and a pyrethroid insecticide, Pesguard FG161 were tested against pyrethroid-susceptible and resistant strains of C. hemipterus using direct spray, residual exposure, and egg dipping assays. Direct spray treatments outperform residual applications against all tested bed bug strains. Cedarcide exhibits the highest consistency in eliminating bed bugs, followed by EcoRaider, EcoSMART, and Provecta that outperform Bio-D and Pesguard FG161. In comparison to Pesguard FG161, all plant-based insecticide products and Provecta showed higher efficacy against pyrethroid-resistant strains. Although effective, product efficacy varies in terms of speed. Cedarcide kills all bed bugs within 1 min after spraying; however, other products can take up to 9 days to achieve 100% mortality. The efficacy of all products was reduced when evaluated on fabric surface (42%–65% mortality). Cedarcide and EcoRaider reduced egg hatchability by 37%–73% and 47%–70%, respectively. This study suggests that certain plant-based insecticides and an unconventional insecticide can serve as alternative direct spray treatments for managing tropical bed bugs, though their residual effects are limited. [ABSTRACT FROM AUTHOR]

Plant protection products derived from plant material are proposed to be a sustainable alternative to conventional synthetic chemical pesticides. This study determines the efficacy of a commercially available bioinsecticide based on garlic (Allium sativum L.; Asparagales: Amaryllidaceae) extract against vine weevil (Otiorhynchus sulcatus F.; Coleoptera: Curculionidae) eggs and larvae in contact, fumigation and a combination of contact and fumigation bioassays under laboratory conditions. Results showed that garlic significantly reduced egg hatch rate compared to the control group when applied as a fumigant. Similarly, the egg hatch rate was reduced compared to the control group when garlic was applied as combined contact and fumigant applications. No effect was observed when the garlic product was applied as a contact application. The bioinsecticide significantly reduced larval survival when either contact or fumigant applications were used. A combined contact and fumigant effect was shown also when vine weevil eggs were exposed to the bioinsecticide for 30 days in plastic containers containing growing media. The number of larvae recovered after this period was significantly reduced compared to the control group. This study demonstrates the potential of garlic-based bioinsecticides, such as Pitcher GR, for vine weevil control. Further studies are, however, needed to determine the efficacy of such bioinsecticides under field conditions and investigate how these products can be most effectively used as a part of a wider vine weevil integrated pest management program. [ABSTRACT FROM AUTHOR]

The clover seed weevil, Tychius picirostris Fabricius (Coleoptera: Curculionidae), is a major pest in Oregon white clover seed crops. Reliance on synthetic pyrethroid insecticides and limited availability of diverse modes of action (MoAs) has increased insecticide resistance selection in regional T. picirostris populations, emphasizing the need to evaluate novel chemistries and rotational strategies for effective insecticide resistance management (IRM). The efficacy of 8 foliar insecticide formulations for managing T. picirostris adult and larval life stages was determined in small and large-plot field trials across 2 crop years. In both years, bifenthrin (Brigade 2EC), the grower's standard, showed negligible adult and larval suppression. Insecticide formulations with isocycloseram and cyantraniliprole active ingredients reduced adult and larval populations when applied at BBCH 59–60 (prebloom) and BBCH 65–66 (full bloom) growth stages, respectively. While differences in T. picirostris abundance were observed among insecticide treatments, seed yield differences were not detected in large-plot trials. Larval abundance was correlated with reduced seed yield, and an economic threshold of ≥3 larvae per 30 inflorescences was determined as a conservative larval threshold to justify foliar applications of diamide insecticides. Additional commercial white clover seed fields were surveyed to compare larval scouting techniques, including a standard Berlese funnel and a grower's do-it-yourself funnel. Both larval extraction techniques were correlated and provided similar estimates of larval abundance. These findings demonstrate new MoAs, optimal insecticide application timing, and larval monitoring methods that can be incorporated into an effective T. picirostris IRM program in white clover seed crops. [ABSTRACT FROM AUTHOR]

The German cockroach, Blattella germanica (L.) (Blattodea: Ectobiidae), is a ubiquitous pest in affordable housing. They represent a major threat to human health due to their contribution of asthma-exacerbating allergens and the potential to transfer pathogenic microorganisms indoors. Despite well-documented pyrethroid resistance, pyrethroid-based broadcast residual insecticide products are often used by residents to control cockroaches in their homes. Additionally, there is little empirical independent testing of these products. Thus, it remains unclear how effective these commonly used do-it-yourself products are at controlling German cockroaches. This study represents a comprehensive examination of the efficacy of these products with direct, limited, and continuous exposure assays on a variety of common household surfaces on field populations of cockroaches with varying levels of pyrethroid resistance. While most products performed well when applied directly to test insects, mortality was substantially lower across all surfaces with limited exposure (30 min). In continuous exposure assays on a nonporous surface, products took at least 24 hr to cause 100% mortality in a field population, with some products taking up to 5 d to achieve 100% mortality. The findings of this study demonstrate a lack of residual efficacy from common pyrethroid-based consumer-use pesticides products. Given that it is not feasible to find and treat every cockroach in a home directly, the residuality of spray-based formulations is critical for products designed to control German cockroaches. Without residual efficacy, as shown in the consumer aerosol and spray products tested, we expect these products to add little to no value to cockroach control. [ABSTRACT FROM AUTHOR]

In the tea-planting process, insecticides are commonly combined, potentially prolonging the pre-harvest interval and heightening the risk of dietary exposure. This study focused on three frequently used insecticides in tea cultivation: thiamethoxam, bifenthrin, and dinotefuran, aiming to investigate their dissipation behaviors and associated dietary risks upon individual and simultaneous application. The dissipation kinetics of thiamethoxam, bifenthrin, and dinotefuran were successfully characterized by first-order kinetics, yielding respective half-lives of 5.44, 9.81, and 10.16 days. Upon joint application, the dissipation half-lives of thiamethoxam and bifenthrin were notably prolonged compared with their individual applications, resulting in final concentrations after 28 days that were correspondingly elevated by 1.41 and 1.29 times. Assessment of the dietary intake risk revealed that the chronic and acute risk quotients associated with thiamethoxam and bifenthrin escalated by 1.44–1.59 times following their combined application. Although dietary risks associated with Tianmuhu white tea, as determined by the exposure assessment model, were deemed acceptable, the cumulative risks stemming from pesticide mixtures across various dietary sources warrant attention. Molecular docking analyses further unveiled that thiamethoxam and bifenthrin competitively bound to glutathione S-transferase (GST) at amino acid residues, notably at the 76th GLU and the 25th PHE, pivotal in the metabolism and absorption of exogenous substances. Moreover, the interactions between P-glycoprotein and pesticides during transport and absorption were likely to influence dissipation behaviors post-joint application. This research offers valuable insights and data support for optimizing joint pesticide application strategies and assessing risks associated with typical pesticides used in tea cultivation. [ABSTRACT FROM AUTHOR]