Eradication and control of livestock ticks: biological, economic and social perspectives

Parasitology ◽  
2011 ◽  
Vol 138 (8) ◽  
pp. 945-959 ◽  
Author(s):  
ALAN R. WALKER

SUMMARYComparisons of successful and failed attempts to eradicate livestock ticks reveal that the social context of farming and management of the campaigns have greater influence than techniques of treatment. The biology of ticks is considered principally where it has contributed to control of ticks as practiced on farms. The timing of treatments by life cycle and season can be exploited to reduce numbers of treatments per year. Pastures can be managed to starve and desiccate vulnerable larvae questing on vegetation. Immunity to ticks acquired by hosts can be enhanced by livestock breeding. The aggregated distribution of ticks on hosts with poor immunity can be used to select animals for removal from the herd. Models of tick population dynamics required for predicting outcomes of control methods need better understanding of drivers of distribution, aggregation, stability, and density-dependent mortality. Changing social circumstances, especially of land-use, has an influence on exposure to tick-borne pathogens that can be exploited for disease control.

2018 ◽  
Vol 86 (6) ◽  
pp. 2713-2744
Author(s):  
Eduardo Souza-Rodrigues

Abstract Deforestation is a matter of pressing global concern, yet surprisingly little is known about the relative efficacy of various policies designed to combat it. This article sets out a framework for measuring the cost effectiveness of alternative policies—both command-and-control and incentive-based—in the Brazilian Amazon. First, I estimate the demand for deforestation on private properties, exploiting regional variation in transportation costs as a means to recover farmers’ responses to permanent policies. Here, rescaling transportation costs using local yields allows me to express changes in farmers’ valuations in dollars per hectare. I then use the estimated demand to infer farmers’ willingness to deforest under different counterfactual policies, such as payments to avoid deforestation and taxes on land use, along with the corresponding potential farmers’ lost surpluses. The results indicate that payment programmes and land use taxes on agricultural land can be highly effective in preserving the rainforest and also be substantially less expensive than command-and-control policies (approximately 8 times less costly). A carbon tax equal to the social cost of carbon could virtually eliminate all agricultural land in the Amazon, given the low agricultural returns there.


2015 ◽  
Vol 8 (1) ◽  
pp. 69-73 ◽  
Author(s):  
Rodrigo Souza Santos ◽  
Antonio José Creão-Duarte ◽  
Aureny Maria Pereira Lunz

O açaizeiro (Euterpe oleracea Martius) é uma palmeira nativa da várzea da região amazônica e pode ser indicada como a espécie de maior valor econômico do gênero. Dos seus frutos é extraída a polpa, largamente consumida, de variadas formas, pela população da região Norte do Brasil. Com a expansão da área plantada, muitos fatores podem comprometer a produção e limitar o cultivo, destacando-se a ocorrência de insetos-praga que causam prejuízos à produção. Este relato configura o primeiro registro de ocorrência da cigarrinha Aetalion reticulatum (Hemiptera: Auchenorrhyncha: Aethalionidae) em plantas de E. oleracea. A ocorrência deste inseto associado ao açaizeiro, em Rio Branco, Acre, aumenta a lista de hospedeiros desta cigarrinha no Brasil e reforça a necessidade de estudos de dinâmica populacional, levantamento de inimigos naturais, níveis de dano e métodos de controle, a fim de antecipar possíveis surtos populacionais desta praga em plantios comerciais de açaí no Estado. Infestation of Aetalion reticulatum (Linnaeus) (Hemiptera: Aethalionidae) in Plants of Euterpe oleracea Martius (Arecaceae) in Acre State, Brazil Abstract. The açai palm (Euterpe oleracea Martius) is a native palm tree from the Amazon region floodplains and may be indicated as the most economically profitable species of this genus. Its fruit pulp is extracted and widely consumed by the population of northern Brazil in several ways. With the expansion of the planted area many factors may affect the production and limit the cultivation, highlighting the occurrence of insect pests that cause losses in production. This report presents the first occurrence of the leafhopper Aetalion reticulatum (Linnaeus) (Hemiptera: Auchenorrhyncha: Aethalionidae) in E. oleracea plants. The occurrence of this insect associated with açai palms in Rio Branco, Acre, increases the list of hosts for this leafhopper in Brazil and reinforces the need for studies of population dynamics, survey of natural enemies, levels of damage and control methods in order to anticipate population outbreaks of this pest in commercial plantations of açai palms in the State.


2012 ◽  
Vol 2012 (1) ◽  
pp. 163-192
Author(s):  
Sonja Rinofner-Kreidl

Autonomy is associated with intellectual self-preservation and self-determination. Shame, on the contrary, bears a loss of approval, self-esteem and control. Being afflicted with shame, we suffer from social dependencies that by no means have been freely chosen. Moreover, undergoing various experiences of shame, our power of reflection turns out to be severly limited owing to emotional embarrassment. In both ways, shame seems to be bound to heteronomy. This situation strongly calls for conceptual clarification. For this purpose, we introduce a threestage model of self-determination which comprises i) autonomy as capability of decision-making relating to given sets of choices, ii) self-commitment in terms of setting and harmonizing goals, and iii) self-realization in compliance with some range of persistently approved goals. Accordingly, the presuppositions and distinctive marks of shame-experiences are made explicit. Within this framework, we explore the intricate relation between autonomy and shame by focusing on two questions: on what conditions could conventional behavior be considered as self-determined? How should one characterize the varying roles of actors that are involved in typical cases of shame-experiences? In this connection, we advance the thesis that the social dynamics of shame turns into ambiguous positions relating to motivation, intentional content,and actors’ roles.


2018 ◽  
Vol 154 (2) ◽  
pp. 149-155
Author(s):  
Michael Archer

1. Yearly records of worker Vespula germanica (Fabricius) taken in suction traps at Silwood Park (28 years) and at Rothamsted Research (39 years) are examined. 2. Using the autocorrelation function (ACF), a significant negative 1-year lag followed by a lesser non-significant positive 2-year lag was found in all, or parts of, each data set, indicating an underlying population dynamic of a 2-year cycle with a damped waveform. 3. The minimum number of years before the 2-year cycle with damped waveform was shown varied between 17 and 26, or was not found in some data sets. 4. Ecological factors delaying or preventing the occurrence of the 2-year cycle are considered.


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