Evaluating the economic impact of quality-reducing,seed-borne diseases: Lessons from Karnal bunt of wheat

Estimates of aggregate disease costs can be used for assigning research resources or to evaluate control measures. Most diseases cause production losses, but others affect quality and marketability. Seed-borne diseases also cause problems for the seed production and distribution industry. The aim in this paper is to examine issues relating to the economic impact of a quality-reducing, seed-borne disease, and to highlight differences compared to non-seed-borne diseases affecting yield only. Economic evaluation of quality-reducing, seed-borne diseases needs to incorporate impacts of trading restrictions such as quarantines or embargoes imposed by purchasers. The costs of measures taken to control diseases also represent part of the economic impact of the disease. Full economic costs of a disease include the direct (yield and quality) costs and costs of the control measures. The costs of Karnal bunt of wheat in Mexico were found to include many control costs that have often been overlooked. The optimal amount of resources to invest in controlling a disease depends on the likely annual costs of the disease and of control measures. Before implementing disease control policies, both the costs and the benefits of the policies need to be considered, taking the risks of each option into account, to ensure that the policy itself does not impose greater costs than the uncontrolled disease.     

Deriving efficient frontiers for effort allocation in the management of invasive species*

Invasive species cause significant losses through their effect on agriculture, human health and the environment. Their importance has increased with time owing to globalisation, as the spread of invasive species is facilitated by the increased movement of people, cargo and genetic material around the world. There is a vast literature on the economics of invasive species and their management. Here, we contribute to this literature by applying a spatio‐temporal model to the allocation of surveillance resources. We focus on three questions regarding resource allocation to control a newly discovered invasion: the budget, which determines the amount of search effort available; the duration of the control program; and the allocation of surveillance and control in time and space. We also explore the complementary role of passive surveillance by members of the public. We derive efficient frontiers for effort allocation that represent the trade‐off between cost and probability of eradication after inefficient strategies have been eliminated. We use the results to illustrate how to evaluate whether introduction of passive surveillance is desirable based on cost and eradication probability. We conclude by discussing the implications of our findings in the design of control programs.     

Public preferences for controlling an invasive species in public and private spaces

Discrete choice experiments have been used in this case study to assess community benefits for the control of red imported fire ants, an aggressive ant species that were introduced by accident in 2001 to Brisbane, Australia. This invasive species could have substantial impacts on agricultural production, biodiversity, ecosystem services, infrastructure and communities. Values for avoiding impacts on three particular land uses have been assessed in this study with discrete choice experiments. The results indicated that on a per hectare basis, the value estimates to avoid infestation in public areas (schools and parks), were much higher than for private areas (housing) or natural bushland areas (protected native vegetation). There were high levels of support for eradication rather than containment strategies, despite the additional costs involved. The use of both random parameters logit and latent class models demonstrates that there is a significant heterogeneity in preferences and values for controlling or eradicating the invasive species, indicating that it may be challenging to gain and maintain political support for management options, particularly if these involve large costs or inconvenience to households.     

Economic Welfare Impacts of Foot‐and‐Mouth Disease in the Canadian Beef Cattle Sector

A foot‐and‐mouth disease outbreak, although having a low probability of occurrence, results in losses of export markets and introduces considerable potential disease management and eradication costs. We develop a dynamic model that integrates beef cattle production, disease dissemination, domestic consumption, and international trade and captures the intertemporal economic welfare impacts of mitigation measures. The model is applied to the case of a hypothetical outbreak in Canada to capture changes in producer profits, consumer price, and government costs due to the outbreak and sums these to measure changes in total economic welfare of the beef industry. Mitigation scenarios are reported for stamping‐out, movement controls, vaccination, and preemptive slaughter.     

Applying search theory to determine the feasibility of eradicating an invasive population in natural environments

The detectability of invasive organisms influences the feasibility of eradicating an infestation. Search theory offers a framework for defining and measuring detectability, taking account of searcher ability, biological factors and the search environment. In this paper, search theory concepts are incorporated into a population model, and the costs of search and control are calculated as functions of the amount of search effort (the decision variable). Simulations are performed on a set of weed scenarios in a natural environment, involving different combinations of plant longevity, seed longevity and plant fecundity. Results provide preliminary estimates of the cost and duration of eradication programs to assist in prioritising weeds for control. The analysis shows that the success of an eradication program depends critically on the detectability of the target plant, the effectiveness of the control method, the labour requirements for search and control, and the germination rate of the plant.     

Hog producer income losses under contagious animal disease restrictions

Eradication measures of a contagious animal disease may force farmers to keep ready-to-slaughter animals on the farm. As feeding heavy animals may reduce carcass quality and farmer income, farmers can adjust their feeding policy in order to decrease losses from delayed slaughter. The problem is interesting also from society's point of view because eradication measures can affect a large number of farms when a single farm is infected. A dynamic programming model is developed to study optimal hog feeding strategies when the timing of slaughter is restricted. The model takes into account carcass quality, its effects on timing of slaughter under given prices, and animal density on the farm. The results show that farmers suffer substantial losses due to delayed slaughter, and can minimize the losses by reducing energy feeding. The results give information on designing compensation schemes so that all farmers have economic incentives to implement preferred eradication policy.     

Regional economic impacts of a plant disease incursion using a general equilibrium approach*

The present study uses a dynamic multiregional computable general equilibrium (CGE) model to estimate the micro‐ and macroeconomic effects of a hypothetical disease or pest outbreak. Our example is a Karnal bunt incursion in wheat in Western Australia. The extent of the incursion, the impact of the disease or pest on plant yields, the response of buyers, the costs of eradication and the time path of the scenario contribute to outcomes at the industry, regional, state and national levels. We decompose the contribution of these individual direct effects to the overall impact of the incursion. This might provide some guidance regarding areas for priority in attempting to eradicate or minimise the impacts of a disease or pest. The study also introduces a theory of dynamic regional labour adjustment in which economic events may lead to both real wage differentials and worker migration between regions.     

Measuring market integration in the presence of transaction costs–a threshold vector error correction approach

Applied econometric analyses of market integration based on price data alone have been criticised because they neglect the role of transaction costs. To meet this objection, threshold vector error correction models are used. Threshold models can account for the effects of transaction costs in price transmission without directly relying upon information about these costs, which are often unavailable. It is argued that threshold models that are based on two thresholds provide results that are economically more intuitive than those obtained from one-threshold models. However, to this point no adequate econometric test is available for threshold significance in a two-threshold model; such tests are only available for the one-threshold model. In this paper a restricted two-threshold model is developed in which the significance of the thresholds can be tested. This model is therefore amenable to economic interpretation and statistical inference. The model is used to estimate market integration in the European pig market.     

Optimal Drug Control under Risk of Drug Resistance – The Case of African Animal Trypanosomosis

We examine two widely used treatment strategies for African animal trypanosomosis in West Africa: preventive drug control ex‐ante trypanosomosis infection and curative drug control ex‐post trypanosomosis infection. We investigate which combination of these alternative strategies is economically optimal for cattle farmers. We apply a dynamic optimisation framework to consider both the negative externality of drug resistance development and human behaviour. We develop a bio‐economic model to simulate the economic consequences of treatment strategies in a dynamic scenario that takes into account the interactions among the vector, host and livestock farmers. This model allows for the evolution of drug‐resistant trypanosomes through trypanocide misuse and simulates the observed behaviours of cattle farmers based on the elicited risk and time preferences of a sample of 202 cattle farmers in Mali and Burkina Faso. The results show that the private optimal mix of treatment strategies for a risk averse and patient farmer involves preventive treatment for susceptible cattle, supported by a small number of curative treatments for infected cattle. Compared with the treatment strategies observed in the field, this optimal mix of treatment strategies would save approximately 5% of the annual income of a livestock farmer in the study area and would reduce the prevalence of trypanosomosis. In addition, we demonstrate that a reduction in a farmer's risk aversion is associated with higher treatment rates that can avoid additional losses. By contrast, a decrease in a farmer's patience is related to lower treatment rates that thwart additional benefits. Our results suggest that individual risk and time preferences need to be considered in the development process of disease control interventions.     

The importance of managing the costs and benefits of bird activity for agricultural sustainability

The behaviour of wild animal species in agricultural landscapes may confer benefits to growers through the provision of ecosystem services (e.g. control of agricultural pests) or inflict costs through direct or indirect damage to crops or livestock. The literature on the costs that species inflict or the benefits they provide has evolved largely independently with few attempts to synthesize information across studies. However, managing cost–benefit trade-offs to maximize agricultural productivity while ensuring native species conservation is vital to the future of ecologically sustainable agriculture. Using birds as a case study, we review the two bodies of literature on the costs and benefits attributed to bird activity in agricultural landscapes. In each case, we examine the major types of costs (e.g. consumption of crops) and benefits (e.g. pollination of crops) and assess approaches to quantifying these in terms of changes in crop yield or monetary value. We then synthesize this information to examine options for balancing cost–benefit trade-offs through coordinated and integrated management strategies that consider all aspects of species activity in agricultural landscapes. Employing strategies that successfully balance costs and benefits is fundamental to future food security and agricultural sustainability.     

Farmers' Perceived Costs of Wetlands: Effects of Wetland Size, Hydration, and Dispersion

We survey landowners to investigate the costs associated with the presence of permanent or seasonal wetland areas in cropland. We find, as predicted by our conceptual model, that dispersion of wetland areas imposes substantial inconvenience costs for producers but that costs respond nonlinearly and irregularly to changes in the frequency of hydration. Producer attitudes toward conservation and environmental regulation have a significant impact on perceived costs, as do some demographic attributes. The analysis suggests that incentives to aggregate dispersed wetlands into larger contiguous areas could benefit landowners and at the same time provide a net increase in wetland area.     

Public Preferences and Willingness to Pay for Forest Disease Control in the UK

Invasive pests and diseases in trees impose a range of costs on society related to reductions in timber values, impacts on recreational opportunities and effects on forest biodiversity. These costs need to be considered when assessing control options and developing public policy. We investigate the preferences and willingness to pay of the UK general public for a range of forest disease control measures using a choice experiment with a sample of 605 people. Respondents were relatively well informed about general tree disease‐related issues, such as causes and general measures to minimise the risk of disease spread. They were less knowledgeable about specific tree diseases, with Dutch elm disease and chalara ash dieback being the most well known. We find that disease control programmes in publicly‐owned forests and forests owned by charitable trusts are more likely to be supported by the public than equivalent control programmes in privately‐owned and/or commercial forests. The nature of scientific uncertainty about diseases does not affect peoples’ preferences for disease control measures significantly. Higher respondent income, greater ex‐ante knowledge about tree diseases, and more frequent visits to forests are correlated with greater willingness to support publicly‐funded tree disease control programmes in forests. Better knowledge about tree diseases also improves the clarity of respondents’ choices. We find a negative sentiment against some disease control measures, such as clear felling of a forest, and chemical or biocide spraying. We conclude that there is significant public support for part‐financing forest disease control policies in the UK, but that this is conditional on forest ownership and the type of control measures used.     

Jointly determined livestock disease dynamics and decentralised economic behaviour

A dynamic model of livestock disease and decentralised economic behaviour is constructed as a jointly determined system. By accounting for feedbacks between behavioural choices and disease outcomes, the model captures the endogenous nature of infection risks. Government mandated testing of livestock herds and how private biosecurity incentives are affected by the structure of disease eradication polices are considered. How well disease control policies are targeted affects their effectiveness and may result in farmers substituting government testing and disease surveillance for private biosecurity. Numerical simulation results demonstrate that failing to account for feedbacks between the disease ecology and economic systems may overestimate the effectiveness of government disease control policies.     

Costs and benefits of controlling quarantine diseases: a bio-economic modeling approach

This article describes a bio-economic model to quantify the costs and benefits of controlling plant quarantine diseases. The model integrates the epidemiology and economic consequences of a quarantine disease. It allows for ex ante evaluation of control scenarios for their cost-effectiveness, taking into account potential export losses resulting from presence of the disease. The model is applied to brown rot of potato in the Dutch potato production chain. Simulation results show that under the current (2006) control policy, the average yearly costs of brown rot are 7.7 million euros. Reducing monitoring frequency increases the costs to 12.5 million euros, 60% of which are export losses. It is also shown that, due to potential long-term effects of a strategy, conclusions on cost-effectiveness of a strategy depend on the length of the period over which that strategy is observed. These applications illustrate the potential of the bio-economic model to facilitate the development of cost-effective and soundly based control policies.     

Estimating the benefits of recreation-oriented management in state-owned commercial forests in Finland: A choice experiment

As forestlands provide a variety of environmental services, the management of forest resources is a matter of public concern. In the present case of state-owned commercial forests in Finland, legislation requires specific management practices to enhance recreational benefits free of charge to the public. This choice experiment considers Finnish people's valuation of the recreation-oriented management of state-owned commercial forests to evaluate whether the recreational benefits produced justify the related loss of profits from timber sales. We focus on three management attributes: scenic buffer zones along lakes and rivers, habitats for game birds, and the quality of scenery as reflected by the frequency of clear-cut areas along hiking trails. Marginal willingness-to-pay (WTP) effects for the attributes are estimated with random parameters logit models specified in the WTP space, while preference-space models are used to estimate in physical terms the attribute levels that maximize the benefits to the public. Despite regional differences in preferences, people in all parts of Finland valued the current recreation-oriented management of state-owned commercial forests considerably. Nationwide, the aggregate benefits of recreation-enhancing management clearly exceeded the estimated opportunity costs. The most preferred levels of management attributes were slightly above the current levels, suggesting an increase in the provision of recreational services when not considering the associated costs.     

The Economics of Controlling Infectious Diseases on Dairy Farms

Cost‐effective disease control on the dairy farm can enhance productivity and subsequently profitability. Previous economic studies on animal disease have focused on production losses and evaluation of disease eradication programs and have provided little guidance on the optimal prevention action. This paper presents a theoretical model on the economics of livestock disease and develops an empirical model to determine the optimal set of control strategies for four production‐limiting cattle diseases: bovine viral diarrhea (BVD), enzootic bovine leukosis (EBL), Johne's Disease (JD) and neosporosis. Control functions indicating the prevalence of infection with each of the four diseases for each of the 10 strategies are estimated. The optimal strategies that minimize total disease cost (direct production losses and control expenditures) are provided for each disease on the basis of farm survey results from the maritime provinces. The results emphasize the importance of introduction checks before new animals enter the herd and adequate vaccination protection as cost‐effective control strategies. Lutter contre la maladie d'une manière rentable dans les élevages de bovins laitiers peut déboucher sur un meilleur rendement et des profits plus élevés. Les études économiques antérieures s'intéressant à cet aspect portaient essentiellement sur les pertes de production et l'évaluation des programmes d'éradication. Elles donnaient peu d'indications sur la solution idéale au niveau de la prévention. Cet article présente un modèle théorique de l'économique des maladies du bétail et aboutit à un modèle empirique permettant d'établir le jeu optimal de moyens pour lutter contre quatre maladies réduisant la production animale : la diarrhée à virus des bovins (DVB), la leucose bovine enzootique (LBE), la paratuberculose et la néosporose. Les auteurs estiment les fonctions qui indiquent la prévalence d'une infection pour chacune des quatre maladies retenues, dans le cadre des dix stratégies examinées. Ensuite, ils présentent les meilleures stratégies, à savoir celles qui minimisent le coût total de la maladie (pertes de production directes et dépenses associées à la lutte contre la maladie), pour chaque maladie en fonction des résultats d'un sondage auprès des éleveurs des provinces de l'Atlantique. Tout indique que les méthodes de lutte les plus rentables sont l'examen de l'animal avant son addition au troupeau et une vaccination qui protègera les bêtes de manière adéquate.     

Costs and benefits of forest conservation: regional and local comparisons in Eastern Finland

In addition to environmental interests vs. timber production, debates on forest conservation have typically dealt with nationwide vs. local and regional interests. While most previous studies have focused on the nationwide perspective, this paper considers the benefits and costs of existing conservation areas from the regional and local point of view. The non-market benefits of conservation are measured by means of contingent valuation. Unlike most discrete-choice CV studies, we allow for zero willingness to pay. The results of our cost-benefit analysis suggest that the aggregate benefits of conservation clearly exceed the total opportunity costs when viewed from a regional (or nationwide) perspective, but at the local level costs exceed the benefits of conservation. Differences were also found in locally vs. regionally relevant benefits and costs.     

One little Lebanese cucumber is not going to break the bank: Price in the choice of fresh fruits and vegetables

This paper reports on empirical research into individual consumer behaviour in the context of fresh fruit and vegetable purchases. The discussion draws on research results from two studies conducted around the actual shopping process. The findings suggest that consumers' price response behaviour may not be consistent with that predicted by economic theory and that this could be significant at the aggregate level. The existence of 'acceptable price ranges' points to the presence of price thresholds within which consumers are relatively insensitive to price movements. Also of relevance is that the primary influence of the budget constraint may be at a broader level rather than at the level of choosing particular products.     

A Case Study Approach to Comparing Weed Management Strategies under Alternative Farming Systems in Ontario

When research was initiated into comparing alternative method's of managing weeds in Ontario's major field cash crops, no field trial data existed. Twenty-five farmers were therefore surveyed for their production data on corn, beans and fall-seeded cereal grains, including weed management practices, input costs and wage rates, yields and product prices. Nine farmers were classified "conventional" because of their heavy dependence on synthetic herbicides, which were routinely broadcast on the three focus crops. Nine farmers were classified as "reduced input" if they placed reduce dependence on herbicides for at least one of the focus crops. Seven organic farmers placed zero reliance on herbicides, using instead substitutes such as crop rotations, smother crops, soil tillage and timeliness of field operations. Although organic farmers spent the most time and money on weed control, their overall direct costs of production were lowest for all three focus crops. Crop gross margins were highest on organic farms, partly because of lower production costs, but also because of higher product prices along with comparable crop yields. Linear programming model results for whole-farm analyses revealed highest net farm incomes on organic farms and lowest on conventional farms, in part due to lower overhead costs on organic farms, and in part due to greater enterprise diversification and to greater self-sufficiency in material inputs. These case study results need broader-scale testing to verify the conclusion that organic or reduced-input methods of weed management offer viable alternatives to conventional approaches.     

SOCIAL COSTS OF REGULATION OF PRIMARY INDUSTRY: AN APPLICATION TO ANIMAL WELFARE REGULATION OF THE VICTORIAN PIG INDUSTRY*

The effects of state government regulation of primary industry are modelled. An analytical framework is presented for estimating the costs of regulation in terms of changes in economic surplus. The model permits trade between regions of the total market. An illustrative application of the framework is applied to proposed animal welfare regulation of the Victorian pig industry. Some regulations that may provide large gains with regard to the welfare of farm animals involve only small social costs compared to the gross value of production of the industry. Conversely, other regulations that potentially confer only small gains in animal welfare impose large social costs. The distribution of these costs is important. In general, consumers lose, as do some producers. Other producers gain. In some cases, producers in aggregate gain from regulation. Major beneficiaries, such as advocates of animal welfare regulations, are likely to bear little of the cost of regulation.