Edward A. Evans

U.S.-Canadian Tomato Wars: An Economist Tries to Make Sense Out of Recent Antidumping Suits

U.S. growers filed an antidumping case against Canadian growers of greenhouse-grown tomatoes, alleging that U.S. growers were being injured, or threatened with material injury, by imports from Canada. The U.S. Department of Commerce determined that imports of greenhouse-grown tomatoes were being sold in U.S. markets at less than fair market value. The U.S. International Trade Commission determined the “like product” to be all fresh market tomatoes, concluding the domestic industry was not materially injured. Anecdotal evidence used by the Commission Department in determining like product ignores the wealth of knowledge that economics can add. An economic model is proposed for purposes of determining like product.

Recovery plan for laurel wilt of avocado, caused by Raffaelea lauricola

R. C. Ploetz, Tropical Research and Education Center, University of Florida, Homestead 33031; M. A. Hughes, School of Forest Resources and Conservation, University of Florida, Gainesville 32611; P. E. Kendra, USDA-ARS Subtropical Horticulture Research Station, Miami, FL 33158; S. W. Fraedrich, USDA Forest Service, Athens, GA 30602; D. Carrillo, Tropical Research and Education Center, University of Florida, Homestead 33031; L. L. Stelinski, Citrus Research and Education Center, University of Florida, Lake Alfred 33850; J. Hulcr, School of Forest Resources and Conservation and Department of Entomology and Nematology, University of Florida, Gainesville 32611; A. E. Mayfield, III, USDA Forest Service, Southern Research Station, Asheville, NC 28804; T. L. Dreaden, USDA-Forest Service, Southern Research Station, Forest Health Research and Education Center, Lexington, KY 40517; J. H. Crane, E. A. Evans, and B. A. Schaffer, Tropical Research and Education Center, University of Florida, Homestead 33031; and J. A. Rollins, Department of Plant Pathology, University of Florida, Gainesville 32611

RE-GREENING OF LYCHEE (LITCHI CHINENSIS SONN.) LEAVES WITH FOLIAR APPLICATIONS OF IRON SULFATE AND WEAK ACIDS

Lychee (Litchi chinensis Sonn. cv. ‘Mauritius’) trees growing in calcareous soils are prone to iron (Fe) deficiency, typically prevented by soil application of chelated Fe, which is very expensive compared to iron sulfate (FeSO4). Therefore, the effects of foliar applications of weak acids (ascorbic or dilute sulfuric acid), weak acids plus FeSO4, or a soil drench of chelated iron (Fe-EDDHA) on leaf chlorophyll index, leaf ferrous iron (Fe2+) and total Fe concentrations, leaf gas exchange and plant dry weight were determined for 2-year-old lychee trees growing in calcareous soil in containers. Treatments were: foliar applications of ascorbic acid in deionized (DI) water plus surfactant, sulfuric acid in DI water plus surfactant, ascorbic acid in DI water plus FeSO4 plus surfactant, sulfuric acid in DI water plus FeSO4 plus surfactant, FeSO4 in DI water plus surfactant, FeSO4 in DI water with no surfactant, FeSO4 in well water plus surfactant, sulfuric acid plus FeSO4 in well water plus surfactant, surfactant in DI water. An additional treatment was chelated iron (Fe-EDDHA) applied to the soil. The organosilicone compound Freeway® was used as the surfactant. Well water was used instead of DI water in two treatments because fertilizers are often mixed with water from a well that typically has a pH much higher than that of DI water. Foliar treatments were applied at 4-week intervals for 24 weeks and chelated iron was applied to the soil at the time of first foliar treatments and 8 and 16 weeks later. There was generally no difference in leaf chlorophyll index among plants receiving chelated iron as a soil drench or foliar treatments containing FeSO4 plus surfactant with or without organic acid. Foliar applications of acid with no FeSO4 resulted in a lower leaf chlorophyll index than soil-applied Fe-EDDHA or any of the foliar treatments containing FeSO4 plus surfactant. Leaf total Fe and Fe2+ concentrations were generally highest for plants in the soil-applied Fe-EDDHA treatment and all foliar application treatments containing FeSO4 plus surfactant. Net CO2 assimilation (Anet), stomatal conductance (gs), transpiration (Tr) and leaf, stem, root and total plant dry weights were highest for plants treated with soil-applied Fe-EDDHA or foliarly applied FeSO4 with no surfactant. Further studies indicated that the surfactant Freeway® inhibits leaf gas exchange and plant growth. The results indicate that foliar applications of FeSO4 are almost as effective as soil applications of chelated Fe for eliminating or preventing Fe deficiency symptoms of lychee trees growing in calcareous soil. While the addition of a surfactant to the foliar spray mixture appears to be necessary for preventing Fe deficiency, care must be taken when selecting a surfactant for foliar applications of FeSO4 to be sure that there are no negative effects on leaf gas exchange and plant growth.

Modelling decision-making regarding wetland services for wetland management in Tram Chim National Park, Vietnam

In order to support multi-objective wetland management, this study develops a five-step multi-criteria decision framework and uses the Tram Chim National Park case to demonstrate decisions by comparing net benefits, the frameworks outcome, of four wetland zones (A1, A2, A4, and A5) of the Park. Methods include (1) identification of key management priorities using analytic hierarchy process; (2) assessment of use/non-use values using market/non-market valuation techniques. Consumptive direct use values were determined by market assessment of fishing while a travel cost model was employed to estimate non-consumptive direct use values for tourism. Indirect use and non-use values were assessed using contingent valuation method. Results showed the priorities of tourism, fishing, and management costs. Total fishing benefit (fishing income and revenue from permits) was estimated at US

Economic Impact and Trade Implications of the Introduction of Black Sigatoka (Mycosphaerella fijiensis) into Puerto Rico

173/year/person. Willingness to pay for preferred plant communities varied. For tourism, overall consumer surplus was estimated at US

Coupling hydrologic and economic modeling for wetland management multi-optimization in Tram Chim National Park, Vietnam

11/person and tourists would be willing to pay US

Agri-dogs: Using Canines for Earlier Detection of Laurel Wilt Disease Affecting Avocado Trees in South Florida

3–5/person more. In sum, net benefit for a typical year for zone A1 was highest. The framework demonstrates how the decision-making process with regards to managing an environmental resource can be enhanced within a multi-decision framework using a set of market and non-market economic valuation tools.

Trade Liberalization and Small Economies: The Case of the Caribbean Community

This article addresses the issues of the potential impacts of the introduction of black sigatoka into Puerto Rico under situations in which the government assists growers in managing the spread of the disease, with and without prohibitions on imports of plantains and bananas. An equilibrium displacement model is used to quantify the impact of black sigatoka. The results indicate that under both scenarios the net economic benefits to society were negative. Over the long term, the government would be well-advised to invest in research to develop plantain and banana varieties that are resistant to black sigatoka.

Economic Dimensions of Invasive Species

We developed a comprehensive coupling framework with a multi-objective optimization that bridges a water balance model (WBM) and a wetland service model (WSM) to supporting wetland management. The framework was tested for management in Tram Chim National Park (with four wetland zones) where hydro-economic optimization was needed. The framework used (1) a model coupling process bridging WBM and WSM to create a modular hydro-economic model (MHEM), (2) a multi-objective optimization, and (3) an anneal scheduling for scenario optimization. The framework demonstrated its competency in identifying cause–effect/interaction flows (bridges) between WBM and WSM to design MHEM to simulate optimized scenarios; for the case study, the multi-objective optimization was met for all wetland zones. Results suggested a flexible consideration of management scales for optimization, i.e. hydrologic optimization at a zone level and net benefit optimization at a Park level. Our framework is applicable to supporting complex wetland decisions considering multiple objectives.

Potential Economic Impact of Laurel Wilt Disease on the Florida Avocado Industry

The invasive redbay ambrosia beetle (Xyleborus glabratus) was first detected in Savannah,GA, in 2002. This tiny beetle and its symbiotic fungal partner (Raffaelea lauricola) have led to one of the most devastating new plant diseases in recent times affecting laurel trees (Lauraceae), laurel wilt. In Florida, this devastating disease has also affected the agriculturally important avocado (Persea americana), and once symptoms are visible (i.e., wilting leaves), it is too late to save the infected tree. However, prophylactic systemic treatment with propiconazole can protect the trees from the disease for 12 months. This study evaluated the novel approach of using scent-discriminating canines (Canis familiaris) trained on the volatiles of laurel wilt pathogen as a proactive management tool for grove owners. Canine deployments in groves resulted in the detection of 265 presymptomatic avocado trees during two trials. In trial 1, 155 presymptomatic trees were treated with propiconazole and, over the subsequent 14-month monitoring period, 97% remained asymptomatic. In trial 2, the canines detected 100 presymptomatic trees that were not subsequently treated and 22 progressed to wilt within 2–5 weeks, and the remaining trees were removed, thus halting the observation period at 6 weeks. The canines have proven to be an effective proactive management tool.