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1.
J Insect Sci ; 21(1)2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33560362

RESUMO

Laricobius nigrinus (Coleoptera: Derodontidae) Fender and Laricobius osakensis (Coleoptera: Derodontidae) Montgomery and Shiyake have been mass produced by Virginia Tech as biological control agents for the hemlock woolly adelgid (HWA), Adelges tsugae (Hemiptera: Adelgidae) Annand, for the past 15 and 9 yr, respectively. Herein, we describe modifications of our rearing procedures, trends and analyses in the overall production of these agents, and the redistribution of these agents for release to local and federal land managers. Based on these data, we have highlighted three major challenges to the rearing program: 1) high mortality during the subterranean portion of its life cycle (averaging 37% annually) reducing beetle production, 2) asynchrony in estivation emergence relative to the availability of their host HWA minimizing food availability, and 3) unintended field collections of Laricobius spp. larvae on HWA provided to lab-reared larvae complicating rearing procedures. We further highlight corresponding avenues of research aimed at addressing each of these challenges to further improve Laricobius spp. production.


Assuntos
Besouros/fisiologia , Hemípteros/fisiologia , Controle Biológico de Vetores/métodos , Animais , Agentes de Controle Biológico , Besouros/crescimento & desenvolvimento , Hemípteros/crescimento & desenvolvimento , Cicutas (Apiáceas)/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Larva/fisiologia , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Virginia
2.
Bull Entomol Res ; 111(2): 246-256, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33355061

RESUMO

The meadow spittlebug, Philaenus spumarius (L.) (Hemiptera: Aphrophoridae), is the main vector in Europe of the recently detected plant pathogen bacterium Xylella fastidiosa Wells et al. (Xanthomonadales: Xanthomonadaceae). While the ecology of continental populations is well documented, nothing is known about the insular populations of P. spumarius, such as in Corsica, where the bacterium was detected in 2015. Hence, in an epidemiological context, the ecology of P. spumarius has been studied in a maquis landscape in the Ajaccio region between 2017 and 2019. Adults and nymphs were almost exclusively collected on Cistus monspeliensis L. (Cistaceae). However, very few specimens were collected in summer, suggesting a movement of the adults to sheltered habitats. Unfortunately, despite several trapping methods used, the location of adult summer habitat remains unknown for the studied population. It might be tempting to destroy the central plant host of P. spumarius populations. However, as spittlebug nymphs are highly polyphagous on low-growing plant species and as the females can lay eggs in any dead plant tissues, such practice could have limited the impact. Instead, the strong relationship between P. spumarius and C. monspeliensis could be used to monitor spittlebug populations, to limit/concentrate the means of insect control, or in an agronomic context to lure insects away from crops. Maintaining natural arboreal vegetation around agronomic systems could help decrease insect abundance - and potentially, pathogen load - on cultivated species. Such hypotheses need to be further studied by landscape experiments.


Assuntos
Comportamento Alimentar , Hemípteros/fisiologia , Animais , Cistus , Produtos Agrícolas/microbiologia , Vetores de Doenças , Monitorização de Parâmetros Ecológicos , Ecossistema , França/epidemiologia , Hemípteros/microbiologia , Hiperfagia , Insetos Vetores/microbiologia , Insetos Vetores/fisiologia , Ninfa/fisiologia , Controle de Pragas/tendências , Doenças das Plantas/microbiologia , Estações do Ano , Especificidade da Espécie
3.
Sci Rep ; 10(1): 22049, 2020 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-33328547

RESUMO

Projected climate changes are thought to promote emerging infectious diseases, though to date, evidence linking climate changes and such diseases in plants has not been available. Cassava is perhaps the most important crop in Africa for smallholder farmers. Since the late 1990's there have been reports from East and Central Africa of pandemics of begomoviruses in cassava linked to high abundances of whitefly species within the Bemisia tabaci complex. We used CLIMEX, a process-oriented climatic niche model, to explore if this pandemic was linked to recent historical climatic changes. The climatic niche model was corroborated with independent observed field abundance of B. tabaci in Uganda over a 13-year time-series, and with the probability of occurrence of B. tabaci over 2 years across the African study area. Throughout a 39-year climate time-series spanning the period during which the pandemics emerged, the modelled climatic conditions for B. tabaci improved significantly in the areas where the pandemics had been reported and were constant or decreased elsewhere. This is the first reported case where observed historical climate changes have been attributed to the increase in abundance of an insect pest, contributing to a crop disease pandemic.


Assuntos
Aclimatação , Begomovirus , Mudança Climática , Hemípteros/fisiologia , Manihot , Doenças das Plantas , Animais , Manihot/parasitologia , Manihot/virologia , Doenças das Plantas/parasitologia , Doenças das Plantas/virologia , Uganda
4.
Sci Rep ; 10(1): 21898, 2020 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-33318578

RESUMO

Multimodal warning displays often pair one signal modality (odor) with a second modality (color) to avoid predation. Experiments with bird predators suggest these signal components interact synergistically, with aversive odors triggering otherwise hidden aversions to particular prey colors. In a recent study, this phenomenon was found in a jumping spider (Habronattus trimaculatus), with the defensive odor from a coreid bug (Acanthocephala femorata) triggering an aversion to red. Here, we explore how generalizable this phenomenon is by giving H. trimaculatus the choice between red or black prey in the presence or absence of defensive odors secreted from (1) eastern leaf-footed bugs (Leptoglossus phyllopus, Hemiptera), (2) grass stinkbugs (Mormidea pama, Hemiptera), (3) Asian ladybird beetles (Harmonia axyridis, Coleoptera), and (4) eastern lubber grasshoppers (Romalea microptera, Orthoptera). As expected, in the presence of the hemipteran odors, spiders were less likely to attack red prey (compared to no odor). Unexpectedly, the beetle and grasshopper odors did not bias spiders away from red. Our results with the hemipteran odors were unique to red; follow-up experiments indicated that these odors did not affect biases for/against green prey. We discuss our findings in the context of generalized predator foraging behavior and the functions of multimodal warning displays.


Assuntos
Hemípteros/fisiologia , Modelos Biológicos , Odorantes , Pigmentação/fisiologia , Aranhas/fisiologia , Animais , Besouros/fisiologia , Gafanhotos/fisiologia
5.
PLoS One ; 15(10): e0239771, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33022020

RESUMO

Huanglongbing (HLB) is a deadly, incurable citrus disease putatively caused by the unculturable bacterium, 'Candidatus Liberibacter asiaticus' (CLas), and transmitted by Diaphorina citri. Prior studies suggest D. citri transmits CLas in a circulative and propagative manner; however, the precise interactions necessary for CLas transmission remain unknown, and the impact of insect sex on D. citri-CLas interactions is poorly understood despite reports of sex-dependent susceptibilities to CLas. We analyzed the transcriptome, proteome, metabolome, and microbiome of male and female adult D. citri reared on healthy or CLas-infected Citrus medica to determine shared and sex-specific responses of D. citri and its endosymbionts to CLas exposure. More sex-specific than shared D. citri responses to CLas were observed, despite there being no difference between males and females in CLas density or relative abundance. CLas exposure altered the abundance of proteins involved in immunity and cellular and oxidative stress in a sex-dependent manner. CLas exposure impacted cuticular proteins and enzymes involved in chitin degradation, as well as energy metabolism and abundance of the endosymbiont 'Candidatus Profftella armatura' in both sexes similarly. Notably, diaphorin, a toxic Profftella-derived metabolite, was more abundant in both sexes with CLas exposure. The responses reported here resulted from a combination of CLas colonization of D. citri as well as the effect of CLas infection on C. medica. Elucidating these impacts on D. citri and their endosymbionts contributes to our understanding of the HLB pathosystem and identifies the responses potentially critical to limiting or promoting CLas acquisition and propagation in both sexes.


Assuntos
Citrus/microbiologia , Hemípteros/microbiologia , Insetos Vetores/microbiologia , Doenças das Plantas/microbiologia , Rhizobiaceae/fisiologia , Rhizobiaceae/patogenicidade , Simbiose/fisiologia , Animais , Citrus/metabolismo , Citrus/fisiologia , Feminino , Hemípteros/metabolismo , Hemípteros/fisiologia , Insetos Vetores/metabolismo , Insetos Vetores/fisiologia , Masculino , Metaboloma/fisiologia , Microbiota/fisiologia , Estresse Oxidativo/fisiologia , Proteoma/metabolismo , Transcriptoma/fisiologia
6.
Toxicon ; 188: 39-47, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33058930

RESUMO

Entomopathogenic fungi (EPF) produce multiple mycotoxins, which play an essential role in improving fungal pathogenesis and virulence. To characterize various mycotoxins from the crude methanol extract of Cordyceps fumosorosea, a major EPF against various insect pests, we performed ultra-performance liquid chromatography coupled to quadrupole time of flight mass spectrometer (UPLC-QTOF MS) technique, and all compounds were identified through molecular mass and formulae. Bassianolide was assessed against the nymphs and adults of Diaphorina citri reared on healthy and Huánglóngbìng (HLB)-diseased Citrus spp. Plants under laboratory conditions. Overall, 17 compounds were identified from the fungal extract and categorized into three groups, i.e. (1) alkaloids (Isariotins A-C), (2) peptides (Bassianolide, Beauverolides, Beauvericin A, Isaridins and Destruxin E) and (3) polyketide (Tenuipyrone). The detected beauverolides (B, C, F, I, Ja) from C. fumosorosea were novel mycotoxins, and their detection intensity was the highest in the fungal extract. Furthermore, bassianolide caused more than 70% and 80% mortality of D. citri nymphs and adults after two days of application, respectively. After three days of chemical application, all nymphal and adult populations of D. citri were killed by bassianolide. However, the mortality rates of both populations, nymphs and adults, were higher on HLB-diseased plants as compared to healthy plants.


Assuntos
Citrus , Cordyceps , Hemípteros/efeitos dos fármacos , Micotoxinas , Animais , Hemípteros/fisiologia , Ninfa , Doenças das Plantas , Policetídeos , Virulência
7.
PLoS One ; 15(9): e0238549, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32903256

RESUMO

The brown planthopper (BPH), Nilaparvata lugens (Stål), is a destructive pest that poses a significant threat to rice plants worldwide. To explore how BPHs adapt to the resistant rice variety, we analyzed proteomics profiles of two virulent N. lugens populations. We focused on Biotype Y, which can survive on the moderately resistant rice variety YHY15, and Biotype I, which can survive on the susceptible rice variety TN1. We performed protein quantitation using the isobaric tag for relative and absolute quantification (iTRAQ) and then compared the expression patterns between two virulent N. lugens populations and found 258 differentially expressed proteins (DEPs). We found that 151 of the DEPs were up-regulated, while 107 were down-regulated. We evaluated transcript levels of 8 expressed genes from the iTRAQ results by qRT-PCR, which revealed transcriptional changes that were consistent with the changes at the protein level. The determination of the protein changes in two virulent N. lugens populations would help to better understanding BPH adaptation to resistant rice varieties and facilitate the better design of new control strategies for host defense against BPH.


Assuntos
Hemípteros/genética , Proteínas de Insetos/genética , Oryza/parasitologia , Doenças das Plantas/parasitologia , Animais , Resistência à Doença , Regulação para Baixo , Perfilação da Expressão Gênica , Hemípteros/fisiologia , Interações Hospedeiro-Parasita , Proteômica , Transcriptoma , Regulação para Cima
8.
PLoS One ; 15(8): e0237261, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32804957

RESUMO

Soil fertilization with dehydrated sewage sludge (DSS) accelerates the recovery process of degraded areas by improving nutrient concentration, and favors the development of trophic webs with pioneer plants such as Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae), phytophagous Hemiptera, predators, and protocooperanting ants. This study aimed to evaluate the development and production of A. auriculiformis litter with or without dehydrated sewage sludge application and the ecological indices of sucking insects (Hemiptera), their predators and protocooperating ants, as bioindicators, in a degraded area for 24 months. Complete randomization was applied for two treatments (with or without application of dehydrated sewage sludge) in 24 replications (one repetition = one plant). We evaluated the number of leaves/branch and branches/plant, percentage of soil cover (litter), ecological indices of phytophagous Hemiptera, their predators, and protocooperating ants. The plants of A. auriculiformis, that were applied with dehydrated sewage sludge, had superior development when compared to plants where DSS were not applied. The highest abundance and richness of phytophagous Hemiptera species and Sternorrhyncha predators occurred on A. auriculiformis plants that were applied with dehydrated sewage sludge. The increase in richness of species of protocooperanting ants that established mutualistic relationships positively influenced the phytophagous Hemiptera. The use of A. auriculiformis, with application of dehydrated sewage sludge, can increase recovery of degraded areas due to its higher soil cover (e.g., litter) and results in higher ecological indices of phytophagous Hemiptera and their predators.


Assuntos
Acacia/fisiologia , Fertilizantes , Hemípteros/fisiologia , Esgotos/química , Solo/química , Animais , Formigas/fisiologia , Biodiversidade , Fertilizantes/análise , Cadeia Alimentar , Água/química
9.
PLoS One ; 15(7): e0236586, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32726362

RESUMO

Short rotation woody biomass cultivars developed from fast-growing shrub species of willow (Salix spp.) have superior properties as perennial energy crops for the Northeast and Midwest US. However, the insect pest potato leafhopper (PLH) Empoasca fabae (Harris) can cause serious damage and reduce yield of susceptible genotypes. Currently, the willow cultivars in use display varying levels of susceptibility under PLH infestation. However, genes and markers for resistance to PLH are not yet available for marker-assisted selection in breeding. In this study, transcriptome differences between a resistant genotype 94006 (S. purpurea) and a susceptible cultivar 'Jorr' (S. viminalis), and their hybrid progeny were determined. Over 600 million RNA-Seq reads were generated and mapped to the Salix purpurea reference transcriptome. Gene expression analyses revealed the unique defense mechanism in resistant genotype 94006 that involves PLH-induced secondary cell wall modification. In the susceptible genotypes, genes involved in programed cell death were highly expressed, explaining the necrosis symptoms after PLH feeding. Overall, the discovery of resistance genes and defense mechanisms provides new resources for shrub willow breeding and research in the future.


Assuntos
Salix/genética , Transcriptoma , Animais , Apoptose/genética , Parede Celular/química , Parede Celular/metabolismo , Produtos Agrícolas , Perfilação da Expressão Gênica , Redes Reguladoras de Genes/genética , Genótipo , Hemípteros/fisiologia , Herbivoria , Interações Hospedeiro-Parasita/genética , Fenótipo , Análise de Componente Principal , RNA de Plantas/química , RNA de Plantas/metabolismo , Salix/parasitologia
10.
Chemosphere ; 259: 127490, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32650166

RESUMO

Insect resistance to chemical insecticide is a global problem that presents an ongoing threat to sustainable agriculture. Although the increased production of detoxification enzymes has been frequently implicated in resistance development, the mechanisms employed by insecticide-resistant insects for overexpression of these genes remain elusive. Here we report that neuropeptide adipokinetic hormone (AKH) negatively regulates the expression of CYP6ER1 and CYP6AY1, two important cytochrome P450 monooxygenases (P450s) that confer resistance to neonicotinoid imidacloprid in the brown planthopper (BPH). Imidacloprid exposure suppresses AKH synthesis in the susceptible BPH, and AKH is inhibited in the imidacloprid-resistant strain. RNA interference (RNAi) and AKH peptide injection revealed that imidacloprid exposure inhibits the AKH signaling cascade and then provokes reactive oxygen species (ROS) burst. These in turn activate the transcription factors cap 'n' collar isoform-C (CncC) and muscle aponeurosis fibromatosis (MafK). RNAi and ROS scavenger assays showed that ROS induces CYP6ER1 expression by activating CncC and MafK, while ROS mediates induction of CYP6AY1 through another unidentified pathway in the resistant BPH. Collectively, these results provide new insights into the regulation of insecticide resistance and implicate both the neuropeptide AKH-mediated ROS burst and transcription factors are involved in the overexpression of P450 detoxification genes in insecticide-resistant insects.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Hemípteros/química , Hormônios de Inseto/fisiologia , Resistência a Inseticidas/efeitos dos fármacos , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Oligopeptídeos/fisiologia , Ácido Pirrolidonocarboxílico/análogos & derivados , Animais , Família 6 do Citocromo P450/metabolismo , Hemípteros/fisiologia , Imidazóis/metabolismo , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Interferência de RNA , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição/fisiologia
11.
PLoS One ; 15(7): e0235630, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32628739

RESUMO

In several phytophagous hemipterans, behavior appears to be mediated by both visual and chemical cues. For the Asian citrus psyllid (ACP) Diaphorina citri (Hemiptera: Liviidae), olfactometric assays are generally difficult to interpret owing to the low proportion of individuals responding to odors (~30-40%), which compromises the efficiency and reliability of the results of behavioral tests. In the present study, the ACP behavioral response to emitted odors from sweet orange (Citrus sinensis L. Osbeck) flushes in a 4-arm olfactometer using different colors (four white-, two white- and two yellow- on opposite sides, or four yellow-colored fields), and the role of the airflow in the concentration of volatile organic compounds (VOCs) were assessed at two airflows [0.4 and 0.1 L/min (LPM)]. Exposure to 'Pera' sweet orange or clean air in treatments with four yellow-colored-fields increased the response rate of ACP females to the odor sources compared with exposure to 'Pera' sweet orange or clean air in treatments with four white-colored-fields, independently of the odor source and airflow tested. For the assays using two white- and two yellow-colored fields on opposite sides and 0.4 or 0.1 LPM airflow, the residence time of ACP females to odors ('Pera' sweet orange or clean air) was similar or higher in treatments using yellow- than those using white-colored fields. For both assays (VOCs and olfactometric behavioral parameters), the reduction in airflow from 0.4 to 0.1 LPM greatly changed the airborne concentration and ACP behavior. Quantitative chemical analyses revelead that the concentration of most compounds emitted by 'Pera' sweet orange flushes for the headspace using 0.1 LPM airflow were greater than the concentrations measured using 0.4 LPM airflow. Therefore, this treatment design provides an useful tool to assess the ACP behavioral response to the odors from citrus plants, and it can also help in the discrimination of dose-response screenings for VOCs or conspecific insects.


Assuntos
Ar , Comportamento Animal/efeitos dos fármacos , Citrus/metabolismo , Hemípteros/efeitos dos fármacos , Hemípteros/fisiologia , Olfato , Compostos Orgânicos Voláteis/farmacologia , Animais , Cor , Relação Dose-Resposta a Droga , Compostos Orgânicos Voláteis/metabolismo
12.
PLoS One ; 15(6): e0235506, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32603337

RESUMO

The brown planthopper (Nilapavata lugens: BPH) and whitebacked planthopper (Sogatella furcifera: WBPH) co-occur as the principal pests of rice in Asia. A review of previous studies suggests that the two species have similar temperature tolerances and similar temperature thresholds for development. However, the distribution and seasonality of WBPH suggest that its temperature optima for performance (survival, oviposition and growth) may be lower than for BPH. We compared adult longevity, oviposition, nymph survival and development success, as well as nymph biomass in both species across a gradient of constant temperatures from 15°C-40°C, at 5°C intervals. The most suitable temperatures for oviposition, nymph biomass and development success were 5-10°C lower for WBPH than for BPH. Furthermore, compared to BPH, WBPH demonstrated clear differences in oviposition on different rice subspecies and on rice at different growth stages at 25°C and 30°C, but not at other temperatures. The results suggest that aspects of herbivore performance within tolerable temperature ranges, which are not often included in temperature models, may be more useful than thermal tolerances or development thresholds in predicting the effects of global warming on pest damage to crops.


Assuntos
Hemípteros/fisiologia , Oviposição/fisiologia , Especificidade da Espécie , Temperatura , Animais , Ásia , Produtos Agrícolas , Ecossistema , Aquecimento Global , Herbivoria/fisiologia , Modelos Teóricos , Ninfa/crescimento & desenvolvimento , Oryza , Controle de Pragas
13.
J Vis Exp ; (159)2020 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-32510484

RESUMO

Exploiting insect-resistant rice germplasm resources and related genes is the primary need for breeding insect-resistant varieties, but the accuracy of the identification of insect-resistant phenotypes of rice is a major difficulty. It is urgent to develop a new method or improve existing methods to screen rice for insect resistance. This article describes a simple and feasible method to assess nonpreference-type resistance of rice to the white-backed planthopper (WBPH), Sogatella furcifera, in the laboratory. The preference of adult WBPHs feeding or inhabiting on maturing rice plants is continuously analyzed by pairwise comparison. The dynamic changes of WBPHs on rice plants are recorded and compared as an index of resistance identification. The current method is simply operable and easily observable and has a short cycle. The use of this method could be extended to investigate the feeding and oviposition preference of similar hemipterans, such as the brown planthopper (BPH), Nilaparvata lugens(Stål).


Assuntos
Comportamento Alimentar , Hemípteros/fisiologia , Oryza , Animais , Feminino , Laboratórios , Oviposição , Fenótipo
14.
PLoS One ; 15(6): e0233710, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32530963

RESUMO

BACKGROUND: Phlebopus portentosus and mealy bugs form a fungus-insect gall on the roots of host plants. The fungus and mealy bugs benefit mutually through the gall, which is the key link in the nutritional mechanism of P. portentosus. The cavity of the fungus-insect gall provides an ideal shelter for mealy bugs survival and reproduction, but how does P. portentosus benefit from this symbiotic relationship? METHODOLOGY AND RESULTS: Anatomical examination of fungus-insect galls revealed that one or more mealy bugs of different generations were living inside the galls. The mealy bug's mouthpart could penetrate through the mycelium layer of the inside of the gall and suck plant juice from the host plant root. Mealy bugs excreted honeydew inside or outside the galls. The results of both honeydew agar medium and quartz tests showed that the honeydew can attract and promote the mycelial growth of P. portentosus. A test of the relationship between the honeydew and the formation of the fungus-insect gall showed that honeydew promoted gall formation. CONCLUSIONS: All experimental results in this study show that the honeydew secreted by mealy bugs can attract and promote the mycelial growth of P. portentosus, forming a fungus-insect gall, because mealy bugs' honeydew is rich in amino acids and sugars.


Assuntos
Basidiomycota/fisiologia , Hemípteros/fisiologia , Tumores de Planta/microbiologia , Animais , Basidiomycota/crescimento & desenvolvimento , Basidiomycota/patogenicidade , Fabaceae/microbiologia , Fabaceae/parasitologia , Hemípteros/patogenicidade , Tumores de Planta/parasitologia
15.
PLoS One ; 15(4): e0232363, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32353044

RESUMO

Xylella fastidiosa pauca ST53 is the bacterium responsible for the Olive Quick Decline Syndrome that has killed millions of olive trees in Southern Italy. A recent work demonstrates that a rational integration of vector and transmission control measures, into a strategy based on chemical and physical control means, can manage Xylella fastidiosa invasion and impact below an acceptable economic threshold. In the present study, we propose a biological alternative to the chemical control action, which involves the predetermined use of an available natural enemy of Philaenus spumarius, i.e., Zelus renardii, for adult vector population and infection biocontrol. The paper combines two different approaches: a laboratory experiment to test the predation dynamics of Zelus renardii on Philaenus spumarius and its attitude as candidate for an inundation strategy; a simulated experiment of inundation, to preliminary test the efficacy of such strategy, before eventually proceeding to an in-field experimentation. With this double-fold approach we show that an inundation strategy with Zelus renardii has the potential to furnish an efficient and "green" solution to Xylella fastidiosa invasion, with a reduction of the pathogen incidence below 10%. The biocontrol model presented here could be promising for containing the impact and spread of Xylella fastidiosa, after an in-field validation of the inundation technique. Saving the fruit orchard, the production and the industry in susceptible areas could thus become an attainable goal, within comfortable parameters for sustainability, environmental safety, and effective plant health protection in organic orchard management.


Assuntos
Hemípteros/microbiologia , Insetos Vetores/microbiologia , Olea/microbiologia , Controle Biológico de Vetores/métodos , Doenças das Plantas/prevenção & controle , Xylella/patogenicidade , Animais , Hemípteros/patogenicidade , Hemípteros/fisiologia , Insetos Vetores/patogenicidade , Insetos Vetores/fisiologia , Olea/parasitologia , Comportamento Predatório
16.
Chemosphere ; 255: 126778, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32388266

RESUMO

The predatory bug Orius sauteri (Poppius) is currently one of the most important beneficial arthropods in Northeast Asia and used as a biological control agent of several small pest arthropods including Frankliniella occidentalis (Pergande). Two neonicotinoid chemical insecticides, acetamiprid and imidacloprid, mainly used in China as chemical control on F. occidentalis, although applied at sublethal concentrations in the field or greenhouse to protect beneficial arthropods, still may affect the predator O. sauteri. The objective of present work is to assess the long-term effects of 24-h exposure time to these two insecticides on the life-cycle of O. sauteri at application rates similar to the laboratory 24-h LC10, LC20 and LC30 of O. sauteri. Results showed that acetamiprid and imidacloprid at all tested concentrations significantly decreased the fecundity of O. sauteri females, while the effect of acetamiprid was higher than that of imidacloprid. Moreover, the oviposition period and longevity of O. sauteri to both insecticides shortened. The sublethal effects on the first progeny (F1 generation) were also found to increase nymphal mortality, shorten adult longevity and reduce fecundity. However, all treatments of acetamiprid and imidacloprid at the concentration of LC10, LC20 and LC30 caused no significant effect on the developmental time of different nymphal stages and sex ratio of the F1 generation. This paper is the first one that assesses the compatibility between neonicotinoid insecticides and O. sauteri, and shows that the application of acetamiprid and imidacloprid likely interferes with the population dynamic of O. sauteri.


Assuntos
Hemípteros/fisiologia , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Animais , China , Feminino , Fertilidade/efeitos dos fármacos , Heterópteros/efeitos dos fármacos , Ninfa/efeitos dos fármacos , Oviposição/efeitos dos fármacos
17.
PLoS One ; 15(4): e0231973, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32343710

RESUMO

Potato psyllid (Bactericera cockerelli Sulc)-transmitted "Candidatus Liberibacter solanacearum" (Lso) has been negatively impacting the potato industry in the United States as well as other potato-producing countries. Lso has been linked to a condition known as zebra chip (ZC) that affects yield and quality of potato tubers. Efforts to find sources of resistance to ZC have primarily focused on greenhouse evaluations based on a single inoculation time prior to harvest. Plant response to infection, however, could be influenced by the developmental stage of the host plant, and ZC may continue to develop after harvest. The objectives of this study were to quantify Lso inoculation success, Lso titer, ZC severity and Lso development during storage in eight potato genotypes. These evaluations were conducted on plants infested with Lso-positive psyllids at 77, 12, and 4 days before vine removal (DBVR). The evaluated genotypes were categorized according to their relative resistance to Lso and tolerance to ZC symptoms. Lso inoculation success in the genotype family A07781, derived from Solanum chacoense, was lower than that of the susceptible control ('Russet Burbank'). A07781-4LB and A07781-3LB genotypes were characterized relatively resistant to the pathogen and highly tolerant to ZC symptoms, while A07781-10LB was categorized as susceptible to Lso but relatively tolerant to symptom expression. In stored potatoes, increase in Lso concentrations was observed for all infestation times. However, significantly higher Lso titer was detected in tubers infested 12 DBVR and the effect was similar across genotypes. Overall, the A07781 family can be considered as a promising source of resistance or tolerance to ZC.


Assuntos
Hemípteros/fisiologia , Doenças das Plantas/etiologia , Solanum tuberosum/genética , Animais , DNA de Plantas/isolamento & purificação , DNA de Plantas/metabolismo , Resistência à Doença , Suscetibilidade a Doenças , Genótipo , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Tubérculos/genética , Tubérculos/crescimento & desenvolvimento
18.
Sci Rep ; 10(1): 6637, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313143

RESUMO

Rhynocoris longifrons (Hemiptera: Reduviidae) is a generalist predator of many cotton insect pests. The hiding behaviour of this predator, which is one of the key factors of predation success, was investigated under screen house conditions. Moreover, we evaluated its biocontrol potential against Aphis gossypii (Hemiptera: Aphididae), Dysdercus cingulatus (Hemiptera: Pyrrhocoridae), Phenacoccus solenopsis (Hemiptera: Pseudococcidae), and Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) under screen house and field conditions. Results showed that R. longifrons life stages preferred to hide under small pebbles in the screen house tests. All the R. longifrons life stages showed a biocontrol potential against the four insect pests under screen house conditions. However, their biocontrol potential had not varied in relation to day and night hours. Augmentative releases of R. longifrons were carried out for two seasons such as South-west monsoon, 2011 and post-monsoon, 2012. The augmentative release of R. longifrons reduced significantly insect pests on cotton. In fact, the release of this predator in cotton fields was capable to reduce the population of H. armigera (50%), P. solenopsis (28%), D. cingulatus (18.8%), and A. gossypii (11.8%) during the rain fed condition (south-west monsoon season). During irrigated condition (post-monsoon season), populations of D. cingulatus were reduced by 26%, than P. solenopsis (20.6%), and A. gossypii (16.8%). Except ants, no negative impact was reported on other natural enemies present in the cotton field. Significantly higher crop yield and cost benefit ratio was observed in the predator release plots indicating that R. longifrons can be used in an integrated pest management program for multiple cotton pests.


Assuntos
Afídeos/fisiologia , Hemípteros/fisiologia , Lepidópteros/fisiologia , Estágios do Ciclo de Vida/fisiologia , Controle Biológico de Vetores/métodos , Comportamento Predatório/fisiologia , Reduviidae/fisiologia , Animais , Feminino , Gossypium/parasitologia , Índia , Masculino , Fotoperíodo , Estações do Ano
19.
J Insect Sci ; 20(2)2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32294181

RESUMO

The potato/tomato psyllid Bactericera cockerelli (Sulc) transmits 'Candidatus Liberibacter solanacearum' (Lso) (also known as 'Candidatus Liberibacter psyllaurous'), the bacterium associated with zebra chip disease (ZC) in potato. When disease incidence is high, ZC causes large economic losses through reductions in potato yield and tuber quality. No commercial potato variety has been found totally resistant to the pathogen. We evaluated host acceptance behaviors using no-choice assays on three breeding clones derived from Solanum chacoense Bitter with putative tolerance to Lso and/or ZC as part of an effort to determine whether the disease tolerance observed in those breeding clones was related to effects on psyllid settling behavior. We also counted the number of eggs laid and nymphs hatched on the different genotypes to observe any differences in reproduction. The potato variety 'Russet Burbank' was used as a susceptible control. Probing frequency and female walking duration were greater on Russet Burbank than the other genotypes. Oviposition did not differ among genotypes. However, female psyllids on two of the Lso-tolerant genotypes displayed reduced fertility 18-24 d after confinement with a male, relative to females on Russet Burbank. These results suggest that although the germplasms display minor abiotic activity on psyllid fertility, tolerance to Lso may be more strongly linked with plant tolerance to the pathogen rather than effects on host acceptance behaviors.


Assuntos
Hemípteros/fisiologia , Doenças das Plantas/microbiologia , Rhizobiaceae/fisiologia , Solanum tuberosum , Animais , Antibiose/genética , Feminino , Genótipo , Hemípteros/microbiologia , Locomoção , Masculino , Solanum tuberosum/genética
20.
J Insect Sci ; 20(2)2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32252064

RESUMO

Candidatus Liberibacter asiaticus Jagoueix, Bové, and Garnier (Rhizobiales: Rhizobiaceae) is transmitted by the psyllid Diaphorina citri Kuwayama and putatively causes Huanglongbing disease in citrus. Huanglongbing has reduced yields by 68% relative to pre-disease yields in Florida. Disease management is partly through vector control. Understanding vector biology is essential in this endeavor. Our goal was to document differences in probing behavior linked to sex. Based on both a literature review and our results, we conclude that there is either no effect of sex or that identifying such an effect requires a sample size at least four times larger than standard methodologies. Including both color and sex in statistical models did not improve model performance. Both sex and color are correlated with body size, and body size has not been considered in previous studies on sex in D. citri in terms of probing behavior. An effect of body size was found wherein larger psyllids took longer to reach ingestion behaviors and larger individuals spent more time-ingesting phloem, but these relationships explained little of the variability in these data. We suggest that the effects of sex can be ignored when running EPG experiments on healthy psyllids.


Assuntos
Citrus sinensis/fisiologia , Hemípteros/fisiologia , Herbivoria , Pigmentação , Animais , Tamanho Corporal , Cor , Comportamento Alimentar , Florida , Frutas/fisiologia , Hemípteros/microbiologia , Doenças das Plantas/microbiologia , Rhizobiaceae/fisiologia , Fatores Sexuais
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