Weed biological control in low- and middle-income countries.

Invasive alien plants have a significant impact on biodiversity, crop and pasture production, human and animal health, water resources, and economic development. As most low- and middle-income countries do not have the resources to actively manage invasive plants, many have intentionally introduced biological control agents to help manage their most important weeds. Some of these introductions have resulted in the successful control of numerous weeds such as Chromolaena odorata, Mimosa diplotricha, Pistia stratiotes, and Salvinia molesta. These successes are partly due to the reliance on biological control agents that have been tested and utilized elsewhere. However, despite the successes in weed biological control to date, many low- and middle-income countries are reluctant to pursue weed biological control, due to poor perceptions of biological control and lack of capacity. This results in missed opportunities to manage many weeds cost-effectively, and in so doing, increasing production costs and a dependency on herbicides.

Biopesticides: state of the art and future opportunities.

The use of biopesticides and related alternative management products is increasing. New tools, including semiochemicals and plant-incorporated protectants (PIPs), as well as botanical and microbially derived chemicals, are playing an increasing role in pest management, along with plant and animal genetics, biological control, cultural methods, and newer synthetics. The goal of this Perspective is to highlight promising new biopesticide research and development (R&D), based upon recently published work and that presented in the American Chemical Society (ACS) symposium "Biopesticides: State of the Art and Future Opportunities," as well as the authors' own perspectives. Although the focus is on biopesticides, included in this Perspective is progress with products exhibiting similar characteristics, namely those naturally occurring or derived from natural products. These are target specific, of low toxicity to nontarget organisms, reduced in persistence in the environment, and potentially usable in organic agriculture. Progress is being made, illustrated by the number of biopesticides and related products in the registration pipeline, yet major commercial opportunities exist for new bioherbicides and bionematicides, in part occasioned by the emergence of weeds resistant to glyphosate and the phase-out of methyl bromide. The emergence of entrepreneurial start-up companies, the U.S. Environmental Protection Agency (EPA) fast track for biopesticides, and the availability of funding for registration-related R&D for biorational pesticides through the U.S. IR-4 program provide incentives for biopesticide development, but an expanded effort is warranted both in the United States and worldwide to support this relatively nascent industry.

Designing a community engagement framework for a new dengue control method: a case study from central Vietnam.

BACKGROUND: The Wolbachia strategy aims to manipulate mosquito populations to make them incapable of transmitting dengue viruses between people. To test its efficacy, this strategy requires field trials. Public consultation and engagement are recognized as critical to the future success of these programs, but questions remain regarding how to proceed. This paper reports on a case study where social research was used to design a community engagement framework for a new dengue control method, at a potential release site in central Vietnam. METHODOLOGY/PRINCIPAL FINDINGS: The approach described here, draws on an anthropological methodology and uses both qualitative and quantitative methods to design an engagement framework tailored to the concerns, expectations, and socio-political setting of a potential trial release site for Wolbachia-infected Aedes aegypti mosquitoes. The process, research activities, key findings and how these were responded to are described. Safety of the method to humans and the environment was the most common and significant concern, followed by efficacy and impact on local lives. Residents expected to be fully informed and engaged about the science, the project, its safety, the release and who would be responsible should something go wrong. They desired a level of engagement that included regular updates and authorization from government and at least one member of every household at the release site. CONCLUSIONS/SIGNIFICANCE: Results demonstrate that social research can provide important and reliable insights into public concerns and expectations at a potential release site, as well as guidance on how these might be addressed. Findings support the argument that using research to develop more targeted, engagement frameworks can lead to more sensitive, thorough, culturally comprehensible and therefore ethical consultation processes. This approach has now been used successfully to seek public input and eventually support for releases Wolbachia-infected mosquitoes, in two different international settings--Australia and Vietnam.

Threshold conditions for integrated pest management models with pesticides that have residual effects.

Impulsive differential equations (hybrid dynamical systems) can provide a natural description of pulse-like actions such as when a pesticide kills a pest instantly. However, pesticides may have long-term residual effects, with some remaining active against pests for several weeks, months or years. Therefore, a more realistic method for modelling chemical control in such cases is to use continuous or piecewise-continuous periodic functions which affect growth rates. How to evaluate the effects of the duration of the pesticide residual effectiveness on successful pest control is key to the implementation of integrated pest management (IPM) in practice. To address these questions in detail, we have modelled IPM including residual effects of pesticides in terms of fixed pulse-type actions. The stability threshold conditions for pest eradication are given. Moreover, effects of the killing efficiency rate and the decay rate of the pesticide on the pest and on its natural enemies, the duration of residual effectiveness, the number of pesticide applications and the number of natural enemy releases on the threshold conditions are investigated with regard to the extent of depression or resurgence resulting from pulses of pesticide applications and predator releases. Latin Hypercube Sampling/Partial Rank Correlation uncertainty and sensitivity analysis techniques are employed to investigate the key control parameters which are most significantly related to threshold values. The findings combined with Volterra's principle confirm that when the pesticide has a strong effect on the natural enemies, repeated use of the same pesticide can result in target pest resurgence. The results also indicate that there exists an optimal number of pesticide applications which can suppress the pest most effectively, and this may help in the design of an optimal control strategy.

Implicaciones sanitarias del establecimientos y expansión en España del mosquito Aedes Albopitus / Health implications of the establishment and spread of Aedes Albopictus in Spain

La expansión de Aedes albopictus por el Levante español no ha cesado desde su primigenia detección en nuestro país en el año 2004, habiéndose constatado ya su presencia en las provincias de Girona, Barcelona, Tarragona, Castellón, Alicante y Murcia. La elevada sinantropía de la especie, unida al alto grado de antropofília y extensa capacidad vectorial para transmitir diversas arbovirosis, han propiciado el retorno al sur de Europa de ciclos de transmisión activa de enfermedades frecuentes en el pasado como el Dengue o la aparición de virosis tropicales inéditas hasta entonces como Chikungunya. El presente manuscrito analiza de forma pormenorizada las implicaciones para la salud pública de la previsible expansión de Ae. albopictus por gran parte del territorio peninsular, en el contexto climático y sociodemográfico actual. Adicionalmente, también se discuten diversas cuestiones relativas al control poblacional de la especie en ambientes urbanos y periurbanos, así como los datos preliminares existentes acerca de otros aedinos invasores de reciente hallazgo en el continente europeo(AU)

The spread of Aedes albopictus by Eastern Spain has been constant since its first finding in 2004. Currently the species has been collected in the coastal provinces of Girona, Barcelona, Tarragona, Castellón, Alicante and Murcia. The high synanthropism of the species, together with its anthropophilic behaviour and vectorial capacity to transmit several arboviruses, have led to the return of active transmission cycles of common diseases in the past such as Dengue virus and even the appearance of new tropical viruses as Chikungunya in southern Europe. This manuscript discusses the public health implications of the expected expansion of Ae. albopictus for much of the Iberian Peninsula, in the context of current climatic and sociodemographic situation. Moreover, several issues related with the control of the species in urban and suburban environments are exposed. Finally the preliminary data about other invasive aedines recently collected in the European continent are presented(AU)

[The reemergence of the Chikungunya virus in Réunion Island on 2010: evolution of the mosquito control practices]. / La réémergence du chikungunya à La Réunion en 2010: évolution des actions de lutte antivectorielle.

The re-emergence of local transmission of chikungunya virus caused by Aedes albopictus since March 2010 in the Réunion Island, French territory in the southwest Indian Ocean, calls for better epidemiological surveys, vector control, and community-based chikungunya control. This paper describes the strategy and the new ways of vector control applied since the last major chikungunya virus outbreak in 2005-2007, and the high levels of collaboration with mayors and local associations for community involvement. Between March 17, 2010 (first chikungunya case) and July 1, 2010, 313 cases were investigated, 13,036 premises inspected, and 34,393 premises concerned by spatial treatment. The traditional entomologic indices don't explain the distribution map of chikungunya cases, and many other factors have to be measured for evaluating the risk of transmission, such as lifestyle, habitat, and the kind of environment the people live in. A big information campaign was conducted beside the implementation of traditional mosquito control techniques. The two themes of this campaign are environmental management and individual protection, considered as important components of chikungunya prevention. The outcome of the mosquito control strategy demonstrates that community participation is not enough, and more studies are required to define new ways of communication for promoting community-oriented activities to prevent chikungunya epidemics.

Modelo multidimensional para o controle da dengue: uma proposta com base na reprodução social e situações de riscos / Multidimensional model for dengue control: a proposal based on social reproduction and risk situations

O objetivo do artigo consiste em apresentar e discutir um modelo compreensivo/explicativo, de caráter ecossistêmico, sobre o processo de transmissão da dengue nos níveis de micro e macrocontexto, a partir da identificação das situações de riscos envolvidas. Considerou-se a dengue como doença infecciosa viral de transmissão vetorial que traz, na sua dinâmica de transmissão, elementos das dimensões biológicas, de conduta, ecológicas, políticas e econômicas, o que a caracteriza como um problema complexo e exige um enfoque sistêmico para seu controle. Assim, para a construção da modelagem, utilizaram-se o enfoque teórico da reprodução social de Juan Samaja e seus condicionantes de macro e microcontexto, e o enfoque operativo ecossistêmico, que buscou responder à pergunta condutora desta construção: quais são as situações de risco para transmissão da dengue, considerando as diversas dimensões da "reprodução social da saúde" no nível local? A visão ampliada das inter-relações entre as diversas situações de risco envolvidas na determinação multidimensional da dengue poderá servir como eixo direcionador para uma gestão integrada das ações do programa de controle da doença, articuladas entre os diversos setores envolvidos.

This paper aims to present and discuss a comprehensive / explanatory model, of ecosystem approach, on the process of transmission of dengue in the levels of micro and macro context, from the identification of the risks involved. Dengue was considered a viral infectious disease of vectorial transmission that carries on its transmission dynamics, elements of the biological, behavioral, ecological, political and economic dimensions, that make it a complex problem and require a systemic approach to its control. Thus, for the construction of modeling, we used the theoretical framework of social reproduction of Juan Samaja and its conditions of macro and micro-context, and the operating ecosystem approach, which sought to answer the question driving this construction: what are the risk situations for the transmission of dengue, considering the different dimensions of "social reproduction of health" at the local level? The enlarged view of the interrelationships among the various risk situations involved in determining multidimensional dengue could guide the integrated management of actions of a disease control program, coordinated by the several sectors involved.

Situación organizacional de los Grupos de Control de Vectores en Ciudad de La Habana / Organizational situation of Vector Control Groups in the City of Havana

Se desarrolló una investigación operativa en octubre de 2006, que en breve tiempo aportó información útil para la toma de decisiones en el trabajo de erradicación del mosquito Aedes aegypti. Caracterizar la situación organizacional existente en los Grupos de Control de Vectores de la provincia Ciudad de La Habana, la llamada Campaña e identificar aquellos factores que obstaculizaban el trabajo. Métodos Se realizó un estudio descriptivo y transversal. Se trabajó con una muestra intencional que incluyó 278 trabajadores de diferentes categorías ocupacionales y procedentes de 15 áreas de salud, seleccionadas a partir de una estratificación de la provincia por criterio cualitativo. Se estudiaron también 57 directivos. Se exploraron las variables tiempo en la actividad y otras relacionadas con el propósito de la organización, estructura organizativa, capacitación, relaciones entre trabajadores y con los superiores en rango (jefes), dentro y fuera del sector; mecanismos de apoyo, uso y formas de reconocimiento, condiciones de trabajo y recursos. Además, se evaluó el clima organizacional a partir de 16 criterios en las dimensiones: Liderazgo, Motivación, Reciprocidad y Participación. Se emplearon técnicas cuantitativas y cualitativas: encuesta, entrevista a profundidad y grupo focal, y se trianguló la información obtenida. Resultados Los principales resultados estuvieron en la inadecuada selección del personal y poco tiempo en la actividad, insuficiente integración de los operarios al trabajo del Equipo Básico de Salud no inherente a la estructura organizativa, inadecuadas normas de trabajo que propiciaban conductas fraudulentas, insuficiencias en los mecanismos de apoyo, de estimulación y reconocimiento que generaban desmotivación en los trabajadores; estilos de dirección que dificultaban la comunicación y las relaciones interpersonales y métodos de dirección poco participativos. Conclusiones Se localizan numerosos y ...

An operational research was made in October, 1996 that quickly offered useful information for decision-making on the work carried out to eradicate Aedes aegypti. Objectives To characterize the organizational situation of Vector Control Groups in the City of Havana province and identify those factors that hinder its work. Methods A descriptive cross-sectional study that uses an intentional sample of 278 workers of various occupational categories from 15 health areas that have been previously selected on the basis of stratification by qualitative criteria. Fifty seven directors were also included. Variables such as length of time performing this activity and others related to the objective of the organization; organizational structure, training, relationship between workers and higher rank staff (heads) within and outside the sector, supporting mechanisms, use and ways of acknowledgement, working conditions and resources were examined. Additionally, the organizational environment based on 16 criteria in dimensions, i.e., leadership, motivation, reciprocity and participation. Quantitative and qualitative techniques were used like survey, in-depth interview, and focal groups. Obtained information was triangled. Results The main results were the poor selection of the staff and short length of time in the activity; low integration of workers to the Basic Health Team non-inherent to the organizational structure, inappropriate working standards that facilitate fraud, deficiencies found in the supporting, stimulation and acknowledgement mechanisms, thus discouraging workers, management methods that make it difficult to communicate each others, and inter-personal relations; management methods with low participation. Conclusions Many diverse organizational problems were found. They unfavorably influence the working environment, and consequently restrict the work dynamics of the studied group.

Situación organizacional de los Grupos de Control de Vectores en Ciudad de La Habana / Organizational situation of Vector Control Groups in the City of Havana

Se desarrolló una investigación operativa en octubre de 2006, que en breve tiempo aportó información útil para la toma de decisiones en el trabajo de erradicación del mosquito Aedes aegypti. Caracterizar la situación organizacional existente en los Grupos de Control de Vectores de la provincia Ciudad de La Habana, la llamada Campaña e identificar aquellos factores que obstaculizaban el trabajo. Métodos Se realizó un estudio descriptivo y transversal. Se trabajó con una muestra intencional que incluyó 278 trabajadores de diferentes categorías ocupacionales y procedentes de 15 áreas de salud, seleccionadas a partir de una estratificación de la provincia por criterio cualitativo. Se estudiaron también 57 directivos. Se exploraron las variables tiempo en la actividad y otras relacionadas con el propósito de la organización, estructura organizativa, capacitación, relaciones entre trabajadores y con los superiores en rango (jefes), dentro y fuera del sector; mecanismos de apoyo, uso y formas de reconocimiento, condiciones de trabajo y recursos. Además, se evaluó el clima organizacional a partir de 16 criterios en las dimensiones: Liderazgo, Motivación, Reciprocidad y Participación. Se emplearon técnicas cuantitativas y cualitativas: encuesta, entrevista a profundidad y grupo focal, y se trianguló la información obtenida. Resultados Los principales resultados estuvieron en la inadecuada selección del personal y poco tiempo en la actividad, insuficiente integración de los operarios al trabajo del Equipo Básico de Salud no inherente a la estructura organizativa, inadecuadas normas de trabajo que propiciaban conductas fraudulentas, insuficiencias en los mecanismos de apoyo, de estimulación y reconocimiento que generaban desmotivación en los trabajadores; estilos de dirección que dificultaban la comunicación y las relaciones interpersonales y métodos de dirección poco participativos. Conclusiones Se localizan numerosos y ...(AU)

An operational research was made in October, 1996 that quickly offered useful information for decision-making on the work carried out to eradicate Aedes aegypti. Objectives To characterize the organizational situation of Vector Control Groups in the City of Havana province and identify those factors that hinder its work. Methods A descriptive cross-sectional study that uses an intentional sample of 278 workers of various occupational categories from 15 health areas that have been previously selected on the basis of stratification by qualitative criteria. Fifty seven directors were also included. Variables such as length of time performing this activity and others related to the objective of the organization; organizational structure, training, relationship between workers and higher rank staff (heads) within and outside the sector, supporting mechanisms, use and ways of acknowledgement, working conditions and resources were examined. Additionally, the organizational environment based on 16 criteria in dimensions, i.e., leadership, motivation, reciprocity and participation. Quantitative and qualitative techniques were used like survey, in-depth interview, and focal groups. Obtained information was triangled. Results The main results were the poor selection of the staff and short length of time in the activity; low integration of workers to the Basic Health Team non-inherent to the organizational structure, inappropriate working standards that facilitate fraud, deficiencies found in the supporting, stimulation and acknowledgement mechanisms, thus discouraging workers, management methods that make it difficult to communicate each others, and inter-personal relations; management methods with low participation. Conclusions Many diverse organizational problems were found. They unfavorably influence the working environment, and consequently restrict the work dynamics of the studied group(AU)

Multiple attractors of host-parasitoid models with integrated pest management strategies: eradication, persistence and outbreak.

Host-parasitoid models including integrated pest management (IPM) interventions with impulsive effects at both fixed and unfixed times were analyzed with regard to host-eradication, host-parasitoid persistence and host-outbreak solutions. The host-eradication periodic solution with fixed moments is globally stable if the host's intrinsic growth rate is less than the summation of the mean host-killing rate and the mean parasitization rate during the impulsive period. Solutions for all three categories can coexist, with switch-like transitions among their attractors showing that varying dosages and frequencies of insecticide applications and the numbers of parasitoids released are crucial. Periodic solutions also exist for models with unfixed moments for which the maximum amplitude of the host is less than the economic threshold. The dosages and frequencies of IPM interventions for these solutions are much reduced in comparison with the pest-eradication periodic solution. Our results, which are robust to inclusion of stochastic effects and with a wide range of parameter values, confirm that IPM is more effective than any single control tactic.

A amylase activity of nymphal stages of sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae).

Wheat production in Iran has changed substantially over the past one or two decades with development of higher-yielding cultivars and improved methods of planting. Sunn pest, Eurygaster integriceps (Heteroptera: Pentatomidae), is the most important cereal pest in Iran. Sunn pest like other insect pests of wheat lives on a polysaccharide-rich diet and depends to a large extent on effectiveness of their alpha-amylases for survival. alpha-amylase (1-4-alpha-D-glucan glucanohydrolase) hydrolyses starch, and related polysaccharides by randomly cleaving internal alpha-1,4-glucosidic linkages and has a major role in the utilization of polysaccharides. The recent increase in study of insect digestive enzymes seems to make sense in the realization that the gut is the major interface between the insect and its environment. Hence, an understanding of digestive enzyme function is essential when developing methods of insect control such as the use of enzyme inhibitor's and transgenic plants to control phytophagous insects. The aim of the current study is to identify and characterize alpha-amylase activity in order to gain a better understanding of its digestive physiology, which hopefully will lead to new strategies of the insect control. In order to analyze a-amylase activity adult and different nymphal stages were collected from wheat field from Karaj area and midgut complex from these individuals were dissected under a light microscope in ice-cold saline buffer (0.006M NaCl). After homogenization in buffer, homogenate was centrifuged at 15000 g for 20 min at 4 degrees C. The supernatant was pooled and stored at -20 degrees C for subsequent analysis. alpha-amylase activity was assayed by the dinitrosalicylic acid (DNS) procedure using soluble starch as substrate (starch 1%). Our result showed that enzyme activities in different nymphal stages (first, second, third, fourth and fifth stadium) were 0.19, 0.78, 1.21, 1.23, 1.25 units/mg protein, respectively.

Effect of plant a-amylase inhibitors on sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), alpha-amylase activity.

Plant-insect interaction is a dynamic system, subjected to continual variation and change. In order to reduce insect attack, plants developed different defence mechanisms including chemical and physical barriers such as the induction of defensive proteins, volatiles that attract predators of the insect herbivores and secondary metabolites. Proteinaceous inhibitors of alpha-amylase and proteases are widely distributed in cereals, legumes and some other plants. Because of the possible importance of these inhibitors in plant physiology and animal nutrition, extensive research has been conducted on their properties and biological effects. Sunn pest like other insect pests of wheat lives on a polysaccharide-rich diet and depends to a large extent on effectiveness of their alpha-amylases for survival, a-amylase (1-4-alpha-D-glucan glucanohydrolase) hydrolyses starch, and related polysaccharides by randomly cleaving internal alpha-1,4-glucosidic linkages and has a major role in the utilization of polysaccharides. The enzyme inhibitors act on key insect gut digestive hydrolyses, alpha-amylase. Several kinds of a-amylase inhibitors present in seeds and vegetative organs of plant, act to regulate number of phytophagous insects. Therefore, the aim of the current study is to study cereal proteinaceous inhibitors of insect digestive enzymes and their potential use as resistance factors against Sunn pest. The proteinaceous inhibitors from different cereal species including barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) were extracted and tested in in vitro condition against Sunn pest alpha-amylase. Extraction was made with NaCl (0.15 M) at room temperature and further purification was done by ammonium sulphate precipitation. It was found that fractions obtained from barley had more inhibitory effect on amylase activity of Sunn pest than fractions obtained from wheat. Knowledge gained through these studies can be used to select resistant plant against insect pest.