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| Mitchell, Paul D.; Gray, Michael E.; Steffey, Kevin L.. |
| This paper describes a composed error model for estimating the conditional distribution of yield loss to serve as an insect damage function. The two-part error separates yield variability due to pest damage from other non-pest factors such as soil heterogeneity, non-uniform application of agronomic practices, and measurement errors. Various common functional forms (linear, quadratic, Cobb-Douglas, negative exponential, hyperbolic, sigmoid) for the pest damage function are presented and parameter estimation is described. As an empirical illustration, the model is used to estimate a damage function for corn rootworm, the most damaging insect pest of corn in the United States. The estimated damage function gives expected proportional yield loss as a... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Crop Production/Industries. |
| Ano: 2002 |
URL: http://purl.umn.edu/19602 |
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| Yang, Juan; Mitchell, Paul D.; Gray, Michael E.; Steffey, Kevin L.. |
| We describe four recently developed panel data estimators for unbalanced and nested data, a common problem for economic and experimental data. We estimate a western corn rootworm damage function with each estimator, including separate parameters for random effects from year, location, and experimental errors. We then use each estimator to assess the cost of the western corn rootworm soybean variant and the net benefit of soil insecticide and Bt corn for controlling this pest. At current prices, we find that soil insecticide generates a net loss ranging about $0.50-$3.25/ac, while Bt corn generates a net benefit ranging $2.50-$7.00/ac. |
| Tipo: Working or Discussion Paper |
Palavras-chave: Research Methods/ Statistical Methods. |
| Ano: 2007 |
URL: http://purl.umn.edu/92127 |
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| Mitchell, Paul D.; Gray, Michael E.; Steffey, Kevin L.. |
| This paper describes a composed error model for estimating the conditional distribution of yield loss to serve as an insect damage function. The two-part error separates yield variability due to pest damage from other non-pest factors such as soil heterogeneity, non-uniform application of agronomic practices, and measurement errors. Various common functional forms (linear, quadratic, Cobb-Douglas, negative exponential, hyperbolic, sigmoid) for the pest damage function are presented and parameter estimation is described. As an empirical illustration, the model is used to estimate a damage function for corn rootworm, the most damaging insect pest of corn in the United States. The estimated damage function gives expected proportional yield loss as a function... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Crop Production/Industries. |
| Ano: 2002 |
URL: http://purl.umn.edu/24020 |
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