Ghorbani, K., Atallah, S. (2024) “Strategic Responses to Ban Enforcement Uncertainty: Antibiotic Application Decisions in Plant Agriculture”., European Review of Agricultural Economics (Revise and resubmit)
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Abstract: The rise of antibiotic resistance in plant agriculture, coupled with limited disease management options and potential antibiotic bans, complicates growers' disease management decision-making. We develop the first dynamic model of optimal antibiotic use in plant agriculture under ban enforcement uncertainty. We find that proactive growers who adjust to anticipated bans overexploit antibiotic efficacy and gain benefits over business-as-usual growers. The magnitude of these benefits increases monotonically with the resource value if a ban takes place, but that relationship is nonlinear otherwise. We propose an instrument to compensate proactive growers for adapting to unmaterialized bans.
Ghorbani, K., Atallah, S. (2024) “Climate-change impacts mediated by crop diseases: The case of coffee leaf rust”., American Journal of Agricultural Economics (Revise and resubmit) (Link)
Abstract: The indirect impact of climate change on agriculture through diseases and pests is understudied. However, estimating the direct and indirect impacts separately is necessary for selecting adaptation strategies based on the direction and magnitude of each impact channel. We investigate the relative contribution of the indirect climate impact in the context of coffee and coffee leaf rust, the crop’s most damaging disease. We construct a farm-level bioeconomic model and assess the impact of projected warmer temperatures and more prolonged droughts on the expected net present values of four farm types in Colombia: sun and shade-grown farms at low and high altitudes. We find that sun-grown farms at both altitudes and shade-grown farms at low altitudes benefit from a warmer and drier climate. The relative magnitudes and directions of the direct and indirect climatic impacts suggest different adaptation priorities at different altitudes for each system: resilience to the disease is a priority for sun-grown systems at high altitudes whereas heat tolerance is most important for sun and shade-grown coffee farms at low altitudes. Our results indicate that, while shade-grown coffee is optimal under historical climate, its advantage over sun-grown coffee is lost under the projected climate. We identify climate-adjusted, altitude-specific price premiums for shade-grown coffee that can avoid a transition from shade to sun-grown systems and prevent the associated potential loss of ecosystem services.
Winfree, J., Atallah, S., Gallardo, K., Ghorbani, K. (2024) “The Economic Effects of Persistent Plant Diseases: The Case of Fire blight”., Journal of Agricultural and Resource Economics (Manuscript available upon request)
Abstract: This study examines the economic impact of fire blight on pear production, differentiating between anticipated and unanticipated disease shocks. Using a Cournot model and empirical price-quantity relationships, the analysis reveals that fire blight reduces industry yield and welfare, with mixed effects on producer profits depending on disease severity and market conditions.
Ghorbani, K., Atallah, S., Gallardo, K., (2024) “Commentary on Extension Programming: An Online Platform for Area-Wide Management of Western X-Disease Extension Program”., Applied Economics Teaching Resources (Link)
Abstract: The extension program discussed in this commentary article was developed using a logic model to provide an economic analysis of Western-X disease (WXD) management at the farm and landscape levels. This program entered the Graduate Student Extension Competition organized by the Agricultural and Applied Economics Association (AAEA). It consisted of a simulated presentation to sweet cherry growers on the economics of tree removal as a disease management practice. The program’s delivery and communication strategies include an online platform, fact sheets, research articles, conference presentations, and workshops. This commentary shows how young professionals can create a successful program using a logic model.
Ghorbani, K., Atallah, S., Gallardo, K., (2024) “Growers’ Willingness to Adopt Non-Antibiotic Disease Management Strategies to Cope with Antibiotic Resistance” (Target journal: Ecological Economics - Manuscript available upon request)
Abstract: The emergence of antibiotic resistance in plant agriculture poses a growing challenge to sustainable disease management and public health. Despite increasing regulatory scrutiny and rising concerns about the overuse of antibiotics in fruit trees, little is known about growers’ willingness to adopt integrated disease management (IDM) strategies that consist of reducing and rotating antibiotics and using novel, non-antibiotic products such as biopesticides. This chapter evaluates the preferences of U.S. apple growers for adopting such IDM strategies to control fire blight and manage antibiotic resistance. We conducted a discrete choice experiment among commercial apple producers in major apple-producing states in the US, incorporating a randomized information treatment suggesting a potential ban policy implemented on the use of antibiotics in plant agriculture. In addition to disease management alternatives, the choice experiment design includes attributes capturing both immediate and long-term disease management effectiveness, the cost of treatment, and the adoption behavior of neighboring growers. In addition to assessing whether farmers would adopt proposed IDM bundles, this study tests whether the prospect of an antibiotic ban leads to an overuse of antibiotics or an adoption of alternatives. Plus, we test whether adoption by neighbors exacerbates or mitigates the effects of an anticipated ban.
Ghorbani, K., Atallah, S., Gallardo, K., (2024) “The Bio-Economics of Tree Disease Management with Partial Observability” (Target journal: Journal of Agricultural and Resource Economics - Manuscript available upon request)
Abstract: Western X-disease (WXD), a vector-borne phytoplasma affecting cherry orchards in the western United States, has caused substantial economic losses through yield decline, tree mortality, and costly orchard re-establishment. The management of WXD presents complex decision-making challenges for growers, who must navigate uncertain disease progression, partial observability of the infection, and the long-term economic consequences of removing and replacing trees. This chapter develops a spatially explicit bioeconomic model to evaluate the economic performance of alternative WXD management strategies over a 25-year horizon in a representative cherry orchard in Washington State. The model integrates tree-level disease dynamics with a partially observable Markov decision process (POMDP), simulating how growers update beliefs about tree health using visual cues and testing outcomes, and choose among three actions: do nothing, remove infected trees, or remove and replant. The modeling framework captures stochastic transitions between health states, the epidemiological role of an insect vector, and trade-offs between short-term yield and long-term disease suppression. A parallel rollout algorithm is used to identify near-optimal sequences of management actions based on expected net present values (NPV). Scenario analysis explores baseline disease progression, no-disease benchmarks, full-information strategies, and testing-based interventions under varying assumptions about testing costs and accuracy. [SA1] [KG2] This framework provides a decision-support tool for evaluating adaptive, spatially targeted disease management policies under biological uncertainty.
Ghorbani, K., Atallah, S., Gallardo, K., Tianna Dupont., (2024) “Return on Investment in Alternative Fire Blight Management Strategies: Evidence from Field Trials in Washington State” (Target journal: Plant Disease - Manuscript available upon request)
Abstract: This study evaluates the return on investment (ROI) of alternative fire blight management strategies, incorporating direct costs and yield loss due to infection. Data are from field trials conducted in a 0.25 ha research block of gala apples in East Wenatchee, WA, where biopesticides (Streptomycin standard (Firewall 50WP), Alum (potassium aluminum sulfate), Actigard®, Blossom Proect + Buffer Protect, Agriphage, Thyme Guard, FAL 1301 (ASM), Oxidate 5.0, Serenade ASO, Cinnerate) and a 1.0 acre block of fugi, gala, honeycrisp, pink lady and WA38 apples where systemic acquired resistance (SAR) inducers (ASM, Actigard® 50WG) at 1 and 2 oz/100 gal with additional drench treatment, ProCa (Kudos® 27.5 WDG) at 2 and 6 oz/100 gal, and a combined treatment with ASM at 1 oz/100 gal and ProCa at 2 oz/100 gal) were tested at different disease severity levels and compared to water treatment as control. Disease incidence after treatments was assessed based on infections per 100 clusters and infections per shoot and severity on lesion length in inoculated shoots. Yield loss per acre was calculated from disease incidence and the percentage of fruit lost estimated from fruit and bearing area removed. A one-way ANOVA on yield loss data showed significant treatment effects across all severity levels (P<0.001). Under high disease pressure, streptomycin and alum were the most effective, reducing yield loss by 86% and 75% respectively, and generating the highest ROI. Applying fire blight treatments under low disease severity resulted in negative ROI for all alternatives. Low dose of Kudos resulted in the highest ROI among SAR treatments.
Ghorbani, K., Jared Hutchins, Jonathan Coppess “Spatial Distribution of Farm Service Agency (FSA) Farm Payments”
We are curating FSA payment dataset to enhance data availability for researchers, policymakers, and agricultural stakeholders through the National Center for Supercomputing Applications (NCSA).
Ghorbani, K. “A Game-Theoretic Mechanism to Combat Antibiotic Resistance in Livestock Production”
This study develops a game-theoretic compensation mechanism to incentivize farmers to reduce antibiotic use while internalizing resistance-related externalities. Findings highlight the role of farmers' perceptions in the mechanism’s effectiveness and suggest that aligning compensation strategies with education campaigns enhances antibiotic stewardship in agriculture.
Ghorbani, K., & Mashange, G. (2024). The Dynamics of Sweet Cherry Orchards: Trends and Transitions from 2008 to 2023. farmdoc daily, 14(151).
“This study examines the evolution of U.S. sweet cherry production, highlighting Washington’s dominance, California’s expansion, and Oregon’s decline due to environmental constraints. It also explores land use transitions and the economic impact of pest and disease pressures, emphasizing the industry's need for adaptive strategies.”