Terrance M. Hurley

Seeds of Change: Corn Seed Mixtures for Resistance Management and Integrated Pest Management

ABSTRACT The use of mixtures of transgenic insecticidal seed and nontransgenic seed to provide an in-field refuge for susceptible insects in insect-resistance-management (IRM) plans has been considered for at least two decades. However, the U.S. Environmental Protection Agency has only recently authorized the practice. This commentary explores issues that regulators, industry, and other stakeholders should consider as the use of biotechnology increases and seed mixtures are implemented as a major tactic for IRM. We discuss how block refuges and seed mixtures in transgenic insecticidal corn, Zea mays L., production will influence integrated pest management (IPM) and the evolution of pest resistance. We conclude that seed mixtures will make pest monitoring more difficult and that seed mixtures may make IRM riskier because of larval behavior and greater adoption of insecticidal corn. Conversely, block refuges present a different suite of risks because of adult pest behavior and the lower compliance with IRM rules expected from farmers. It is likely that secondary pests not targeted by the insecticidal corn as well as natural enemies will respond differently to block refuges and seed mixtures.

Effort levels in a Cournot Nash contest with asymmetric information

Abstract Many contests exist where one player does not know his opponents value of a fixed prize, e.g. unobservable non-market preferences for preservation. This paper explores how changes in the nature of a one-sided information asymmetry affect effort levels in a Cournot Nash contest. The results indicate that the uninformed players effort is an uncertain input such that his effort is inversely related to risk. This reduces his average odds of success. Comparative static results are driven by the perceived odds of success and risk for the uninformed player and the actual odds of success for the informed player.

Risk and the Value of Bt Corn

A conceptual model is developed to evaluate the effect of Bt corn on risk. Results highlight the importance of distinguishing between marginal and aggregate risk effects and demonstrate that the effect of Bt corn on risk depends crucially on the price paid for the technology. Empirical results show that, depending on the price, Bt corn can be marginally risk increasing or decreasing and can either increase or decrease corn acreage. Also, depending on the price, Bt corn can provide a risk benefit to farmers, even when Bt corn is risk increasing. Copyright 2004, Oxford University Press.

Re-examining the Reported Rates of Return to Food and Agricultural Research and Development

Hurley, Rao and Pardey (2014) analytically and empirically evaluate the internal rate of return (IRR) vis a vis the modified internal rate of return (MIRR) for investments in agricultural research and development (R&D). They find that estimates of the IRR are 2.5 to 5 times larger than the MIRR for a wide range of assumptions, leading them to question the value of the IRR as a metric to represent the rate of return to agricultural R&D. Oehmke (2016) defends the IRR by arguing that it has important properties that the MIRR does not possess. In this article, we critically examine these properties demonstrating that some are not inherent to the MIRR. For other properties, we simply disagree with Oehmke’s assessment of their desirability. Therefore, we are not compelled to change our original recommendation.

Early Detection and Mitigation of Resistance to Bt Maize by Western Corn Rootworm (Coleoptera: Chrysomelidae)

Abstract Transgenic Bt maize that produces less than a high-dose has been widely adopted and presents considerable insect resistance management (IRM) challenges. Western corn rootworm, Diabrotica virgifera virgifera LeConte, has rapidly evolved resistance to Bt maize in the field, leading to local loss of efficacy for some corn rootworm Bt maize events. Documenting and responding to this resistance has been complicated by a lack of rapid diagnostic bioassays and by regulatory triggers that hinder timely and effective management responses. These failures are of great concern to the scientific and agricultural community. Specific challenges posed by western corn rootworm resistance to Bt maize, and more general concerns around Bt crops that produce less than a high-dose of Bt toxin, have caused uncertainty around current IRM protocols. More than 15 years of experience with IRM has shown that high-dose and refuge-based IRM is not applicable to Bt crops that produce less than a high-dose. Adaptive IRM approaches and pro-active, integrated IRM-pest management strategies are needed and should be in place before release of new technologies that produce less than a high-dose. We suggest changes in IRM strategies to preserve the utility of corn rootworm Bt maize by 1) targeting local resistance management earlier in the sequence of responses to resistance and 2) developing area-wide criteria to address widespread economic losses. We also favor consideration of policies and programs to counteract economic forces that are contributing to rapid resistance evolution.

Estimating Site-Specific Nitrogen Crop Response Functions

Confirming the precision agriculture hypothesis for variable-rate N applications (VRAs) is challenging. To confront this challenge, researchers have used increasingly sophisticated statistical models to estimate and compare site-specific crop response functions (SSCRFs). While progress has been made, it has been hampered by the lack of a conceptual framework to guide the development of appropriate statistical models. This paper provides such a framework and demonstrates its utility by developing a heteroscedastic, fixed and random effects, geostatistical model to test if VRA can increase N returns. The novelty of the model is the inclusion of site, spatial, treatment, and treatment strip heteroscedasticity and correlation. Applied to data collected in 1995 from two corn (Zea mays L.) N response experiments in south-central Minnesota, results demonstrate the importance of including site, spatial, treatment, and treatment strip effects in the estimation of SSCRFs. Results also indicate a significant potential for VRA to increase N returns and that these potential returns increase as the area of the management unit decreases. At one location, there was greater than a 95% chance that VRA could have increased profitability if the cost of implementing VRA was less than

Research investment implications of shifts in the global geography of wheat stripe rust

14.5 ha -1 . At the other location, if implementation costs were less than

Rent Dissipation and Efficiency in a Contest with Asymmetric Valuations

48.3 ha -1 , there was greater than a 95% chance of increased profitability.

The Structure of Wages and Benefits in the U.S. Pork Industry

Breeding new crop varieties with resistance to the biotic stresses that undermine crop yields is tantamount to increasing the amount and quality of biological capital in agriculture. However, the success of genes that confer resistance to pests induces a co-evolutionary response that depreciates the biological capital embodied in the crop, as pests evolve the capacity to overcome the crops new defences. Thus, simply maintaining this biological capital, and the beneficial production and economic outcomes it bestows, requires continual reinvestment in new crop defences. Here we use observed and modelled data on stripe rust occurrence to gauge changes in the geographic spread of the disease over recent decades. We document a significant increase in the spread of stripe rust since 1960, with 88% of the worlds wheat production now susceptible to infection. Using a probabilistic Monte Carlo simulation model we estimate that 5.47 million tonnes of wheat are lost to the pathogen each year, equivalent to a loss of US

Adverse Selection, Moral Hazard, and Grower Compliance with Bt Corn Refuge

979 million per year. Comparing the cost of developing stripe-rust-resistant varieties of wheat with the cost of stripe-rust-induced yield losses, we estimate that a sustained annual research investment of at least US