Unbalanced Nested Component Error Model and the Value of Soil Insecticide and Bt Corn for Controlling Western Corn Rootworm

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.

Bt Corn, Insecticidal Seed Treatments, and Soil Insecticides for Managing Corn Rootworms: Experiences from 2004, Issues for 2005

The corn rootworm management situation in Illinois in 2004 can be characterized with four statements

Long-term Benefits of GM crops: Potential for Diabrotica Suppression in Europe using Bt Maize

Transgenic crops producing insecticidal proteins from _Bacillus thuringiensis_ (Bt) have been widely adopted since 1996 in the United States of America to combat important pests of maize and cotton. There is growing evidence that several target pest populations have been dramatically reduced in areas where the Bt crops have been most intensively adopted over multiple years. The evidence is most dramatic for nonmigratory monophagous and oligophagous species that show high mortality on Bt crops, such as European corn borer (_Ostrinia nubilalis_), and tobacco budworm (_Heliothis virescens_). Bt cotton is currently being used in the southwestern USA as part of an area-wide eradication program for pink bollworm (_Pectinophora gossypiella_). Single, stacked, and pyramided Bt maize lines producing coleopteran-active insecticidal proteins have been shown in some cases to cause >99% mortality of western corn rootworm (_Diabrotica virgifera virgifera_) larvae every year. Simulation models suggest that long-term area-wide cultivation of these Bt corn lines can lead to dramatic population reduction, and even local extinction, of corn rootworms. An eradication program for this economically important pest, based around Bt maize and incorporating a combination of other tools, would benefit European agriculture and the environment. Post-commercial monitoring programs should be designed to investigate long-term benefits to agricultural production systems that can be reasonably expected from the widespread cultivation of Bt crops in Europe

Another Corn Rootworm Management Tool Fails: Assessing the Status of Western Corn Rootworms Laying Eggs in Soybeans

A variant of western com rootworm that lays eggs in crops other than com was recognized in east-central Illinois as early as 1987 (Steffey et al. 1992), although at the time we believed we were witnessing the phenomenon of extended diapause. Thereafter, the problem with com rootworm larvae damaging com planted after soybean in east-central Illinois and northwestern Indiana increased in frequency and severity during the early 1990s and emerged as a full-blown crisis in 1995. Since then, entomologists throughout the Com Belt have watched warily as the problem spread throughout northern Indiana and into southern Michigan and western Ohio. The spread of the problem westward and northward in Illinois has occurred relatively slowly. However, we annually add counties to the list of counties threatened by the new variant of western corn rootworm

Western Corn Rootworm in Soybeans: Is an Adjustment in the Economic Threshold Necessary?

Com rootworm larval injury in first-year com (rotated com) was first reported in six seed production fields near Piper City, Illinois, in 1987. Initially, prolonged diapause of northern com rootworm, Diabrotica barberi, was offered as the primary explanation for this injury to rotated com. However, some of the larvae collected from affected fields were reared in the laboratory and later found to be western com rootworms, Diabrotica virgifera virgifera (Levine and Gray 1996, O\u27Neal et al. 1997). Six years later (1993), again near Piper City, new observations of com rootworm injury to first-year com seed production fields were reported. Unlike the explanation offered in the mid-1980s, a shift in the ovipositional behavior of the western com rootworm was suggested as the underlying cause of the problem. Since that first report, researchers have sought explanations for this remarkable adaptation by western com rootworm to crop rotation, including repellency by pyrethroid insecticides, prolonged diapause, and changes in feeding preferences (Steffey et al. 1992; Levine and Oloumi-Sadeghi 1996; Spencer et al. 1998, 1999): To improve immediate management options, an economic threshold based upon adult captures in soybeans and subsequent larval injury in rotated com was developed (O\u27Neal et al. 1998, 1999)

Biotechnology and the European Corn Borer: Measuring Historical Farmer Perceptions and Adoption of Transgenic Bt Corn as a Pest Management Strategy

A 3-yr, multi-state survey of farmers who had planted transgenic Bacillus thuringiensis (Bt) corn was conducted to evaluate perceptions of Bt corn performance and its utility as a management option for European corn borer, Ostrinia nubilalis (Hu¨ bner). A questionnaire was sent to farmers in Illinois, Iowa, Kansas, Minnesota, Nebraska, and Pennsylvania who had grown Bt corn during the growing seasons of 1996, 1997, or 1998. There were 7,427 usable questionnaires returned with the following response percentages: 1996 (42.1%), 1997 (35.0%), and 1998 (22.6%). Adoption rates, based on percentage of acreage planted to Bt corn, increased dramatically from 1996 (10.5%) to 1998 (40.7%). The states growing the highest percentage of Bt corn were Minnesota, Iowa, and then Nebraska. However, Illinois, was adopting Bt corn at the fastest rate. Historical use of insecticides did not inßuence the adoption of Bt corn. In addition, of those farmers who used insecticides to control European corn borer, the percentage that decreased their use of insecticides nearly doubled from 13.2% (1996) to 26.0% (1998) over this 3-yr period. The primary reason farmers planted Bt corn was to eliminate the yield loss caused by European corn borer. Scouting for European corn borers decreased from 91% (scouting 2.2 times a year) in 1996 to 75% (scouting 1.8 times a year) in 1998. The percentage of farmers not scouting for European corn borers increased from 9.6% (1996) to 25% (1998). Most farmers believed yields of Bt hybrids were either similar to or greater than the yields of non-Bt hybrids. Minnesota farmers perceived the greatest yield advantages. Farmers are becoming more aware of insect resistance management guidelines; however, they also clearly show preferences for having the ßexibility to use different spatial plantings of Bt and non-Bt corn. Finally, after having planted Bt corn and obtained excellent control of European corn borer, most farmers believed that this insect had been causing more yield loss than they previously had suspected in their non-Bt corn. The data represented here provide an historical foundation for how transgenic Bt corn was used by farmers during the Þrst 3 yr of commercial availability, their initial perceptions on the performance of this technology, and their attitudes regarding management of the European corn borer

Initial clinical experience with frameless optically guided stereotactic radiosurgery/radiotherapy in pediatric patients

The objective of this study is to report our initial experience treating pediatric patients with central nervous system tumors using a frameless, optically guided linear accelerator. Pediatric patients were selected for treatment after evaluation by a multidisciplinary neuro-oncology team including neurosurgery, neurology, pathology, oncology, and radiation oncology. Prior to treatment, all patients underwent treatment planning using magnetic resonance imaging (MRI) and treatment simulation on a standard computed tomography scanner (CT). For CT simulation, patients were fitted with a customized plastic face mask with a bite block attached to an optical array with four reflective markers. After ensuring adequate reproducibility, these markers were tracked during treatment by an infra-red camera. All treatments were delivered on a Varian Trilogy linear accelerator. The follow-up period ranges from 1–18 months, with a median follow-up of 6 months. Nine patients, ages ranging from 12 to 19 years old (median age 15 years old), with a variety of tumors have been treated. Patients were treated for juvenile pilocytic astrocytoma (JPA; n = 2), pontine low-grade astrocytoma (n = 1), pituitary adenoma (n = 3), metastatic medulloblastoma (n = 1), acoustic neuroma (n = 1), and pineocytoma (n = 1). We followed patients for a median of 12 months (range 3–18 months) with no in-field failures and were able to obtain encouraging toxicity profiles. Frameless stereotactic optically guided radiosurgery and radiotherapy provides a feasible and accurate tool to treat a number of benign and malignant tumors in children with minimal treatment-related morbidity

On Target: 2006 Annual Summary of Field Crop Insect Management Trials

Since its inception in 1984, the University of Illinois Insect Management and Insecticide Evaluation Program has provided the producers of Illinois complete and informative evaluations of registered insecticides and new chemical and transgenic tools for the management of insect pests in Illinois. It is our intention to provide scientifically sound efficacy data to aid the producers of Illinois in their insect pest management decision making.University of Illinois Extension and Department of Crop Science