Diseases Caused by Xylella fastidiosa in Prunus Genus: An Overview of the Research on an Increasingly Widespread Pathogen

Cultivated plants belonging to the genus Prunus are globally widespread and for some countries, are economically important crops; and they play a key role in the composition of a landscape. Xylella fastidiosa is a key threat to plant health, and several Prunus species are heavily stressed by this pathogen, such as almond, peach, and plum; many strain types of different subspecies can cause severe diseases. This review highlights different approaches to managing epidemic events related to X. fastidiosa in stone fruit plants. In fact, in most new European and Asian outbreaks, almond is the main and very common host and peach, plum, apricot, and cherry are widespread and profitable crops for the involved areas. Various diseases associated with stone fruit plants show different degrees of severity in relation to cultivar, although investigations are still limited. The development and selection of tolerant and resistant cultivars and the study of resistance mechanisms activated by the plant against X. fastidiosa infections seem to be the best way to find long-term solutions aimed at making affected areas recover. In addition, observations in orchards severely affected by the disease can be essential for collecting tolerant or resistant materials within the local germplasm. In areas where the bacterium is not yet present, a qualitative-quantitative study on entomofauna is also important for the timely identification of potential vectors and for developing effective control strategies.

Download Full-text

Introduction to pertussis transmission and epidemiological dynamics

Pertussis ◽

10.1093/oso/9780198811879.003.0001 ◽

2018 ◽

pp. 6-25

Author(s):

Pejman Rohani ◽

Samuel V. Scarpino

Keyword(s):

Control Strategies ◽

Age Distribution ◽

Population Level ◽

Vaccine Uptake ◽

Effective Control ◽

Transmission Potential ◽

Epidemic Period ◽

The Impact ◽

Pertussis Epidemiology

Resolving the long-term, population-level consequences of changes in pertussis epidemiology, arising from bacterial evolution, shifts in vaccine-induced immunity, or changes in surveillance, are key challenges for devising effective control strategies. This chapter reviews some of the key features of pertussis epidemiology, together with the underlying epidemiological principles that set the context for their interpretation. These include the relationship between the age distribution of cases and pertussis transmission potential, the impact of vaccine uptake on incidence, periodicity and age incidence, as well as spatially explicit recurrent pertussis epidemics and associated extinction frequency. This review highlights some of the predictable and consistent aspects of pertussis epidemiology (e.g. the systematic increase in the inter-epidemic period with the introduction of whole-cell vaccines) and a number of important heterogeneities, including variations in contemporary patterns of incidence and geographic spread.

Download Full-text

Modeling Population Dynamics of Kochia (Bassia scoparia) in Response to Diverse Weed Control Options

Weed Science ◽

10.1017/wsc.2018.85 ◽

2019 ◽

Vol 67 (1) ◽

pp. 57-67 ◽

Cited By ~ 1

Author(s):

O. Adewale Osipitan ◽

J. Anita Dille ◽

Muthukumar V. Bagavathiannan ◽

Stevan Z. Knezevic

Keyword(s):

Population Dynamics ◽

Population Growth ◽

Weed Control ◽

Seed Production ◽

Seedling Recruitment ◽

Control Strategies ◽

Effective Control ◽

Parameter Estimates ◽

Herbicide Resistant

AbstractKochia [Bassia scoparia(L.) A. J. Scott] is a problematic weed species across the Great Plains, as it is spreading fast and has developed herbicide-resistant biotypes. It is imperative to understand key life-history stages that promote population expansion ofB. scopariaand control strategies that would provide effective control of these key stages, thereby reducing population growth. Diversifying weed control strategies has been widely recommended for the management of herbicide-resistant weeds. Therefore, the objectives of this study were to develop a simulation model to assess the population dynamics ofB. scopariaand to evaluate the effectiveness of diverse weed control strategies on long-term growth rates ofB. scopariapopulations. The model assumed the existence of a glyphosate-resistant (GR) biotype in theB. scopariapopulation, but at a very low proportion in a crop rotation that included glyphosate-tolerant corn (Zea maysL.) and soybean [Glycine max(L.) Merr.]. The parameter estimates used in the model were obtained from various ecological and management studies onB. scoparia. Model simulations indicated that seedling recruitment and survival to seed production were more important than seedbank persistence forB. scopariapopulation growth rate. Results showed that a diversified management program, including glyphosate, could provide excellent control ofB. scopariapopulations and potentially eliminate already evolved GRB. scopariabiotypes within a given location. The most successful scenario was a diverse control strategy that included one or two preplant tillage operations followed by preplant or PRE application of herbicides with residual activities and POST application of glyphosate; this strategy reduced seedling recruitment, survival, and seed production during the growing season, with tremendous negative impacts on long-term population growth and resistance risk inB. scoparia.

Download Full-text

Functional genetic validation of key genes conferring insecticide resistance in the major African malaria vector, Anopheles gambiae

10.1101/749457 ◽

2019 ◽

Cited By ~ 1

Author(s):

Adriana Adolfi ◽

Beth Poulton ◽

Amalia Anthousi ◽

Stephanie Macilwee ◽

Hilary Ranson ◽

...

Keyword(s):

Public Health ◽

Insecticide Resistance ◽

Anopheles Gambiae ◽

Pyrethroid Resistance ◽

Control Strategies ◽

Resistance Mechanisms ◽

Effective Control ◽

Cross Resistance ◽

Toxic Metabolite ◽

Control Programs

ABSTRACTResistance in Anopheles gambiae to members of all four major classes (pyrethroids, carbamates, organochlorines and organophosphates) of public health insecticides limits effective control of malaria transmission in Africa. Increased expression of detoxifying enzymes has been associated with resistance, but direct functional validation in An. gambiae has been lacking. Here we perform transgenic analysis using the GAL4/UAS system to examine insecticide resistance phenotypes conferred by increased expression of the three genes - Cyp6m2, Cyp6p3 and Gste2 - most often found upregulated in resistant An. gambiae. We report the first evidence in An. gambiae that organophosphate and organochlorine resistance is conferred by overexpression of GSTE2 in a broad tissue profile. Pyrethroid and carbamate resistance is bestowed by similar Cyp6p3 overexpression, and Cyp6m2 confers only pyrethroid resistance when overexpressed in the same tissues. Conversely, such Cyp6m2 overexpression increases susceptibility to the organophosphate malathion, presumably due to conversion to a more toxic metabolite. No resistant phenotypes are conferred when either Cyp6 gene overexpression is restricted to the midgut or oenocytes, answering long standing questions related to the importance of these tissues in resistance to contact insecticides. Validation of genes conferring resistance provides markers to guide control strategies, and the observed negative cross-resistance due to Cyp6m2 gives credence to proposed dual insecticide strategies to overcome pyrethroid resistance. These trasnsgenic An. gambiae resistant lines are being used to test potential liabilities in new active compounds early in development.SIGNIFICANCE STATEMENTInsecticide resistance in Anopheles gambiae mosquitoes can derail malaria control programs, and to overcome it we need to discover the underlying molecular basis. Here, for the first time, we characterise three genes most often associated with insecticide resistance directly by their overproduction in genetically modified An. gambiae. We show that overexpression of each gene confers resistance to representatives of at least one insecticide class and, taken together, the three genes provide cross-resistance to all four major insecticide classes currently used in public health. These data validate the candidate genes as markers to monitor the spread of resistance in mosquito populations. The modified mosquitoes produced are also valuable tools to pre-screen new insecticides for potential liabilities to existing resistance mechanisms.

Download Full-text

Benefits and feasibility of local elimination of possum populations

Wildlife Research ◽

10.1071/wr06055 ◽

2006 ◽

Vol 33 (7) ◽

pp. 605 ◽

Cited By ~ 15

Author(s):

D. R. Morgan ◽

G. Nugent ◽

B. Warburton

Keyword(s):

Control Strategies ◽

Cost Effective ◽

Population Characteristics ◽

Effective Control ◽

Brushtail Possum ◽

Control Approach ◽

Initial Cost ◽

Regulatory Status ◽

The Cost

Introduction of the brushtail possum (Trichosurus vulpecula) to New Zealand has resulted in serious ecological and economic impacts and considerable control efforts. Recovery of possum populations after control occurs through immigration from adjacent areas and breeding of survivors and immigrants. If complete local elimination can be achieved, the recovery of populations will depend solely on immigration and therefore should be substantially slowed (particularly in very large areas). To compare the cost-effectiveness of four control strategies over the long term (60 years), we constructed a deterministic bioeconomic model based on 23 variables describing population characteristics, sizes of the sink (i.e. area controlled) and source (of reinfestation) areas, and costs. Sensitivity analysis showed that the most influential variables related primarily to cost and effectiveness of control, whereas factors describing immigration after control had relatively little influence. When the most influential variables were varied, the model predicted that local elimination of possums followed by ‘perimeter’ control is likely to be a more cost-effective control strategy under most scenarios than the current ‘knockdown-then-maintenance-control’ approach. Possum-control technology and its application have improved greatly in the last three decades such that it now appears that local elimination is, technically, a realistic goal, and is possibly already being achieved occasionally. Constraining factors include unreliable monitoring/detection at ultralow densities, inappropriate selection and use of control options, lack of incentive under the present contracting system, initial cost, contracting capacity, and the future regulatory status of poisons. However, these difficulties can be overcome, facilitating the adoption of long-term local elimination strategies that are better suited to managing possum populations in perpetuity.

Download Full-text

The pertussis enigma: reconciling epidemiology, immunology and evolution

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2015.2309 ◽

2016 ◽

Vol 283 (1822) ◽

pp. 20152309 ◽

Cited By ~ 57

Author(s):

Matthieu Domenech de Cellès ◽

Felicia M. G. Magpantay ◽

Aaron A. King ◽

Pejman Rohani

Keyword(s):

Control Strategies ◽

Natural Infection ◽

Population Level ◽

Developed Countries ◽

Effective Control ◽

Simple Explanation ◽

Incidence Data ◽

High Infection ◽

Pertussis Epidemiology

Pertussis, a highly contagious respiratory infection, remains a public health priority despite the availability of vaccines for 70 years. Still a leading cause of mortality in developing countries, pertussis has re-emerged in several developed countries with high vaccination coverage. Resurgence of pertussis in these countries has routinely been attributed to increased awareness of the disease, imperfect vaccinal protection or high infection rates in adults. In this review, we first present 1980–2012 incidence data from 63 countries and show that pertussis resurgence is not universal. We further argue that the large geographical variation in trends probably precludes a simple explanation, such as the transition from whole-cell to acellular pertussis vaccines. Reviewing available evidence, we then propose that prevailing views on pertussis epidemiology are inconsistent with both historical and contemporary data. Indeed, we summarize epidemiological evidence showing that natural infection and vaccination both appear to provide long-term protection against transmission and disease, so that previously infected or vaccinated adults contribute little to overall transmission at a population level. Finally, we identify several promising avenues that may lead to a consistent explanation of global pertussis epidemiology and to more effective control strategies.

Download Full-text

Herbicide programs to manage glyphosate/dicamba-resistant kochia (Bassia scoparia) in glyphosate/dicamba-resistant soybean

Weed Technology ◽

10.1017/wet.2020.3 ◽

2020 ◽

Vol 34 (4) ◽

pp. 568-574

Author(s):

Ramawatar Yadav ◽

Vipan Kumar ◽

Prashant Jha

Keyword(s):

Grain Yield ◽

Weed Control ◽

Great Plains ◽

Field Experiments ◽

Control Strategies ◽

Effective Control ◽

The Us ◽

Herbicide Programs ◽

Us Great Plains

AbstractEvolution of kochia resistance to glyphosate and dicamba is a concern for growers in the US Great Plains. An increasing use of glyphosate and dicamba with the widespread adoption of glyphosate/dicamba-resistant (GDR) soybean in recent years may warrant greater attention. Long-term stewardship of this new stacked-trait technology will require the implementation of diverse weed control strategies, such as the use of soil-residual herbicides (PRE) aimed at effective control of GDR kochia. Field experiments were conducted in Huntley, MT, in 2017 and 2018, and Hays, KS, in 2018 to determine the effectiveness of various PRE herbicides applied alone or followed by (fb) a POST treatment of glyphosate plus dicamba for controlling GDR kochia in GDR soybean. Among PRE herbicides tested, sulfentrazone provided complete (100%), season-long control of GDR kochia at both sites. In addition, PRE fb POST programs tested in this study brought 71% to 100% control of GDR kochia throughout the season at both sites. Pyroxasulfone applied PRE resulted in 57% to 70% control across sites at 9 to 10 wk after PRE (WAPRE). However, mixing dicamba with pyroxasulfone improved control up to 25% at both sites. Kochia plants surviving pyroxasulfone applied PRE alone produced 2,530 seeds m−2 compared with pyroxasulfone + dicamba (230 seeds m−2) at the Montana site. No differences in soybean grain yields were observed with PRE alone or PRE fb POST treatments at the Montana site; however, dicamba, pyroxasulfone, and pendimethalin + dimethenamid-P applied PRE brought lower grain yield (1,150 kg ha−1) compared to all other tested programs at the Kansas site. In conclusion, effective PRE or PRE fb POST (two-pass) programs tested in this research should be proactively utilized by the growers to manage GDR kochia in GDR soybean.

Download Full-text

Anophelesbionomics, insecticide resistance mechanisms and malaria transmission in the Korhogo area, northern Côte d’Ivoire: a pre-intervention study

10.1101/589556 ◽

2019 ◽

Cited By ~ 1

Author(s):

Barnabas Zogo ◽

Dieudonné Diloma Soma ◽

Bertin N’Cho Tchiekoi ◽

Anthony Somé ◽

Ludovic P. Ahoua Alou ◽

...

Keyword(s):

Insecticide Resistance ◽

Malaria Transmission ◽

Cote D'ivoire ◽

Rainy Season ◽

Côte D’Ivoire ◽

Control Strategies ◽

Resistance Mechanisms ◽

Effective Control ◽

Cote D’Ivoire ◽

Côte D'ivoire

AbstractBackgroundA better understanding of malaria transmission at a local scale is essential for developing and implementing effective control strategies. In the frame of a randomized control trial, we aimed to provide an updated description of malaria transmission in the Korhogo area, northern Côte d’Ivoire, and to get baseline data for the trial.MethodsWe performed Human Landing Collections in 26 villages in the Korhogo area during the rainy season (September-October 2016, April-May 2017) and the dry season (November-December 2016, February-March 2017). We used Polymerase chain reaction techniques to ascertain the species of theAn. gambiaecomplex,Plasmodium spsporozoite infection and insecticide resistance mechanisms in a subset ofAnophelesvectors.ResultsAnopheles gambiae s.l. was the predominant malaria vector in the Korhogo area. Overall, more vectors were collected outdoors than indoors (P < 0.001). Of the 774An. gambiae s.l. tested in the laboratory, 89.65% wereAn. gambiae s.s. and 10.35% wereAn. coluzzii. The frequencies of thekdrallele were very high inAn. gambiae s.s. but theace-1allele was found at moderate frequencies. An unprotected individual living in the Korhogo area received an average of 9.04, 0.63, 0.06 and 0.12 infected bites per night in September-October, November-December, February-March, and April-May, respectively.ConclusionsThe intensity of malaria transmission is extremely high in the Korhogo area, especially during the rainy season. Malaria control in highly endemic areas such as Korhogo needs to be strengthened with complementary tools in order to reduce the burden of the disease.

Download Full-text

Mindtree: Tryst with the Corporate Control Market

South Asian Journal of Business and Management Cases ◽

10.1177/2277977921991900 ◽

2021 ◽

pp. 227797792199190

Author(s):

P. Bala Bhaskaran

Keyword(s):

Capital Market ◽

Corporate Control ◽

Theory And Practice ◽

Effective Control ◽

Small Fish ◽

Market Theory ◽

Strategic Fit ◽

Sequence Of Events ◽

The Capital Market

The case is structured around the takeover of Mindtree Ltd (ML) by Larsen & Toubro Ltd (L&T) in June 2019. ML was founded and nurtured by a group of software professionals. In two decades, it had blossomed into an enterprise with global presence, US$ 1 billion turnover and a unique organizational culture. In a strange sequence of events, more than 20% of ML’s shares landed in L&T’s lap. L&T grabbed this opportunity and ran a systematic campaign to acquire the company. In about 100 days, L&T achieved its objective and got into the driver’s seat. The case traces the evolution of ML from a start-up to a publicly held company with global standing. It examines the circumstances and events leading to L&T getting the initial stake in the company; it examines the acquisition campaign of L&T and the response of the top management of ML. Research Questions Was there a strategic fit between ML and L&T? Were the capital market processes just and fair to all the stakeholders involved in the acquisition? Was L&T fair, prudent and sensitive in the acquisition process? Was Siddhartha loyal and fair to the founders of ML? Link to Theory The theoretical concepts that would enable a better comprehension of the case are: Analysis of strategic fit in M&A situations Capital market: Theory and practice Strategy for corporate control of an enterprise Significance of culture and ecosystem in knowledge organizations Phenomenon Studied Leadership styles relevant at different stages of evolution of an enterprise are different. A leader, at a given point of time, is successful when he is able to match his aspirations with the leadership needs of the enterprise at that point of time. The case can be used to demonstrate this phenomenon. Case Context Context of the case is that of an emerging infotech enterprise, coming under corporate raid and the unfolding capital market processes. The case highlights the shortcomings of the co-founders, leading to their unseating as also the sensitivity of the incoming management in handling the transition. Findings The case demonstrates the ability of the capital market to be fair to all stakeholders ensuring reward for competence and punishment for sloppiness. The case emphasizes the need for co-founders to have an effective strategy for corporate control; only then they could hope to achieve the long-term objectives. The case also illustrates the significance of sensitivity in handling softer issues like people and ecosystem in ensuring long-term success. Discussions At the outset, the case may appear to be that of a big fish swallowing a small fish. But a closer scrutiny would reveal the multiple dimensions of the case. Consider the role of Siddhartha. He seeded the idea of the company; he was a financier to it; he remained an investor in the company longer than most of the founders; when he pulled out, the co-founders could not hold the company together. Neither Siddhartha nor the co-founders had the far-sightedness to consolidate their shareholdings for effective control of the company into the future. This would trigger discussions on the differing roles of technocrats, managers, leaders and founders. Another point worthy of discussion would be: How were the co-founders choosing their leaders? Was it by rotation among themselves, or did they engage a set of criteria to identify an incumbent capable of leading a global company?

Download Full-text

Marine Organisms for the Sustainable Management of Plant Parasitic Nematodes

Plants ◽

10.3390/plants10020369 ◽

2021 ◽

Vol 10 (2) ◽

pp. 369

Author(s):

Pasqua Veronico ◽

Maria Teresa Melillo

Keyword(s):

Crop Production ◽

Control Strategies ◽

Marine Organisms ◽

New Drugs ◽

Effective Control ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Wide Range ◽

Plant Growth Stimulants ◽

Plant Parasitic

Plant parasitic nematodes are annually responsible for the loss of 10%–25% of worldwide crop production, most of which is attributable to root-knot nematodes (RKNs) that infest a wide range of agricultural crops throughout the world. Current nematode control tools are not enough to ensure the effective management of these parasites, mainly due to the severe restrictions imposed on the use of chemical pesticides. Therefore, it is important to discover new potential nematicidal sources that are suitable for the development of additional safe and effective control strategies. In the last few decades, there has been an explosion of information about the use of seaweeds as plant growth stimulants and potential nematicides. Novel bioactive compounds have been isolated from marine cyanobacteria and sponges in an effort to find their application outside marine ecosystems and in the discovery of new drugs. Their potential as antihelmintics could also be exploited to find applicability against plant parasitic nematodes. The present review focuses on the activity of marine organisms on RKNs and their potential application as safe nematicidal agents.

Download Full-text

Label-Free Comparative Proteomics of Differentially Expressed Mycobacterium tuberculosis Protein in Rifampicin-Related Drug-Resistant Strains

Pathogens ◽

10.3390/pathogens10050607 ◽

2021 ◽

Vol 10 (5) ◽

pp. 607

Author(s):

Nadeem Ullah ◽

Ling Hao ◽

Jo-Lewis Banga Ndzouboukou ◽

Shiyun Chen ◽

Yaqi Wu ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Drug Targets ◽

Control Strategies ◽

Multidrug Resistant ◽

Differentially Expressed ◽

Effective Control ◽

Drug Resistant ◽

Differentially Expressed Proteins ◽

Label Free ◽

Candidate Target

Rifampicin (RIF) is one of the most important first-line anti-tuberculosis (TB) drugs, and more than 90% of RIF-resistant (RR) Mycobacterium tuberculosis clinical isolates belong to multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB. In order to identify specific candidate target proteins as diagnostic markers or drug targets, differential protein expression between drug-sensitive (DS) and drug-resistant (DR) strains remains to be investigated. In the present study, a label-free, quantitative proteomics technique was performed to compare the proteome of DS, RR, MDR, and XDR clinical strains. We found iniC, Rv2141c, folB, and Rv2561 were up-regulated in both RR and MDR strains, while fadE9, espB, espL, esxK, and Rv3175 were down-regulated in the three DR strains when compared to the DS strain. In addition, lprF, mce2R, mce2B, and Rv2627c were specifically expressed in the three DR strains, and 41 proteins were not detected in the DS strain. Functional category showed that these differentially expressed proteins were mainly involved in the cell wall and cell processes. When compared to the RR strain, Rv2272, smtB, lpqB, icd1, and folK were up-regulated, while esxK, PPE19, Rv1534, rpmI, ureA, tpx, mpt64, frr, Rv3678c, esxB, esxA, and espL were down-regulated in both MDR and XDR strains. Additionally, nrp, PPE3, mntH, Rv1188, Rv1473, nadB, PPE36, and sseA were specifically expressed in both MDR and XDR strains, whereas 292 proteins were not identified when compared to the RR strain. When compared between MDR and XDR strains, 52 proteins were up-regulated, while 45 proteins were down-regulated in the XDR strain. 316 proteins were especially expressed in the XDR strain, while 92 proteins were especially detected in the MDR strain. Protein interaction networks further revealed the mechanism of their involvement in virulence and drug resistance. Therefore, these differentially expressed proteins are of great significance for exploring effective control strategies of DR-TB.

Download Full-text