Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Ecol Appl ; 33(2): e2761, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36218183

RESUMO

Some introduced species cause severe damage, although the majority have little impact. Robust predictions of which species are most likely to cause substantial impacts could focus efforts to mitigate those impacts or prevent certain invasions entirely. Introduced herbivorous insects can reduce crop yield, fundamentally alter natural and managed forest ecosystems, and are unique among invasive species in that they require certain host plants to succeed. Recent studies have demonstrated that understanding the evolutionary history of introduced herbivores and their host plants can provide robust predictions of impact. Specifically, divergence times between hosts in the native and introduced ranges of a nonnative insect can be used to predict the potential impact of the insect should it establish in a novel ecosystem. However, divergence time estimates vary among published phylogenetic datasets, making it crucial to understand if and how the choice of phylogeny affects prediction of impact. Here, we tested the robustness of impact prediction to variation in host phylogeny by using insects that feed on conifers and predicting the likelihood of high impact using four different published phylogenies. Our analyses ranked 62 insects that are not established in North America and 47 North American conifer species according to overall risk and vulnerability, respectively. We found that results were robust to the choice of phylogeny. Although published vascular plant phylogenies continue to be refined, our analysis indicates that those differences are not substantial enough to alter the predictions of invader impact. Our results can assist in focusing biosecurity programs for conifer pests and can be more generally applied to nonnative insects and their potential hosts by prioritizing surveillance for those insects most likely to be damaging invaders.


Assuntos
Ecossistema , Traqueófitas , Animais , Filogenia , Insetos , Plantas , Espécies Introduzidas
2.
BMC Gastroenterol ; 23(1): 81, 2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-36949385

RESUMO

BACKGROUND: The impact of pre-existing comorbidities on acute pancreatitis (AP) mortality is not clearly defined. Our study aims to determine the trend in AP hospital mortality and the role of comorbidities as a predictor of hospital mortality. METHODS: We analyzed patients aged ≥ 18 years hospitalized with AP diagnosis between 2016 and 2019. The data have been extracted from the Spanish National Hospital Discharge Database of the Spanish Ministry of Health. We performed a univariate and multivariable analysis of the association of age, sex, and comorbidities with hospital mortality in patients with AP. The role of the Charlson and Elixhauser comorbidity indices as predictors of mortality was evaluated. RESULTS: A total of 110,021 patients diagnosed with AP were hospitalized during the analyzed period. Hospital mortality was 3.8%, with a progressive decrease observed in the years evaluated. In multivariable analysis, age ≥ 65 years (OR: 4.11, p < 0.001), heart disease (OR: 1.73, p < 0.001), renal disease (OR: 1.99, p < 0.001), moderate-severe liver disease (OR: 2.86, p < 0.001), peripheral vascular disease (OR: 1.43, p < 0.001), and cerebrovascular disease (OR: 1.63, p < 0.001) were independent risk factors for mortality. The Charlson > 1.5 (OR: 2.03, p < 0.001) and Elixhauser > 1.5 (OR: 2.71, p < 0.001) comorbidity indices were also independently associated with mortality, and ROC curve analysis showed that they are useful for predicting hospital mortality. CONCLUSIONS: Advanced age, heart disease, renal disease, moderate-severe liver disease, peripheral vascular disease, and cerebrovascular disease before admission were independently associated with hospital mortality. The Charlson and Elixhauser comorbidity indices are useful for predicting hospital mortality in AP patients.


Assuntos
Mortalidade Hospitalar , Pancreatite , Pancreatite/mortalidade , Comorbidade , Cardiopatias/epidemiologia , Nefropatias/epidemiologia , Transtornos Cerebrovasculares/epidemiologia , Fatores Etários , Humanos , Idoso , Idoso de 80 Anos ou mais , Doenças Vasculares Periféricas/epidemiologia , Hepatopatias/epidemiologia
3.
Langenbecks Arch Surg ; 409(1): 21, 2023 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-38151676

RESUMO

BACKGROUND: There is controversial evidence regarding the impact of clinically relevant postoperative intra-abdominal collections (CR-IC) on the clinical course after pancreaticoduodenectomy. C-reactive Protein (CRP) has been validated as a predictor of postoperative pancreatic fistula (POPF). Still, its role in predicting CR-IC has not been studied. METHODS: A retrospective analysis was conducted on patients who underwent PD at a tertiary hospital between October 2012 and October 2017. The incidence of CR-IC, clinically relevant POPF and other complications, as well as mortality and length of hospitalisation, was retrieved. The impact of CR-IR on mortality and major complications was analysed. The serum CRP levels were retrieved on the third and fifth postoperative days (POD3 and POD5), followed by an analysis of sensitivity, specificity, and area under the curve to predict CR-IC using CRP. RESULTS: One hundred forty patients were enrolled following inclusion and exclusion criteria. The mean age was 66.5 years (15-83). The incidence of CR-IC was 33.7% (47), and CR-POPF was 24.3%. Pancreatic duct diameter ≤ 4 mm was identified as a risk factor related to CR-IC occurrence. The group of patients who developed CR-IC after PD exhibited a higher rate of complications Clavien-Dindo ≥ III compared to patients without CR-IC (40.4% vs 7.5%, p < 0.001), as well as other events such as admission to the intensive care unit (25.5% vs 4.3%, p < 0.001), the incidence of CR-POPF (66% vs 3.2%, p < 0.001), prolonged hospital stay (32 vs 13 days, p < 0.001), postoperative haemorrhage (23.4 vs 5.4%, p = 0.002), and delayed gastric empty (38.8% vs 11.8%, p < 0.001) respectively. Logistic regression analysis identified CR-IC related to POPF as a risk factor for Clavien-Dindo > III: OR = 10.6 (95% CI: 3.90-28.7). No differences in mortality were reported between the CR-IC group and non-CR-IC group. CRP at postoperative day 3 (POD3) > 17.55 mg/dl and CRP at postoperative day 5 (POD5) > 13.46 mg/dl were predictors of CR-IC (AUC: 0.731 and AUC:0.821, respectively). CONCLUSIONS: CR-IC has a significant impact after pancreaticoduodenectomy and is associated with a higher incidence of Clavien-Dindo ≥ III complications. Additionally, CRP levels at POD3 and POD5 play a role in predicting CR-IC. Prospective studies are essential to explore strategies for mitigating the occurrence of CR-IC after PD.


Assuntos
Pâncreas , Pancreaticoduodenectomia , Humanos , Idoso , Pancreaticoduodenectomia/efeitos adversos , Estudos Retrospectivos , Estudos Prospectivos , Fístula Pancreática/epidemiologia , Fístula Pancreática/etiologia , Fatores de Risco , Proteína C-Reativa , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia
4.
Chirurgia (Bucur) ; 118(5): 455-463, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37965830

RESUMO

Introduction: Robotic bariatric surgery (RBS) has seen a surge in popularity in recent years, yet questions persist about its utility concerning postoperative complications, costs, and technical aspects. RBS, while increasing in number, presents a greater technical challenge associated with more post-operative complications compared to primary bariatric surgery. In this study, we present our single institution experience and review the literature to assess the value of robotic revisional surgery. Material and Method: The retrospective review involved 42 patients (31 females, 11 males) who underwent various procedures, with the most frequent being the conversion of sleeve gastrectomy to gastric bypass (n=30). Encouragingly, no leaks or severe complications were identified. Furthermore, a systematic review indicated comparable outcomes, with decreased complication rates favoring robotic revisional surgery. Results: In direct comparison to standard laparoscopic revisional bariatric surgery, revisional robotic surgery demonstrated superior results in terms of efficacy, safety, and reduced hospital stay. However, rates of mortality, morbidity, and reintervention did not significantly differ between the two approaches. Conclusions: Considering these findings, we advocate for surgeons to acquire proficiency in the robotic technique, as part of the broader process of democratization and standardization of bariatric surgery. Embracing revisional robotic bariatric surgery can lead to improved patient outcomes, and its wider implementation may lead to enhanced surgical care and patient satisfaction in the field of bariatric procedures.


Assuntos
Cirurgia Bariátrica , Derivação Gástrica , Laparoscopia , Obesidade Mórbida , Procedimentos Cirúrgicos Robóticos , Masculino , Feminino , Humanos , Obesidade Mórbida/cirurgia , Procedimentos Cirúrgicos Robóticos/métodos , Estudos Prospectivos , Laparoscopia/métodos , Resultado do Tratamento , Reoperação/métodos , Cirurgia Bariátrica/efeitos adversos , Cirurgia Bariátrica/métodos , Derivação Gástrica/métodos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Estudos Retrospectivos
5.
New For (Dordr) ; : 1-22, 2022 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-35344318

RESUMO

Emerald ash borer (Agrilus planipennis; EAB) has devastated populations of ash (Fraxinus spp.) trees in dozens of U.S. states and Canada over the past few decades. The continued survival of scattered ash trees known as "lingering ash" in heavily infested natural stands, however, offers evidence of genetic resistance or tolerance to EAB. These surviving or "lingering" ash individuals may form the basis for reforestation programs in EAB-impacted areas, and clonal mass-propagation of these genotypes can help accelerate these efforts. Between 2013 and 2018, we initiated embryogenic cultures by culturing immature zygotic embryos from open-pollinated (OP) seeds collected from several surviving white ash and green ash trees in Michigan and Pennsylvania. In addition, in 2018, we initiated cultures from crosses made between lingering green ash parents from the USDA Forest Service ash breeding program in Ohio. Somatic embryos were produced by growing cultures in liquid suspension, followed by fractionation and plating on semisolid medium to produce developmentally synchronous populations of somatic embryos. Somatic embryo germination and conversion were enhanced by a combination of pre-germination cold treatment and inclusion of activated charcoal and gibberellic acid in the germination medium. Ash somatic seedlings derived from OP explants grew rapidly following transfer to potting mix and somatic seedlings representing nine ash clones were acclimatized, grown in the greenhouse and planted in a preliminary field test, along with EAB-resistant Manchurian ash (F. mandshurica) and EAB-susceptible control seedlings. Somatic seedlings have now been produced from cultures that originated from seeds derived from the progeny of lingering green ash parents and an ex vitro germination protocol has shown some promise for accelerating early somatic seedling growth. Results of this research could provide the basis for scaled-up production of EAB-resistant ash varieties for seed orchard production for forest restoration and cultivar development for urban tree restoration.

6.
Oecologia ; 190(4): 867-878, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31317270

RESUMO

Phenological synchrony between herbivorous insects and host plants is an important determinant of insect distribution and abundance. Non-native insects often experience novel climates, photoperiods, and host plants. How critical time periods of insect life cycles coincide with-or diverge from-phenological windows of host plant suitability could affect invasion success and the dynamics of outbreaks. Larch casebearer is an invasive defoliator that has recently undergone anomalous outbreaks on eastern larch in North America. We conducted growth chamber, greenhouse, and field studies to quantify the spring phenological window for larch casebearer on eastern larch and importance of phenological synchrony for casebearer development and survival. We constructed degree-day models of spring activity for both species and investigated responses of casebearers to early and delayed activation relative to bud break. Both species had lower developmental thresholds of ~ 5 °C, but mean activation of casebearers occurred 245 degree-days after bud break by eastern larch. In addition to forcing temperatures, phenologies of eastern larch and casebearer larvae were significantly influenced by chilling and photoperiod, respectively. Larvae were robust to both starvation and delayed activation; days between larval activation and bud break (range: 0-58 days) had no influence on larval development and survival to adulthood. Disparate plant-insect responses to environmental cues and robustness of casebearers to changes in phenology result in a wide phenological window that likely has contributed to the insect's broad distribution in eastern North America. Changes in phenological synchrony, however, do not appear to have facilitated recent outbreaks of larch casebearer on eastern larch.


Assuntos
Herbivoria , Traqueófitas , Animais , Insetos , América do Norte , Plantas , Estações do Ano
7.
J Chem Ecol ; 43(8): 831-842, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28752407

RESUMO

Emerald ash borer (EAB; Agrilus planipennis) is a devastating pest of ash (Fraxinus spp.) in its invaded range in North America. Its coevolved Asian hosts are more resistant and less preferred for oviposition than susceptible North American species. We compared EAB oviposition preferences and bark and canopy volatile organic compound (VOC) emissions of resistant Manchurian ash and susceptible black ash, and examined relationships between VOC profiles and oviposition. In the field, black ash was highly preferred for oviposition while no eggs were laid on Manchurian ash, and we found clear differences in the VOC profiles of Manchurian and black ash. We detected 78 compounds emitted from these species, including 16 compounds that elicited EAB antennal activity in prior studies. Four compounds were unique to black and 11 to Manchurian ash. Emission rates of 14 canopy and 19 bark volatiles varied among the two species, including four previously reported as antennally active. Specifically, 7-epi-sesquithujene (bark) emissions were greater from black ash, while ß-caryophyllene (canopy), linalool (bark), and α-cubebene (bark) were emitted at higher rates by Manchurian ash. No relationships were found between the emission rate of any single compound or group of compounds (e.g. monoterpenes) suggesting that preference may be based on complex profile combinations. This is the first study to directly compare VOCs of black and Manchurian ash as well as the first to examine bark- and canopy-specific VOCs. The unique bark and canopy VOC profiles of these two species implicates potentially important variation in VOCs between a closely related resistant and susceptible species that provides a foundation for future studies of host preferences of EAB.


Assuntos
Besouros/fisiologia , Fraxinus/química , Compostos Orgânicos Voláteis/química , Monoterpenos Acíclicos , Animais , Feminino , Fraxinus/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Sesquiterpenos Monocíclicos , Monoterpenos/química , Monoterpenos/farmacologia , Oviposição/efeitos dos fármacos , Casca de Planta/química , Casca de Planta/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Sesquiterpenos Policíclicos , Sesquiterpenos/química , Sesquiterpenos/farmacologia , Compostos Orgânicos Voláteis/farmacologia
8.
Annu Rev Entomol ; 61: 335-52, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26667377

RESUMO

Eradication is the deliberate elimination of a species from an area. Given that international quarantine measures can never be 100% effective, surveillance for newly arrived populations of nonnative species coupled with their eradication represents an important strategy for excluding potentially damaging insect species. Historically, eradication efforts have not always been successful and have sometimes been met with public opposition. But new developments in our understanding of the dynamics of low-density populations, the availability of highly effective treatment tactics, and bioeconomic analyses of eradication strategies offer new opportunities for developing more effective surveillance and eradication programs. A key component that connects these new developments is the harnessing of Allee effects, which naturally promote localized species extinction. Here we review these developments and suggest how research might enhance eradication strategies.


Assuntos
Controle de Insetos/métodos , Insetos/fisiologia , Espécies Introduzidas , Animais , Extinção Biológica , Dinâmica Populacional
9.
New Phytol ; 209(1): 63-79, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26268949

RESUMO

We review the literature on host resistance of ash to emerald ash borer (EAB, Agrilus planipennis), an invasive species that causes widespread mortality of ash. Manchurian ash (Fraxinus mandshurica), which coevolved with EAB, is more resistant than evolutionarily naïve North American and European congeners. Manchurian ash was less preferred for adult feeding and oviposition than susceptible hosts, more resistant to larval feeding, had higher constitutive concentrations of bark lignans, coumarins, proline, tyramine and defensive proteins, and was characterized by faster oxidation of phenolics. Consistent with EAB being a secondary colonizer of coevolved hosts, drought stress decreased the resistance of Manchurian ash, but had no effect on constitutive bark phenolics, suggesting that they do not contribute to increased susceptibility in response to drought stress. The induced resistance of North American species to EAB in response to the exogenous application of methyl jasmonate was associated with increased bark concentrations of verbascoside, lignin and/or trypsin inhibitors, which decreased larval survival and/or growth in bioassays. This finding suggests that these inherently susceptible species possess latent defenses that are not induced naturally by larval colonization, perhaps because they fail to recognize larval cues or respond quickly enough. Finally, we propose future research directions that would address some critical knowledge gaps.


Assuntos
Besouros/fisiologia , Fraxinus/imunologia , Magnoliopsida/imunologia , Reguladores de Crescimento de Plantas/farmacologia , Acetatos/farmacologia , Animais , Anti-Infecciosos/metabolismo , Antibiose , Ciclopentanos/farmacologia , Fraxinus/parasitologia , Glucosídeos/metabolismo , Larva , Lignina/metabolismo , Magnoliopsida/parasitologia , Modelos Biológicos , Oviposição , Oxilipinas/farmacologia , Fenóis/metabolismo , Especificidade da Espécie , Inibidores da Tripsina/metabolismo , Madeira
10.
J Chem Ecol ; 42(8): 782-792, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27484881

RESUMO

Emerald ash borer (EAB) is an invasive beetle native to Asia that infests and kills ash (Fraxinus spp.) in North America. Previous experiments indicated that larvae feeding on co-evolved, resistant Manchurian ash (F. mandshurica) have increased antioxidant and quinone-protective enzyme activities compared to larvae feeding on susceptible North American species. Here, we examined mechanisms of host-generated oxidative and quinone-based stress and other putative defenses in Manchurian ash and the closely related and chemically similar, but susceptible, black ash (F. nigra), with and without exogenous application of methyl jasmonate (MeJA) to induce resistance mechanisms. Peroxidase activities were 4.6-13.3 times higher in Manchurian than black ash, although both species appeared to express the same three peroxidase isozymes. Additionally, peroxidase-mediated protein cross-linking activity was stronger in Manchurian ash. Polyphenol oxidase, ß-glucosidase, chitinase, and lipoxygenase activities also were greater in Manchurian ash, but only lipoxygenase activity increased with MeJA application. Phloem H2O2 levels were similar and were increased by MeJA application in both species. Lastly, trypsin inhibitor activity was detected in methanol and water extracts that were not allowed to oxidize, indicating the presence of phenolic-based trypsin inhibitors. However, no proteinaceous trypsin inhibitor activity was detected in either species. In response to MeJA application, Manchurian ash had higher trypsin inhibitor activity than black ash using the unoxidized water extracts, but no treatment effects were detected using methanol extracts. Based on these results we hypothesize that peroxidases, lignin polymerization, and quinone generation contribute to the greater resistance to EAB displayed by Manchurian ash.


Assuntos
Besouros , Enzimas/química , Enzimas/metabolismo , Fraxinus/enzimologia , Animais , Fraxinus/química , Fraxinus/fisiologia , Peróxido de Hidrogênio/metabolismo , Especificidade da Espécie , Inibidores da Tripsina/metabolismo , Água/química
11.
J Econ Entomol ; 108(5): 2344-53, 2015 10.
Artigo em Inglês | MEDLINE | ID: mdl-26453723

RESUMO

Protection of green ash trees (Fraxinus pennsylvanica Marshall) from the emerald ash borer (EAB), Agrilus planipennis Fairmaire, by soil applications of neonicotinoids (imidacloprid, clothianidin, and dinotefuran) was tested at five locations between 2005 and 2013. Application rate and spring versus fall application dates were evaluated in tests with neighborhood street trees and in one plantation of 65 ash trees. Insecticide treatments of ash trees at all five sites were initiated as the leading edge of the EAB invasion began to kill the first ash trees at each location. Trees were treated and evaluated at each site for 4 to 7 yr. Spring applications of imidacloprid were more efficacious than fall applications. Application rates of 0.8 g a.i./cm dbh or greater per year gave a higher level of protection and were more consistent than rates of 0.56 g a.i./cm dbh per year or less. The number of years between the first observation of canopy loss due to EAB and death of most of the control trees varied from three to seven years among test sites, depending on how many non-treated ash trees were nearby.


Assuntos
Besouros , Controle de Insetos , Inseticidas , Animais , Besouros/crescimento & desenvolvimento , Fraxinus/crescimento & desenvolvimento , Guanidinas , Imidazóis , Larva/crescimento & desenvolvimento , Neonicotinoides , Nitrocompostos , Ohio , Solo/química , Tiazóis
12.
Annu Rev Entomol ; 59: 13-30, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24112110

RESUMO

Since its accidental introduction from Asia, emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), has killed millions of ash trees in North America. As it continues to spread, it could functionally extirpate ash with devastating economic and ecological impacts. Little was known about EAB when it was first discovered in North America in 2002, but substantial advances in understanding of EAB biology, ecology, and management have occurred since. Ash species indigenous to China are generally resistant to EAB and may eventually provide resistance genes for introgression into North American species. EAB is characterized by stratified dispersal resulting from natural and human-assisted spread, and substantial effort has been devoted to the development of survey methods. Early eradication efforts were abandoned largely because of the difficulty of detecting and delineating infestations. Current management is focused on biological control, insecticide protection of high-value trees, and integrated efforts to slow ash mortality.


Assuntos
Besouros/fisiologia , Cadeia Alimentar , Fraxinus/crescimento & desenvolvimento , Controle de Insetos/métodos , Distribuição Animal , Animais , Canadá , Besouros/crescimento & desenvolvimento , Fraxinus/genética , Espécies Introduzidas , Larva/crescimento & desenvolvimento , Larva/fisiologia , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Estados Unidos
13.
Plant Cell Environ ; 37(4): 1009-21, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24125060

RESUMO

The invasive emerald ash borer (EAB) beetle is a significant threat to the survival of North American ash. In previous work, we identified putative biochemical and molecular markers of constitutive EAB resistance in Manchurian ash, an Asian species co-evolved with EAB. Here, we employed high-throughput high-performance liquid chromatography with photodiode array detection and mass spectrometry (HPLC-PDA-MS) to characterize the induced response of soluble phloem phenolics to EAB attack in resistant Manchurian and susceptible black ash under conditions of either normal or low water availability, and the effects of water availability on larval performance. Total larval mass per tree was lower in Manchurian than in black ash. Low water increased larval numbers and mean larval mass overall, but more so in Manchurian ash. Low water did not affect levels of phenolics in either host species, but six phenolics decreased in response to EAB. In both ashes, pinoresinol A was induced by EAB, especially in Manchurian ash. Pinoresinol A and pinoresinol B were negatively correlated with each other in both species. The higher accumulation of pinoresinol A in Manchurian ash after attack may help explain the resistance of this species to EAB, but none of the responses measured here could explain increased larval performance in trees subjected to low water availability.


Assuntos
Besouros/fisiologia , Fraxinus/fisiologia , Fraxinus/parasitologia , Fenóis/metabolismo , Floema/metabolismo , Água/fisiologia , Análise de Variância , Animais , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Furanos/metabolismo , Larva/fisiologia , Lignanas/metabolismo , Modelos Lineares , Espectrometria de Massas , Análise Multivariada , Folhas de Planta/fisiologia , Análise de Componente Principal , Estatísticas não Paramétricas
14.
Oecologia ; 176(4): 1047-59, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25231373

RESUMO

The emerald ash borer (EAB; Agrilus planipennis Fairmaire) is causing widespread mortality of ash (Fraxinus spp.) in North America. To date, no mechanisms of host resistance have been identified against this pest. Methyl jasmonate was applied to susceptible North American and resistant Asian ash species to determine if it can elicit induced responses in bark that enhance resistance to EAB. In particular, phenolic compounds, lignin, and defense-related proteins were quantified, and compounds associated with resistance were subsequently tested directly against EAB larvae in bioassays with artificial diet. MeJA application decreased adult emergence in susceptible ash species, comparable to levels achieved by insecticide application. Concentration of the phenolic compound verbascoside sharply increased after MeJA application to green and white ash. When incorporated in an artificial diet, verbascoside decreased survival and growth of EAB neonates in a dose-dependent fashion. Lignin and trypsin inhibitors were also induced by MeJA, and analogs of both compounds reduced growth of EAB larvae in artificial diets. We conclude that the application of MeJA prior to EAB attack has the ability to enhance resistance of susceptible ash trees by inducing endogenous plant defenses, and report evidence that induction of verbascoside is a mechanism of resistance to EAB.


Assuntos
Acetatos/farmacologia , Besouros , Ciclopentanos/farmacologia , Resistência à Doença/efeitos dos fármacos , Fraxinus/efeitos dos fármacos , Glucosídeos/metabolismo , Inseticidas , Oxilipinas/farmacologia , Fenóis/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Adaptação Fisiológica , Animais , Besouros/efeitos dos fármacos , Besouros/crescimento & desenvolvimento , Fraxinus/metabolismo , Fraxinus/fisiologia , Glucosídeos/farmacologia , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Lignina/metabolismo , Lignina/farmacologia , América do Norte , Fenóis/farmacologia , Especificidade da Espécie , Inibidores da Tripsina/metabolismo , Inibidores da Tripsina/farmacologia
15.
J Chem Ecol ; 38(5): 499-511, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22588569

RESUMO

The emerald ash borer (Agrilus planipennis, EAB) is an invasive wood-borer indigenous to Asia and is responsible for widespread ash (Fraxinus spp.) mortality in the U.S. and Canada. Resistance and susceptibility to EAB varies among Fraxinus spp., which is a result of their co-evolutionary history with the pest. We characterized constitutive phenolic profiles and lignin levels in the phloem of green, white, black, blue, European, and Manchurian ash. Phloem was sampled twice during the growing season, coinciding with phenology of early and late instar EAB. We identified 66 metabolites that displayed a pattern of variation, which corresponded strongly with phylogeny. Previously identified lignans and lignan derivatives were confirmed to be unique to Manchurian ash, and may contribute to its high level of resistance to EAB. Other compounds that had been considered unique to Manchurian ash, including hydroxycoumarins and the phenylethanoids calceolarioside A and B, were detected in closely related, but susceptible species, and thus are unlikely to contribute to EAB resistance of Manchurian ash. The distinct phenolic profile of blue ash may contribute to its relatively high resistance to EAB.


Assuntos
Besouros/fisiologia , Fraxinus/fisiologia , Lignina/química , Fenóis/química , Floema/química , Animais , Fraxinus/química , Lignina/isolamento & purificação , Lignina/metabolismo , Fenóis/isolamento & purificação , Fenóis/metabolismo , Floema/metabolismo , Estações do Ano , Especificidade da Espécie
16.
J Econ Entomol ; 105(1): 1-13, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22420248

RESUMO

Invasive species increasingly threaten ecosystems, food production, and human welfare worldwide. Hundreds of eradication programs have targeted a wide range of nonnative insect species to mitigate the economic and ecological impacts of biological invasions. Many such programs used multiple tactics to achieve this goal, but interactions between tactics have received little formal consideration, specifically as they interact with Allee dynamics. If a population can be driven below an Allee threshold, extinction becomes more probable because of factors such as the failure to find mates, satiate natural enemies, or successfully exploit food resources, as well as demographic and environmental stochasticity. A key implication of an Allee threshold is that the population can be eradicated without the need and expense of killing the last individuals. Some combinations of control tactics could interact with Allee dynamics to increase the probability of successful eradication. Combinations of tactics can be considered to have synergistic (greater efficiency in achieving extinction from the combination), additive (no improvement over single tactics alone), or antagonistic (reduced efficiency from the combination) effects on Allee dynamics. We highlight examples of combinations of tactics likely to act synergistically, additively, or antagonistically on pest populations. By exploiting the interacting effects of multiple tactics on Allee dynamics, the success and cost-effectiveness of eradication programs can be enhanced.


Assuntos
Controle de Insetos/métodos , Insetos , Espécies Introduzidas , Animais , Feminino , Inseticidas , Masculino , Controle Biológico de Vetores/métodos , Feromônios , Densidade Demográfica
17.
J Chem Ecol ; 37(5): 450-9, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21537902

RESUMO

We examined the extent to which three Fraxinus cultivars and a wild population that vary in their resistance to Emerald Ash Borer (EAB) could be differentiated on the basis of a suite of constitutive chemical defense traits in phloem extracts. The EAB-resistant Manchurian ash (F. mandshurica, cv. Mancana) was characterized by having a rapid rate of wound browning, a high soluble protein concentration, low trypsin inhibitor activities, and intermediate levels of peroxidase activity and total soluble phenolic concentration. The EAB-susceptible white ash (F. americana, cv. Autumn Purple) was characterized by a slow wound browning rate and low levels of peroxidase activity and total soluble phenolic concentrations. An EAB-susceptible green ash cultivar (F. pennsylvanica, cv. Patmore) and a wild accession were similar to each other on the basis of several chemical defense traits, and were characterized by high activities of peroxidase and trypsin inhibitor, a high total soluble phenolic concentration, and an intermediate rate of wound browning. Lignin concentration and polyphenol oxidase activities did not differentiate resistant and susceptible species. Of 33 phenolic compounds separated by HPLC and meeting a minimum criterion for analysis, nine were unique to Manchurian ash, five were shared among all species, and four were found in North American ashes and not in the Manchurian ash. Principal components analysis revealed clear separations between Manchurian, white, and green ashes on the basis of all phenolics, as well as clear separations on the basis of quantities of phenolics that all species shared. Variation in some of these constitutive chemical defense traits may contribute to variation in resistance to EAB in these species.


Assuntos
Besouros/fisiologia , Fraxinus/metabolismo , Fraxinus/parasitologia , Interações Hospedeiro-Parasita , Floema/metabolismo , Proteínas de Plantas/metabolismo , Animais , Catecol Oxidase/isolamento & purificação , Catecol Oxidase/metabolismo , Lignina/isolamento & purificação , Lignina/metabolismo , Peroxidase/isolamento & purificação , Peroxidase/metabolismo , Fenóis/isolamento & purificação , Fenóis/metabolismo , Proteínas de Plantas/isolamento & purificação
18.
J Econ Entomol ; 104(2): 574-9, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21510207

RESUMO

Field-based trapping experiments were conducted in Ohio in 2003, 2004, and 2008 to determine the influence of (-)-alpha-pinene on the attraction of exotic and native ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) to ethanol-baited traps. In 2003 and 2004, we determined the effect of adding an (-)-alpha-pinene ultrahigh release lure (UHR; 2 g/d at 20 degrees C) to traps baited with an ethanol UHR lure (0.39 g/d). FewerAnisandrus (Xyleborus) sayi (Hopkins) and Xyleborinus saxeseni (Ratzeburg) were collected in 2003 and 2004 from traps baited with ethanol UHR plus (-)-alpha-pinene UHR compared with ethanol UHR. (-)-alpha-Pinene also reduced the attraction of Xyloterinus politus (Say) to ethanol-baited traps in 2004. Total captures of Xylosandrus germanus (Blandford) in 2003 were higher in traps baited with ethanol UHR plus (-)-alpha-pinene UHR than in traps with ethanol UHR alone but not in 2004. In 2008, captures were compared among traps baited with eight combinations of ethanol and (-)-a-pinene at both UHR and low release (LR) rates. Release rates for ethanol LR and (-)-alpha-pinene LR were 0.027 and 0.0015 g/d, respectively. (-)-alpha-Pinene UHR and (-)-alpha-pinene LR reduced the attractiveness of ethanol UHR to A. sayi and X. saxeseni. Ethanol UHR was also more attractive than ethanol LR to A. sayi and X. germanus. These findings demonstrate traps baited with ethanol alone are more effective than ethanol plus (-)-alpha-pinene for monitoring ambrosia beetle flight activity in ornamental nurseries. Ethanol release rate is also an important consideration for monitoring purposes.


Assuntos
Comportamento Animal/efeitos dos fármacos , Besouros/efeitos dos fármacos , Controle de Insetos , Monoterpenos/farmacologia , Agricultura , Animais , Monoterpenos Bicíclicos , Etanol
19.
Annu Rev Entomol ; 55: 19-38, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-19961321

RESUMO

Urbanization affects communities of herbivorous arthropods and provides opportunities for dramatic changes in their abundance and richness. Underlying these changes are creation of impervious surfaces; variation in the density, diversity, and complexity of vegetation; and maintenance practices including pulsed inputs of fertilizers, water, and pesticides. A rich body of knowledge provides theoretical underpinnings for predicting and understanding impacts of urbanization on arthropods. However, relatively few studies have elucidated mechanisms that explain patterns of insect and mite abundance and diversity across urbanization gradients. Published accounts suggest that responses to urbanization are often taxon specific, highly variable, and linked to properties of urbanization that weaken top-down and/or bottom-up processes, thereby destabilizing populations of herbivores and their natural enemies. In addition to revealing patterns in diversity and abundance of herbivores across urbanization gradients, a primary objective of this review is to examine mechanisms underlying these patterns and to identify potential hypotheses for future testing.


Assuntos
Artrópodes , Cidades , Ecossistema , Animais , Densidade Demográfica
20.
J Econ Entomol ; 114(3): 1201-1210, 2021 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-33837788

RESUMO

Management responses to invasive forest insects are facilitated by the use of detection traps ideally baited with species-specific semiochemicals. Emerald ash borer, Agrilus planipennis Fairmaire, is currently invading North American forests, and since its detection in 2002, development of monitoring tools has been a primary research objective. We compared six trapping schemes for A. planipennis over 2 yr at sites in four U.S. states and one Canadian province that represented a range of background A. planipennis densities, canopy coverage, and ash basal area. We also developed a region-wide phenology model. Across all sites and both years, the 10th, 50th, and 90th percentile of adult flight occurred at 428, 587, and 837 accumulated degree-days, respectively, using a base temperature threshold of 10°C and a start date of 1 January. Most trapping schemes captured comparable numbers of beetles with the exception of purple prism traps (USDA APHIS PPQ), which captured significantly fewer adults. Trapping schemes varied in their trap catch across the gradient of ash basal area, although when considering trap catch as a binary response variable, trapping schemes were more likely to detect A. planipennis in areas with a higher ash component. Results could assist managers in optimizing trap selection, placement, and timing of deployment given local weather conditions, forest composition, and A. planipennis density.


Assuntos
Besouros , Fraxinus , Animais , Canadá , Controle de Insetos , Insetos , Larva , Feromônios
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA