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Insect growth regulators (IGRs) have been playing a major role in the effective management of a range of stored product insect pests including species that have developed resistance to major groups of insecticides, such as organophosphates (OPs) and synthetic pyrethroids (SPs). In the present study, we evaluated the efficacy of S-methoprene alone and in combination with piperonyl butoxide (PBO), an adjuvant component of insecticides for synergy, against two strains, Lab-S (susceptible) and Met-R (Methoprene resistant) of an economically important pest species, the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). Adults of both Lab-S and Met-R strains were exposed to wheat treated with multiple concentrations of S-methoprene ranging from 0.001 to 0.01 and 10 to 60 mg/kg, respectively, alone and in combination with PBO. A variety of concentrations, including 0.27, 0.53, 0.80, and 1.07 g/kg, were evaluated for PBO. Mortality of adults and percent reduction in progeny were assessed after 14 and 65 days of treatment, respectively. As anticipated, the adult mortality rates of both strains were not significantly affected by S-methoprene alone. However, the number of progeny produced confirmed that the Met-R strain exhibited a high level of resistance to S-methoprene alone, with over 50 F1 progeny adults surviving in wheat treated with the maximal rate, 10 mg/kg. In contrast, the toxicity of S-methoprene was increased against the same resistant strain (Met-R), by 0.80 or 1.07 g/kg of PBO in combination treatment, resulting in a significant reduction in progeny numbers (25 adults per container). Although the tested concentrations of S-methoprene and PBO were well above the currently registered rate globally, our results highlight the fact that PBO enhances the toxicity of S-methoprene to some extent, reaffirming that the mode of action of the latter involves the inhibition of mixed-function oxidases (MFOs) and highlights the need for further research into developing potential binary or triplet formulations containing these two active ingredients (AIs). [ABSTRACT FROM AUTHOR]

Insect growth regulators, like S-methoprene, are heavily relied upon worldwide for larval mosquito chemical control due to their target specificity and long-lasting effects. In this study, susceptibility to S-methoprene was evaluated in Culex pipiens, a globally important vector species. Populations from 14 sites throughout the Chicago area with a long history of S-methoprene use and two sites with minimal use in Wisconsin were examined. Using a bioassay methodology and probit analyses, LC50 and LC90 values were calculated and compared to a susceptible laboratory strain to develop resistance ratios, then categorized for resistance intensity. The resistance ratios observed required the addition of another category, termed 'extreme' resistance, indicating resistance ratios greater than 100. 'Low' to 'extreme' levels of resistance to S-methoprene were detected throughout Illinois populations, with resistance ratios ranging from 2.33 to 1010.52. Resistance was not detected in populations where S-methoprene pressure has been very limited. These 'extreme' resistance ratios observed have never been documented in a wild vector species mosquito population. The relationships between historical S-methoprene use, resistance detected with laboratory bioassays, and the potential for field product failure remain unclear. However, the profound resistance detected here demonstrates a potential critical threat to protecting public health from mosquito-borne diseases. [ABSTRACT FROM AUTHOR]

Introduction: Control of the mosquito Aedes albopictus is confounded by its behavior due to females preferring to oviposition in small natural and artificial containers that are often difficult to remove or treat with insecticides. Autodissemination strategies utilizing highly potent insect growth regulators (IGRs) have emerged as promising tools for the control of this container- inhabiting species. The intended goal of autodissemination approaches is to use mosquitoes to self-deliver an IGR to these cryptic oviposition locations. Previous studies have focused on the efficacy of these approaches to impact natural populations, but little focus has been placed on the impacts on mosquitoes when exposed to non-lethal doses of IGRs similar to the levels they would be exposed to with autodissemination approaches. Methods: In this study, the impact of non-lethal doses of pyriproxyfen (PPF) on the reproductive fitness of Ae. albopictus was investigated. Female and male Ae. albopictus mosquitoes were exposed to non-lethal doses of PPF and their fecundity and fertility were measured. To examine the impact of non-lethal doses of PPF, the expression of the ecdysone-regulated genes USP, HR3, and Vg, which are involved in vitellogenesis, was determined. Results: Our results demonstrated a significant reduction in female fecundity and in the blood feeding and egg hatching rates upon exposure to non-lethal doses of PPF. Oocyte development was also delayed in PPF-treated females. Furthermore, exposure to non-lethal doses of PPF altered the expression of the genes involved in vitellogenesis, indicating disruption of hormonal regulation. Interestingly, PPF exposure also reduced the sperm production in males, suggesting a potential semi-sterilization effect. Discussion: These findings suggest that non-lethal doses of PPF could enhance the efficacy of autodissemination approaches by impacting the reproductive fitness of both males and females. However, further research is needed to validate these laboratory findings in field settings and to assess their practical implications for vector control strategies. [ABSTRACT FROM AUTHOR]

Entomopathogenic nematodes (EPNs) are biocontrol agents against various insect pests in the world for their characteristics of infectivity and compatibility with different control agents. Several environmental factors directly affect the EPN populations in the soil, as well as the resistance of certain insect pests to EPN penetration. Under these circumstances, EPNs cannot exhibit high virulence on the targeted insect pest; therefore, they should be applied in combination with some of the other control agents. In this context, the main objective of this review was to summarize the current knowledge on the compatibility of EPNs with various agrochemicals and examine the interactions of EPNs and these agents in combined application against insect pests. This review highlighted firstly the growing research attention worldwide concerning the compatibility of EPNs with other control agents. Then, the compatibility of EPNs with synthetic insecticides of different classes was reviewed. In this regard, also, some special attention has been paid to herbicides, fungicides and nematicidal compounds as possible compatible agents to EPNs. Later on, the current review discussed the importance of EPN application in combination with different insect growth regulators, juvenoids, ecdysteroids and chitin synthesis inhibitors. An overview of agricultural management practices and soil amendments in relation to EPNs was provided including the compatibility of EPNs with organic and inorganic fertilizers. Some attention has been paid to the EPN tolerance and susceptibility to heavy metals and other soil chemical pollutants, and EPNs as good bio-indicators of the environmental pollutants. The last aspect was the compatibility of EPNs with crude plant extracts and isolated phytochemicals. In conclusion, a combination of EPNs with compatible agrochemicals is a promising approach to the pest control strategy. EPNs may be combined with various compatible agrochemicals with additive, or preferably synergistic, effects on pest mortality. For this purpose, also, the exposure period should also be taken into consideration, because the exposure of EPNs to agrochemicals for a prolonged exposure period may turn their interaction to antagonistic and subsequently low control efficiency against the targeted insect due to the reduction of the EPN viability and infectivity. [ABSTRACT FROM AUTHOR]

Sandfly, Phlebotomus papatasi (Diptera: Psychodidae) is the potential vector of leishmania in Egypt. In this study, an attempt was made to investigate the ultrastructure and histopathological alteration in the midgut of Phlebotomus papatasi post-treatment with methoprene (IGR) and B. sphaericus 6184 and 6446 using transmission electron micrographs (TEM). After 48 h, the TEM of the midgut treated with methoprene (IGR) showed sloughing of the periepithelial layer, and overgrowth of the brush border of the midgut wall. After 48 h post-treatment, B. sphaericus 6184 spores were discovered in the lumen and the bacterium began to enter the microvilli. Certain ultrastructural abnormalities were found in the midgut of treated P. papatasi larvae after 48 h of treatment with B. sphaericus 6446, the cytoplasm was distinguished by many vacuoles and a broken brush border. Using the light microscope, IGR-treated third instar larvae showed brush boundary overgrowth and multifocal disintegration of the midgut wall. Focused areas were sloughed and epithelial cells were dissociated from each other in larvae treated with B. sphaericus 6184. The 3rd instar P. papatasi larvae treated with B. sphaericus 6446 showed clear alterations such as total epithelial cell degradation. These results demonstrated that B. sphaericus 6446 showed the best results and great effect on P. papatasi 3rd instar larvae. More research is needed to establish the appropriate control strategies for the many leishmaniasis vectors in their various ecological environments. [ABSTRACT FROM AUTHOR]

Cockroaches, widespread pests found in metropolitan areas, are known as vectors of various disease agents, including viruses, fungi and antibiotic‐resistant bacteria, as well as causing allergies in humans. Insect growth regulators have been used in pest management for several decades. These insecticides disrupt insect development and reproduction. Chitin synthesis inhibitors interfere with chitin biosynthesis in insects, causing abortive moulting and mortality, as well as inhibiting egg fertility, and larval hatching in insects. In this research, we evaluated the various effects of diflubenzuron, a chitin synthesis inhibitor, on synthetic pyrethroid‐resistant German cockroach (Blattella germanica L. Blattodea: Ectobiidae), including ootheca production, oothecal viability, ootheca incubation time, the number of nymphs emerging from the ootheca and survivorship of nymphs. The cockroaches were fed diets that contained diflubenzuron, which was added to solid bait (impregnated fish food) and ingestible aqueous bait (impregnated cotton). Three concentrations (0.5%, 1% and 2%) were used in the experiments. As a result, diflubenzuron treatment led to ootheca production ranging from 60% to 100%; statistically, no difference was found between the treatment and the control groups. The number of nymphs emerging from the first and second ootheca was reduced by 40%–100% in the diflubenzuron‐treated groups compared with the control. Nymphs exposed to diflubenzuron‐impregnated solid bait and ingestible aqueous bait experienced mortality exceeding 92.1% and 66.27% within 15 days, respectively. In conclusion, diflubenzuron is a potential insecticide for use in cockroach baits to control B. germanica, as it caused high nymphal and embryonic mortality in the synthetic pyrethroid‐resistant population and decreased the number of nymphs emerging from the ootheca. [ABSTRACT FROM AUTHOR]

Simple Summary: As an invasive pest, whitefly causes great losses in agricultural production, and resistance increases in whitefly to chemical insecticides are an important problem in plant protection. Our study revealed that imidacloprid stress inhibits the expression of AKH, thereby increasing ROS and the expression levels of the resistance gene CYP6CM1 and upstream regulatory factors in Bemisia tabaci. AKH silencing by RNA interference affected the resistance of whiteflies to imidacloprid. These results provide insight into the resistance mechanism in whitefly. Synthetic insecticides used to control Bemisia tabaci include organophosphorus, pyrethroids, insect growth regulators, nicotinoids, and neonicotinoids. Among these, neonicotinoids have been used continuously, which has led to the emergence of high-level resistance to this class of chemical insecticides in the whitefly, making whitefly management difficult. The adipokinetic hormone gene (AKH) and reactive oxygen species (ROS) play roles in the development of insect resistance. Therefore, the roles of AKH and ROS in imidacloprid resistance in Bemisia tabaci Mediterranean (MED; formerly biotype Q) were evaluated in this study. The expression level of AKH in resistant B. tabaci MED was significantly lower than that in sensitive B. tabaci (MED) (p < 0.05). AKH expression showed a decreasing trend. After AKH silencing by RNAi, we found that ROS levels as well as the expression levels of the resistance gene CYP6CM1 and its upstream regulatory factors CREB, ERK, and P38 increased significantly (p < 0.05); additionally, whitefly resistance to imidacloprid increased and mortality decreased (p < 0.001). These results suggest that AKH regulates the expression of resistance genes via ROS in Bemisia tabaci. [ABSTRACT FROM AUTHOR]

Insect growth regulators (IGRs) have been developed as effective control measures against harmful insect pests to disrupt their normal development. This study is to propose a mathematical model to evaluate the cost-effectiveness of IGRs for pest management. The key features of the model include the temperature-dependent growth of insects and realistic impulsive IGRs releasing strategies. The impulsive releases are carefully modeled by counting the number of implements during an insect’s temperature-dependent development duration, which introduces a surviving probability determined by a product of terms corresponding to each release. Dynamical behavior of the model is illustrated through dynamical system analysis and a threshold-type result is established in terms of the net reproduction number. Further numerical simulations are performed to quantitatively evaluate the effectiveness of IGRs to control populations of harmful insect pests. It is interesting to observe that the time-changing environment plays an important role in determining an optimal pest control scheme with appropriate release frequencies and time instants. [ABSTRACT FROM AUTHOR]

Mosquitoes and mosquito-borne illnesses remain one of the major public threats which is intensified by the emergence and resurgence of new and existing vector species. Mosquito control is often the only sustainable measure to combat mosquito-borne diseases due to lack or limitation in vaccinations and/or effective medications. Among mosquito control interventions, larviciding to target aquatic habitats is more cost-effective and feasible as opposite to adulticiding which focuses on air-borne adult stages. The available mosquito larvicides are at a historical low owing to numerous reasons. Currently, available larvicides are based on microbial agents, insect growth regulators (IGRs), and a few others of botanical origins. In the IGR arena, juvenile hormone mimics have drawn a lot of attention in research, development, and application. Pyriproxyfen (PPF) was first developed in the early 1970s by Sumitomo Chemical Co. Ltd. (SCC). Its great potential and safety profile to control a wide variety of arthropod pests have been recognized ever since. The current review provides general information and highlights the following advantages of PPF: unique mode of action to mimic the action of natural juvenile hormone (JH) in mosquitoes, broad target spectrum against many mosquito species, the highest bioactivity against mosquitoes as compared with all other known or potential mosquito larvicides, low risk in resistance development and lack of cross-resistance with other larvicides studied, and high activity against species in Stegomyia group. Recently, more potential uses of PPF against adult mosquitoes in bait, barrier treatment, and bed net treatment have been on the horizon. Environmental concerns about PPF residues and their metabolites are also discussed. In general, PPF is one of the critical tools in combating mosquito species of public health importance for now and the foreseeable future. [ABSTRACT FROM AUTHOR]

Background: Nets containing pyriproxyfen, an insect growth regulator that sterilizes adult mosquitoes, have become available for malaria control. Suitable methods for investigating vector susceptibility to pyriproxyfen and evaluating its efficacy on nets need to be identified. The sterilizing effects of pyriproxyfen on adult malaria vectors can be assessed by measuring oviposition or by dissecting mosquito ovaries to determine damage by pyriproxyfen (ovary dissection). Method: Laboratory bioassays were performed to compare the oviposition and ovary dissection methods for monitoring susceptibility to pyriproxyfen in wild malaria vectors using WHO bottle bioassays and for evaluating its efficacy on nets in cone bioassays. Blood-fed mosquitoes of susceptible and pyrethroid-resistant strains of Anopheles gambiae sensu lato were exposed to pyriproxyfen-treated bottles (100 μg and 200 μg) and to unwashed and washed pieces of a pyriproxyfen long-lasting net in cone bioassays. Survivors were assessed for the sterilizing effects of pyriproxyfen using both methods. The methods were compared in terms of their reliability, sensitivity, specificity, resources (cost and time) required and perceived difficulties by trained laboratory technicians. Results: The total number of An. gambiae s.l. mosquitoes assessed for the sterilizing effects of pyriproxyfen were 1745 for the oviposition method and 1698 for the ovary dissection method. Fertility rates of control unexposed mosquitoes were significantly higher with ovary dissection compared to oviposition in both bottle bioassays (99–100% vs. 34–59%, P < 0.05) and cone bioassays (99–100% vs. 18–33%, P < 0.001). Oviposition rates of control unexposed mosquitoes were lower with wild pyrethroid-resistant An. gambiae s.l. Cové, compared to the laboratory-maintained reference susceptible An gambiae sensu stricto Kisumu (18–34% vs. 58–76%, P < 0.05). Sterilization rates of the Kisumu strain in bottle bioassays with the pyriproxyfen diagnostic dose (100 μg) were suboptimal with the oviposition method (90%) but showed full susceptibility with ovary dissection (99%). Wild pyrethroid-resistant Cové mosquitoes were fully susceptible to pyriproxyfen in bottle bioassays using ovary dissection (> 99%), but not with the oviposition method (69%). Both methods showed similar levels of sensitivity (89–98% vs. 89–100%). Specificity was substantially higher with ovary dissection compared to the oviposition method in both bottle bioassays (99–100% vs. 34–48%) and cone tests (100% vs.18–76%). Ovary dissection was also more sensitive for detecting the residual activity of pyriproxyfen in a washed net compared to oviposition. The oviposition method though cheaper, was less reliable and more time-consuming. Laboratory technicians preferred ovary dissection mostly due to its reliability. Conclusion: The ovary dissection method was more accurate, more reliable and more efficient compared to the oviposition method for evaluating the sterilizing effects of pyriproxyfen on adult malaria vectors in susceptibility bioassays and for evaluating the efficacy of pyriproxyfen-treated nets. [ABSTRACT FROM AUTHOR]

Background: Juvenile hormones (JH) play crucial role in regulating development and reproduction in insects. The most common form of JH is JH III, derived from MF through epoxidation by CYP15 enzymes. However, in the higher dipterans, such as the fruitfly, Drosophila melanogaster, a bis-epoxide form of JHB3, accounted most of the JH detected. Moreover, these higher dipterans have lost the CYP15 gene from their genomes. As a result, the identity of the P450 epoxidase in the JH biosynthesis pathway in higher dipterans remains unknown. Results: In this study, we show that Cyp6g2 serves as the major JH epoxidase responsible for the biosynthesis of JHB3 and JH III in D. melanogaster. The Cyp6g2 is predominantly expressed in the corpus allatum (CA), concurring with the expression pattern of jhamt, another well-studied gene that is crucial in the last steps of JH biosynthesis. Mutation in Cyp6g2 leads to severe disruptions in larval-pupal metamorphosis and exhibits reproductive deficiencies, exceeding those seen in jhamt mutants. Notably, Cyp6g2−/−::jhamt2 double mutants all died at the pupal stage but could be rescued through the topical application of JH analogs. JH titer analyses revealed that both Cyp6g2−/− mutant and jhamt2 mutant lacking JHB3 and JH III, while overexpression of Cyp6g2 or jhamt caused a significant increase in JHB3 and JH III titer. Conclusions: These findings collectively established that Cyp6g2 as the major JH epoxidase in the higher dipterans and laid the groundwork for the further understanding of JH biosynthesis. Moreover, these findings pave the way for developing specific Cyp6g2 inhibitors as insect growth regulators or insecticides. [ABSTRACT FROM AUTHOR]

The integration of untargeted lipidomics approaches in ecotoxicology has emerged as a strategy to enhance the comprehensiveness of environmental risk assessment. Although current toxicity tests with soil microarthropods focus on species performance, that is, growth, reproduction, and survival, understanding the mechanisms of toxicity across all levels of biological organization, from molecule to community is essential for informed decision‐making. Our study focused on the impacts of sublethal concentrations of the insecticide teflubenzuron on the springtail Folsomia candida. Untargeted lipidomics was applied to link changes in growth, reproduction, and the overall stress response with lipid profile changes over various exposure durations. The accumulation of teflubenzuron in organisms exposed to the highest test concentration (0.035 mg a.s. kg–1 soil dry wt) significantly impacted reproductive output without compromising growth. The results suggested a resource allocation shift from reproduction to size maintenance. This hypothesis was supported by lipid shifts on day 7, at which point reductions in triacylglycerol and diacylglycerol content corresponded with decreased offspring production on day 21. The hypermetabolism of fatty acids and N‐acylethanolamines on days 2 and 7 of exposure indicated oxidative stress and inflammation in the animals in response to teflubenzuron bioaccumulation, as measured using high‐performance liquid chromatography–tandem mass spectrometry. Overall, the changes in lipid profiles in comparison with phenotypic adverse outcomes highlight the potential of lipid analysis as an early‐warning tool for reproductive disturbances caused by pesticides in F. candida. Environ Toxicol Chem 2024;43:1149–1160. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Current standard toxicity tests on nontarget soil invertebrates mainly focus on the endpoints survival and reproduction. Such results are likely insufficient to predict effects at higher organizational levels, for example, the population level. We assessed the effects of exposure to the pesticide teflubenzuron on the collembolan Folsomia candida, by performing a full life‐cycle experiment exposing single individuals via contaminated food (uncontaminated control and 0.2, 0.32, 0.48, 0.72, 1.08, and 1.6 mg/kg dry yeast). Several life‐history traits were considered by following the growth and development of newly hatched individuals over a period of 65 days. We assessed survival, body length, time to first oviposition, cumulative egg production, and hatchability of eggs. A two‐stage model was applied to calculate the population growth rate (λ) combined with elasticity analysis to reveal the relative sensitivity of λ to the effects of teflubenzuron on each life‐history parameter. Body length was the least sensitive life‐history parameter (median effective concentration = 1.10 mg teflubenzuron/kg dry yeast) followed by time to first oviposition (0.96 mg/kg), survival (median lethal concentration = 0.87 mg/kg), cumulative egg production (0.32 mg/kg), and egg hatchability (0.27 mg/kg). Population growth decreased with increasing concentrations of teflubenzuron (λ = 1.162/day in control to 1.005/day in 0.72 mg/kg dry yeast, with populations going extinct at 1.08 and 1.6 mg/kg dry yeast). Elasticity analysis showed that changes in juvenile survival had a greater impact on the population growth rate compared with the other life‐history traits. Our study provides a comprehensive overview of individual‐level effects of long‐term exposure to teflubenzuron and integrates these effects to assess the potential risk to collembolan populations. Environ Toxicol Chem 2024;43:1173–1183. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Background & objectives: Insect growth regulators (IGRs) are biological hormone analogue or mimics used as pesticides to inhibit the growth of larva during their molting and skin shedding. This study aimed to test the effect of IGRs on the eggs hatching and post-hatching inhibition of Aedes mosquitoes and understanding its effect in the mosquito breeding habitats for reduction in adult emergence. Methods: Experiments on the evaluation of three insect growth regulators (IGRs) for the control of different stages of Aedes aegypti was carried out during 2020-21. Each experiment consisted of four treatments viz., Pyriproxyfen, Novaluron, and Larvicol at 1.0 ppm and distilled water as a control. All experiments were carried out in completely randomized design (CRD) except eggs which were carried out in factorial design each with three replications. Results: All tested IGRs performed better in affecting eggs, larval and pupal stages of Ae. aegypti. Highest eggs hatching inhibition (80%) of fresh eggs occurred in Pyriproxyfen followed by Novaluron (66%) and lowest in Larvicol (62%). Eggs hatch inhibition of embryonated eggs was lower than fresh eggs. Pyriproxyfen caused 69%, Novaluron 59% and Larvicol 39% eggs hatch inhibition of embryonated eggs. Both Pyriproxyfen and Novaluron performed better in causing 98–100% larval mortality followed by Larvicol (39%). Larval development to pupal stage was completely prevented by both Pyriproxyfen and Novaluron. Although Larvicol resulted in lowest eggs hatch and larval inhibition but prevented pupae to emerge as adults. Results further showed 70–89% mortality of 3rd instar larvae of Ae. aegypti when exposed to Pyriproxyfen and Novaluron solutions after 30 days storage at lab. temperature (27±2°C), RH 70±5. Interpretation & conclusion: None of the IGRs was more effective at the pupal stage but showed carry-on activity of growth inhibition and mortality of the successive stages of development when used against eggs stages. Therefore, we recommend early application of IGRs at mosquito habitats during the beginning and onset of the season when very early stages of mosquitoes are available in the field.

Drosophila suzukii (Diptera: Drosophilidae) is an invasive species that causes great damages to many stone and small fruits, resulting in reduced fruit production and high economic losses. The concern about this pest has led to the research of a wide range of possible control methods. However, the main control strategies are still based in insecticide applications. The efficacy of different insect growth regulators (IGRs), which have better ecotoxicological profile than conventional pesticides, was evaluated to test their feasibility for the control of this pest. When adult flies fed for three days on artificial diet surface-treated with lufenuron, cyromazine or pyriproxyfen, no adult offspring developed. However, adult offspring production progressively recovered when flies were transferred to non-treated diet. When adult flies fed continuously for 19 days on surface-treated artificial diet, lufenuron, cyromazine and pyriproxyfen completely suppressed the production of viable offspring while azadirachtin and tebufenozide reduced offspring production by more than a half compared to the untreated control. Nevertheless, these were transient non-permanent effects since viable offspring was produced shortly after females fed on treated diet were transferred to non-treated diet. The results observed in additional choice and egg-transfer assays indicate a vertical transmission of lufenuron and cyromazine from treated females to their offspring whereas the effect of pyriproxyfen seems to be related to the feeding of larvae on treated diet, although effects on reproductive processes cannot be discarded. In addition, choice assays showed no repellent effect on oviposition by lufenuron, cyromazine and pyriproxyfen. [ABSTRACT FROM AUTHOR]

Simple Summary: Cabbage whitefly (Aleyrodes proletella) is a destructive sucking insect pest of brassica crops, particularly white cabbage and kale. Its importance has been increased over the last decade in many geographic regions, particularly in European countries. The control of cabbage whiteflies largely relies on the application of synthetic insecticides to protect yield if populations reach economic damage thresholds. One class of insecticides to control this pest are cyclic ketoenols targeting acetyl-CoA carboxylase (ACC), an enzyme involved in fatty acid biosynthesis. In 2019, reduced efficacy of ketoenol insecticides at recommended label rates were reported. Subsequently, we collected field samples of A. proletella in different European countries and confirmed the presence of ketoenol resistance in laboratory bioassays. The resistance allele was shown to be an autosomal dominant trait in crossing experiments between susceptible and resistant individuals. RNA sequencing and subsequent analysis revealed a mutation, an amino acid substitution, at the ketoenol binding site in ACC. The mutation has been previously functionally validated to confer high levels of ketoenol insecticide resistance in cotton whiteflies, too. A molecular screening of 49 populations revealed the presence of the mutations in several countries. We recommend the implementation of resistance management strategies for sustainable cabbage whitefly control. Cabbage whitefly, Aleyrodes proletella L., is an invasive hemipteran pest of cruciferous plants, particularly field brassica crops. Its importance has been increased over the last decade, particularly in European countries. The control of cabbage whiteflies largely relies on the application of synthetic insecticides, including tetronic and tetramic acid derivatives such as spiromesifen and spirotetramat (cyclic ketoenol insecticides), acting as insect growth regulators targeting acetyl-CoA carboxylase (ACC). In 2019, reduced efficacy against cabbage whiteflies of ketoenol insecticides at recommended label rates has been reported. Subsequently we collected field samples of A. proletella in different European countries and confirmed the presence of ketoenol resistance in laboratory bioassays. Reciprocal crossing experiments revealed an autosomal dominant trait, i.e., heterozygotes express a fully resistant phenotype. Transcriptome sequencing and assembly of ACC variants from resistant strains revealed the presence of an ACC target-site mutation, A2083V, as previously described and functionally validated in Bemisia tabaci (A2084V in A. proletella). Next, we employed a molecular genotyping assay to investigate the geographic spread of resistance and analyzed 49 populations collected in eight European countries. Resistance allele frequency was highest in the Netherlands, followed by Germany. Finally, we provide a proposal for the implementation of appropriate resistance management strategies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Improving the mating competitiveness and survival of sterile males are direct means to increase the effectiveness of the sterile insect technique (SIT). Some insecticide growth regulators, such as the juvenile hormone analogue (JHA) methoprene, have been used to improve the mating competitiveness of male tephritid flies by reducing their sexual maturation period. However, the application of methoprene reduces fly resistance to stress and decreases survival. Here, we compared the effects of methoprene and pyriproxyfen (PPF), another JHA, in Anastrepha ludens males. PPF is an insect growth regulator that exhibits higher negative effects on the larval molting process than methoprene or natural juvenile hormone. Both compounds were administered at two doses (0.05% and 0.10%) via the male diet immediately after emergence. RESULTS: Our results show that both PPF and methoprene reduced male sexual maturation. However, PPF‐treated males exhibited a shorter maturation period and obtained more matings at a given age than methoprene‐treated males. No significant differences were observed between the two PPF doses tested (0.05% and 0.10%). Male survival was equally reduced by the two compounds. CONCLUSION: Our results demonstrate that PPF accelerated sexual development without reducing the mating propensity of sterile male flies and can be used as a suitable alternative for methoprene. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Insect Growth Regulator (IGR) novaluron is an alternative to synthetic neuro-inhibitory insecticides. Present study was designed to assess appropriate dosages of novaluron for dengue vector control. Larvae of Aedes aegypti and Ae. albopictus were exposed to a concentration series of novaluron (Rimon EC10) for two fixed exposure periods of 7-days and 14-days to determined LC50 and LC99 values. Inhibition of adult emergence (IE50 and IE99) was determined by a 14-day exposure. Semi-field experiments were conducted by exposing cohorts of Ae. aegypti larvae to IE99, 2 × IE99 and 10 × IE99 novaluron concentrations in water storage buckets (10 L) and plastic barrels (200 L). For the 7-day exposure, LC50 values were 0.047–0.049 ppm and LC99 were 0.144–0.151 ppm. For 14-day exposure, these values were 0.002–0.005 ppm and 0.006–0.01 ppm respectively. For both species, IE99 was 0.001 ppb under semi-field conditions, and was effective for nearly 2 months. Novaluron concentration 0.01 ppb was effective up to 3 months, with an IE of 89–95%. Authorities should critically review a reduction of the presently recommended field dosage of 200 ppm novaluron by × 100 or more. This would provide the same efficacy but mitigate environmental pollution, development of vector resistance, and financial losses. [ABSTRACT FROM AUTHOR]

Storage grain infestation is a critical problem, with insect pests and rodents causing economic losses and reductions in the quality of food grains and food products. It has been assessed as affecting 9% of goods in developed countries and more than 20% of goods in developing countries. The chemical insecticides used for storing products protect against insect pests, but introduce hazards associated with handling insecticides and the residues on food, which threaten nontarget organisms, and so represent a serious problem to the environment. Biorational methods are low risk, are obtained from animals, plants, bacteria and some minerals, and are segregated into microbial, plant‐associated protectant and biochemical substances. This method encompasses temperature management, modified atmospheric storage, ionizing irradiation, the mixing of inert materials, pheromone traps, botanicals, insect growth regulators, entomopathogens and host plant resistance. Biorational methods have emerged as alternative or supplemental pest control methods. Biopesticides would help in preventing the use of large quantities of pesticides across the globe, thus providing residue‐free food and a safe environment for living. Further investigation is needed to integrate these elements to enhance the efficacy, minimize the losses and diminish the reliance on pesticides for the preservation of stored commodities. [ABSTRACT FROM AUTHOR]

Using Pyriproxyfen in controlling Aedes aegypti shows great potential considering its high competence in low dosages. As an endocrine disruptor, temperature can interfere with its efficiency, related to a decrease in larval emergence inhibition in hotter environments. However, previous studies have been performed at constant temperatures in the laboratory, which may not precisely reflect the environmental conditions in the field. The aim of this study was to assess the effect of the fluctuating temperatures in Pyriproxyfen efficiency on controlling Aedes aegypti larvae. We selected maximum and minimum temperatures from the Brazilian Meteorological Institute database from September to April for cities grouped by five regions. Five fluctuating temperatures (17–26; 20–28.5; 23–32.5; 23–30.5; 19.5–31 °C) were applied to bioassays assessing Pyriproxyfen efficiency in preventing adult emergence in Aedes aegypti larvae in five concentrations. In the lowest temperatures, the most diluted Pyriproxyfen treatment (0.0025 mg/L) was efficient in preventing the emergence of almost thrice the larvae than in the hottest temperatures (61% and 21%, respectively, p value = 0.00015). The concentration that inhibits the emergence of 50% of the population was lower than that preconized by the World Health Organization (0.01 mg/L) in all treatments, except for the hottest temperatures, for which we estimated 0.010 mg/L. We concluded that fluctuating temperatures in laboratory bioassays can provide a more realistic result to integrate the strategies in vector surveillance. For a country with continental proportions such as Brazil, considering regionalities is crucial to the rational use of insecticides. [ABSTRACT FROM AUTHOR]

The current study was carried out to evaluate the biochemical effects of 4th and 6th instar larvae of S. littoralis provided with treated castor bean leaves for three different insect growth regulators (IGRs) (Novaluron, Pyriproxyfen, and Cyromazine). To determine the effect of these IGRs on total protein, total carbohydrate, total lipids, the activity of chitinase, the activity of acetylcholinesterase and carbohydrates hydrolyzing enzymes (Amylase, invertase, and trehalase activities) at LC50 concentrations of this treatment. The results showed that total proteins, lipids, and carbohydrate content were significantly decreased with all tested IGRs, except for an increase in total carbohydrates with Novaluron and Cyromazine for the 6th instar larvae of S. littoralis. Cyromazine induced a significant decrease in chitinase activity, followed by Pyriproxyfen then Novaluron. The tested IGRs significantly increased the acetylcholinesterase activity. A significant decrease in the activity of amylase and Invertase activity was induced by the tested IGRs, except with Novaluron for 6th instar larvae in the case of amylase and increased with all treatments for 6th instar larvae of Invertase, in contrast, all tested IGRs led to an increase in the activity of Trehalasec except Cyromazine decreased the enzyme activity. [ABSTRACT FROM AUTHOR]

Cyromazine is a triazine insect growth regulator insecticide that is recommended for control of Musca domestica worldwide. Cyromazine is highly effective in causing mortality of M. domestica; however, some aspects of its lethal and sublethal effects on the biology of M. domestica are still unknown. The present study explored lethal and sublethal effects on several biological traits and population parameters of M. domestica. Concentration–response bioassays of cyromazine against third-instar larvae of M. domestica exhibited sublethal and lethal effects from concentrations of 0.03 (LC10), 0.06 (LC25), and 0.14 (LC50) μg/g of a larval medium. Exposure of M. domestica larvae to these concentrations resulted in reduced fecundity, survival, longevity and oviposition period, and delayed development of immature stages (i.e., egg hatch time and larval and pupal durations) in the upcoming generation of M. domestica. The values of population parameters such as intrinsic rate of increase, finite rate of increase, net reproductive rate, age-specific survival rate and fecundity, and age–stage life expectancy and reproductive value, analyzed using the age–stage and two-sex life table theory, were significantly reduced in a concentration-dependent manner in comparison with the control group. In conclusion, the study highlights the significant effects of cyromazine on the biology of M. domestica that could help suppress its population in cases of severe infestations. [ABSTRACT FROM AUTHOR]

A qualitative review published in the Veterinary Ireland Journal discusses the control of companion animal parasites (CAPs). The review highlights the range of parasiticides available for CAPs, the role of diagnostics, and best practices and veterinary advice. It also addresses concerns about the environmental impact of parasiticides and the increasing prevalence of parasitic infections in pets. The review emphasizes the need for responsible use of parasiticides and calls for more research in various areas related to parasite control. [Extracted from the article]

BACKGROUND: Juvenile hormone (JH) signaling inhibitors may be used as insect growth regulators because of their ability to control metamorphosis and reproduction in insects by regulating the action of JH. RESULTS: We identified ethyl (E)‐3‐(4‐{[7‐ (4‐methoxycarbonylbenzyloxy)‐1,4‐benzodioxan‐6‐yl]methyl}phenyl)prop‐2‐enoate (EMBP) and observed its strong precocious metamorphosis‐inducing activity against silkworm larvae. To further elucidate its mechanism of action, we investigated the effect of EMBP on the JH‐mediated signaling pathway in vitro and in vivo. In a reporter assay using a Bombyx mori cell line, EMBP strongly suppressed the induction of reporter gene expression by Juvenile hormone I (JH I) in a concentration‐dependent manner. A parallel rightward shift was observed in the dose–response curve of JH I after treatment with EMBP, indicating that EMBP competitively inhibited JH. Moreover, we monitored developmental changes in the JH‐responsive gene, Krüppel homolog 1 (Kr‐h1), and ecdysone‐responsive gene, Broad‐Complex (BRC), in EMBP‐treated silkworm larvae. EMBP suppressed only the expression of Kr‐h1 in third‐instar larvae. CONCLUSION: Our results demonstrated that EMBP specifically regulates the JH‐mediated Kr‐h1 signaling pathway. EMBP could be used as a lead compound in the development of new insect growth regulators. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In this project we aim to share in increasing the production of the most important non-food agricultural product i.e. cotton via protection of it is plant. The usage of safe alternatives to the pesticides has become crucial due to several serious issues associated with the use of insecticides. Therefore, the families of new eco-friendly organic compounds that contain manly oxopropylthiourea scaffold will synthesis in their pure state by using green procedures. This compounds includes (i) poly functional substituted oxopropylthiourea, (ii) dihydroquinoline carboxylic acid, In second category, the structure of this compounds which may be related to the most famous insect growth regulators insecticides, will confirmed by elemental and modern spectroscopic analyses (such as IR, UV, 1HNMR and 13CNMR). In the final category, the synthesized compounds was checked toward the second & forth instar larvae of cotton leafworm, Spodoptera littoralis. The present data proved that values of LC50 of the most effected synthesized compound 8 was 2.412 ppm in which LC50 for commercial lufenuron was 2.295 ppm. Component 8 may be particularly effective due to the presence of fluorophenyl, cyanoacetamide, and carboxalic acid groups in their chemical makeup. In an additional effort to slightly improve insecticidal compounds, evaluation of the latent effects of the examined components on a number of biological parameters, such as adult longevity, pupal weight, proportion of normal, deformed pupae, & adult emergency, fecundity, & egg hatchability, was carried out. [ABSTRACT FROM AUTHOR]

In the present study, the spectroscopic investigation of pyriproxyfen (PYR) has been carried out using density functional theory and experimental methods. The FT‐IR, 1H and 13C NMR spectra of PYR were recorded, interpreted and compared with the theoretical spectra. The polarizability and hyperpolarizabilities are responsible for higher lipophilicity which leads to the acute aquatic toxicity of the PYR molecule. The UV‐Visible spectra of PYR exhibited the presence of π→ ${\to }$ π* transition between the π‐orbitals of phenoxyphenyl and pyridyl ring. The standard entropy, heat capacity at constant volume and total energy have been computed to assess the toxicity of the compound. Molecular docking revealed the insecticidal potential of PYR owing to the presence of hydrogen bond interactions between PYR and mosquito juvenile hormone binding protein of aedes aegypti. The biophysical study predicts the possible DNA‐PYR interactions and carcinogenic properties of PYR molecule. [ABSTRACT FROM AUTHOR]

The citrus mealybug, Planococcus citri, is an insect pest of greenhousegrown horticultural crops. Citrus mealybug causes plant damage when feeding on plant leaves, stems, flowers, and fruits, resulting in a substantial economic loss. Insecticides are applied to manage citrus mealybug populations in greenhouse production systems. Anecdotal information suggests that mixing entomopathogenic fungal-based insecticides with insect growth regulators may be effective for managing citrus mealybug populations under greenhouse conditions. Consequently, we conducted two experiments in a research greenhouse at Kansas State University (Manhattan, KS, USA) in 2023. The experiments were designed to determine the efficacy of three commercially available entomopathogenic fungal-based insecticides [Beauveria bassiana Strain GHA (BotaniGard®), B. bassiana strain PPRI 5339 (Velifer™) and Isaria fumosorosea Apopka Strain 97 (Ancora®)] when mixed with three insect growth regulators [azadirachtin (Azatin®O), novaluron (Pedestal®), and pyriproxyfen (Distance®)] on citrus mealybug feeding on coleus, Solenostemon scutellarioides, plants. The entomopathogenic fungal-based insecticides alone or when mixed with the insect growth regulators were not effective in managing citrus mealybug populations, with <20% mortality during each experiment. In addition, all coleus plants treated with the entomopathogenic fungal-based insecticides had a white, powdery residue on the leaves. Our study demonstrates that entomopathogenic fungal-based insecticides, even when mixed with insect growth regulators, are not effective in managing citrus mealybug populations in greenhouses, which is likely because the environmental conditions (temperature and relative humidity) are not optimal for conidial germination and hyphal infection to occur. Therefore, entomopathogenic fungal-based insecticides have limited use for managing insect pests in greenhouse production systems. [ABSTRACT FROM AUTHOR]

Spodoptera litura (Lepidoptera: Noctuidae) is a polyphagous pest of agricultural crops and causes severe economic loss. In the present study, the biological effect and enzymatic activity of two insect growth regulators, pyriproxyfen and diofenolan was evaluated against S. litura larva. The penultimate instar larvae (0, 24, and 48-hours old) were treated topically at the last three abdominal tergites with sublethal doses (1, 2, and 4µg/µl) of both the juvenile hormonal analogues (JHAs). Several effects were observed such as prolongation in larval-larval and larval-pupal ecdysial duration, larval and pupal mortality, eclosion failure, formation of intermediates, low pupation and reduced adult emergence. Along with these metamorphic catastrophe effects, both JHAs had inhibitory effects for acetylcholinesterase (AChE) but excitatory effects for glutathione –S-transferase enzyme (GST). Whereas, Log IC50 and IC50 values for adult emergence inhibition rate were found to be -0.98 and 0.1 µg/ µl for 24-hours old larvae (Pyriproxyfen); 0.005 and 1.01 µg/ µl for 48-hours old larvae (Pyriproxyfen); -0.085 and 0.82 µg/ µl for 24-hours old larvae (Diofenolan); -0.09 and 1.23 µg/ µl for 48-hours old larvae (Diofenolan). Our result manifests the insecticidal potency of both the IGRs against S. litura. [ABSTRACT FROM AUTHOR]

The biological impact of insect growth regulators (IGRs) pesticides on ecologically important soil oribatid mites' fauna was evaluated using life history parameters in Scheloribates laevigatus (Koch) (Acari: Oribatida: Scheloribatidae), under microcosm conditions. Four novel IGR pesticides namely, Easo 30% WG (Indoxacarb), Kafrozed 5% EC (Chlorfluazuron), Alsystin 48% SC (Triflumuron) and Klegron 10% EC (Flufenoxuron) were tested. Laboratory fresh adults were reared on plaster of Paris (9:1) supplied with fungal food treated with agricultural doses of tested IGR pesticides. There was negligible mortality of individuals in control vessels 3.23%, Klegron 10% EC caused the highest mortality of 35.16 %, and significantly decreased the longevity of adults to 17.26. The growth rate of S. laevigatus decreased in IGRs reared vessels with moderate influence of Kafrozed 5% EC and Alsystin 48% SC, while a significantly toxic effect of Klegron 10% EC on all instars was recorded (P<0.05). Furthermore, fecundity declined to 1.8/day in Easo 30% WG and 1.1 in Klegron 10% EC than the control vessels. Chitin formation in adults was decreased and the hard brown exoskeleton looks pale in all reared vessels treated with IGR pesticides. [ABSTRACT FROM AUTHOR]

The two invasive mosquito species in Indonesia are Aedes aegypti and Ae. albopictus. These mosquitoes are a serious nuisance to humans and are also the primary vectors of several foreign pathogens, such as dengue, Zika, and chikungunya viruses. Efforts must be made to reduce the possibility of mosquito bites and the potential for disease transmission. Given the invasion of these two Aedes species, this approach should be considered as part of an integrated strategy to manage them. This review discusses existing and developing control techniques for invasive Ae. aegypti and Ae. albopictus, with an emphasis on those that have been and are being used in Indonesia. Environmental, mechanical, biological (e.g., Bacillus thuringiensis and Wolbachia), and chemical (e.g., insect growth regulators and pyrethroids) approaches are discussed in this review, considering their effectiveness, sustainability, and control methods. [ABSTRACT FROM AUTHOR]

Malaria vectors have demonstrated resistance to pyrethroid-based insecticides used in insecticide-treated nets, diminishing their effectiveness. This systematic review and meta-analysis investigated two forms of dual active-ingredient (DAI) insecticide-treated nets (ITN(s)) for malaria prevention. A comprehensive search was conducted on July 6th 2022. The databases searched included PubMed, Embase, CINAHL, amongst others. Trials were eligible if they were conducted in a region with ongoing malaria transmission. The first DAI ITN investigated were those that combined a pyrethroid with a non-pyrethroid insecticides. The second DAI ITN investigated were that combined a pyrethroid with an insect growth regulator. These interventions were compared against either a pyrethroid-only ITN, or ITNs treated with pyrethroid and piperonyl-butoxide. Assessment of risk of bias was conducted in duplicate using the Cochrane risk of bias 2 tool for cluster-randomised trials. Summary data was extracted using a custom data-extraction instrument. This was conducted by authors THB, JCS and SH. Malaria case incidence was the primary outcome and has been meta-analysed, adverse events were narratively synthesised. The review protocol is registered on PROSPERO (CRD42022333044). From 9494 records, 48 reports were screened and 13 reports for three studies were included. These studies contained data from 186 clusters and all reported a low risk of bias. Compared to pyrethroid-only ITNs, clusters that received pyrethroid-non-pyrethroid DAI ITNs were associated with 305 fewer cases per 1000-person years (from 380 fewer cases to 216 fewer cases) (IRR = 0.55, 95%CI: 0.44–0.68). However, this trend was not observed in clusters that received pyrethroid-insect growth regulator ITNs compared to pyrethroid-only ITNs (from 280 fewer cases to 135 more) (IRR = 0.90, 95%CI: 0.73–1.13). Pyrethroid-non-pyrethroid DAI ITNs demonstrated consistent reductions in malaria case incidence and other outcomes across multiple comparisons. Pyrethroid-non-pyrethroid DAI ITNs may present a novel intervention for the control of malaria. [ABSTRACT FROM AUTHOR]

Brassinosteroids (BRs) are steroid hormones that regulate plant growth, development, and stress resistance. In this study, we evaluated the effect of agrochemicals on dark-induced hypocotyl elongation, which is regulated by BRs, to identify novel chemicals that regulate BR action. We found that the juvenile hormone agonist fenoxycarb inhibited dark-induced hypocotyl elongation in Arabidopsis. Treatment with the same class of juvenile hormone agonist, pyriproxyfen, did not affect hypocotyl elongation. Co-treatment with fenoxycarb and BR partly canceled the fenoxycarb-induced hypocotyl suppression. In addition, gene expression analysis revealed that fenoxycarb altered the BR-responsive gene expression. These results indicate that fenoxycarb is a BR action inhibitor. [ABSTRACT FROM AUTHOR]

Derivatives of 1-benzyl-2-methylbenzimidazoles (BMBIs) were synthesized to evaluate their biological activities against Bombyx mori, a lepidopteran model insect. Synthesized BMBIs exhibited two different biological activities: inhibition of development and acute lethality. From a structural perspective, the activity varied with the position of the substitutions on the 1-benzyl moiety; BMBIs with substitutions on the 2 and/or 4 positions had comparatively high activity in comparison with those with substitutions on the 3-position. There was more activity for the inhibition of development with low doses, and more for acute lethality with high doses. The activity was also affected by the applied stage, that is, application in the 4th instar mostly interfered the larval molting or pupation, whereas that in the 3rd instar caused more acute mortality. Taken together, these results suggest that BMBIs have multiple modes of action. [ABSTRACT FROM AUTHOR]

Commercial formulations of some botanical products azadirachtin, orange oil, and jojoba oil and insect growth regulators (IGRs) buprofezin, novaluron, and pyriproxyfen were evaluated as safe alternatives to synthetic insecticides imidacloprid and Pymetrozine against aphid Aphis gossypii Glover and whitefly Bemisia tabaci Gennadius in cucumber fields. Two experiments were conducted during 2021 and 2022 seasons, at El-hager area, Abou El-matameer, Al-Behira governorate. Side effects of the tested insecticides were also observed on the two predators lady beetle Coccinella septumpunctata Linnaeus and aphid lion Chrysoperla carnea Stephens. Imidacloprid significantly (P<0.05) achieved the highest initial and residual activity against aphid and whitefly in both seasons. The initial and residual reduction percentages of aphid were 94.5 and 98.9% in 2021 and 91.5 and 96.5% in 2022 as well as reduction percentages of whitefly was 85.7 and 92.4% in 2021 and 86.8 and 93.1% in 2022. Novaluron, buprofezin, pyriproxyfen and azadirachtin showed a moderate activity against whitefly and aphid in both seasons while orange and jojoba oils revealed the least reduction percentages. However, orange and jojoba oils have the least side effects on the aphid lion where the residual reduction percentages were 5.3 and 6.4% in 2021 and 6.4 and 7.3% in 2022. The least side effects on the lady beetle were exhibited by jojoba oil followed by orange oil and azadirachtin where the residual reduction percentages were 10.8, 14.7 and 15.6% in 2021 and 11.1, 16.1 and 15.3% in 2022, respectively. Pyriproxyfen, novaluron and buprofezin achieved more initial and residual toxicity on the two predators. On the other hand, imidacloprid and pymetrozine have the highest initial and residual side effects against the two predators. The reduction percentages of all treatments on the two predators were less than 50%. Therefore, all treatments were considered harmless according to the IOBC classification. The good selectivity feature of these formulated botanical products and IGRs, makes them good tools and suitable for integrated pest management (IPM) programs of sucking piercing insects. [ABSTRACT FROM AUTHOR]

Simple Summary: The mosquito Aedes aegypti has developed insecticide resistance in Thailand and around the world. We investigated the effective forms between wet and dry spent coffee grounds (wSCGs and dSCGs) and novaluron on larval mortality and adult emergence inhibition of Ae. aegypti. The main chemical compound concentration in wSCGs was higher than that in dSCGs. Then, the effective SCGs were selected to combine with novaluron and determined the synergistic effects of its combination. At sublethal concentrations wSCGs and novaluron had low efficacies when present individually; however, when combined at low concentrations, they showed greater efficacy. Therefore, wSCGs combined with novaluron could be utilized as an alternative control for this mosquito vector. Aedes aegypti (Diptera: Culicidae) is a vector for mosquito-borne diseases worldwide. Insecticide resistance is a major concern in controlling this mosquito. We investigated the chemical compounds in wet and dry spent coffee grounds (wSCGs and dSCGs) and evaluated the efficacy of dSCGs, wSCGs, and novaluron on the mortality and adult emergence inhibition of Ae. aegypti. We found higher concentrations of chemical compounds in wSCGs than in dSCGs. The wSCGs and dSCGs both contained total phenolic compounds, total flavonoid compounds, caffeic acid, coumaric acid, protocatechuic acid, and vanillic acid. Complete mortality was observed after 48 h of exposure to 50 g/L wSCGs, while similar mortality was found after 120 h of exposure to 10 µg/L of novaluron. The sublethal dose was a concentration of wSCGs (5 g/L) and novaluron (0.01, 0.1, and 1 µg/L) combined that resulted in a larval mortality lower than twenty percent (at 72 h) to determine their synergistic effects. The death rate of larvae exposed in sublethal combination of wSCGs and novaluron was significantly higher than that of its stand-alone. The findings indicate that the combination of wSCGs and novaluron at sublethal concentrations had synergistic effects on the mortality of Ae. aegypti larvae and could be applied as an alternative control measure. [ABSTRACT FROM AUTHOR]

Simple Summary: Malaria is transmitted by Anopheles mosquitoes. An important control tool against malaria is insecticidal bed nets containing a pyrethroid insecticide and another active ingredient, such as pyriproxyfen (PPF), which sterilizes adult mosquitoes by disrupting egg development. To evaluate the impact of PPF-treated bed nets, there are two potential techniques available to measure mosquito sterility: (1) observing egg-laying rates and (2) ovarial dissection. Our aim was to show which technique was most effective by exposing adult mosquitoes to PPF-treated or untreated nets and comparing sterility outcomes. When identifying the true percentage of mosquitoes sterilized from PPF exposure (i.e., true positives), both techniques showed similar sensitivity (egg-laying: 99% vs. dissection: 100%). For identifying non-exposed mosquitoes in the untreated group (i.e., true negatives), dissection had a higher specificity than egg-laying (53% vs. 19%). To show that ovary dissection remains effective under different conditions, we exposed mosquitoes to insecticides using two different exposure methods, including nets treated with pyrethroids, and blinded the investigator to reduce bias when scoring. The investigator predicted the exposure status of dissected females across all conditions with >90% accuracy. We conclude that ovary dissection is a more sensitive and specific tool for measuring sterility in Anopheles mosquitoes exposed to PPF. Pyriproxyfen (PPF) is an insect growth regulator used in the co-treatment of long-lasting insecticidal nets for its ability to sterilize female mosquitoes. To evaluate the efficacy of PPF-treated nets on mosquito reproductivity, most studies observe oviposition (egg-laying) rates in the laboratory. This technique has several technical disadvantages. Our study assessed if ovarial dissection could serve as an effective proxy for evaluating sterility in Anopheles gambiae mosquitoes. Blood-fed females were exposed to untreated or PPF-treated nets in cylinder assays and followed over several days to observe oviposition rates or egg development by dissection. For identifying PPF-exposed mosquitoes, both techniques demonstrated high sensitivity (oviposition: 99.1%; dissection: 100.0%), but for identifying non-exposed mosquitoes, specificity was significantly higher in the dissection group (52.5% vs. 18.9%). To assess whether dissection could be applied to nets treated with a pyrethroid or co-treated with a pyrethroid and PPF in tunnel tests, a blinded investigator performed dissections to predict the PPF exposure status across different treatment groups. The exposure status of dissected females was predicted with >90% accuracy. We report that dissection is a sensitive technique to assess sterility in female Anopheles gambiae mosquitoes and can be used as a predictor of PPF exposure. [ABSTRACT FROM AUTHOR]

Simple Summary: Currently, alternatives for pest control in crops with lower environmental impact and risk are being sought. This study aims to evaluate the compatibility between different control alternatives/agents that can be incorporated into integrated pest management. In this case, compatible control alternatives for reducing larval populations of the harmful insect Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) were assessed. Chrysoperla carnea (Siemens), whose larvae are highly voracious and feed on a wide range of prey, is an attractive biological control option against a variety of insect pests. This predator resides naturally in agroecosystems or can also be added artificially by man. To find new possibilities for joint pest treatments, compatibility of insect growth regulators, IGRs (the most selective chemical insecticides), such as tebufenozide, with the predator C. carnea were investigated. Laboratory tests were conducted to evaluate the lethal (direct) and sublethal (indirect) effects of tebufenozide on C. carnea. Tebufenozide exhibited low toxicity on the developmental stages of egg, larvae and adult and is a valuable contribution to the development of integrated management programmes for S. littoralis that incorporate tebufenozide and C. carnea in a compatible and effective way, choosing the best combinations and the most appropriate time for its application. Quantifying compatibility among control agents is essential for development of integrated pest management (IPM). Chrysoperla carnea (Siemens) and insect growth regulator insecticides are widely used in IPM of Lepidoptera. C. carnea is a generalist predator naturally present in the Mediterranean agroecosystems and bred in insectariums for commercial purposes. Here, we evaluated lethal and sublethal effects of tebufenozide on C. carnea under laboratory conditions. The treatment of eggs with tebufenozide 24 or 48 h after they were laid did not affect the hatching rate or survival of the neonate larvae. Toxic effects of tebufenozide on topically treated larvae was low; development times of surviving larvae and pupae decreased significantly compared with controls. In choice bioassays, a high percentage of third-instar larvae chose prey (Spodoptera littoralis) treated with tebufenozide in preference to untreated prey. Moreover, second-instar larvae of C. carnea that had previously consumed tebufenozide-treated prey (0.75 mL/L) had significantly reduced larval development time compared with controls, while longevity of surviving adults, fecundity and egg viability were unaffected. Ingestion of tebufenozide by adults of C. carnea at the recommended field dose had no significant effect on female fecundity, egg viability or adult longevity. Tebufenozide exhibited low toxicity towards the developmental stages of C. carnea and is therefore a candidate for inclusion in IPM strategies. [ABSTRACT FROM AUTHOR]

Lufenuron (LUF) and Methoxyfenozide (MET) as Insect Growth Regulators (IGRs) contribute to the current control of the catastrophic crop pest, Spodoptera exigua (Lepidoptera, Noctuidae). Yet S. exigua has evolved resistance to LUF and MET, which is possibly mediated by cytochrome P450 monooxygenases (P450s), particularly from the CYP3 clade family, as it plays a key role in the detoxification of insecticides. However, a mixture of LUF and MET (MML) (optimal ratio: 6:4) remains highly insecticidal. Here, we analysed the response of S. exigua to sublethal concentrations of LUF, MET, and MML via transcriptomics. Twelve differentially expressed genes (DEGs) encoding CYP3 clade members were observed in transcriptomes and CYP9A9 was significantly upregulated after treatment with LUF, MET, and MML. Further, CYP9A9 was most highly expressed in the midgut of L4 S. exigua larvae. RNAi‐mediated knockdown of CYP9A9 reduced the activity of CYP450 and increased the susceptibility of S. exigua larvae to LUF, MET, and MML. Thus, CYP9A9 plays a key role in the detoxification of LUF, MET, and MML in S. exigua. These findings provide new insights into insecticidal actions of IGRs, which can be applied to the establishment of novel pest management strategies. [ABSTRACT FROM AUTHOR]

Pesticides have been used to kill pests such as insects, fungi, rodents, and unwanted plants. As these compounds are potentially toxic to the target organisms, they could also be harmful to human health and the environment. Several chronic adverse effects have been identified even after months or years of exposure. The adverse effects of pesticides on the agricultural ecosystem have been a matter of concern in recent decades. In this review, we present an overview of the studies, including our previous studies, monitoring currently used pesticides in the Tunisian agricultural soils that belong to the class of insect growth regulators (IGRs). Triflumuron (TFM) is a benzoyl phenyl urea insecticide belonging to the class of IGRs. TFM is widely used around the world to increase crop yield by protecting them from damage caused by insects. TFM works by inhibiting the synthesis of chitin, an essential part of the insect cuticle, making it susceptible to pathogens and deformities. Consequently, insects become more susceptible to pathogens and malformations. However, studies revealing its toxicity and its mode of action in mammalian systems remain very limited. The aim of this review is to better inform the community about the impact of TFM on crops, the environment, and human beings by summarizing its toxic effects. [ABSTRACT FROM AUTHOR]

According to the previous research of our group, we found compound ZQ-8 ((1S,2R,4S)-1,3,3-trimethylbicyclo [2.2.1]heptan-2-yl-4-(tert-butyl)benzoate). This compound showed a strong growth inhibitory effect on Helicoverpa armigera by inhibiting chitinase 2 and endochitinase. To further understand the mechanism of ZQ-8 interfering with the growth and development of H. armigera, ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) was utilized to analyze the metabolomics of the epidermis and viscera of H. armigera after ZQ-8 stress. The results revealed that the content of most metabolites was down-regulated after ZQ-8 treatment. Through the analysis of metabolic pathways, it was found that ZQ -8 mainly interfered with energy metabolism and amino acid biosynthesis pathways, which may be one of the important factors in which ZQ-8 caused the death of H. armigera larvae. Furthermore, ZQ-8 not only inhibits chitin degradation but also inhibits chitin synthesis in vivo. These findings provide new insights into a better understanding of the mechanism of action of ZQ-8. [ABSTRACT FROM AUTHOR]

Ecdysone receptor (EcR) and chitinase play a critical role in the molting stage of insect pests. Each of them is considered a promising target for the development of novel insect growth regulators (IGRs). In the present paper, a total of 24 (23 novel) hexacyclic pyrazolamide derivatives were designed and synthesized by reducing the heptacycle and inserting small flexible linkers on the basis of the previously discovered dual-target compound D-27 acting simultaneously on EcR and Ostrinia furnacalis chitinase (OfChtI). Their insecticidal activities against Plutella xylostella, Spodoptera frugiperda, and Ostrinia furnacalis larvae were evaluated. The results revealed that the insecticidal activity was not significantly enhanced when the heptacycle on the pyrazole ring was reduced to a hexacycle. However, the insertion of an additional methylene spacer between the substituted phenyl ring and the amide bond can improve the insecticidal activity. Among the derivatives, the most potent compound, 6j, exhibited promising insecticidal activities against P. xylostella and S. frugiperda. Further protein binding assays and molecular docking indicated that 6j could target both EcR and OfChtI, and is a potential lead compound for IGRs. The present work provides valuable clues for the development of new dual-target IGRs. [ABSTRACT FROM AUTHOR]

Natural products are considered a good choice in the biological control of mosquitoes because they are an effective way to eliminate larvae and prevent an increase in mosquito numbers, while simultaneously not polluting the environment or damaging health. This investigation was designed to study the potential toxicity of three species of algae, Caulerpa racemosa (Weber‐van Bosse, 1909), Padina boryana (Thivy, 1966), and Turbinaria ornata (Turner J. Agardh, 1848), on the larvae of Aedes aegypti mosquito, the vector of dengue and Zika viruses. Among the studied species, Caulerpa racemosa showed the greatest effectiveness in eradicating A. aegypti larvae with an LC50 = 43.5 ppm, followed by Padina boryana with an LC50 = 51.93 ppm. Both species proved to be excellent candidates as a source of larvicidal agents and could be used commercially in mosquito control programs as eco‐friendly biopesticides. The combined activity of different mixtures against mosquito larvae was expressed as the coeffective factor (C.F.). C.F. values showed that the joint activity of insect growth regulator Dudim in combination with Caulerpa racemosa and Padina boryana extracts produced degrees of potentiation effects and degrees of additive effects were obtained with Dudim in combination with Turbinaria ornata extract. [ABSTRACT FROM AUTHOR]

Rice swarming caterpillar, Spodoptera mauritia, is a major pest of paddy. Insect growth regulators are a class of substances that interfere with insects' natural growth, development, and reproduction by disrupting physiological processes. Insect growth regulators are appropriate for pest management as they are more target-specific, non-persistent, biodegradable, and ecologically benign compounds with reduced toxicity to non-target organisms. In this study, we showed that treatment of 5th instar day 0 larvae of S. mauritia with the JH-mimic, pyriproxyfen, increases the level of an 83 kDa haemolymph protein band in SDS-PAGE compared to control. The pyriproxyfen–responsive protein was identified by mass spectrometry as arylphorin, a hexameric storage protein. It is revealed that in native state it is a high molecular weight multimeric protein. Also we showed that the increase in level of arylphorin on exposure to pyriproxyfen is the result of induction of protein synthesis. As storage proteins are crucial for insect development and metamorphosis and the level is altered by insecticides like pyriproxyfen, the role of arylphorin in the physiology of the larvae exposed to insecticides needs to be explored. [ABSTRACT FROM AUTHOR]

Spodoptera littoralis (Boisd) (Lepidoptera: Noctuidae), management requires the implementation of effective and sustainable control strategies. In this study, we aimed to compare the insecticidal activity and field performance of four commonly used insect growth regulators (IGRs) against S. littoralis larvae for helping in decision making to get the most effective and sustainable pest management for S. littoralis under local condition. The tested IGRs included Benzoylphenyl ureas BPUs (Lufenuron, Chlorfluazuron, Diflubenzuron), and an ecdysone receptor agonist (Methoxyfenozide). Laboratory bioassays were conducted to determine the toxicity of these IGRs against 2nd and 4th instar of S. littoralis larvae. Lufenuron exhibited the highest toxicity, with the lowest LC50 values (0106 & 0.069 and 0.889 &0.453 mg\l) at 72 and 96h of exposure, respectively. Chlorfluazuron, Diflubenzuron, and Methoxyfenozide displayed relatively lower toxicity compared to lufenuron, as their toxicity indexes were (2.59, 1.99 and 4.50) refereeing to the lowest LC50 value of Lufenuron against the 2nd instar after 72h of exposure. Moreover, positive significant correlations were observed between the log LC50 values of each IGR and other tested ones (pairwise comparison) which alert the possibility of cross resistance between these IGRs. Field experiments were performed over two cotton seasons to assess the efficacy of the IGRs in reducing S. littoralis larval populations. All treatments resulted in a significant reduction in larvae compared to the control group. Lufenuron consistently demonstrated the highest initial efficacy (73.5 and 75.2%) and mean reduction (83.9 and 81.5%) after 15 days of treatment in both 2020 and 2021 seasons, respectively. In contrary, the lowest efficacy was recorded for Diflubenzuton with mean reduction (68.2 and 71.2) after 15 days of treatment in 2020 and 2021 cotton seasons, respectively. This finding highlights the importance of selecting IGRs with higher toxicity to achieve effective larval control. The work underscores the potential of lufenuron as a highly effective IGR for managing S. littoralis. Furthermore, our research emphasis the crucial of the continuous evaluation of IGRs efficacy and persistence as well as resistance and cross resistance to IGRs under local field conditions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Eriopis connexa is an important predator in the Neotropical region, associated with pests of economic relevance on horticultural crops in Argentina. The use of broad‐spectrum insecticides could reduce the biodiversity of these natural enemies in agroecosystems and put at risk its conservation. New, selective "risk reduced" insecticides could be an alternative to conventional chemical control to promote sustainable agriculture. The goal of this work was to assess the lethal and sublethal effects of two insect growth regulator (IGR) insecticides on eggs and two larval instars of E. connexa exposed to insecticides. RESULTS: Pyriproxyfen and cypermethrin significantly affected egg hatching by 28.8% and 70.4%, respectively. Pyriproxyfen reduced the survival of larvae that emerged by ≈52% from Day (D3)3 after hatching and caused the lengthening of developmental time for both larval and pupal stages. By contrast, teflubenzuron did not reduce hatching and survival but shortened the developmental time of the pupae stage. Cypermethrin reduced the survival of 2nd (L2) and 4th (L4) larval instars by 36.4% and 74.6%, respectively, and lengthened the development time of L2. Pyriproxyfen lengthened the development time of L4 and reduced the fecundity and fertility of females. Teflubenzuron reduced survival of L2 and L4 larval instars by 46.9% and 28.6%, respectively, and lengthened the total development time for the larval stage. In addition, teflubenzuron reduced the fecundity and fertility of females. CONCLUSIONS: Both eggs and larvae were susceptible to exposure to IGR, showing lethal and sublethal effects. This study highlights, once again, the higher toxicity of cypermethrin to E. connexa. The toxicity of both IGR insecticides could impair the performance of E. connexa as a biological control agent in agroecosystems. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Glutathione S-transferases (GSTs) are conserved in a wide range of organisms, including insects. In 2014, an epsilon GST, known as Noppera-bo (Nobo), was shown to regulate the biosynthesis of ecdysteroid, the principal steroid hormone in insects. Studies on fruit flies, Drosophila melanogaster, and silkworms, Bombyx mori, demonstrated that loss-of-function mutants of nobo fail to synthesize ecdysteroid and die during development, consistent with the essential function of ecdysteroids in insect molting and metamorphosis. This genetic evidence suggests that chemical compounds that inhibit activity of Nobo could be insect growth regulators (IGRs) that kill insects by disrupting their molting and metamorphosis. In addition, because nobo is conserved only in Diptera and Lepidoptera, a Nobo inhibitor could be used to target IGRs in a narrow spectrum of insect taxa. Dipterans include mosquitoes, some of which are vectors of diseases such as malaria and dengue fever. Given that mosquito control is essential to reduce mosquito-borne diseases, new IGRs that specifically kill mosquito vectors are always in demand. We have addressed this issue by identifying and characterizing several chemical compounds that inhibit Nobo protein in both D. melanogaster and the yellow fever mosquito, Aedes aegypti. In this review, we summarize our findings from the search for Nobo inhibitors. [ABSTRACT FROM AUTHOR]