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2.
Pest Manag Sci ; 78(1): 296-303, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34487617

RESUMO

BACKGROUND: Hyblaea puera, commonly known as the teak defoliator, is a serious pest in teak plantations. Despite the availability of control measures, this pest causes losses in yield and quality of timber through voracious feeding. RNA interference (RNAi) is a promising strategy for the control of this pest. Chitin metabolism, which is vital for the growth and development of arthropods, is a potential target for developing RNAi-based insecticides. RESULTS: To assess the effects of chitin metabolism inhibition, H. puera larvae were treated with a chitin synthesis inhibitor, diflubenzuron (DFB). DFB treatment caused pupal deformities and disrupted eclosion. Partial gene sequences for three key genes of H. puera chitin metabolism were cloned and sequenced: chitin synthase 1 (HpCHS1), chitinase-h (HpChi-h) and ecdysone receptor (HpEcR). Feeding dsRNA cognate for these three target genes to the first instar of H. puera resulted in mortality and reduction in the corresponding transcript levels as assessed through qRT-PCR. This is the first report of RNAi in this forestry pest. The highest mortality was 45.9%, in response to dsHpEcR treatment; HpChi-h transcripts were the most down-regulated in response to dsHpEcR feeding. DsHpEcR RNAi resulted in growth inhibition and molting arrest. The mortalities were 29.7% and 32.4% for dsHpCHS1 and dsHpChi-h feeding, respectively. CONCLUSION: Chitin metabolism could be a potential target for RNAi-based control of H. puera, and HpCHS1, HpChi-h and HpEcR could be suitable target genes. However, the RNAi efficacy needs to be improved through formulations that improve stability and uptake, and employing better delivery strategies. © 2021 Society of Chemical Industry.


Assuntos
Quitina/metabolismo , Controle de Insetos , Mariposas , Animais , Quitina Sintase/genética , Agricultura Florestal , Larva/genética , Larva/metabolismo , Mariposas/genética , Mariposas/metabolismo , Interferência de RNA
3.
Colloids Surf B Biointerfaces ; 209(Pt 2): 112176, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34785423

RESUMO

Although safe and eco-friendly botanical pesticides have been intensively promoted to combat pest attacks in agriculture, but their stability and efficacies remain an issue for their wide acceptability as sustained and effective approaches. The purpose of this work was to develop stable neem oil based nano-emulsion (NE) formulation with enhanced activity employing suitable bio-inspired adjuvant. So, Neem NEs (with and without) natural adjuvants (Cymbopogon citratus and Prosopis juliflora) in different concentrations were prepared and quality parameters dictating kinetic stability, acidity/alkalinity, viscosity, droplet size, zeta potential, surface tension, stability and compatibility were monitored using Viscometer, Zetasizer, Surface Tensiometer, High Performance Liquid Chromatography (HPLC) and Fourier Transform Infrared Spectroscopy (FTIR). Nano-emulsion biosynthesis optimization studies suggested that slightly acidic (5.9-6.5) NE is kinetically stable with no phase separation; creaming or crystallization may be due to botanical adjuvant (lemongrass oil). Findings proved that Prosopis juliflora, acted as bio-polymeric adjuvant to stabilize NE by increasing Brownian motion and weakening the attractive forces with smaller droplets (25-50 nm), low zeta potential (-30 mV) and poly-dispersive index (<0.3). Botanical adjuvant (30%) based NE with optimum viscosity (98.8cPs) can give long term storage stability and improved adhesiveness and wetting with reduced surface tension and contact angle. FT-IR analysis assured azadirachtin's stability and compatibility with adjuvant. With negligible degradation (1.42%) and higher half-life (t1/2) of 492.95 days, natural adjuvant based NE is substantially stable formulation, may be due to presence of glycosidic and phenolics compounds. Neem 20NE (with 30% adjuvant) exhibited remarkable insecticidal activity (91.24%) against whitefly (Bemisia tabaci G.) in brinjal (Solanum melongena) as evidenced by in-vivo assay. Results thus obtained suggest, bio-pesticide formulation may be used as safer alternative to chemical pesticides to minimize pesticide residues and presence of natural adjuvant may improves the stability and efficacy of biopesticides for safe crop protection in organic agriculture and Integrated Pest Management.


Assuntos
Adjuvantes Imunológicos , Controle de Insetos , Bioengenharia , Emulsões , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Acta Trop ; 225: 106157, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34634265

RESUMO

The Pan American Health Organization (PAHO) has defined Chagas Disease hotspots in Central America associated with the vector Triatoma spp. Triatoma dimidiata is a native vector adapted to multiple environments, including intra-domestic and peri-domestic habitats. A multi-institutional project named "Alliances for the elimination of Chagas in Central America" was created to help reduce the incidence of the disease in the region. Activities performed in the field as part of the project included aspects of vector surveillance and control, improvement of houses, diagnosis and treatment of individuals, health promotion, training of human resources and identification of access barriers to diagnosis and treatment. As a base line study, eleven villages, comprised of 1,572 households, were entomologically evaluated (83.4% overall participation); five were found to have very high infestation rates (>20%), three had high infestation rates (8-20%) and three had low-infestation rates (<8%), coinciding with the category of infestation-risk of the houses within each village. Serological tests were carried out in 812 people (>80% participation) in two of the 11 villages and none of the 128 children tested, less than 5 years of age, were positive for Trypanosoma cruzi infection. Community participation in all the activities was high (>70%). The collaboration between several subnational, national, and international institutions, each with specific roles, promoted community participation in the activities of vector control and patient care, thus, establishing a baseline to continue implementing and monitoring project progress.


Assuntos
Doença de Chagas , Triatoma , Trypanosoma cruzi , Animais , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Doença de Chagas/prevenção & controle , Criança , Guatemala/epidemiologia , Humanos , Controle de Insetos , Insetos Vetores , Saúde Pública
5.
Methods Mol Biol ; 2360: 279-294, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34495521

RESUMO

RNA interference (RNAi) is a powerful mechanism that can be exploited not only for physiology research but also for designing insect pest management approaches. Some insects cause harm by vectoring diseases dangerous to humans, livestock, or plants or by damaging crops. For at least a decade now, different insect control strategies that induce RNAi by delivering double stranded RNA (dsRNA) targeting essential genes have been proposed. Here, we focus on nontransgenic RNAi-based approaches that use oral delivery of dsRNA through feeding of inactivated bacteria to produce RNAi in disease vectors and in a crop pest. This potential pest management method could be easily adapted to target different genes or similar organisms.


Assuntos
Escherichia coli , Animais , Escherichia coli/genética , Humanos , Controle de Insetos , Insetos/genética , Interferência de RNA , RNA de Cadeia Dupla/genética
6.
Methods Mol Biol ; 2360: 253-277, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34495520

RESUMO

RNAi is a gene-silencing mechanism conserved in the vast majority of eukaryotes. It is widely used to study gene function in animals due to the ease of eliciting gene knockdown. Beyond research applications, RNAi technology based on exogenous dsRNA is a promising candidate for next generation insect pest control. An advantage of using RNAi is that design of dsRNA essentially requires only the sequence of the target gene. The greatest challenge, however, is dsRNA delivery for large-scale insect control. Delivery methods that have widely been used are oral, injection, or via soaking. Unfortunately, each insect presents its own challenges owing to the differences in the presence of dsRNA degrading enzymes, cellular uptake efficiency, expression of core RNAi machinery, the nature of the target gene, the concentration and persistence of the dsRNA, as well as the particular way of feeding of each insect, which together cause variations in the efficiency of RNAi. In this chapter, a protocol for the synthetic production of dsRNA is described along with three methods for delivery that have been successful in one of the more problematic insects, Diaphorina citri.


Assuntos
Hemípteros , Animais , Hemípteros/genética , Controle de Insetos , Proteínas de Insetos/genética , Interferência de RNA , RNA de Cadeia Dupla/genética
7.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34718645

RESUMO

Radiation is considered as a promising insect pest control strategy for minimizing postharvest yield losses. Among various techniques, irradiation is a method of choice as it induces lethal biochemical or molecular changes that cause a downstream cascade of abrupt physiological abnormalities at the cellular level. In this study, we evaluated the effect of 60Co-γ radiation on various developmental stages of Zeugodacus cucurbitae Coquillett and subsequent carry-over effects on the progeny. For this purpose, we treated eggs with 30- and 50-Gy radiation doses of 60Co-γ. We found that radiation significantly affected cellular antioxidants, insect morphology, and gene expression profiles. Our results indicate that in response to various doses of irradiation reactive oxygen species, catalase, peroxidase, and superoxide dismutase activities were increased along with a significant increase in the malondialdehyde (MDA) content. We observed higher mortality rates during the pupal stage of the insects that hatched from irradiated eggs (50 Gy). Furthermore, the life span of the adults was reduced in response to 50 Gy radiation. The negative effects carried over to the next generation were marked by significantly lower fecundity in the F1 generation of the irradiation groups as compared to control. The radiation induced morphological abnormalities at the pupal, as well as the adult, stages. Furthermore, variations in the gene expression following irradiation are discussed. Taken together, our results signify the utility of 60Co-γ radiation for fruit fly postharvest management.


Assuntos
Apoptose/efeitos da radiação , Raios gama , Expressão Gênica/efeitos da radiação , Tephritidae/efeitos da radiação , Animais , Antioxidantes/metabolismo , Antioxidantes/efeitos da radiação , Apoptose/genética , Catalase/metabolismo , Catalase/efeitos da radiação , Radioisótopos de Cobalto/farmacologia , Controle de Insetos/métodos , Proteínas de Insetos/metabolismo , Proteínas de Insetos/efeitos da radiação , Larva/genética , Larva/metabolismo , Larva/fisiologia , Larva/efeitos da radiação , Longevidade/efeitos da radiação , Malondialdeído/metabolismo , Malondialdeído/efeitos da radiação , Peroxidase/metabolismo , Peroxidase/efeitos da radiação , Controle de Pragas/métodos , Pupa/genética , Pupa/metabolismo , Pupa/fisiologia , Pupa/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Espécies Reativas de Oxigênio/efeitos da radiação , Tephritidae/genética , Tephritidae/metabolismo , Tephritidae/fisiologia
8.
PLoS One ; 16(10): e0257952, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34644343

RESUMO

Wheat (Triticum aestivum L.) production is significantly altered by the infestation of sucking insects, particularly aphids. Chemical sprays are not recommended for the management of aphids as wheat grains are consumed soon after crop harvests. Therefore, determining the susceptibility of different wheat genotypes and selecting the most tolerant genotype could significantly lower aphid infestation. This study evaluated the susceptibility of six different wheat genotypes ('Sehar-2006', 'Shafaq-2006', 'Faisalabad-2008', 'Lasani-2008', 'Millat-2011' and 'Punjab-2011') to three aphid species (Rhopalosiphum padi Linnaeus, Schizaphis graminum Rondani, Sitobion avenae Fabricius) at various growth stages. Seed dressing with insecticides and plant extracts were also evaluated for their efficacy to reduce the incidence of these aphid species. Afterwards, an economic analysis was performed to compute cost-benefit ratio and assess the economic feasibility for the use of insecticides and plant extracts. Aphids' infestation was recorded from the seedling stage and their population gradually increased as growth progressed towards tillering, stem elongation, heading, dough and ripening stages. The most susceptible growth stage was heading with 21.89 aphids/tiller followed by stem elongation (14.89 aphids/tiller) and dough stage (13.56 aphids/tiller). The genotype 'Punjab-2011' recorded the lower aphid infestation than 'Faisalabad-2008', 'Sehar-2006', 'Lasani-2008' and 'Shafaq-2006'. Rhopalosiphum padi appeared during mid-February, whereas S. graminum and S. avenae appeared during first week of March. Significant differences were recorded for losses in number of grains/spike and 1000-grain weight among tested wheat genotypes. The aphid population had non-significant correlation with yield-related traits. Hicap proved the most effective for the management of aphid species followed by Hombre and Husk among tested seed dressers, while Citrullus colocynthis L. and Moringa oleifera Lam. plant extracts exhibited the highest efficacy among different plant extracts used in the study. Economic analysis depicted that use of Hombre and Hicap resulted in the highest income and benefit cost ratio. Therefore, use of genotype Punjab-2011' and seed dressing with Hombre and Hicap can be successfully used to lower aphid infestation and get higher economic returns for wheat crop.


Assuntos
Controle de Insetos/métodos , Controle Biológico de Vetores/métodos , Triticum/genética , Predisposição Genética para Doença , Fenótipo
9.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34655291

RESUMO

Crop resistance plays a role in preventing aphid damage, benefiting food production industries, but its effects are limited due to aphid adaptation and phenotypic plasticity. Therefore, furthering understanding of aphid-crop interactions will improve our ability to protect crops from aphids. To determine how aphids adapt to resistant varieties of wheat, Triticum aestivum L. over time, we performed a laboratory experiment to assess the multi-generational effects of three wheat varieties, Batis, Ww2730, and Xiaoyan22, with different resistance levels on the fitness of Sitobion avenae (Fab.) (Hemiptera: Aphididae). The results showed that Ww2730 and Xiaoyan22 were more resistant than Batis to S. avenae, regardless of whether the aphids were newly introduced or had been acclimated before being introduced to the three wheat varieties. However, the effect of resistance on aphid life-history traits was time dependent. Aphid weigh gain increased and they development faster of the acclimated generation compared to the newly introduced generation on all three varieties. And the fecundity on the three varieties and net reproduction rates on Batis and Xiaoyan22 significantly decreased. Aphid fitness in terms of individual life-history parameters improved, whereas aphid fitness in terms of reproductive decreased, and a convergence effect, the difference gaps and standard errors of all life-history traits among the three acclimated populations had narrowed and were less than those in the three first-generation populations, was observed during the 3-mo experimental period. We suggested that S. avenae could rapidly respond to wheat resistance through life-history plasticity.


Assuntos
Afídeos , Controle de Insetos , Triticum , Animais , Afídeos/crescimento & desenvolvimento , Afídeos/fisiologia , Produtos Agrícolas , Fertilidade , Traços de História de Vida , Defesa das Plantas contra Herbivoria , Folhas de Planta , Reprodução
10.
CRISPR J ; 4(5): 628-630, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34661432
11.
Molecules ; 26(19)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34641444

RESUMO

The family Tephritidae (Diptera) includes species that are highly invasive and harmful to crops. Due to globalization, international trade, and human displacement, their spread is continuously increasing. Unfortunately, the control of tephritid flies is still closely linked to the use of synthetic insecticides, which are responsible for detrimental effects on the environment and human health. Recently, research is looking for alternative and more eco-friendly tools to be adopted in Integrated Pest Management (IPM) programs. In this regard, essential oils (EOs) and their main compounds represent a promising alternative to chemical insecticides. EOs are made up of phytoconstituents formed from the secondary metabolism of many plants and can act as attractants or toxics, depending on the dose. Because of this unique characteristic, EOs and their main constituents are promising tools that can be used both in Sterile Insect Technique (SIT) programs and in the "lure and kill" technique, exploiting the attractiveness of the product in the former case and its toxicity in the latter. In this article, current knowledge on the biological and behavioral effects of EOs and their main constituents on tephritid fruit flies is reviewed, mainly focusing on species belonging to the Anastrepha, Bactrocera, Ceratitis, and Zeugodacus genera. The mechanisms of action of EOs, their real-world applications, and challenges related to their use in IPM are critically discussed.


Assuntos
Controle de Insetos/métodos , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Tephritidae/efeitos dos fármacos , Animais
12.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34536079

RESUMO

Native to the neotropics, the avocado seed moth Stenoma catenifer Walsingham (Lepidoptera: Elachistidae) is a specialist pest of the family Lauraceae and considered one of the most important pests of avocados worldwide. However, little is known regarding its spatial distribution within a single tree. Therefore, we designed a study to evaluate the effects of canopy height and aspect (i.e., side of the tree) on fruit infestation by S. catenifer larvae in avocados. The study was conducted in three commercial organic avocado orchards located in São Paulo, Brazil. At each orchard, 40 fruit from 30 random trees were sampled weekly from October 2017 through February 2018, evaluating the number of fruits infested by S. catenifer larvae at three tree heights (bottom, middle, and top). In addition, fruits on the ground were also sampled. We also evaluated the effect of the side of the tree where the fruits were collected, i.e., whether they were on the side facing the east (sunrise) or the west (sunset). Within the avocado canopy, the level of fruit infestation by S. catenifer larvae was significantly higher at the top of the trees than in the middle and bottom. Fruit on the ground had lower levels of infestation than those on the tree canopy. The level of fruit infestation was also higher on the side of avocado trees facing the east (sunrise). Understanding the within-tree distribution of S. catenifer will help to better target monitoring and control activities against this pest in avocados.


Assuntos
Demografia , Mariposas/fisiologia , Animais , Frutas , Controle de Insetos/métodos , Larva/efeitos dos fármacos , Larva/fisiologia , Persea , Árvores
13.
J Econ Entomol ; 114(5): 1950-1974, 2021 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-34516634

RESUMO

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) also known as spotted-wing drosophila (SWD), is a pest native to Southeast Asia. In the last few decades, the pest has expanded its range to affect all major European and American fruit production regions. SWD is a highly adaptive insect that is able to disperse, survive, and flourish under a range of environmental conditions. Infestation by SWD generates both direct and indirect economic impacts through yield losses, shorter shelf life of infested fruit, and increased production costs. Fresh markets, frozen berries, and fruit export programs have been impacted by the pest due to zero tolerance for fruit infestation. As SWD control programs rely heavily on insecticides, exceedance of maximum residue levels (MRLs) has also resulted in crop rejections. The economic impact of SWD has been particularly severe for organic operations, mainly due to the limited availability of effective insecticides. Integrated pest management (IPM) of SWD could significantly reduce chemical inputs but would require substantial changes to horticultural management practices. This review evaluates the most promising methods studied as part of an IPM strategy against SWD across the world. For each of the considered techniques, the effectiveness, impact, sustainability, and stage of development are discussed.


Assuntos
Drosophila , Inseticidas , Animais , Frutas , Controle de Insetos
14.
J Invertebr Pathol ; 185: 107666, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34530028

RESUMO

Beekeepers need sustainable control options to treat Nosema ceranae infection in colonies of western honey bees (Apis mellifera L.) they manage. Propolis is a natural product derived from plant resins and contains chemical compounds with potential antimicrobial activity against N. ceranae. Here, we determined the efficacy of propolis from A. mellifera (USA) and Tetrigona apicalis (stingless bees, Thailand) colonies as treatments for N. ceranae infection in honey bee workers. Newly emerged bees were individually fed 2 µL of 50% (w/v) sucrose solution containing 1 × 105N. ceranae spores. Following this, the infected bees were treated with 50% propolis extracted from A. mellifera or T. apicalis hives and fed in 50% sucrose solution (v/v). All bees were maintained at 34 ± 2 °C and 55 ± 5% RH. Dead bees were counted daily for 30 d to calculate survival. We also determined infection rate (# infected bees/100 bees), infectivity (number of spores per bee) and protein content in the hypopharyngeal glands and hemolymph on 7, 14, and 21 d post infection as measures of bee health. Propolis from both bee species significantly reduced bee mortality, infection rate and infectivity compared with those of untreated bees and led to significantly greater protein contents in hypopharyngeal glands and hemolymph in treated bees than in untreated ones (p < 0.0001). In conclusion, propolis from A. mellifera and T. apicalis colonies shows promise as a control against N. ceranae infection in honey bees.


Assuntos
Abelhas/fisiologia , Agentes de Controle Biológico/farmacologia , Nosema/fisiologia , Controle Biológico de Vetores , Própole/farmacologia , Animais , Controle de Insetos , Tailândia
15.
Environ Monit Assess ; 193(10): 625, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34480221

RESUMO

Controlling forest pests to maintain the sustainability of forests and ecosystem balance is one of the interests of modern forestry. In the evaluation of damage risks associated with forest pests, pheromone traps attract attention by providing early warnings. With the development of these traps in line with modern technology, more reliable data are obtained; these data are important in the identification and planning of pest management. In this study, a pheromone trap with electronic control unit was tested under field conditions. The capture of adult Ips sexdentatus under natural conditions during 103 days of the flying period was evaluated; 97.2% of the beetles captured in the trap were the target species. The comparison of the number of beetles recorded by the trap and manual counts revealed that the trap worked with an error margin of approximately 4%. However, no statistically significant difference was noted between these two counting methods. During the study, 59% of the total beetles were captured between May 27 and June 25. The average temperature at the period of the capture was 20.09 °C, average humidity was 66%, and average wind speed was 2.9 m/s. Of the captures, 73.9% occurred in the temperature range of 15-24.9 °C, 61.1% occurred in humidity range of 61-90%, 89.6% occurred at a wind speed of 0.3-5.4 m/s, and 77.3% occurred within the period from sunrise to sunset. When these four parameters were evaluated together, the most strongly associated parameter was daylight, followed by temperature, wind speed, and humidity.


Assuntos
Besouros , Gorgulhos , Animais , Ecossistema , Eletrônica , Monitoramento Ambiental , Controle de Insetos , Feromônios
16.
J Invertebr Pathol ; 185: 107657, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34487747

RESUMO

Bacillus thuringiensis (Bt) has been used globally as a biopesticide for effective and environmentally friendly pest control. Research has intensified following the development of resistance by lepidopteran species to Bt insecticidal crystal proteins. Discovering new Bt strains with novel toxin properties which can overcome resistance is one of the strategies to improve pesticide sustainability. The genome of the Bacillus thuringiensis LTS290 strain was sequenced and assembled in 252 contigs containing a total of 6,391,328 bp. The novel cry79Aa1 gene from this strain was identified and cloned. Cry79Aa1 contains 729 amino acid residues and a molecular mass of 84.8 kDa by SDS-PAGE analysis. Cry79Aa1 was found to be active against the lepidopteran larvae of Spodoptera exigua, Helicoverpa armigera, and Plutella xylostella with LC50 values of 13.627 µg/mL, 42.8 µg/mL, and 38.086 µg/mL, respectively. However, Cry79Aa1 protein showed almost no insecticidal activity against Leguminivora glycinivorella, although some degree of growth retardation was observed.


Assuntos
Toxinas de Bacillus thuringiensis/genética , Bacillus thuringiensis/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Mariposas/efeitos dos fármacos , Animais , Bacillus thuringiensis/metabolismo , Toxinas de Bacillus thuringiensis/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Controle de Insetos , Mariposas/crescimento & desenvolvimento , Controle Biológico de Vetores , Spodoptera/efeitos dos fármacos , Spodoptera/crescimento & desenvolvimento
17.
PLoS Negl Trop Dis ; 15(8): e0009101, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34370731

RESUMO

BACKGROUND: In 2005, Bangladesh, India and Nepal agreed to eliminate visceral leishmaniasis (VL) as a public health problem. The approach to this was through improved case detection and treatment, and controlling transmission by the sand fly vector Phlebotomus argentipes, with indoor residual spraying (IRS) of insecticide. Initially, India applied DDT with stirrup pumps for IRS, however, this did not reduce transmission. After 2015 onwards, the pyrethroid alpha-cypermethrin was applied with compression pumps, and entomological surveillance was initiated in 2016. METHODS: Eight sentinel sites were established in the Indian states of Bihar, Jharkhand and West Bengal. IRS coverage was monitored by household survey, quality of insecticide application was measured by HPLC, presence and abundance of the VL vector was monitored by CDC light traps, insecticide resistance was measured with WHO diagnostic assays and case incidence was determined from the VL case register KAMIS. RESULTS: Complete treatment of houses with IRS increased across all sites from 57% in 2016 to 70% of houses in 2019, rising to >80% if partial house IRS coverage is included (except West Bengal). The quality of insecticide application has improved compared to previous studies, average doses of insecticide on filters papers ranged from 1.52 times the target dose of 25mg/m2 alpha-cypermethrin in 2019 to 1.67 times in 2018. Resistance to DDT has continued to increase, but the vector was not resistant to carbamates, organophosphates or pyrethroids. The annual and seasonal abundance of P. argentipes declined between 2016 to 2019 with an overall infection rate of 0.03%. This was associated with a decline in VL incidence for the blocks represented by the sentinel sites from 1.16 per 10,000 population in 2016 to 0.51 per 10,000 in 2019. CONCLUSION: Through effective case detection and management reducing the infection reservoirs for P. argentipes in the human population combined with IRS keeping P. argentipes abundance and infectivity low has reduced VL transmission. This combination of effective case management and vector control has now brought India within reach of the VL elimination targets.


Assuntos
Controle de Insetos/normas , Insetos Vetores/parasitologia , Inseticidas/administração & dosagem , Leishmaniose Visceral/prevenção & controle , Phlebotomus/parasitologia , Animais , Bioensaio , Feminino , Humanos , Índia/epidemiologia , Controle de Insetos/métodos , Resistência a Inseticidas , Leishmaniose Visceral/epidemiologia , Psychodidae/efeitos dos fármacos , Piretrinas/administração & dosagem
18.
Biomolecules ; 11(7)2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34356655

RESUMO

Calcium (Ca2+) homeostasis is vital for insect development and metabolism, and the endoplasmic reticulum (ER) is a major intracellular reservoir for Ca2+. The inositol 1,4,5- triphosphate receptor (IP3R) and ryanodine receptor (RyR) are large homotetrameric channels associated with the ER and serve as two major actors in ER-derived Ca2+ supply. Most of the knowledge on these receptors derives from mammalian systems that possess three genes for each receptor. These studies have inspired work on synonymous receptors in insects, which encode a single IP3R and RyR. In the current review, we focus on a fundamental, common question: "why do insect cells possess two Ca2+ channel receptors in the ER?". Through a comparative approach, this review covers the discovery of RyRs and IP3Rs, examines their structures/functions, the pathways that they interact with, and their potential as target sites in pest control. Although insects RyRs and IP3Rs share structural similarities, they are phylogenetically distinct, have their own structural organization, regulatory mechanisms, and expression patterns, which explains their functional distinction. Nevertheless, both have great potential as target sites in pest control, with RyRs currently being targeted by commercial insecticide, the diamides.


Assuntos
Receptores de Inositol 1,4,5-Trifosfato/química , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Proteínas de Insetos/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/química , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Animais , Sinalização do Cálcio , Controle de Insetos , Proteínas de Insetos/química , Insetos/fisiologia , Resistência a Inseticidas , Metabolismo dos Lipídeos , Mamíferos/metabolismo
19.
Acta Trop ; 223: 106076, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34358514

RESUMO

Considering the fact that new, safe and incorporable treatment alternatives to therapeutic prophylaxis for tungiasis are lacking and sometimes proving difficult, this present study evaluated the potentials of integrating control approach involving focal premise treatment using 5% emulsifiable concentrate of cypermethrin, and topical application of Piper guineense oil with personal protection. Of the 90 houses selected, their floors were classified into paved rooms & unpaved verandas, paved verandas & unpaved rooms, paved rooms & verandas, and unpaved rooms & verandas, and tested for the presence of sand fleas using the sweeping and beating as well as soil collection and extraction by tullgren funnel method before fumigation. A total of 100 individuals partitioned into four groups of 25 individuals each were assigned 3%, 5%, 10% and 15% of P. guineense oil irrespective of stages of embedded fleas. The mean of sand fleas decreased from 1.14, 0.07, 0.21, and 1.66 to 0.37, 0.02, 0.09 and 1.08 after two weeks of single spray compared to the untreated location (p <  0.001). Furthermore, the mean lesions of stage I reduced to 0 after 2 to 6 days of 3%, 5%, 10% and 15% ointment application, and stage II and III after 10 to 12 days of 10% and 15% application respectively. The difference between tungiasis stages and exposure time for P. guineense ointment was highly significant p = 0.007 and p = 0.0002. Notable reduction in severity score of acute and chronic tungiasis was observed thus indicating effectiveness of the topical ointment. Hexanolic oil extracts of P. guineense in 10% and 15% concentration would kill embedded sand flea and ameliorate the sufferings in endemic settings.


Assuntos
Infestações por Pulgas , Controle de Insetos , Óleos Vegetais/uso terapêutico , Sifonápteros , Tungíase , Animais , Infestações por Pulgas/prevenção & controle , Fumigação , Humanos , Nigéria , Piper/química , Tunga , Tungíase/tratamento farmacológico , Tungíase/epidemiologia , Tungíase/prevenção & controle
20.
J Econ Entomol ; 114(5): 2162-2171, 2021 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-34378779

RESUMO

The ambrosia beetle Xylosandrus germanus (Blandford) is an invasive pest that has caused tree decline and death in numerous NY dwarf apple orchards during the past ten years, despite efforts to control them using trunk sprays of chlorpyrifos or pyrethroids, either alone or combined with the repellent verbenone. From 2017 to 2019, we tested trunk applications of different repellents and plant defense compounds for protection against X. germanus in potted apple trees adjacent to infested orchards. Treatments included topical formulations of verbenone and methyl salicylate (MeSa), alone and in combination, at different rates and timings. Additional treatments evaluated included the systemic acquired resistance activators acibenzolar-S-methyl, Reynoutria sachalinensis extract, and salicylic acid. The combination verbenone+MeSa treatments had the lowest incidences of attack sites and galleries containing adults or brood, although results varied among years. In a separate trial, we found no significant difference in numbers of adults caught in ethanol-baited traps placed 5-20 m from an apple bolt treated with the verbenone+MeSa repellent, suggesting that the repellent's effect did not extend to those distances from the treated target. Cross-sectional discs of trunk tissue sampled in August were analyzed for levels of phytohormones. Quantities of ergosterol, abscissic acid, salicylic acid, jasmonic acid, methyl salicylate, methyl jasmonate, trans-cinnamic acid, and indole-3-cinnamic acid did not significantly vary across treatments; however, trees with greater beetle damage contained higher levels of jasmonic and salicylic acid, which are key molecules in plant defense pathways.


Assuntos
Besouros , Malus , Gorgulhos , Animais , Estudos Transversais , Controle de Insetos , Árvores
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