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18 pages, 1336 KB

Open AccessArticle

Temporal Variation in Target Site Mutations Is Associated with Diamide Cross-Resistance in Diamondback Moth Populations (Lepidoptera: Plutellidae) from Florida and Georgia, USA

by Thomas P. Dunn, Md. Abdullah Al Baki, Paulo S. G. Cremonez, David G. Riley, Alton N. Sparks, Jr., Hugh Smith and Donald E. Champagne

Insects 2025, 16(11), 1179; https://doi.org/10.3390/insects16111179 - 19 Nov 2025

Viewed by 574

Abstract

The Diamondback moth (DBM), Plutella xylostella (L.), the most significant worldwide pest of Brassica crops, is notorious for resistance to a diverse number of insecticides. Field populations bioassayed in Georgia and Florida, USA, in 2018 were resistant to chlorantraniliprole but susceptible to cyantraniliprole. [...] Read more.

The Diamondback moth (DBM), Plutella xylostella (L.), the most significant worldwide pest of Brassica crops, is notorious for resistance to a diverse number of insecticides. Field populations bioassayed in Georgia and Florida, USA, in 2018 were resistant to chlorantraniliprole but susceptible to cyantraniliprole. Subsequently, populations assayed in 2021, 2022, and 2023 were cross-resistant to both diamides. We used NextSeq analysis of the ryanodine receptor PxRyR, the target of diamides, to quantify target site mutations associated with resistance. Three populations sampled in 2018 had a high prevalence (75.0–98.3% of total reads) of the G4946E mutation, associated with resistance to chlorantraniliprole, and additionally, in one population, a very low (2.7%) prevalence of another mutation, I4790K, was associated with diamide cross-resistance. Populations sampled in 2021 had a decreased prevalence of G4946E (0.7 and 8.4%) and increased prevalence of I4790K (9.3 and 18.0%). The G4946E allele was almost absent (0.2% to 3.9%) in populations sampled in 2022 and 2023, while I4790K was present at frequencies from 34.1% to 84.0%. These data suggest a remarkable shift in PxRyR target site mutations, replacing G4946E with I4790K, which occurred between 2018 and 2022, and were associated with the recent occurrence of cross-resistance in DBM populations in the Southeastern USA. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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17 pages, 2697 KB

Open AccessArticle

Tetraniliprole Triggers Transgenerational Hormesis in an Invasive Insect Herbivore: Molecular and Biological Insights

by Farman Ullah, Zeeshan Ullah, Ali Güncan, Guru-Pirasanna-Pandi Govindharaj, Hina Gul, Prabhu Prasanna Pradhan, Ghulam Murtaza, Xiaowei Li, Nicolas Desneux and Yaobin Lu

Insects 2025, 16(10), 1073; https://doi.org/10.3390/insects16101073 - 21 Oct 2025

Cited by 1 | Viewed by 725

Abstract

The South American tomato pinworm, Tuta absoluta (Meyrick), is among the most destructive invasive pests of tomato globally. The diamide insecticide tetraniliprole is increasingly used for its management. This study examines the sublethal effects of tetraniliprole on T. absoluta larvae, with a focus [...] Read more.

The South American tomato pinworm, Tuta absoluta (Meyrick), is among the most destructive invasive pests of tomato globally. The diamide insecticide tetraniliprole is increasingly used for its management. This study examines the sublethal effects of tetraniliprole on T. absoluta larvae, with a focus on its transgenerational impacts. Bioassays demonstrated that tetraniliprole was highly toxic to third-instar T. absoluta larvae, with an LC₅₀ of 0.029 mg/L. Sublethal (LC₁₀) and low lethal concentrations (LC₃₀) were used to investigate their impact on developmental, reproductive, and population parameters across two subsequent generations (F₁ and F₂). In the parental (F₀) generation, exposure to tetraniliprole at both concentrations significantly prolonged larval and pupal durations and reduced adult longevity and fecundity. In both F₁ and F₂ generations, concentration-dependent effects were observed—LC₁₀ accelerated development and enhanced fecundity and population growth, indicative of a hormetic response, whereas LC₃₀ delayed development and suppressed reproduction and survival. Life table analyses revealed significant changes in the r, λ, and T, particularly under LC₃₀. Additionally, the RT-qPCR analysis revealed the downregulation of development and reproduction-related genes (Vg, VgR, and JHBP) in the F₀ generation following exposure to tetraniliprole (LC₁₀ and LC₃₀). In contrast, these genes were upregulated in the progeny generations (F₁ and F₂) at LC₁₀. Furthermore, the overexpression of key detoxification genes, particularly CYP4M116 and CYP6AW1, persisted across all three generations. Taken together, these findings reveal a substantial risk of unintended population resurgence (hormesis effects) at sublethal concentrations, underscoring the importance of integrating transgenerational consequences into insecticide resistance management programs for sustainable control of this key insect pest. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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15 pages, 3028 KB

Open AccessArticle

Stage-Specific Toxicity of Novaluron to Second-Instar Spodoptera frugiperda and Plutella xylostella and Associated Enzyme Responses

by Qing Feng, Jian Yang, Weikang Huang, Jingjing Jia, Jialing Wang, Fei Pan and Xuncong Ji

Insects 2025, 16(10), 1051; https://doi.org/10.3390/insects16101051 - 15 Oct 2025

Viewed by 712

Abstract

To provide a scientific basis for pest control, this study evaluated the insecticidal activity of novaluron against the fall armyworm (Spodoptera frugiperda) and diamondback moth (Plutella xylostella). The leaf-dip method determined the toxicity of novaluron to second-instar larvae, while [...] Read more.

To provide a scientific basis for pest control, this study evaluated the insecticidal activity of novaluron against the fall armyworm (Spodoptera frugiperda) and diamondback moth (Plutella xylostella). The leaf-dip method determined the toxicity of novaluron to second-instar larvae, while corn leaves and cabbage treated with sublethal (LC₁₀) and median lethal concentrations (LC₅₀) of novaluron were used to feed the larvae. Enzyme-linked immunosorbent assays (ELISA) measured the activities of detoxifying enzymes [carboxylesterase (CarE), cytochrome P450 (P450), glutathione S-transferase (GST), and acetylcholinesterase (AChE)] and ecdysteroid (Ecd) levels in the pests after 24 and 48 h of treatment. Results indicated that after 24 h, AChE was involved in diamondback moth metabolism and CarE activity was inhibited. After 48 h, P450 and GST participated in fall armyworm detoxification, whereas P450 and GST were active in diamondback moth detoxification, with other enzyme activities normalizing. Novaluron also altered Ecd levels in both pests. These results demonstrate differing detoxification mechanisms in fall armyworm and diamondback moth, likely due to their unique physiological and ecological traits, and support the potential use of novaluron in pest management strategies. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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12 pages, 1863 KB

Open AccessArticle

Sublethal and Transgenerational Effects of Cyclaniliprole on Demographic Parameters in Rhopalosiphum padi and Schizaphis graminum (Hemiptera: Aphididae)

by Xinan Li, Xiaoya Zhang, Wen Zhang, Chengze Song, Fengfan Wang, Ruiyang Qin, Ganyu Zhu, Guochang Wang, Jiangao Yu and Hongliang Wang

Insects 2025, 16(9), 882; https://doi.org/10.3390/insects16090882 - 25 Aug 2025

Viewed by 800

Abstract

Cyclaniliprole is a novel third-generation anthranilic diamide insecticide which has broad-spectrum efficacy against various pests, including aphids. Rhopalosiphum padi and Schizaphis graminum are the two primary aphid species that infest wheat crops. This investigation evaluates cyclaniliprole’s acute toxicity and sublethal and transgenerational effects [...] Read more.

Cyclaniliprole is a novel third-generation anthranilic diamide insecticide which has broad-spectrum efficacy against various pests, including aphids. Rhopalosiphum padi and Schizaphis graminum are the two primary aphid species that infest wheat crops. This investigation evaluates cyclaniliprole’s acute toxicity and sublethal and transgenerational effects on both aphid species. The acute toxicity assessment revealed obvious insecticidal activity, with 24 h LC₅₀ values of 38.56 mg/L for R. padi and 33.71 mg/L for S. graminum. Sublethal exposure (LC₁₅ and LC₃₅ in R. padi; LC₃₅ in S. graminum) significantly reduced adult longevity and fecundity in the F₀ generation. In the F₁ generation, cyclaniliprole at LC₃₅ significantly reduced the fourth nymph stage in R. padi, whereas at LC₁₅, it shortened the third nymph stage duration in S. graminum compared to the control. Sublethal concentrations (LC₁₅ and LC₃₅) of cyclaniliprole significantly reduced age-stage-specific survival rate (s_xj), age-specific survival rate (l_x), age-specific maternity (l_xm_x), and age-stage life expectancy (e_xj) in the F₁ generation of R. padi, while only LC₃₅ decreased l_x, l_xm_x, and e_xj in S. graminum. Additionally, LC₃₅ significantly reduced the net reproductive rate (R₀) in the F₁ generation of R. padi compared to the control. These findings suggest that cyclaniliprole exhibit notable acute toxicity against both aphid species and that sublethal concentrations adversely affected the F₀ generation, with no observed hormetic effects in the F₁ generations of R. padi and S. graminum. The findings offer valuable insights for assessing the comprehensive insecticidal potential of cyclaniliprole. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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8 pages, 229 KB

Open AccessArticle

Susceptibility of Aedes aegypti Larvae to Temephos and Fenitrothion in Niamey (Niger) and Ouagadougou (Burkina Faso), Two West African Cities Recently Affected by Dengue

by Abdoul-Aziz Maiga, Aboubacar Sombié, Nicolas Zanré, Rahmatoulaye Maiga, Ibrahim Maman Laminou, Ali Doumma, Antoine Sanon and Athanase Badolo

Insects 2025, 16(9), 870; https://doi.org/10.3390/insects16090870 - 22 Aug 2025

Viewed by 1048

Abstract

In the absence of commercialized vaccines for most arboviruses, including dengue, chikungunya, and Zika, which are transmitted by Aedes aegypti, the management of vector populations to prevent disease transmission remains the cornerstone of arbovirus control strategies. Larviciding targets the early stages of [...] Read more.

In the absence of commercialized vaccines for most arboviruses, including dengue, chikungunya, and Zika, which are transmitted by Aedes aegypti, the management of vector populations to prevent disease transmission remains the cornerstone of arbovirus control strategies. Larviciding targets the early stages of the mosquito life cycle and subsequently reduces the capacity of adult population to transmit pathogens. Here, we report the susceptibility profile of Ae. aegypti larval populations from two West Africa cities, namely Niamey and Ouagadougou, to organophosphates larvicides. In Niamey, sampling was carried out using ovitraps at two sites, whereas in Ouagadougou, larvae were collected from three different types of larval containers at a single site. Temephos and fenitrothion were tested at six different concentrations each. Mosquito populations from Niamey and Ouagadougou were found susceptible to temephos and fenitrothion, with LD₅₀ < 0.015 mg/L and RR₅₀ < 5. However, Ae. aegypti populations from Ouagadougou showed reduced susceptibility to temephos compared to baseline data from 2016, as indicated by RR₅₀ values. This observation highlights the need for regular surveillance of larval susceptibility, as it may signal the emergence of temephos resistance in Ouagadougou. The acetylcholinesterase (AChE) mutation and the expression levels of metabolic genes Carboxy-/Cholinesterase (CCE) should be characterized to understand the molecular mechanisms underlying the observed phenotype response. Our results provide up-to-date data that could inform the potential deployment of these larvicides for the prevention and control of dengue and chikungunya outbreaks in Ouagadougou and Niamey. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

15 pages, 1849 KB

Open AccessArticle

Sublethal Effects of Abamectin and Acetamiprid on the Longevity, Fecundity and Detoxification Enzyme Activity of Rhopalosiphum padi

by Bokun Wang, Hongming Hui, Xingye Li, Xueqing Yang and Yuting Li

Insects 2025, 16(6), 629; https://doi.org/10.3390/insects16060629 - 15 Jun 2025

Viewed by 1304

Abstract

The bird cherry-oat aphid Rhopalosiphum padi (L.) poses a significant threat to wheat production, resulting in substantial yield reductions. Abamectin and acetamiprid are frequently utilized for management. This study assessed the sublethal effects of abamectin and acetamiprid on R. padi through life table [...] Read more.

The bird cherry-oat aphid Rhopalosiphum padi (L.) poses a significant threat to wheat production, resulting in substantial yield reductions. Abamectin and acetamiprid are frequently utilized for management. This study assessed the sublethal effects of abamectin and acetamiprid on R. padi through life table analysis and enzyme activity assays. At 24 h, the LC₁₀ and LC₃₀ values for abamectin to R. padi were 0.063 mg/L and 0.252 mg/L, respectively, while, for acetamiprid, the corresponding values were 0.065 and 0.293 mg/L. The results indicated that exposure to sublethal concentrations of abamectin (AB-LC₁₀) extended the longevity of R. padi F₀ generation, while acetamiprid (AC-LC₁₀ and AC-LC₃₀) decreased it. Furthermore, the fecundity of the F₀ generation was significantly reduced following exposure to AB-LC₃₀, AC-LC₁₀ and AC-LC₃₀. In the F₁ generation, exposure to sublethal concentrations of acetamiprid negatively impacted on R. padi, as evidenced by a significant reduction in longevity; fecundity and population parameters (R₀, r, λ, s_xj, l_x, l_xm_x, v_xj and e_xj). Conversely, sublethal concentrations of abamectin did not significantly affect these parameters. Additionally, population projections revealed a significantly smaller total population size of R. padi in the acetamiprid-exposed group compared to both the abamectin-exposed and control groups. Except these population-level effects, the activities of detoxification enzymes, including cytochrome P450 monooxygenases (P450), glutathione S-transferases (GST) and carboxylesterases (CarE), changed differently after treatments. These results suggest that sublethal concentrations of acetamiprid, but not abamectin, significantly inhibit the population growth of R. padi. These insights are crucial for R. padi control and facilitate the development of effective control strategies that take into account these sublethal effects in integrated pest management strategies targeting R. padi. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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14 pages, 1747 KB

Open AccessArticle

GSTD1 Mediates the Tolerance to Abamectin and Beta-Cypermethrin in the Fall Armyworm Spodoptera frugiperda

by Qian Ding, Yangyang Liu, Baoxiang Dai, Yujie Han, Yan Zhang, Zhongyuan Deng, Lixiang Wang and Xianchun Li

Insects 2025, 16(3), 299; https://doi.org/10.3390/insects16030299 - 12 Mar 2025

Cited by 4 | Viewed by 1492

Abstract

Glutathione S-transferase (GST) is a class of detoxifying enzymes in the second stage of insect metabolism and plays a key role in insecticide resistance. In this study, based on the transcriptome sequences of S. frugiperda, the full-length cDNA of SfGSTD1 was cloned [...] Read more.

Glutathione S-transferase (GST) is a class of detoxifying enzymes in the second stage of insect metabolism and plays a key role in insecticide resistance. In this study, based on the transcriptome sequences of S. frugiperda, the full-length cDNA of SfGSTD1 was cloned and characterized. The temporal and spatial expression pattern showed that SfGSTD1 was highly expressed in Malpighian tubules, which are key excretion organs. Knocking down SfGSTD1 reduced S. frugiperd tolerance to abamectin and beta-cypermethrin. The overexpression of SfGSTD1 enhanced the viability of Sf9 cell under abamectin and beta-cypermethrin treatment. Furthermore, SfGSTD1 was overexpressed in Drosophila melanogaster using the GAL4/UAS binary expression system, and this overexpression strain was also less susceptible to abamectin and beta-cypermethrin. The enzyme activity of recombinant SfGSTD1 could also be significantly inhibited by abamectin and beta-cypermethrin. Taken together, our findings indicate that SfGSTD1 might be involved in the tolerance of abamectin and beta-cypermethrin in S. frugiperda. And these results provide theoretical foundations for understanding the resistance mechanism of S. frugiperda to abamectin and beta-cypermethrin. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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15 pages, 1297 KB

Open AccessArticle

Assessing Temperature-Dependent Deltamethrin Toxicity in Various kdr Genotypes of Aedes aegypti Mosquitoes

by Joshua Kalmouni, Brook M. Jensen, Joshua Ain, Krijn P. Paaijmans and Silvie Huijben

Insects 2025, 16(3), 254; https://doi.org/10.3390/insects16030254 - 1 Mar 2025

Viewed by 2457

Abstract

Insecticide resistance surveillance systems for vector-borne diseases are crucial for early detection of resistance and the implementation of evidence-based resistance management strategies. While insecticide susceptibility bioassays are typically conducted under controlled laboratory conditions, mosquitoes in the field experience varying environmental conditions, with temperature [...] Read more.

Insecticide resistance surveillance systems for vector-borne diseases are crucial for early detection of resistance and the implementation of evidence-based resistance management strategies. While insecticide susceptibility bioassays are typically conducted under controlled laboratory conditions, mosquitoes in the field experience varying environmental conditions, with temperature being a key determinant. Understanding the relationship between temperature and insecticide toxicity is essential for interpreting and extrapolating assay results across different climate zones or more locally across days with different weather conditions. In this study, we examined Aedes aegypti mosquitoes with different genetic backgrounds of insecticide resistance. Mosquitoes were homozygous for the knockdown resistance (kdr) F1534C mutation, plus either (1) homozygous for the kdr 1016V wildtype allele, (2) homozygous for the kdr V1016I mutant allele, or (3) heterozygous genetic crosses. These three genotypes were exposed to deltamethrin using WHO tube tests at three temperatures (22 °C, 27 °C, and 32 °C) and varying dosages. LC50 values were determined for each genotype and temperature combination. A negative temperature coefficient was observed exclusively in female mosquitoes homozygous for the 1016V wildtype allele, indicating reduced pyrethroid toxicity at higher temperatures. No temperature–toxicity relationship was found in males of this genotype or in other genotypes of either sex. These findings suggest that temperature may interact with kdr mutations and possibly even sex, highlighting the complex interactions between genetic mutations and environmental factors, such as temperature, in determining the insecticide resistance phenotype. Given the wide distribution of Ae. aegypti, understanding how local climate conditions influence insecticide performance will help improve control strategies and slow resistance evolution, protecting public health efforts against mosquito-borne diseases Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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10 pages, 636 KB

Open AccessArticle

Fitness Costs in Diamondback Moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) Resistant to Lufenuron, A Chitin-Synthesis Inhibitor Insecticide

by Natalia C. Bermúdez, Nataly de la Pava, Deividy V. Nascimento, Lilian M. S. Ribeiro, Herbert A. A. Siqueira and Jorge B. Torres

Insects 2024, 15(11), 856; https://doi.org/10.3390/insects15110856 - 2 Nov 2024

Cited by 1 | Viewed by 2109

Abstract

The diamondback moth (DBM), Plutella xylostella, is the main pest of Brassicas crops worldwide, and its recorded resistance to 101 active ingredients indicates it is difficult to control. The purpose of this study was to investigate the hypothesis that P. xylostella has fitness [...] Read more.

The diamondback moth (DBM), Plutella xylostella, is the main pest of Brassicas crops worldwide, and its recorded resistance to 101 active ingredients indicates it is difficult to control. The purpose of this study was to investigate the hypothesis that P. xylostella has fitness costs associated with its resistance to lufenuron, a chitin-synthesis inhibitor insecticide. Thus, concentration–mortality bioassays were performed for susceptible (REC-S), resistant (BZR-R) populations, their progenies F1 and F1′, and one established population without selection pressure (BZR-Rns) after four generations. A fertility life table was used to assess the biological performance of the REC-S and BZR-R. BZR-Rns of P. xylostella. The larval stage, longevity, and survival differed between populations. The reproductive rate (R₀) was significantly lower in the F1 (♀R × ♂S) (28.19) and F1′ (♀S × ♂R) (34.06) progenies compared with their parents, but not with the relaxed BZR-Rns (39.39). The mean generation time (T), intrinsic rate of population growth (r_m), and doubling time (DT) differed between REC-S and progenies, with fitness of 0.52 and 0.64 for F1 and F1′, respectively. Overall, the results suggest that the resistance of P. xylostella to lufenuron is stable and that low fitness costs appear to be associated with resistance to lufenuron, although heterozygotes showed lower fitness than their parents. Strategies such as preserving refuge areas, rotation of modes of action, etc., are essential for resistance management and prolonging the efficacy of control agents; this highlights the importance of integrated insecticide resistance management. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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12 pages, 2325 KB

Open AccessArticle

Crossbreeding and Backcrossing in the Pyrethroid-Resistant Ladybird Beetle Eriopis connexa (Germar) Determines Resistance in Offspring

by Alice S. Rodrigues, Paulo R. R. Barbosa, Deividy V. Nascimento and Jorge B. Torres

Insects 2024, 15(11), 853; https://doi.org/10.3390/insects15110853 - 31 Oct 2024

Cited by 1 | Viewed by 1260

Abstract

The conservation of the predatory ladybird beetle, Eriopis connexa (Germar) after its release also relies on its resistance and the performance of its progenies. When resistant individuals are released or evolve in the field through mating with susceptible pairs, we anticipate that they [...] Read more.

The conservation of the predatory ladybird beetle, Eriopis connexa (Germar) after its release also relies on its resistance and the performance of its progenies. When resistant individuals are released or evolve in the field through mating with susceptible pairs, we anticipate that they will generate a resistant progeny, inheriting the resistance to lambda-cyhalothrin through an autosomal mechanism. The susceptibility of a field-collected population (EcGA) was characterized and determined by the performance of their progenies generated through mating with a resistant parent (EcViR). We paired virgin adults from the EcGA and EcViR populations, observing how their progenies developed, reproduced, and survived when exposed to dried lambda-cyhalothrin residues applied at field rates. Adults from the EcGA population were ~200-fold more susceptible than those of the EcViR population. Developmental times from larva to adult emergence for EcGA individuals were delayed by approximately 6 days and generated smaller adults compared to EcViR and their progenies. The egg production did not differ across parents and progenies, but females from EcGA and EcGA × EcViR progenies produced 130 more eggs in comparison to EcViR females during the 35-day evaluation period. Exposure to lambda-cyhalothrin resulted in 77.4 to 100% survival for adults from EcViR × EcGA progenies and EcViR parents, while EcGA and the population standard for susceptibility maintained in the laboratory (EcFM) did not survive the insecticide exposure. These findings indicate that field crosses between EcViR and EcGA will improve their progenies’ biological performance compared to the EcViR parents and will maintain a high lambda-cyhalothrin survival rate. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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12 pages, 3994 KB

Open AccessArticle

Insecticide Resistance in Aedes aegypti from the National Capital Region of the Philippines

by Richard Paul B. Malijan, Jason R. Angeles, Ariza Minelle A. Apilado, Mary Ann T. Ammugauan and Ferdinand V. Salazar

Insects 2024, 15(10), 782; https://doi.org/10.3390/insects15100782 - 9 Oct 2024

Cited by 2 | Viewed by 11033

Abstract

Human arboviral diseases such as dengue, chikungunya, and Zika can be transmitted by the mosquito Aedes aegypti. The insecticide-based vector control strategy is critical in reducing transmission of these Aedes-borne diseases but is threatened mainly by the emergence of insecticide resistance. [...] Read more.

Human arboviral diseases such as dengue, chikungunya, and Zika can be transmitted by the mosquito Aedes aegypti. The insecticide-based vector control strategy is critical in reducing transmission of these Aedes-borne diseases but is threatened mainly by the emergence of insecticide resistance. Adult Ae. aegypti from the National Capital Region (NCR), Philippines, were subjected to bioassays to determine their susceptibility to diagnostic doses of pyrethroid, organochlorine, and organophosphate insecticides following the standard World Health Organization insecticide susceptibility test. This study reports the detection of insecticide resistance to pyrethroids and organochlorine in Ae. aegypti from the Philippines for the first time. Most of the Ae. aegypti populations from NCR exhibited phenotypic resistance to permethrin, etofenprox, and DDT. Varying resistance levels to deltamethrin, cyfluthrin, and lambda-cyhalothrin were observed in the different mosquito populations, while all populations tested to malathion were susceptible to this organophosphate. This finding should alert public health authorities to consider modifying the existing vector management package for greater control efficacy. Best practices proven to prevent or delay the development of insecticide resistance, such as insecticide rotation, should also be implemented, while alternative chemicals with a different mode of action should be explored to ensure the continuing efficacy of program interventions. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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15 pages, 1539 KB

Open AccessArticle

Genome-Wide Search for Gene Mutations Likely Conferring Insecticide Resistance in the Common Bed Bug, Cimex lectularius

by Kouhei Toga, Fumiko Kimoto, Hiroki Fujii and Hidemasa Bono

Insects 2024, 15(10), 737; https://doi.org/10.3390/insects15100737 - 24 Sep 2024

Cited by 1 | Viewed by 5401

Abstract

Insecticide resistance in the bed bug Cimex lectularius is poorly understood due to the lack of genome sequences for resistant strains. In Japan, we identified a resistant strain of C. lectularius that exhibits a higher pyrethroid resistance ratio compared to many previously discovered [...] Read more.

Insecticide resistance in the bed bug Cimex lectularius is poorly understood due to the lack of genome sequences for resistant strains. In Japan, we identified a resistant strain of C. lectularius that exhibits a higher pyrethroid resistance ratio compared to many previously discovered strains. We sequenced the genomes of the pyrethroid-resistant and susceptible strains using long-read sequencing, resulting in the construction of highly contiguous genomes (N50 of the resistant strain: 2.1 Mb and N50 of the susceptible strain: 1.5 Mb). Gene prediction was performed by BRAKER3, and the functional annotation was performed by the Fanflow4insects workflow. Next, we compared their amino acid sequences to identify gene mutations, identifying 729 mutated transcripts that were specific to the resistant strain. Among them, those defined previously as resistance genes were included. Additionally, enrichment analysis implicated DNA damage response, cell cycle regulation, insulin metabolism, and lysosomes in the development of pyrethroid resistance. Genome editing of these genes can provide insights into the evolution and mechanisms of insecticide resistance. This study expanded the target genes to monitor allele distribution and frequency changes, which will likely contribute to the assessment of resistance levels. These findings highlight the potential of genome-wide approaches to understand insecticide resistance in bed bugs. Full article

(This article belongs to the Special Issue Insecticide Resistance and Toxicology: Challenges in Pest Management and Basic Research—2nd Edition)

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