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1.
PLoS One ; 15(8): e0236791, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760094

RESUMO

In May 2010 the large white butterfly, Pieris brassicae L. (Lepidoptera: Pieridae), was discovered to have established in New Zealand. It is a Palearctic species that-due to its wide host plant range within the Brassicaceae-was regarded as a risk to New Zealand's native brassicas. New Zealand has 83 native species of Brassicaceae including 81 that are endemic, and many are threatened by both habitat loss and herbivory by other organisms. Initially a program was implemented to slow its spread, then an eradication attempt commenced in November 2012. The P. brassicae population was distributed over an area of approximately 100 km2 primarily in urban residential gardens. The eradication attempt involved promoting public engagement and reports of sightings, including offering a bounty for a two week period, systematically searching gardens for P. brassicae and its host plants, removing host plants, ground-based spraying of insecticide to kill eggs and larvae, searching for pupae, capturing adults with nets, and augmenting natural enemy populations. The attempt was supported by research that helped to progressively refine the eradication strategy and evaluate its performance. The last New Zealand detection of P. brassicae occurred on 16 December 2014, the eradication program ceased on 4 June 2016 and P. brassicae was officially declared eradicated from New Zealand on 22 November 2016, 6.5 years after it was first detected and 4 years after the eradication attempt commenced. This is the first species of butterfly ever to have been eradicated worldwide.


Assuntos
Brassicaceae/parasitologia , Borboletas/crescimento & desenvolvimento , Animais , Borboletas/fisiologia , Ecossistema , Herbivoria , Controle de Insetos , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Larva/fisiologia , Nova Zelândia , Óvulo/efeitos dos fármacos , Vespas/fisiologia
2.
Nature ; 584(7822): 584-588, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32788724

RESUMO

Locust plagues threaten agricultural and environmental safety throughout the world1,2. Aggregation pheromones have a crucial role in the transition of locusts from a solitary form to the devastating gregarious form and the formation of large-scale swarms3,4. However, none of the candidate compounds reported5-7 meet all the criteria for a locust aggregation pheromone. Here, using behavioural assays, electrophysiological recording, olfactory receptor characterization and field experiments, we demonstrate that 4-vinylanisole (4VA) (also known as 4-methoxystyrene) is an aggregation pheromone of the migratory locust (Locusta migratoria). Both gregarious and solitary locusts are strongly attracted to 4VA, regardless of age and sex. Although it is emitted specifically by gregarious locusts, 4VA production can be triggered by aggregation of four to five solitary locusts. It elicits responses specifically from basiconic sensilla on locust antennae. We also identified OR35 as a specific olfactory receptor of 4VA. Knockout of OR35 using CRISPR-Cas9 markedly reduced the electrophysiological responses of the antennae and impaired 4VA behavioural attractiveness. Finally, field trapping experiments verified the attractiveness of 4VA to experimental and wild populations. These findings identify a locust aggregation pheromone and provide insights for the development of novel control strategies for locusts.


Assuntos
Locusta migratoria/efeitos dos fármacos , Locusta migratoria/fisiologia , Feromônios/metabolismo , Feromônios/farmacologia , Estirenos/metabolismo , Estirenos/farmacologia , Envelhecimento , Migração Animal/efeitos dos fármacos , Animais , Ecossistema , Feminino , Controle de Insetos , Locusta migratoria/química , Masculino , Densidade Demográfica , Receptores Odorantes/deficiência , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Sensilas/fisiologia
3.
PLoS Negl Trop Dis ; 14(7): e0008404, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32687497

RESUMO

The northeastern semiarid region stands out in the Brazilian context regarding the eco-epidemiology of Chagas disease, in which Triatoma brasiliensis is the main vector of Trypanosoma cruzi. Persistent house invasion threatens the relative levels of progress achieved over previous decades. We conducted an intervention trial with a five-year follow-up to assess the impacts of residual spraying with pyrethroid insecticides on house infestation with T. brasiliensis in 18 rural villages (242 houses) located in the Tauá, Ceará. House infestations were assessed by systematic manual searches for triatomines in every domestic and peridomestic habitat on five occasions. Triatomines were collected in peridomestic (57.5%), sylvatic (35.8%), and intradomiciliary (6.7%) habitats. The most important ecotopes of T. brasiliensis were containing roofing tiles, bricks or rocks (23.4% ± 9.1). Residual insecticide spraying substantially reduced baseline house infestation rates from 27.9% to 5.9% by 6 months post first spraying (MPS). The decline was substantially greater in intradomiciles (11.2% to 0.8%) than in peridomiciles (16.7% to 5%). The mean relative density of triatomines recovered its preintervention values at 14 MPS in intradomiciles, and in the main peridomestic ecotopes. The house infestation levels recorded at 14 MPS persisted thereafter despite all reinfested houses were selectively sprayed on every occasion. Overall average bug infection rates with T. cruzi in the five occasions were in intradomiciles (11.1%), peridomiciles (4.7%) and wild habitats (3.3%). In peridomicile T. cruzi infection rates decreased significantly at all stages after chemical intervention. In intradomicile, the only significant difference occurred at 20 MPS (7.7% to 30.8%). The vectorial capacity of T. brasiliensis, combined with its invasive potential from sylvatic sources and the limited effectiveness of chemical control in the harsh caatinga landscape, pose serious obstacles to the definite elimination of domestic transmission risks. Systematic vector surveillance supported by community participation and locally adapted environmental management measures are needed to reduce the risks of establishment of domestic transmission with T. cruzi in this region.


Assuntos
Controle de Insetos/métodos , Insetos Vetores/efeitos dos fármacos , Inseticidas/farmacologia , Triatoma/efeitos dos fármacos , Distribuição Animal , Animais , Brasil , Habitação , Humanos , Insetos Vetores/fisiologia , Piretrinas/farmacologia , Saúde da População Rural , Triatoma/fisiologia
4.
Artigo em Inglês | MEDLINE | ID: mdl-32613481

RESUMO

Plutella xylostella, is the main pest infesting Brassica crops, and products based on Bacillus thuringiensis (Bt) are frequently used in strategies for its biocontrol. The present study aimed to evaluate whether a Bt-based bioinsecticide affects the predation behavior of Ceraeochrysa cincta when preying on P. xylostella. Three larval instars of the predator and the eggs and second-instar larvae of the moth were used, with the prey either untreated or treated with a Bt-based product (Xentari®). Results showed that, the first larval instar of C. cincta presented a type II functional response when preying upon untreated eggs, and a type III response when preying upon Bt-treated eggs, while the second and third instars presented type II and III responses, respectively, in both situations. The predator's first and third larval instars presented a type II functional response when preying upon untreated larvae and a type III response when preying upon Bt-treated larvae. However, the predator's second-instar larvae showed a type II response in both treatments. The results obtained allowed us to conclude that the Bt-based insecticide tested affects the predation behavior of the first-instar larvae of C. cincta on eggs and of both the first- and third-instar larvae of this predator on P. xylostella larvae.


Assuntos
Bacillus thuringiensis/química , Controle de Insetos , Insetos/fisiologia , Inseticidas/administração & dosagem , Controle Biológico de Vetores , Comportamento Predatório , Animais , Brasil , Insetos/efeitos dos fármacos , Resistência a Inseticidas , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/fisiologia , Mariposas/crescimento & desenvolvimento , Óvulo/efeitos dos fármacos , Óvulo/crescimento & desenvolvimento
5.
PLoS One ; 15(7): e0229476, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32649703

RESUMO

Recent debates on insect decline require sound assessments on the relative drivers that may negatively impact insect populations. Often, baseline data rely on insect monitorings that integrate catches over long time periods. If, however, effects of time-critical environmental factors (e.g., light pollution) are of interest, higher temporal resolution of insect data is required during very specific time intervals (e.g., between dusk and dawn). Conventional time-critical insect trapping is labour-intensive (manual activation/deactivation) and temporally inaccurate as not all traps can be serviced synchronically at different sites. Also, temporal shifts of environmental conditions (e.g., sunset/sunrise) are not accounted for. We present a battery-driven automated insect flight-interception trap which samples insects during seven user-defined time intervals. A commercially available flight-interception trap is fitted to a turntable containing eight positions, seven of them holding cups and one consisting of a pass-through hole. While the cups sample insects during period of interest, the pass-through hole avoids unwanted sampling during time-intervals not of interest. Comparisons between two manual and two automated traps during 71 nights in 2018 showed no difference in caught insects. A study using 20 automated traps during 104 nights in 2019 proved that the automated flight-interception traps are reliable. The automated trap opens new research and application possibilities as arbitrary insect-sampling intervals can be defined. The trap proves efficient, saving manpower and associated costs as activation/deactivation is required only every seven sampling intervals. In addition, the timing of the traps is accurate, as all traps sample at exactly the same intervals and ensure comparability. The automated trap is low maintenance and robust due to straightforward technical design. It can be controlled manually or via smartphone through a Bluetooth connection. Full construction details are given in Appendices.


Assuntos
Voo Animal , Controle de Insetos/métodos , Insetos/fisiologia , Animais , Automação , Desenho de Equipamento
6.
Ecotoxicol Environ Saf ; 203: 110947, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32678751

RESUMO

Cyantraniliprole was recently registered for controlling the coffee berry borer Hypothenemus hampei, the main coffee pest in the world. In this study, baseline determination and resistance monitoring to cyantraniliprole were carried out in Brazilian populations of H. hampei. Evaluations were carried out for three years with representative field-collected populations from nine coffee-producing states in Brazil, using artificial diet containing the insecticide. The likelihood of control failure due to cyantraniliprole resistance was also determined. Populations from Campo do Meio, Linhares and Jaú were more susceptible (<2-fold resistance) to cyantraniliprole than populations from Patrocínio and Londrina (17-fold). Nonetheless, the frequency of cyantraniliprole resistance insects was low and not significant throughout the regions survey and the likelihood of control failure was negligible. Therefore, cyantraniliprole remains an important management tool against the coffee berry borer without current problems of control failure. However, enough field variation in susceptibility to cyantraniliprole exists justifying attention and careful management of this insecticide to prevent quick development of insecticide resistance in populations of this insect pest species.


Assuntos
Coffea/parasitologia , Controle de Insetos/métodos , Resistência a Inseticidas , Inseticidas/farmacologia , Pirazóis/farmacologia , Gorgulhos/efeitos dos fármacos , ortoaminobenzoatos/farmacologia , Animais , Brasil , Coffea/crescimento & desenvolvimento , Probabilidade , Inquéritos e Questionários
7.
PLoS One ; 15(7): e0235700, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32701965

RESUMO

The dosage sprayed upon per unit area is an important index to measure the effects of pesticide application. Owing to the fact that parameters such as flight height, flight speed, and spray swath can change at any given time, it is impossible to ensure a consistent amount of pesticide application per unit area during the course of aerial variable spray. In order to ensure a consistent amount of pesticide application per unit area, a set of control models of aerial variable spray using an unmanned aerial vehicle (UAV) was proposed, and the corresponding control system was developed based on the technology of aerial variable spray. According to the change of flight parameters, this system was able to adjust the opening degree of solenoid valve through the control model of aerial variable spray. After that, the amount per unit time would change to ensure a consistent amount of pesticide application per unit area, which effectively avoided the phenomenon of uneven pesticide application and improved the accuracy. According to the actual demand for the area in need of pesticide application, the operator can manually control the amount of pesticide applied and change the dosage sprayed upon per unit area to achieve a better effect. Through field tests, it was verified that the system has high accuracy of variable control. The deviation range was between 0.11% and 9.79%, which met the demands of agricultural aviation pesticide application. Furthermore, the system had strong stability for working continuously for more than 6 h at 30°C to meet the environmental requirements of pesticide application via UAV. All the data related to the pesticide application were stored in this system, which provided a reference for the further study of the precision technology in pesticide application. The model proposed in this paper also provided a theoretical basis for the technology development of aerial variable spray.


Assuntos
Controle de Insetos/métodos , Modelos Teóricos , Agricultura , Aeronaves , Controle de Insetos/instrumentação , Doenças das Plantas/prevenção & controle , Robótica
10.
An Acad Bras Cienc ; 92 Suppl 1: e20180477, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32491140

RESUMO

Anticarsia gemmatalis Hübner, 1818 (Lepidoptera) is a major pest of soybean in the Brazil. It is known that the reduction of proteolytic activity by the ingestion of protease inhibitors reduces digestion and larval development of the insects. Control via inhibition of the digestive enzymes necessitates deeper knowledge of the enzyme kinetics and the characterization of the inhibition kinetics of these proteases, for better understanding of the active centers and action mechanisms of this enzyme. Trypsin-like proteases found in the gut of Anticarsia gemmatalis were purified in a p-aminobenzamidine agarose column. Kinetic characterization showed KM 0.503 mM for the L-BApNA substrate; Vmax= 46.650 nM s-1; Vmax/[E]= 9.256 nM s-1 mg L-1 and Vmax/[E]/KM= 18.402 nM s-1 mg L-1 mM. The Ki values for the inhibitors benzamidine, berenil, SKTI and SBBI were 11.2 µM, 32.4 µM, 0.25 nM and 1.4 nM, respectively, and all revealed linear competitive inhibition. The SKTI showed the greatest inhibition, which makes it a promising subject for future research to manufacture peptide mimetic inhibitors.


Assuntos
Trato Gastrointestinal/enzimologia , Lepidópteros/enzimologia , Inibidores de Proteases/farmacologia , Animais , Controle de Insetos/métodos , Cinética , Lepidópteros/crescimento & desenvolvimento
11.
J Med Microbiol ; 69(6): 781-791, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32478654

RESUMO

Ticks are the most important vectors of human pathogens, leading to increased public health burdens worldwide. Tick-borne pathogens include viruses (e.g. tick-borne encephalitis and Powassan); bacteria, such as the causative agents of Lyme disease, spotted fever rickettsiosis and human anaplasmosis; and malaria-like protozoan parasites causing babesiosis. Tick-borne diseases are emerging due to the geographical expansion of their tick vectors, especially in the northern hemisphere. Two examples of this phenomenon are Ixodes scapularis and Amblyomma americanum, which have expanded their ranges in the USA in recent decades and are responsible for the continuous emergence of Lyme disease and human ehrlichiosis, respectively. This phenomenon is also occurring worldwide and is reflected by the increasing number of tick-borne encephalitis and haemorrhagic fever cases in Europe and Asia. In this review, we provide a concise synopsis of the most medically important tick-borne pathogen worldwide, with a particular emphasis on emerging public health threats.


Assuntos
Saúde Pública , Doenças Transmitidas por Carrapatos/etiologia , Animais , Humanos , Controle de Insetos , Insetos Vetores , Picadas de Carrapatos/complicações , Doenças Transmitidas por Carrapatos/microbiologia , Doenças Transmitidas por Carrapatos/parasitologia , Doenças Transmitidas por Carrapatos/virologia , Carrapatos
12.
Pest Manag Sci ; 76(10): 3459-3468, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32520421

RESUMO

BACKGROUND: Spotted wing drosophila (SWD), Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is a pest of stone and small fruits causing considerable economic losses. Current management strategies rely primarily on calendar-based spraying, owing to the poor relationship between monitoring data and damage levels, and the lack of success of mass-trapping tools. The aim of this study was to evaluate different trap models for SWD, with an emphasis on their fly-retention capacity. To this end, we examined and quantified the added value of two fly-retaining trap features; tunnel entries to impede escape and an insecticide-coated inner surface as a killing agent. RESULTS: An insecticide-coated inner surface resulted in significantly higher trap retention after 24 h in the laboratory (4.9- to 7.4-fold greater, depending on trap type) compared to a noncoated trap. Trapping efficacy was significantly improved in field trials by such a killing agent in the trap (1.2- to 4.5-fold greater). Tunnel entries significantly improved trap retention in the laboratory and field (by 1.5-fold). CONCLUSION: The outcomes of this study clearly reveal the substantial impact of the fly-retention capacity of SWD traps on their overall capture performances. It was demonstrated for the first time that an insecticide-coated inner surface as a killing agent significantly improves trap efficacy for SWD. This finding can readily be implemented in any trap model to improve monitoring and mass trapping of SWD. Also tunnel entries were shown to have a significant influence on the fly retention and, hence, substantially enhance trapping efficacy.


Assuntos
Drosophila , Animais , Frutas , Controle de Insetos , Inseticidas , Fosfatase Ácida Resistente a Tartarato
13.
PLoS One ; 15(5): e0232172, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32365106

RESUMO

BACKGROUND: The fungal toxin acts as effective, low-cost chemical substances for pest control worldwide and also an alternative to synthetic insecticides. This study assessed the larvicidal potential of Metarhizium anisopliae fungi derived metabolites against Aedes aegypti, Anopheles stephensi, Culex quinquefasciatus and non-targeted organisms at 24hr post treatment. METHOD: Isolation of entomopathogenic fungi M. anisopliae from natural traps confirmed by using 18s rDNA biotechnological tools. Crude extracts from M. anisopliae solvent extraction and their secondary metabolites were bio-assayed following WHO standard procedures against Ae. aegypti, An. stephensi and Cx. quinquefasciatus, Artemia nauplii, Eudrilus eugeniae, and Solanum lycopersicum after 24 hr exposure. Histopathological analysis of E. eugeniae treated with fungi metabolites toxicity compared to those treated with Monocrotophos after 24hrpost-treatment. M. anisopliae metabolites were characterized using GC-MS and FT-IR analysis. RESULTS: The larvicidal activity was recorded in highest concentration of 75µg/ml, with 85%, 97% and 89% mortality in Ae. aegypti, An. stephensi and Cx. quinquefasciatus respectively. M. anisopliae metabolites produced LC50 values in Ae. aegypti, 59.83µg/ml, in An. stephensi, 50.16µg/ml and in Cx. quinquefasciatus, 51.15µg/ml respectively. M. anisopliae metabolites produced lower toxic effects on A. nauplii, LC50 values were, 54.96µg/ml respectively. Bio-indicator toxicity results show 18% and 58% mortality was recorded in E. eugeniae and A. nauplii and also there is no phytotoxicity that was observed on S. lycopersicum L. under semi-field condition. E. eugeniae histopathological studies shows fungal metabolites showed lower sub-lethal effects compared to synthetic chemical pesticide at 24hrs of the treatment. The GC-MS and FT-IR analysis identified five major components of active ingredients. CONCLUSION: Findings of this study indicate that, M. anisopliae ethyl acetate derived secondary metabolites are effective against larvae of Ae. aegypti, An. stephensi and Cx. quinquefasciatus mosquito species, lower toxicity effects were observed on non-target organisms such as, Artemia nauplii, Eudrilus eugeniae as well as, no toxicity effect were observed on Solanum lycopersicum. Further research should be conducted in laboratory for separation of single pure molecule and be tested semifield conditions.


Assuntos
Aedes/efeitos dos fármacos , Anopheles/efeitos dos fármacos , Produtos Biológicos/farmacologia , Culex/efeitos dos fármacos , Metarhizium/química , Animais , Produtos Biológicos/química , DNA Fúngico/genética , DNA Ribossômico/genética , Cromatografia Gasosa-Espectrometria de Massas , Controle de Insetos , Larva/efeitos dos fármacos , Metarhizium/genética , Metarhizium/isolamento & purificação , Monocrotofós/farmacologia , RNA Ribossômico 18S/genética , Metabolismo Secundário , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Arch Insect Biochem Physiol ; 104(4): e21685, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32350927

RESUMO

The Colorado potato beetle (CPB; Leptinotarsa decemlineata) is one of the most notorious and difficult to control pests of potato and other solanaceous crops in North America. This insect has evolved a remarkable ability to detoxify both plant and synthetic toxins, allowing it to feed on solanaceous plants containing toxic alkaloids and to develop resistance to synthetic chemicals used for its control. RNA interference (RNAi) is a natural mechanism that evolved as an immune response to double-stranded RNA (dsRNA) viruses where dsRNA triggers silencing of target gene expression. RNAi is being developed as a method to control CPB. Here, we evaluated four CPB-specific genes to identify targets for RNAi-mediated control of this insect. Out of the four dsRNAs evaluated in CPB larvae and adults, dsIAP (dsRNA targeting inhibitor of apoptosis, iap gene) performed better than dsActin, dsHSP70, and dsDynamin in inducing larval mortality. However, in adults, the mortality induced by dsActin is significantly higher than the mortality induced by dsIAP, dsHSP70, and dsDynamin. Interestingly, a combination of dsIAP and dsActin performed better than either dsIAP or dsActin alone by inducing feeding inhibition in 24 hr and mortality in 48 hr in larvae. When the dsIAP and dsActin were expressed in the Escherichia coli HT115 strain and applied as a heat-killed bacterial spray on potato plants, it protected the plants from CPB damage. These studies show that the combination of dsIAP and dsActin shows promise as an insecticide to control CPB.


Assuntos
Besouros/genética , Proteínas Inibidoras de Apoptose/genética , Interferência de RNA , Actinas/genética , Animais , Besouros/efeitos dos fármacos , Besouros/crescimento & desenvolvimento , Escherichia coli , Controle de Insetos/métodos , Proteínas de Insetos/genética , Larva/efeitos dos fármacos , RNA de Cadeia Dupla , Solanum tuberosum
15.
Arch Insect Biochem Physiol ; 104(4): e21690, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32394499

RESUMO

The harlequin bug (HB), Murgantia histrionica, is a major pest of cabbage family plants throughout its range in the United States. RNA interference (RNAi) is a posttranscriptional gene silencing mechanism that is showing promise as a biopesticide due to the ability to target species-specific genes necessary for growth and/or survival with synthetic double-stranded RNA (dsRNA). In the present study, dsRNA stability assays revealed that nucleases present in the saliva of harlequin bugs did not rapidly degrade dsRNA. We tracked the movement and localization of radioactively labeled dsRNA in both mustard plant seedlings and harlequin bug nymphs that fed on treated host plants. Movement of 32 P-labeled-dsRNA from soil to plant and plant to insect was detected. The efficacy of RNAi in inducing mortality in harlequin bug adults and nymphs injected or fed with dsRNA targeting inhibitor of apoptosis (IAP), ATPase N2B (ATPase), serine/threonine-protein phosphatase PP1-ß catalytic subunit (PP1), signal recognition particle 54 kDa protein (SRP), and G protein-coupled receptor 161-like (GPCR) genes was evaluated. Injection of dsRNA targeting candidate genes into adults caused between 40% and 75% mortality and induced significant knockdown of target gene expression. Feeding dsRNA targeting the IAP gene to nymphs by plant-mediated and droplet feeding methods induced knockdown of the target gene and caused 40-55% mortality. These findings suggest that RNAi may be a viable approach for managing this pest.


Assuntos
Heterópteros/genética , Mostardeira/metabolismo , Interferência de RNA , Animais , Perfilação da Expressão Gênica , Heterópteros/crescimento & desenvolvimento , Heterópteros/metabolismo , Proteínas Inibidoras de Apoptose/genética , Controle de Insetos/métodos , Mostardeira/parasitologia , Ninfa/genética , Ninfa/metabolismo , Fenômenos Fisiológicos Vegetais , RNA de Cadeia Dupla , Ribonucleases , Saliva/enzimologia , Solo/química
16.
Arch Insect Biochem Physiol ; 104(4): e21689, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32394607

RESUMO

Apoptosis has been widely studied from mammals to insects. Inhibitor of apoptosis (IAP) protein is a negative regulator of apoptosis. Recent studies suggest that iap genes could be excellent targets for RNA interference (RNAi)-mediated control of insect pests. However, not much is known about iap genes in one of the well-known insect model species, Tribolium castaneum. The orthologues of five iap genes were identified in T. castaneum by searching its genome at NCBI (https://www.ncbi.nlm.nih.gov/) and UniProt (https://www.uniprot.org/) databases using Drosophila melanogaster and Aedes aegypti IAP protein sequences as queries. RNAi assays were performed in T. castaneum cell line (TcA) and larvae. The knockdown of iap1 gene induced a distinct apoptotic phenotype in TcA cells and induced 91% mortality in T. castaneum larvae. Whereas, knockdown of iap5 resulted in a decrease in cell proliferation in TcA cells and developmental defects in T. castaneum larvae which led to 100% mortality. Knockdown of the other three iap genes identified did not cause a significant effect on cells or insects. These data increase our understanding of iap genes in insects and provide opportunities for developing iap1 and iap5 as targets for RNAi-based insect pest control.


Assuntos
Proteína 3 com Repetições IAP de Baculovírus/genética , Interferência de RNA , Tribolium/genética , Animais , Linhagem Celular , Controle de Insetos/métodos , Proteínas de Insetos/genética , Larva/genética , Larva/crescimento & desenvolvimento , Tribolium/crescimento & desenvolvimento
17.
Arch Insect Biochem Physiol ; 104(4): e21692, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32441400

RESUMO

The southern green stink bug (SGSB, Nezara viridula) is an emerging polyphagous pest in many regions of the world. RNA interference (RNAi) is a valuable method for understanding gene function and holds great potential for pest management. However, RNAi efficiency is variable among insects and the differences in transport of double-stranded RNA (dsRNA) are one of the major factors that contribute to this variability. In this study, Cy3 labeled dsRNA was used to track the transport of dsRNA in SGSB tissues. Cy3_dsRNA was detected in the hemocytes, fat body (FB), epidermis, and midgut tissues at 24-72 hr after injection. Orally delivered Cy3_dsRNA or Cypher-5E labeled dsRNA was mostly detected in the midgut and a few signals were detected in parts of the FB and epidermis. Both injected and fed Cy3_dsRNA showed stronger signals in SGSB tissues when compared to Cy3_siRNA (small interfering RNA) or Cy3_shRNA (short hairpin RNA). dsRNA targeting the gene for a vacuolar-sorting protein, SNF7, induced higher knockdown of the target gene and greater SGSB mortality compared to siRNA or shRNA targeting this gene. 32 P-labeled dsRNA injected into SGSB was processed into siRNA, but fed 32 P-labeled dsRNA was not efficiently processed into siRNA. These data suggest that transport of orally delivered dsRNA across the midgut epithelium is not efficient in SGSB which may contribute to variable RNAi efficiency. Targeting genes expressed in the midgut rather than other tissues and using dsRNA instead of siRNA or shRNA would be more effective for RNAi-mediated control of this pest.


Assuntos
Heterópteros/metabolismo , Interferência de RNA , RNA de Cadeia Dupla/metabolismo , Administração Oral , Animais , Heterópteros/genética , Injeções , Controle de Insetos/métodos , Proteínas de Insetos/genética , Mucosa Intestinal/metabolismo , RNA Interferente Pequeno
18.
J Insect Sci ; 20(3)2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32365174

RESUMO

Stink bugs (Hemiptera: Pentatomidae) are agricultural pests of increasing significance in the North Central Region of the United States, posing a threat to major crops such as soybean. Biological control can reduce the need for insecticides to manage these pests, but the parasitism of stink bugs by Tachinidae (Diptera) is poorly characterized in this region. The objective of this study was to evaluate the rate of parasitism of stink bugs by tachinids over 2 yr from nine states across the North Central Region. Parasitism was assessed by quantifying tachinid eggs on the integument of stink bug adults. Parasitism rates (i.e., percent of adult stink bugs with tachinid eggs) were compared across stink bug species, states, stink bug sex, and years. The mean percent parasitism of stink bugs by tachinids was about 6% across the region and did not differ among stink bug species. Mean percent parasitism was significantly higher in Missouri than in northern and western states. In addition, male stink bugs had significantly higher mean percent parasitism than females. Stink bug species commonly found in soybean in the region showed some parasitism and are therefore potentially vulnerable to oviposition by these parasitoids. This is the first study to characterize the level of parasitism of stink bugs by tachinids across the North Central Region.


Assuntos
Dípteros/fisiologia , Heterópteros/parasitologia , Interações Hospedeiro-Parasita , Controle de Insetos , Controle Biológico de Vetores , Animais , Produtos Agrícolas/crescimento & desenvolvimento , Feminino , Masculino , Meio-Oeste dos Estados Unidos , Soja/crescimento & desenvolvimento
19.
J Insect Sci ; 20(3)2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32396201

RESUMO

The African parasitoids Cephalonomia stephanoderis Waterston (Bethylidae: Hymenoptera), Prorops nasuta Betrem (Bethylidae: Hymenoptera), and Phymastichus coffea LaSalle (Eulophidae: Hymenoptera) are biological control agents of the coffee berry borer (Coleoptera: Curculionidae). In this study, we investigated in laboratory the female behavioral responses of these parasitoids to 14 different wavelengths (340-670 nm) against a control (570 nm, yellow). When nonchooser females were included in the analysis, none parasitoids species showed a preference between 340, 350, 370, 460, 490, 520, 540, 590, 640, and 650 nm with respect to the control wavelength. In contrast, the three species of parasitoids were more attracted to wavelengths of 380, 400, and 420 nm than the control wavelength. Phymastichus coffea and P. nasuta were more attracted to the wavelength of 400 and 420 nm compared to C. stephanoderis. At 380 nm, P. coffea and C. stephanoderis wasps showed the higher responses in comparison to P. nasuta females. When nonchooser wasps were excluded from the analysis, we observed other differences among the parasitoid species. For instance, P. coffea were more attracted to 490-540 nm than to 570 nm, whereas the bethylids did not discriminate between 490-540 nm or 570 nm. Our results are discussed in relation to possible implications associated with the vision of these parasitoid species.


Assuntos
Percepção de Cores , Interações Hospedeiro-Parasita , Controle de Insetos , Controle Biológico de Vetores , Vespas/fisiologia , Gorgulhos/parasitologia , Animais , Cor , Feminino , México
20.
J Insect Sci ; 20(3)2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32458990

RESUMO

Survival and parasitism activity of Trichopria drosophilae Perkins adults, a cosmopolitan parasitoid of Drosophila spp., were studied under laboratory conditions using five constant temperatures at the lower range known for this enemy, from 4 to 20°C in 4°C increments. Drosophila suzukii Matsumura, an invasive pest of small fruits, was used as a host. Commercially available adult parasitoids were provided with 1) food and D. suzukii pupae; 2) food and no D. suzukii pupae; 3) no food and no pupae. The results show that adult females of T. drosophilae lived longer than males, and both generally benefitted from food supply. The highest level of survival was observed between 8 and 12°C for fed insects, irrespective of whether they were offered host pupae or not. The absence of food led to the highest mortality, but the parasitoid demonstrated considerably resistance to prolonged starvation. Successful parasitism increased steadily with temperature and reached the highest value at 20°C. Conversely, D. suzukii emergence rate was high after exposure of pupae to parasitoids at 4°C, while pupal mortality increased strongly with temperature until 12°C. The findings indicate that T. drosophilae is well adapted to the relatively cold conditions experienced in early spring and in autumn or at high elevations, when the host pupae could be largely available. The long lifespan of the adults and the ability to parasitize the host at low temperature make T. drosophilae potentially useful for the biocontrol of D. suzukii.


Assuntos
Drosophila/parasitologia , Interações Hospedeiro-Parasita , Controle de Insetos , Controle Biológico de Vetores , Vespas/fisiologia , Animais , Temperatura Baixa , Drosophila/crescimento & desenvolvimento , Feminino , Masculino , Pupa/crescimento & desenvolvimento , Pupa/parasitologia , Estações do Ano , Fatores Sexuais , Vespas/crescimento & desenvolvimento
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