@article{owen_young_shaw_wilson_jordan_dixon_weller_2011, title={Benchmark study on glyphosate-resistant crop systems in the United States. Part 2: Perspectives}, volume={67}, ISSN={["1526-4998"]}, DOI={10.1002/ps.2159}, abstractNote={AbstractA six‐state, 5 year field project was initiated in 2006 to study weed management methods that foster the sustainability of genetically engineered (GE) glyphosate‐resistant (GR) crop systems. The benchmark study field‐scale experiments were initiated following a survey, conducted in the winter of 2005–2006, of farmer opinions on weed management practices and their views on GR weeds and management tactics. The main survey findings supported the premise that growers were generally less aware of the significance of evolved herbicide resistance and did not have a high recognition of the strong selection pressure from herbicides on the evolution of herbicide‐resistant (HR) weeds. The results of the benchmark study survey indicated that there are educational challenges to implement sustainable GR‐based crop systems and helped guide the development of the field‐scale benchmark study. Paramount is the need to develop consistent and clearly articulated science‐based management recommendations that enable farmers to reduce the potential for HR weeds. This paper provides background perspectives about the use of GR crops, the impact of these crops and an overview of different opinions about the use of GR crops on agriculture and society, as well as defining how the benchmark study will address these issues. Copyright © 2011 Society of Chemical Industry}, number={7}, journal={PEST MANAGEMENT SCIENCE}, author={Owen, Micheal D. K. and Young, Bryan G. and Shaw, David R. and Wilson, Robert G. and Jordan, David L. and Dixon, Philip M. and Weller, Stephen C.}, year={2011}, month={Jul}, pages={747–757} }
 @article{shaw_owen_dixon_weller_young_wilson_jordan_2011, title={Benchmark study on glyphosate-resistant cropping systems in the United States. Part 1: Introduction to 2006-2008}, volume={67}, ISSN={["1526-498X"]}, DOI={10.1002/ps.2160}, abstractNote={AbstractGlyphosate‐resistant (GR) crop technology has dramatically impacted agriculture. The adoption of GR systems in canola, maize, cotton, soybean and sugar beets has been widespread in the United States. However, weed scientists are concerned that growers' current herbicide programs and weed management tactics will affect their sustainability and effectiveness. Without proper management, the potential for weed populations to express a high degree of resistance to glyphosate will adversely impact the utility of glyphosate. In 2005, weed scientists from six universities initiated a long‐term research study to assess the sustainability of GR technology. This paper introduces five other articles in this series. Over 150 fields of at least 10 ha were selected to participate in a long‐term field‐scale study, and each field was split in half. On one‐half the grower continued using the current weed management program; on the other half the grower used academic‐recommended herbicide resistance best management practices. Field data were collected in 2006–2008 to determine the impact of the two weed management programs on weed populations, diversity, seedbank, crop yields and economic returns. This long‐term study will provide invaluable data for determining the sustainability and profitability of diversified weed management programs designed to lower the risk of evolving weed resistance to glyphosate. Copyright © 2011 Society of Chemical Industry}, number={7}, journal={PEST MANAGEMENT SCIENCE}, author={Shaw, David R. and Owen, Micheal D. K. and Dixon, Philip M. and Weller, Stephen C. and Young, Bryan G. and Wilson, Robert G. and Jordan, David L.}, year={2011}, month={Jul}, pages={741–746} }
 @article{wilson_young_matthews_weller_johnson_jordan_owen_dixon_shaw_2011, title={Benchmark study on glyphosate-resistant cropping systems in the United States. Part 4: Weed management practices and effects on weed populations and soil seedbanks}, volume={67}, ISSN={["1526-4998"]}, DOI={10.1002/ps.2176}, abstractNote={AbstractBACKGROUND: Weed management in glyphosate‐resistant (GR) maize, cotton and soybean in the United States relies almost exclusively on glyphosate, which raises criticism for facilitating shifts in weed populations. In 2006, the benchmark study, a field‐scale investigation, was initiated in three different GR cropping systems to characterize academic recommendations for weed management and to determine the level to which these recommendations would reduce weed population shifts.RESULTS: A majority of growers used glyphosate as the only herbicide for weed management, as opposed to 98% of the academic recommendations implementing at least two herbicide active ingredients and modes of action. The additional herbicides were applied with glyphosate and as soil residual treatments. The greater herbicide diversity with academic recommendations reduced weed population densities before and after post‐emergence herbicide applications in 2006 and 2007, particularly in continuous GR crops.CONCLUSION: Diversifying herbicides reduces weed population densities and lowers the risk of weed population shifts and the associated potential for the evolution of glyphosate‐resistant weeds in continuous GR crops. Altered weed management practices (e.g. herbicides or tillage) enabled by rotating crops, whether GR or non‐GR, improves weed management and thus minimizes the effectiveness of only using chemical tactics to mitigate weed population shifts. Copyright © 2011 Society of Chemical Industry}, number={7}, journal={PEST MANAGEMENT SCIENCE}, author={Wilson, Robert G. and Young, Bryan G. and Matthews, Joseph L. and Weller, Stephen C. and Johnson, William G. and Jordan, David L. and Owen, Micheal D. K. and Dixon, Philip M. and Shaw, David R.}, year={2011}, month={Jul}, pages={771–780} }
 @article{weirich_shaw_owen_dixon_weller_young_wilson_jordan_2011, title={Benchmark study on glyphosate-resistant cropping systems in the United States. Part 5: Effects of glyphosate-based weed management programs on farm-level profitability}, volume={67}, ISSN={["1526-498X"]}, DOI={10.1002/ps.2177}, abstractNote={AbstractBACKGROUND: Glyphosate‐resistant (GR) crops have changed the way growers manage weeds and implement control strategies. Since the introduction of GR crops, growers in many instances have relied on glyphosate almost exclusively to control a broad spectrum of weeds. This overreliance on glyphosate has resulted in the evolution of glyphosate resistance in some weed species. Growers and scientists are concerned about the sustainability of GR crops and glyphosate. When a grower is making decisions about weed control strategies, economic costs and benefits of the program are primary criteria for selection and implementation. Studies across six states were initiated in 2006 to compare the economics of using a weed resistance best management practice (BMP) system with a grower's standard production system.RESULTS: Resistance BMP systems recommended by university scientists were more costly but provided similar yields and economic returns. Rotation of GR crops resulted in a higher net return (maize and soybean) compared with continuous GR crop (cotton or soybean) or rotating a GR crop with a non‐GR crop (maize).CONCLUSION: Growers can implement weed resistance BMP systems with the confidence that their net returns will be equivalent in the short run, and, in the long term, resistance BMP systems will prevent or delay the evolution of GR weeds in their fields, resulting in substantial savings. Copyright © 2011 Society of Chemical Industry}, number={7}, journal={PEST MANAGEMENT SCIENCE}, author={Weirich, Jason W. and Shaw, David R. and Owen, Micheal D. K. and Dixon, Philip M. and Weller, Stephen C. and Young, Bryan G. and Wilson, Robert G. and Jordan, David L.}, year={2011}, month={Jul}, pages={781–784} }
 @article{weirich_shaw_coble_owen_dixon_weller_young_wilson_jordan_2011, title={Benchmark study on glyphosate-resistant cropping systems in the United States. Part 6: Timeliness of economic decision-making in implementing weed resistance management strategies}, volume={67}, ISSN={["1526-498X"]}, DOI={10.1002/ps.2175}, abstractNote={AbstractBACKGROUND:The introduction of glyphosate‐resistant (GR) crops in the late 1990s made weed control in maize, cotton and soybean simple. With the rapid adoption of GR crops, many growers began to rely solely on glyphosate for weed control. This eventually led to the evolution of GR weeds. Growers are often reluctant to adopt a weed resistance best management practice (BMP) because of the added cost of additional herbicides to weed control programs which would reduce short‐term revenue. This study was designed to evaluate when a grower that is risk neutral (profit maximizing) or risk averse should adopt a weed resistance BMP.RESULTS:Whether a grower is risk neutral or risk averse, the optimal decision would be to adopt a weed resistance BMP when the expected loss in revenue is greater than 30% and the probability of resistance evolution is 0.1 or greater. However, if the probability of developing resistance increases to 0.3, then the best decision would be to adopt a weed resistance BMP when the expected loss is 10% or greater.CONCLUSION:Given the scenarios analyzed, risk‐neutral or risk‐averse growers should implement a weed resistance BMP with confidence that they have made the right decision economically and avoided the risk of lost revenue from resistance. If the grower wants to continue to see the same level of return, adoption of BMP is required. Copyright © 2011 Society of Chemical Industry}, number={7}, journal={PEST MANAGEMENT SCIENCE}, author={Weirich, Jason W. and Shaw, David R. and Coble, Keith H. and Owen, Micheal D. K. and Dixon, Philip M. and Weller, Stephen C. and Young, Bryan G. and Wilson, Robert G. and Jordan, David L.}, year={2011}, month={Jul}, pages={785–789} }
 @article{duttweiler_gleason_dixon_sutton_mcmanus_monteiro_2008, title={Adaptation of an apple sooty blotch and flyspeck warning system for the Upper Midwest United States}, volume={92}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS-92-8-1215}, abstractNote={ A warning system for sooty blotch and flyspeck (SBFS) of apple, developed in the southeastern United States, uses cumulative hours of leaf wetness duration (LWD) to predict the timing of the first appearance of signs. In the Upper Midwest United States, however, this warning system has resulted in sporadic disease control failures. The purpose of the present study was to determine whether the warning system's algorithm could be modified to provide more reliable assessment of SBFS risk. Hourly LWD, rainfall, relative humidity (RH), and temperature data were collected from orchards in Iowa, North Carolina, and Wisconsin in 2005 and 2006. Timing of the first appearance of SBFS signs was determined by weekly scouting. Preliminary analysis using scatterplots and boxplots suggested that cumulative hours of RH ≥ 97% could be a useful predictor of SBFS appearance. Receiver operating characteristic curve analysis was used to compare the predictive performance of cumulative LWD and cumulative hours of RH ≥ 97%. Cumulative hours of RH ≥ 97% was a more conservative and accurate predictor than cumulative LWD for 15 site years in the Upper Midwest, but not for four site years in North Carolina. Performance of the SBFS warning system in the Upper Midwest and climatically similar regions may be improved if cumulative hours of RH ≥ 97% were substituted for cumulative LWD to predict the first appearance of SBFS. }, number={8}, journal={PLANT DISEASE}, author={Duttweiler, K. B. and Gleason, M. L. and Dixon, P. M. and Sutton, T. B. and McManus, P. S. and Monteiro, J. E. B. A.}, year={2008}, month={Aug}, pages={1215–1222} }
 @article{easterling_ellner_dixon_2000, title={Size-specific sensitivity: Applying a new structured population model}, volume={81}, number={3}, journal={Ecology (Brooklyn, New York, N.Y.)}, author={Easterling, M. R. and Ellner, S. P. and Dixon, P. M.}, year={2000}, pages={694–708} }