NC_OLD205: Ecology and Management of European Corn Borer and Other Lepidopteran Pests of Corn

(Multistate Research Project)

Status: Inactive/Terminating

NC_OLD205: Ecology and Management of European Corn Borer and Other Lepidopteran Pests of Corn

Duration: 09/01/2005 to 09/30/2010

Administrative Advisor(s):

NIFA Reps:

Statement of Issues and Justification

More than 80 million acres of field corn (Zea mays), worth over $20 billion, is annually grown for grain in the United States. An additional 700,000 acres of sweet corn valued at $770 million also is grown annually. European corn borer (ECB), Ostrinia nubilalis, alone, among several stalk-boring pests, accounts for more than $1.85 billion in control costs and grain losses to field corn growers each year. In 2002, 90% of the fresh market sweet corn acreage was treated with one or more insecticide applications for a total of 479,000 lbs of insecticides applied. European corn borer also attacks many other important crops, such as, sorghum, small grains, cotton, potatoes, snap beans, peppers, and soybeans. The southwestern corn borer, Diatraea grandiosella, causes about $1 million in damage in the Western High Plains (Morrison et al. 1977). Other significant stalk-boring pests include stalk borer, Papaipema nebris, hop vine borer, Hydraecia immanis, potato stem borer, Hydraecia micacea, and sugarcane borer, Diatraea saccharalis. The long-term goal of our research is to develop sustainable ways to manage insect pests of corn. This is a high regional priority, and in the context of demonstrating sustainable practices, it also is an important national priority.

Previous committees extending back to 1950 have focused on the European corn borer and other stalk borers. In addition to stalk borers, we propose to address the other lepidopteran pests of corn, which would include lepidopteran larvae that feed primarily on corn leaves and ears. This is a natural progression for the committee since Bt corn for Lepidoptera affects most of these insects. Importance of the non-stalk-boring Lepidoptera depends on type of corn and area of the country. Corn earworm, Helicoverpa zea, and Fall armyworm, Spodoptera frugiperda, larvae consume leaves, tassels, silk and developing kernels of corn and are particularly important economic pests of sweet corn and popcorn. In southeastern U.S. losses attributed to corn earworm in field corn range from 1.5-16.7%; whereas sweet corn losses can be as high as 50% (Wiseman 1999). Black cutworm, Agrotis ipsilon, is the most devastating of the cutworm complex that attacks young corn in the Corn Belt. Significant loss of plants (>25%) and yields (2,900 kg/ha) are not unusual when infestations occur (Showers et al. 1983; Showers 1999). Western bean cutworm, Richia albicosta, increasingly is a pest of corn ears in the western Corn Belt; and sugarcane borer has emerged as an important pest of corn in Louisiana.

Since the 1996 commercial release of transgenic corn hybrids containing a gene from the bacterium B. thuringiensis subsp. kurstaki (Bt), a revolution in field and sweet corn insect pest management has been underway. This revolution is rapidly moving field corn pest management away from synthetic pesticides to plant-based toxin delivery systems coupled with low dosage commercial seed treatments. The use of Bt sweet corn varieties has been less dramatic but is important because of its higher insecticide inputs due to its higher cosmetic standards. The goal of this movement is to eliminate the need to store and handle toxic chemicals, eliminate the need for special insecticide application equipment, increase the ease of planting, and increase pest control effectiveness. Major seed technology companies continue to develop new transgenic crops for pest protection. These revolutionary changes in corn-hybrid technology are causing major adjustments in the agricultural community, pointing out major knowledge gaps and increasing the need to reevaluate past knowledge about European corn borer and other pests of corn. For instance, an insect resistance management (IRM) program was never a legal requirement for any pest management technology until the introduction of Bt-corn hybrids for protection against European corn borer. Publicity and attention to scientific advisors lead the U.S. Environmental Protection Agency (EPA) to require IRM programs on farms where Bt-corn hybrids are used; consequently, the concept that resistance could be prevented went from a theoretical possibility to an experiment in-progress.

During 2004, 32% of all field corn hybrids planted in the Unites States contained a Bt gene. The area planted to Bt sweet corn has been lower, under 5%. Stacked gene field corn hybrids that have multiple modes of action to prevent injury from both European corn borer and corn rootworm were commercially released in 2004. These stacked hybrids could further increase the percentage of acres planted to Bt corn for European corn borer management since corn rootworm in some areas of the Corn Belt is considered a more important pest than European corn borer. Other new genetically enhanced hybrid types may enter commercial markets within the next five years. As the level of adoption increases, particularly in the western Corn Belt, the potential for resistance evolution increases. Research conducted by this committee has been used to develop models predicting the rates of resistance evolution and to investigate the role of refuge structure in preventing or minimizing resistance evolution. These models suggest that a minimum refuge size of 20% is required to slow resistance development in this species. Although these models were constructed using the best information available on the pest's biology and known population genetic relationships, a number of assumptions had to be made about pest biology for the simulations to be completed. These assumptions need to be tested and research conducted to move them from assumptions to quantified variables with known uncertainty. In addition to addressing information gaps needed to improve these models, information is needed on the economics of this new technology, and the non-target impacts of Bt-corn toxins. Eliminating these information gaps forms the basis for several objectives of the project.

Economics. Corn growers must weigh yield losses due to corn insect pests against the costs of control. Additionally, with Bt technology they must consider the costs of implementing IRM programs. The economic component of this project will provide growers with the tools to make these decisions plus identify economic incentives that encourage growers to comply with IRM refuge requirements. A grower does not manage the European corn borer in a vacuum, but as part of a larger pest management framework. Growers can choose between Bt-corn hybrids that provide protection from European corn borer, black cutworm, corn rootworm, or a combination of these products. Plus, whether they choose to use the Bt technology or not, they need to decide whether to use seed treatments for soil insect pests, which maturity of corn to plant, and when to plant. To make these decisions the grower must understand how pests influence the potential economic value of each product or practice. During the last project we developed a set of tools that can help address questions about tactical implementation of IRM programs and direct research to assess economic value of new and competing technologies. To make a hybrid selection decision the farmer must understand the potential economic value to Bt corn for European corn borer protection and his/her need to managed other pests. The average net benefit for Bt corn varies across the landscape because of changing synchrony between European corn borer tunneling and plant growth stage. For example, the 33-year average net benefit in northern Illinois (based on simulations) varies from 0 to $4.00 per acre, while in southern Illinois the average net benefit varies from $4.00 to $8.00 per acre. However, in areas infested by the southwestern corn borer, like southwest Kansas and the panhandles of Texas and Oklahoma, the per acre value of Bt corn ranged from $12.49 to $34.60. This is well above the technology cost of ca. $5.25 per acre. The value of a pest management practice also is influenced by year-to-year climatic changes. The net returns of using Bt corn over the past 33 years at one location in Iowa would have ranged from just under $7.00 per acre to -$1.50 per acre. Over the same period, the net returns at one location in Pennsylvania would have ranged from $4.50 per acre to -$2.00 per acre; and in 24 of the past 33 years growers would have received a positive return. New tools that help growers assess the economic value of Bt corn for European corn borer is the first step in helping them determine which technology will serve their needs. Because lepidopteran pests and their behavior and agricultural production practices differ across the Corn Belt, regional economic analyses are required to obtain a complete understanding of producer behavior, factors that drive this behavior, and policies that may modify this behavior in positive ways. These new tools now need to be widely verified and made available to economists and growers for regional analyses of pest management and IRM program economics. The economic benefit to growers using Bt sweet corn has also been substantial. In areas of high insect pressure by the lepidopteran complex, the use of foliar sprays has been reduced from > 15 sprays to only one or two.

Ecology and Genetics. During the past 10 to 15 years, U.S. agriculture has been developing and implementing transgenic corn varieties, alternative cropping practices, biological control, and landscape-level planning to achieve effective insect pest management. These developments are transforming management strategies of stalk-boring pests of corn. Regional research and extension efforts are necessary if benefits are to be optimized. The dramatic management of insects via transgenic plants, however, has many scientists (and growers) concerned about high selection pressure associated with broad exposure to these toxins and the subsequent adaptation by pest insects (Gould 1988a, b; Mason et al. 1996). Although there have been no cases of insects having developed resistance in the field to Bt plants (Tabashnik et al. 2003), there is a continuing need for research to address resistance problems in stalk-boring Lepidoptera (Gould 1989) and for outreach to transfer research results to the public. There is a need to balance the desire for maintaining long-term durability of this technology with logistical and economic short-term expectations for effective and uniform management.

Resistance management for transgenic corn depends on a refuge strategy complemented by high expression of Bt protein in the plant (USEPA 2000). However, there is continuing discussion concerning the size and placement of non-Bt refuges. Current risk assessment models have been based on incomplete biological information, particularly on dispersal and genetics, perhaps leading to unnecessary constraints as to how corn growers are permitted to use this technology. Several computer-based models have been developed that provide predictions of likely rates of resistance evolution, but all still lack some level of realism that could change how we structure and implement IRM programs. Work with the model system of the diamondback moth, the only insect that has developed resistance in the field to Bt proteins, and Bt crucifers expressing Bt proteins has demonstrated the need for refuges for Bt plants (Shelton et al. 2000, Tang et al. 2001). Additional work with stacked Bt genes, as currently used in some Bt-cotton varieties, has shown this strategy effective for delaying the evolution of resistance (Zhao et al. 2003). Past work by this committee has provided a major part of the research knowledge required to design the IRM program for European corn borer. But, the committee also realizes that two critical key questions continue to need further research to better predict the rate of resistance evolution: the rate and distance of adult movement between fields and the resistant allele frequencies in European corn borer populations. We also continue to lack a landscape perspective on how environmental factors, such as crop growth stage and year-to-year climate variation can influence the pest's movement. During past NC-205 projects, European corn borer developmental models were developed and expanded to provide 1km2 resolution landscape maps of European corn borer development and corn development. These models coupled with population genetic models can further help the committee gain a better understanding of how topography and weather across the nation influences the timing and movement of European corn borer males and females. Simulation models also will help answer questions such as will area-wide IRM programs work and can the size of the refuge be reduced to increase value returned to the farmer through use of the technology. New biological information will improve the accuracy and precision of resistance management models. Improved models will allow us to investigate the consequences of reducing refuge size and of optimizing refuge placement across variable agricultural landscapes.

European corn borer is not a single, randomly mating population even though it occurs throughout North America east of the Rockies. Clarification of population structure and genetics is necessary to model the likelihood of resistance development and to design resistance management strategies. More information for this species is needed on geographic patterns of genetic variation, voltinism, pheromone blend, sensitivity to B. thuringiensis, and the influence of host plants on genetics and population structure to develop spatial-temporal models of gene flow within an agricultural landscape. Also, little is known of the population structure and genetics of other stalk-boring insects. Acquiring such information will increase our understanding of the spectrum and mechanisms of resistance, genetic basis for resistance, status of cross-resistance, and stability of resistance.

Sugarcane borer has emerged as a common pests on corn in some areas in Louisiana (Castro et al. 2004). Field collections in 2004 showed this insect was the dominant corn borer species, counting 85% of the total collection during 1st and 2nd generations in Louisiana. Laboratory bioassays have demonstrated that sugarcane borer is much less susceptible to Bt toxins in Bt corn compared to European corn borer. There are questions concerning whether the high-dose strategy is a valid approach for this pest.

Natural Enemies. Enhancing natural control is the first line of protection in integrated pest management (IPM). Even though the basic biology of most of the natural enemies associated with corn has been described, the effects and value of these natural enemies in various corn cropping systems and landscapes is not well enough understood to reliably implement. Key information gaps include understanding patterns of variation in natural enemy communities associated with landscapes dominated by corn and soybeans, and more diverse landscapes. Gaps extend to adequately quantifying the role of natural enemies in resistance evolution, improving the use of augmentative biological control agents, and characterizing the economic value of natural enemies in contemporary cropping systems. We hypothesize that 1) natural enemy abundance and diversity in corn may be influenced by natural enemies of pests in soybeans, especially in areas with high populations of soybean aphid, Aphis glycines Matsumura; and 2) some predators and host-specific parasitoids may have such a limited food source that only those with superior host-finding behavior will persist in landscapes dominated by Bt corn.

Non-target Effects and Pest Replacement. Another major adjustment for the agricultural community (growers, seed technology industry, ag-input dealers, extension and researchers) has been the need to more fully understand the impacts of gene-based technologies on non-target organisms and the possibility of human or livestock health effects. Never before in the history of pest management has there been as much pressure placed on the scientific community by the general public to understand the biology of pests and the ecological impacts of new pest management tactics. This is a major problem that must be addressed because no one truly understands how to determine whether a new technology will cause important changes to biodiversity and the functionality of an ecosystem. There is a general lack of knowledge about how field-corn pest management influences biodiversity, in both agricultural and nearby non-agricultural ecosystems. Members of this committee have contributed knowledge about the non-target impacts of transgenic crops, but no one has developed a sound way of judging how much and to what extent change in biodiversity is important. Therefore, research to help understand how ecosystems function, and how new practices are changing the biodiversity in and near cornfields are badly needed.

Management strategies with Bt corn to control European corn borer and southwestern corn borer may have direct and indirect effects on non-target pests, and other organisms that could result in positive, neutral or negative impacts (Ostlie et al. 1997, Schuler et al. 1999). The seed-treatment technologies associated with Bt corn to extend the spectrum of insect control have been shown to have non-target impacts as well. Secondary corn pests, such as corn earworm, fall armyworm, western bean cutworm, dusky sap beetle, Carpophilus lugubris, Banks grass mite, Oligonychus pratensis, and two-spotted spider mite, Tetranychus urticae, are either tolerant to or not affected by the endotoxins expressed in Bt corn. With the exception of spider mites, these organisms may prove to be more problematic with the use of Bt corn and the reduction of broad-spectrum insecticides (Dively et al. 1999). Spider mites are an exception because problems with them are often exacerbated by insecticides. The increased use of Bt corn actually could reduce the need for miticides. Non-target pests require a new set of pest management practices that will need to be compatible with strategies used to delay European corn borer resistance to transgenic corn. Possible effects of transgenic corn on non-target organisms will be investigated with laboratory and field-based studies. This has been high priority research, since questions arose about possible effects of Bt-corn pollen on monarch butterflies, Danaus plexippus (Losey et al. 1999, Hellmich et al. 2001, Stanly-Horn et al. 2001, Sears et al. 2001).

IPM Education, Sustainable Pest Management, and Outreach. A major adjustment facing the agricultural community is the need to move toward more sustainable production systems. Sustainability means a lot of different things to different groups and individuals, but for the purposes of this project its definition will be to develop insect management programs that are compatible with the economic, environment, health and social needs of both the agricultural and non-agricultural community. The major focus of this project on new genetically enhanced hybrids as a pest management tool, must be balanced with research that increases our understanding of how field crop and nearby non-agricultural ecosystems are affected by insect management efforts. We must also focus on research that is more systems oriented to determine how biodiversity can be maintained through management of fencerows and other non-agricultural areas. These efforts will include studies to investigate and improve conservation biological control of lepidopteran pests of corn and cultural practices. Growers rely on a variety of sources for making decisions regarding implementation of traditional and transgenic pest management technologies. Corn hybrids with Bt resistance to European corn borer now can include additional quality traits such as herbicide tolerance, and corn rootworm resistance. Soon transgenic corn could include enhanced traits related to nutrition and pharmaceutical, fuels, etc. To help growers integrate these inputs and options into practical pest management programs, the results of this project must be made available in a timely fashion for use by policymakers and be packaged as unbiased recommendations for the agricultural and public sectors. It is also important to obtain feedback from growers about their constraints and willingness to adopt resistance management practices as part of their European corn borer suppression program. This input is needed to balance short-term logistical and economic expectations for effective management with the desire to maintain long-term durability of the transgenic technology.

Overall. Collectively, a multi-state approach to researching these knowledge gaps and implementing effective technology transfer strategies is appropriate and necessary. As shown above, the geographic location plays an important role in the economics of Bt-corn technology or other technology value and how the pests interact with other organisms in their environment. It is this significant spatial effect of population and community dynamics that make a regional project necessary. Lack of site-specific knowledge has led to fears by the general public about the potential environmental and health risks associated with broad-scale adoption of new technologies, particularly when those technologies are genetically modified. Controversy about non-target effect of transgenic technology, particularly the potential effect of Bt corn on non-target organisms and human health, has fueled public concerns. These fears, whether unfounded or real, have the potential of forcing legislation to ban or slow the introduction of genetically modified crops. Answers to questions regarding Bt-corn impacts (positive, negative or none) on these non-target organisms should help focus the public's perception of this technology and where benefits are clearly demonstrated, allow growers to gain the dramatic pest control advantages provided by this and future technologies. Identifying acceptable methods of determining how changes in biodiversity caused by these technology influence functionality of ecosystems will blaze the trail for how to accomplish effective future risk assessments of other new technologies or interventions by humans.

These multi-state plans will be a model for the development of science-based resistance management programs and risk assessment for other pests, other crops, and future crop protection technologies. Our efforts will provide fundamental advances in the knowledge of pest ecology, genetics, and evolution. Our work will continue to provide scientifically-based assessments essential to the policy decision-making process and should help to increase the public's acceptance of these technologies and to identify potential negative impacts that need further investigation. Our work also will help lead to more sustainable pest management systems for lepidopteran pests of field corn. We also view it as part of our responsibility to provide unbiased, scientifically-based information that fosters subsequent investment in promising novel approaches to pest management. There is ample evidence that the NC-205 research group has the skills, collaborative working relationships, and commitment to provide the missing biological information and to incorporate this new information into current resistance management models.

Related, Current and Previous Work

A CRIS search indicates that there are 36 active projects related to corn insects. Of these NC-205 members are involved with 23 projects, and members of NCR-46 (Rootworm technical committee) are involved with 13 projects. USDA-ARS Units in Tifton, GA (Crop Genetics and Breeding Research Unit), and Stoneville, MS (Southern Insect Management Research Unit) conduct research on corn pests; and an ARS Unit in Manhatton, KS (Biological Research Unit) conducts research related to stored grain insects, which includes lepidopteran pests. With the various sustainable agriculture efforts, based largely on principles of IPM, there are a few projects with one or two insects, but we know of no efforts currently engaged in a regionally coordinated effort focused on the genetics, voltinism, host range, natural enemies, and management of lepidooptran pests of corn. NE-124, Genetic Manipulation of Sweet Corn Quality and Stress Resistance, has little overlap with NC-205. Five regional projects currently involve biological control of insects: W-185, Biological Control in Pest Management Systems in Plants; S-265, Development and Integration of Entomopathogens into Pest Management Systems; S-267, Biological Control of Selected Arthropod Pests and Weeds; SRDC-99-06, Development and Evaluation of Entomopathogens and Their Toxins for Control of Insect Pests; and NCR-125, Arthropod Biological Control. None of these projects deal with the entire array of natural enemies (i.e., predators, parasites, and diseases) in corn for even a single insect herbivore. Our committee has established excellent cooperative interactions with these biological control committees. NC-205 will continue to deal specifically with natural enemies of stalk-boring Lepidoptera and to coordinate efforts with other regional projects investigating biological control.

NCR-46 is a multi-state committee focused on the biology and control of corn rootworms. We have held overlapping meetings with this committee and industry for the past several years to share ideas in the rapidly developing area of transgenic corn. Transgenic corn became commercially available for corn rootworm control in 2003, thus it will be essential to continue to coordinate activities with NCR-46 members; particularly with the commercial release of stacked hybrids in 2004. Growers will need consistent recommendations from both groups. Several members of NC-205 attend NCR-46 meetings regularly, so effective coordination is already the norm.

We know of no other coordinated research program that is focusing on the genetic differences among pest insect populations with taxonomic, chemical, and functional traits of resistance management. NC-94 is developing a multi-state spatial analysis system of thermal unit accumulation reporting, which we may find useful in areawide management of European corn borer, although this committee has already developed more sophisticated high-resolution (1 km2) landscape maps for European corn borer development in collaboration with a private weather data company, ZedX, Inc. Similarly, the role of weather in long-range movement of insects (NCR-148, NC-226) is of interest to NC-205 members studying management tactics in Lepidoptera.

Initial research by the committee on the economics of the value of Bt corn was deterministic (Calvin 1995) or focused on a specific location (Hyde et al. 1998, 1999, 2003, Onstad and Guse 1998). The economic evaluation of insect resistance management to synthetic pesticides has been limited (Hueth and Regev 1974, Taylor and Headley 1975, Regev et al. 1976, 1983). This early work offered some insight into the management of insect resistance to transgenic crops such as Bt corn, but economists and entomologists working with NC-205 conducted additional work to help guide current regulatory policy for using a refuge strategy to manage European corn borer resistance to Bt corn (Hurley et al. 2001, 2002; Onstad and Guse 1999). The results of this effort are simulation models that help evaluate the merits and deficiencies of alternative refuge scenarios based on economic and ecological indicators. This work was instrumental for developing expertise used to design and assess resistance management policies for new transgenic crops active against other insect pests. An on-line Bt-corn Economic Evaluation Tool (BET) is nearing completion, which provides site-specific evaluations of Bt-corn economic value Numerous members of this committee helped in the development of this tool, which incorporates years of research results from this committee. The information provided at the site is the result of simulating how year-to-year climate differences (33 years) influence the synchrony of corn development and timing of injury from European corn borer at a 1 km2 spatial resolution. Further work is currently under way to assess the economics of alternative refuge configurations.

Growers currently have little economic incentive to plant the recommended acreages of non-Bt-corn refuge. Though industry sponsored surveys find high levels of compliance among growers planting more than 200 acres of corn (NCGA 2003), Jaffe (2003) uses USDA-NASS data and finds relatively low implementation of refuge requirements in several states, as do Buttel et al. (submitted) in Minnesota and Wisconsin. Interestingly, BET model simulations suggest that the average net benefit to Bt corn is lower in this area, than many other areas with lower levels of adoption. This suggests that grower attitudes may drive adoption levels more than true need. The U.S. EPA (2000) requested expert opinion on the ability of education, fines, refuge insurance, and sales incentives to encourage grower compliance. In response, Mitchell et al. (2003) analyzed the ability of subsidies, fines and refuge insurance to ensure grower compliance and found that because the risk benefit of ECB insurance is small, subsidy or fine schemes are likely more practical. Recently the EPA required Bt corn registrants to develop a more active program to ensure compliance and the industry responded with the Compliance Assurance Program (ABSTC 2003). NC-205 members are currently conducting surveys measuring farmer compliance and attitudes and are actively developing and assessing compliance programs for Bt corn.

Growers use inputs such as pesticides, fertilizers, and transgenic crops to manage risks (Ostlie et al. 1997; Mitchell and Hennessy 2003). Hurley, Mitchell and Rice (2004) examined how growers use Bt corn to manage risk and found that growers generally use Bt corn to take on more risk and increase their corn acreage. Currently, NC-205 members are examining how Bt corn and crop insurance interact. Does Bt corn increase or decrease farmer incentives to buy crop insurance? How should insurance premiums change, if at all, when a farmer plants Bt corn? Also, members are using field data to carefully examine whether a yield drag exists for Bt corn, since Elmore et al. (2001) have demonstrated a yield drag for Roundup Ready soybeans.

Information on adult European corn borer dispersal, particularly of unmated females, is critical for predicting mixing between possible Bt-resistant and susceptible adults (from refuge), for estimating gene flow between these two populations, and for refuge design and placement. In 1996 and 1997, mark-recapture studies examined local dispersal of bivoltine European corn borers from release sites within cornfields (Hunt 1999). Two important findings were that corn phenology affects adult European corn borer dispersal and that unmated female European corn borers do not disperse far before they mate. Specifically, taller corn (1st flight of European corn borers) and early reproductive-stage corn (2nd flight) reduced mean dispersal distance, and 95% of all recaptured, unmated female European corn borers were trapped within 500 m of their release site. Trapping began at the field edge, so although this information gives a general idea of where mating occurs; it lacks precision and does not provide information on movement and behavior within the field. Also, in all mark-and-recapture studies, recovery rates are always low, so one never knows how far the 90 to 99% of uncaptured individuals moved. Therefore, studies conducted in 1998 examined within-field dispersal of adult European corn borers, focusing on unmated females (Hunt 1999). Within-field dispersal was significantly different between European corn borers released in irrigated, high plant-density corn compared with those released in non-irrigated, lower plant-density corn. The irrigated, high plant-density fields had higher recapture rates, particularly near the release sites. Seventy-five percent of the unmated females were recaptured at traps nearest their release site, indicating these adults moved very little upon emergence. Few unmated European corn borers were recaptured within non-irrigated, lower plant-density corn. The effects of irrigation and plant density could not be separated in this study.

Dispersal studies in Kansas have demonstrated that European corn borers and southwestern corn borers dispersed randomly in irrigated corn fields (Qureshi 2003). The recapture rates were 0.2 to 9.9% for male and 0.08 to 4.4% for female European corn borers and 2.0 to 17.9% for male and 0.0 to 4.4% for female southwestern corn borers. This work suggests that males of both species disperse extensively, but that females disperse less extensively, particularly the female of the southwestern corn borer. In this study feral European and southwestern corn borers dispersed freely into the large irrigated Bt corn fields.

Many NC-205 members participated in a consortium of scientists to address the monarch butterfly and Bt-pollen issue (Losey et al. 1999). Their efforts led to the publication of five papers and a cover in the Proceedings of the National Academy of Sciences (Oberhauser et al. 2001, Pleasants et al. 2001, Hellmich et al. 2001, Stanly-Horn et al. 2001, and Sears et al. 2001) and two follow-up papers (Dively et al. 2004 and Anderson et al. 2004) that showed the impact of Bt corn on monarch populations was negligible. This was one of the most controversial and polarizing issues to face agricultural scientists in recent memory. These studies and others generally show that Bt crops have little or no impact on non-target organisms (Sims 1995, Dogan et al. 1996, Donegan et al. 1996, Pilcher et al. 1997, Yu et al. 1997, Riddick and Barbosa 1998, Acciarri et al. 2000, Al-Deeb and Wilde 2003, Al-Deeb et al. 2003, Jasinski et al. 2003). Other studies indicate Bt crops promote greater populations of non-target organisms relative to other pest management approaches (Orr and Landis 1997, Riddick et al. 2000, Reed et al. 2001) and even greater predation rates on European corn borer (Musser and Shelton 2003). Studies indicating "no effect," however, may simply be unable to detect differences among treatments due to one or more aspects of their design (i.e., have low statistical power). Recent EPA scientific advisory panels note several specific problems with field studies that reduce the likelihood that any real effects of Bt on non-target groups, adverse or beneficial, will be found (USEPA 2001). Critical issues that influence the ability of a field trial to detect possible effects of Bt crops include the selection of appropriate taxa, replication of treatments, plot size, and data analysis. Potential risks of Bt toxins must be put into proper perspective and balanced with the positive impacts of Bt corn. Also these new technologies must be compared with traditional insect control practices so that environmentally-safe methods can move forward. Currently, several NC-205 members are cooperating on studies to address these questions.


  1. Assess economic and sociological factors that influence the management of lepidopteran pests of corn.
  2. Investigate ecological, evolutionary, genetic and behavioral factors that impact pest populations, including resistance management
  3. Conduct research to improve conservation and augmentative biological control of lepidopteran pests of corn.
  4. Assess impact of insect pest management strategies on non-target organisms.
  5. Conduct research and disseminate information related to sustainable management of lepidopteran pests


Objective 1. [Paul Mitchell, Terry Hurley (coordinators), Jeff Hyde, Dennis Calvin, David Onstad, Dave Andow, Larry Buschman, Tom Hunt]

Economic analyses will identify economic, demographic, and societal factors affecting the adoption of Bt corn and implementation of resistance management requirements using farmer surveys and bioeconomic models parameterized with field data. Due to regional differences in corn lepidopteran pests, a regional evaluation approach will be used. Economists and sociologists in Minnesota and Wisconsin will conduct surveys of farmer attitudes concerning transgenic crops and implementation of refuge requirements. These results will be used to develop more accurate models of farmer behavior to incorporate into existing insect resistance models developed in Minnesota and Illinois. In addition, these results will be used to assess the effect of education efforts, crop insurance, and the new Compliance Assurance Program on farmer attitudes and implementation of refuge requirements.

Economists in Wisconsin and Minnesota will work with entomologist in Iowa, Minnesota, Illinois, Nebraska, Texas, Pennsylvania and Kansas to develop different compliance assurance programs and assess their efficacy as methods to ensure that growers comply with resistance management requirements. The goal will be the development of a compliance program to effectively ensure farmer compliance, but balance the costs and benefits of the program to the seed companies, growers, and society.

An economist in Wisconsin and entomologists in Texas and Kansas will use field trial data to develop a yield-loss model for southwestern corn borer that includes damage from stalk tunneling and lodging. Their previous model did not include losses due to lodging, which often can far exceed losses form stalk tunneling. The resulting damage model will be used to update economic assessments of the value of Bt corn in Kansas and Texas.

Wide-scale site-specific analyses of Bt-corn economic value will be simulated using the BET model for use by economists and entomologist in Pennsylvania, Iowa, Nebraska and other states that wish to collaborate. The BET model was developed using USDA Risk Avoidance and Mitigation Program (RAMP) funding and was a collaborative effort between Pennsylvania, Iowa, Nebraska and a private weather data firm, ZedX, Inc. of Bellefonte, PA. The BET model incorporates knowledge about the developmental rates of European corn borer, corn developmental rates by relative maturity, high-resolution spatial interpolation of temperature and other weather data, and calculations of average net benefit. The BET model provides site-specific predictions of the expected proportional loss per first and second generation European corn borer larva, the average net benefit to a technology, and the probability of a positive return to the technology (number of years out of 33 or a proportion). In generating these values, the model spatially interpolated 33 years of temperature data for every 1 km2 in the eastern U.S. and southern Canada. These values then serve as inputs into the European corn borer and corn development models. Output from these models is then used to calculate the economic benefit of a technology. Although, developed to evaluate the economic benefit of Bt-corn technology, BET can be used for any new European corn borer management technology. Theoretically, a similar model could be developed for southwestern corn borer and the economics analysis linked. The BET model also provides a template to evaluate which planting date by relative maturity combinations are likely to provide the best returns to investment for growers at a given geographic location. Analysis using the model also will provide geographic boundaries where using the technology will provide an economic return to investment. During this project, a univoltine model will be developed and the North American boundaries of univoltine, multivoltine and co-occurrence of race will be predicted and used to improve economic analyses.

Objective 2. [Doug Sumerford, Dennis Calvin (coordinators), almost everyone]

Pennsylvania will plant corn on several planting dates in a hexagon shaped field, with three or four corn planting dates radiating out in all six directions. Meteorology data of relative humidity, temperature and wind direction will be recorded in the plot. Over the growth season, red and blue-dyed European corn borer adults will be released at the center of the area and the number of colored eggs recovered in each plot will be recorded. Pheromone traps will be monitored for dyed males at increasing distance from the release site. Data from this study will be used to determine the role that plant growth stage, distance, and direction play in the dispersal and oviposition site selection of female European corn borer. Based on these data, a landscape model of European corn borer oviposition patterns will be constructed to spatially distribute eggs across fields between generations. The large scale (landscape) predictions of adult movement for oviposition will be verified by tracking egg laying in corn fields planted on different dates and relative maturity. The observed data will be compared to model predictions.

In Louisiana, colonies of sugarcane borer will be established from field collections across the major corn growing areas in Louisiana, Mississippi, Texas, and Arkansas. Larval susceptibility to Bt proteins extracted from Bt-corn plants will be determined in laboratory bioassays. Bt resistance allele frequency in sugarcane borer populations across the four states will be estimated by using a novel F2 screen technique developed at LSU Agricultural Center, Baton Rouge, Louisiana. Results from the F2 screens will determine if Bt resistance allele frequency in sugarcane borer populations is low enough (e.g. < 0.001) to qualify the requirement of the "high dose/refuge" strategy. Any confirmed highly resistant individuals that can survive and complete larval development on commercial Bt-corn plants from the study will be used to establish resistant colonies for future studies.

In Pennsylvania, laboratory and field studies will continue to determine how the relative proportions of the population that is univoltine and multivoltine vary over years. Laboratory studies will be conducted to compare life history traits of the two major races of European corn borer and determine if developmental rates are heritable. Using information generated from these studies, a univoltine-development model will be developed to estimate likely geographic range and areas of co-occurrence with multivoltine races.

Illinois and Minnesota will use the information generated from these ecological studies to improve the realism of their models and generate predictions for use in designing IRM implementation strategies. These models also will serve as an integrating template for understanding population dynamics of the pest when new technologies become available.

Research is underway in Iowa and Pennsylvania to develop a method for on-farm within-field mapping of ECB damage that combines Bt/non-Bt strip planting with yield mapping. The premise is that insect damage leading to yield reductions within non-Bt strips can be identified through paired comparisons with yield data from undamaged corn in flanking Bt strips. If areas of high ECB damage are temporally stable, the grower can target his/her Bt corn to those locations most likely to provide a return on investment.

Research is planned to characterize the geographic size of ECB populations and metapopulations in the central Corn Belt, which will permit development of a resistance monitoring system at an appropriate geographic scale. Attainment of this goal will be realized through both spatial and temporal estimates of gene flow. Variability in microsatellite markers and cadherin restriction fragment length polymorphism (RFLP) markers will be analyzed from ECB sampled at 80-km intervals along two 720-km transects (MN-IA-MO and NE-IA-IL), and two sets of 16-km intervals nested in the east-west transect, to determine genetic differentiation and estimate gene flow between all pairs of locations. In a second related experiment, microsatellite and cadherin RFLP markers will be used to monitor genetic change over two years at nine of the 80-km-interval sites in Iowa.

Research to gain insight into the genetic basis for voltine types is ongoing in Pennsylvania and Iowa. Classical genetic research in Pennsylvania has found heritable variation for degree-day accumulation that is also correlated with voltine ecotypes. Crosses will be established to map regions of the ECB genome associated with degree-day accumulation to better understand the inheritance of traits affecting voltinism. Eventually these data can be included into discussions of the geographical patterns of voltinism.

Researchers in Nebraska, Kansas, Iowa and Minnesota will establish and maintain colonies of resistant European corn borers. The resistant colonies will be developed by selection on diets containing various Cry proteins. Purified insecticidal crystal proteins (Cry1Ab, Cry1Ac, Cry1F, and other Cry proteins) and transgenic Bt plants, based on transformation events encoding for the same Cry toxins, will be used in these experiments. These states will investigate mechanisms of resistance and cross-resistance. Studies will include comparisons of the level and profile of midgut proteinases and the affinity and density of Bt binding receptors(s) in midgut brush border membranes between Bt-susceptible and resistant strains of European corn borer. Nebraska will develop the methods to establish and maintain resistant colonies of southwestern corn borer.

Another goal of proposed research in Iowa and Nebraska is to use molecular markers and linkage maps to mark regions of the ECB genome associated with Bt-resistance traits. The marker-trait associations will be used to extend characterizations of the genetic architecture of Cry1Ab resistance found in classical genetic studies of three colonies of ECB. The final product of the research will be isolating and examining what expressed resistance genes are actually linked to our markers ("gene characterization"). Three colonies of resistant ECB with moderate levels of Bt resistance. Knowledge obtained from these studies can be applied to cross resistance issues as well as improving the efficiencies of resistance monitoring methods. Because we do not currently have a physical map for ECB, crosses are designed to allow comparisons to be made among the three resistant lines, and also to maximize linkage disequilibrium between markers and regions of the genome associated with resistance. Our work will use three types of marker loci: (1) amplified fragment length polymorphisms (AFLPs), (2) microsatellites, and (3) cadherin loci. The AFLP markers will be the primary means of saturating our linkage map.

Objective 3. [Dave Andow, Les Lewis (coordinators), Galen Dively, Chris DiFonzo, Eileen Cullen, Michael Hoffman, John Losey, Tony Shelton, Rob Wiedeman, Phil Glogoza]

Michigan, Maryland, and Minnesota will sample some of the surrounding habitats and non-corn crops to evaluate how the natural enemy communities use the entire landscape. Minnesota will focus on how the predator complex uses small grain crops, especially wheat and barley. These natural enemies will be sampled with beat samples to characterize colonization, emigration, and reproductive response of coccinellids and anthocorids in the small grains. Maryland will examine the influence of warm- and cool-season riparian grass buffers enrolled in conservation programs on natural enemy communities. Michigan and Maryland will experimentally manipulate landscapes by selective addition of landscape elements, such as floral or microhabitat diversity, and measure movement of natural enemies.

Michigan, Minnesota, and Ohio will conduct surveys in landscapes where European corn borers have historically been pests or not, and Iowa, Minnesota, South Dakota, Missouri, and Texas will conduct natural enemy surveys associated with Bt corn and non-Bt corn prior to and after the widespread adoption of Bt corn. All sites will map the cropping systems and land use patterns in a 1-mi radius surrounding the surveyed target fields, and will count natural enemies on at least 100 randomly selected corn plants at 2-week intervals beginning in early to mid-June through August. To provide more detailed patterns of abundance and diversity, Michigan and Minnesota will conduct more intensive sampling, as often as twice a week. Michigan, Minnesota, Iowa, and Texas also will collect at least 100 corn borer larvae during the first and second generation and evaluate parasitism rates by specialized insect parasitoids, focusing on Macrocentrus grandii, Eriborus terebrans, and several tachinid species.

Minnesota will conduct experiments to determine if natural enemies of larval European corn borers have the potential to delay or accelerate resistance evolution (Gould et al. 1991). Outbreaks of resistant larvae in a Bt cornfield will be simulated by planting non-Bt plants in small patches and inoculating these plants with European corn borer. Approximately 5,000 female M. grandii will be released in these fields to determine if they key into these incipient outbreaks or avoid them. In addition, by using European corn borer larvae with genetic differences in developmental rate, these experiments will test whether the predicted developmental delay in resistant insects will result in higher mortality from natural enemies.

Illinois and New York will continue efforts to evaluate known natural enemies of other stalk-boring pests for their potential use against European corn borer and southwestern corn borer. Augmentative releases of T. ostriniae will be conducted to evaluate parasitism and potential yield benefits. Work will evaluate ecological and physiological compatibility of exotic parasitoids from other stalk-boring insects (e.g., T. ostriniae from Ostrinia furnacalis, several Cotesia spp. from Old World Chilo spp.). The specificity of these parasitoids for stalk borers in corn will be evaluated to characterize the potential environmental risks of introducing these species. As they become available, other crambid and pyralid species will be tested as potential hosts, as well as rare and charismatic species of Lepidoptera. Additional species will be assessed as potential candidates for introduction (Wiedenmann and Smith 1997).

Objective 4. [Galen Dively, Rick Hellmich (coordinators), Dave Andow, Mark Sears, Billy Fuller, John Losey, Bill Hutchinson, Tony Shelton, Larry Bledsoe, Larry Buschman]

Field studies will be conducted in Maryland and Iowa to develop protocols for non-target sampling, including plot size, appropriate taxa, replication, and sample timing in Bt corn. Also, existing data sets from industry groups and other NC-205 members will be combined in order to make the analyses and resultant protocols more robust and to increase statistical power. Rearing techniques and identification methods also will be developed for unresolved larval forms of non-target beetles. These studies will provide improved methods to detect differences between Bt-crop production and alternative management practices.

Field studies will be conducted to develop management tactics and decision support systems for non-target pests that survive Bt-corn exposure. Maryland, Delaware, Virginia, Illinois and Minnesota will conduct replicated plot experiments of multiple treatment regimes initiated at various plant phenology stages to determine the optimal number and timing of insecticide applications required to manage lepidopteran survivors of Bt sweet corn and dusky sap beetle. A census of insect stages infesting the ear will be taken at each plant stage to determine when lepidopteran larvae recover from B. thuringiensis intoxication and enter the ear. Cost-benefit analyses will be conducted to evaluate the economic feasibility of Bt sweet corn under various target and non-target pest risk scenarios and technology costs. Maryland will evaluate sweet corn hybrids with varying ear tip coverage and husk characteristics and determine the effects of these features on ear-invading insects. Studies will continue in New York to evaluate the effect of various insect control strategies, including Bt sweet corn, on control of European corn borer and its the natural enemy complex.

Studies are planned to determine the impact of Bt corn on local suppression of European corn borer and other lepidopterans in host plants grown nearby. Corn serves as a nursery for many lepidopteran pests and produces a major portion of the late summer populations of European corn borers and corn earworms. Thus, as Bt corn acreage increases, local suppression of these pests will likely occur. This hypothesis will be tested in Maryland, and North Carolina where a geostatistical approach of grid sampling infestations of corn earworm will be used to quantify the spatial dependence of corn earworm populations between corn and soybean fields. This study will provide information for landscape modeling to determine if Bt corn indirectly reduces the risks of corn earworm in soybean on a local scale. Expected outcomes of both studies will include recommendations on the amount and spatial arrangement of Bt-corn acreage required on farms to achieve localized suppression, thus reducing insecticides beyond the target area. Maryland will also conduct a bioclimatic analysis of 32 years of blacklight trap data to indirectly assess whether adoption of Bt corn has had an impact on European corn borer and corn earworm moth activity, particularly during the last broods of the growing season.

Objective 5. [Mark Sears, Eileen Cullen (coordinators), Dennis Calvin, Greg Cronholm, Pat Porter, Chuck Mason, Randy Higgins, Phil Sloderbeck].

A major focus will be to educate growers, cooperative extension personnel, and private consultants about how and when to use genetically enhanced corn hybrids as an insect pest management tool. Key to this process is growers' perceptions of the relative advantage, compatibility, complexity, and observability (Rogers 1995) of a new idea, practice or technology. With the 2003 release of transgenic Bt-corn rootworm hybrids, 2004 availability of stacked gene hybrids with activity against European corn borer and corn rootworm, and ever-evolving market segregation, insect resistance management, and public opinion issues associated with biotechnology, growers will continue to be in need of timely, science-based, unbiased recommendations for use of transgenic insect pest management information. Equally important will be uniform recommendations on the use of transgenic corn hybrids within the context of integrated pest management and continued dissemination of research information on non-transgenic insect control tactics.

Ontario, Texas, Wisconsin, Pennsylvania and Delaware will facilitate communication between growers, consultants, seed industry, extension personnel and researchers who deal with issues around pest management in corn. Such a working group in Ontario was instrumental in developing a consensus report titled, Responsible Deployment of Bt Transgenic Corn in Canada, which became the basis of policy adopted by the Canadian Food Inspection Agency and required of seed companies and corn producers concerning management of resistance to Bt crops. Ontario will continue this work, serving as a model for similar efforts of participating entomologists in U.S. Corn Belt states. In 2003, NC-205 members provided input to the National Corn Growers Association (NCGA) prior to launch of NCGA web-based IRM training modules (

Wisconsin Extension IPM personnel will assist Minnesota vegetable crop entomologists by conducting collaborative processing sweet corn insecticide efficacy trials. In 2003, Wisconsin and Minnesota populations of corn earworm appeared to exhibit a level of resistance to pyrethroid insecticides (Hutchison et al. 2004). Corn earworms will be collected from Wisconsin locations and sent to a collaborator at Louisiana State University Agricultural Center for dose-response resistance assays to pyrethroids. The situation will continue to be monitored and insect resistance management strategies developed as part of Extension programming for the vegetable processing crop industry in the upper Midwest.

Extension entomologists in Kansas and Texas will conduct insecticide efficacy trials within the context of building IPM recommendations for southwestern corn borer in corn. Texas will also continue efforts to introduce drought, corn earworm, and spider mite resistant hybrids developed in Texas. Similar efforts for European corn borer and black cutworm will be conducted by extension entomology in Wisconsin and other states as a traditional delivery method to growers of unbiased product performance and related pest biological information. Evaluation of novel, reduced-risk insecticides will be highlighted in these NC-205 field demonstrations, particularly in comparison with conventional insecticide standards in the pyrethroid and organophosphate classes. Efficacy data from university extension trials will be used to educate growers on the efficacy and relative value of reduced-risk insecticides for use in IPM and IRM programs.

NC-205 participants, Objective 5 team members in particular, will contribute to an updated edition of the NCR-327 publication European Corn Borer Ecology and Management over the next NC-205 project cycle. Members have discussed addition of a Bt-corn section, including decision guidelines for the use of Bt corn. Other additions under consideration include an organic management section and an irrigated corn management section.

During this project, Texas, Wisconsin, Delaware, Maryland, Ontario, Iowa, Kansas, and Pennsylvania and collaborators in neighboring states/provinces will conduct field evaluations to determine the efficacy, yield, economic and environmental implications of European corn borer and other lepidopteran management approaches as described above. The information generated from this research will be used to develop multi-media materials for use in regional, national and international (U.S. and Canada) educational outreach efforts with growers, agricultural service providers, seed industry, and the general public. Traditional face-to-face extension meetings and educational programs conducted by Extension entomologists will be held with producers, industry, consultants, and regulators to discuss findings, and share information, questions and ideas to enhance policy and regulatory decisions compatible with the economic, environmental, health and social needs of both the agricultural and non-agricultural communities. Objective 5 team members will utilize feedback from growers to help direct NC-205 research activities. Newsletters, traditional extension materials such as fact sheets, Web pages, videos, interactive CD training modules, scientific publications, IPM adoption surveys and focus groups, and position statements will be used to disseminate information to the agricultural and public sectors. Iowa will expand the Corn Insect webpage to link with the Pennsylvania State University BET program and provide an archive of NC-205 publications.

Measurement of Progress and Results


  • Identify economic, demographic, and societal factors affecting the adoption of Bt corn and implementation of insect resistance management strategies.
  • Develop a yield-loss model for southwestern corn borer that includes field data for damage from stalk tunneling and lodging.
  • Wide-scale site-specific analyses of Bt-corn economic values based on economic, entomological and meteorological models will be made available to the public.
  • A model that predicts oviposition site selection of female European corn borer moths based on plant growth stage and landscape factors.
  • Geographic size of European corn borer populations and metapopulations in the central Corn Belt will be characterized through both spatial and temporal estimates of gene flow.
  • The genetic basis of voltinism will be determined.
  • A model to predict voltine patterns in North America will be developed.
  • A model that predicts the influence of climate change on European corn voltine patterns and management will be development and published.
  • Economic thresholds for first generation European corn borer will be published.
  • Develop linkage maps for research of European corn borer genetics.
  • Field protocols for evaluating possible affects of transgenic corn on non-target organisms, including plot size, appropriate taxa, replication, and sample timing.
  • Information for landscape modeling to determine if Bt corn indirectly reduces the risks of corn earworm in soybean on a local scale.
  • Design elements and recommendations for the establishment and management of riparian grass buffers adjacent to cornfields to enhance conversation biological control.

Outcomes or Projected Impacts

  • Economic models that incorporate farmer behavior towards insect resistance management strategies will lead to ways to improve grower implementation of refuge requirements.
  • Yield-loss model for southwestern corn borer will be used to update economic assessments of the value of Bt corn and to evaluate the economics of resistance management for Bt corn in Kansas and Texas.
  • Based on maps generated from combined economic, entomological and meteorological models growers will be able to determine whether Bt technology will provide an economic return.
  • If areas of high European corn borer damage are predictable and temporally stable, growers will be able to target control practices to those locations most likely to provide a return on investment.
  • Genetic characterization of European corn borer populations will permit development of a resistance monitoring system at an appropriate geographic scale.
  • Characterization of European corn borer voltine races across the North American landscape will help growers to time pest management activities. This characterization also will allow economists and entomologists to evaluate economic value of new technologies, and provide basic insights into how climate can influence voltinism in insect populations.
  • Many members of this committee have been interested in the genetic basis of voltinism for years. This basic information will provide clues about why corn borers have one, two or more generations per year.
  • A linkage map will be enormously useful for characterizing possible moth resistance to Bt toxins.
  • The public demands a thorough evaluation of possible environmental impacts of transgenic crops. Improved field protocols for non-target evaluations will help improve public confidence in such evaluations.
  • The Bt-corn landscape information will include recommendations on the amount and spatial arrangement of Bt-corn acreage required on farms to achieve localized suppression, thus reducing insecticides beyond the target area.
  • Provide knowledge on the importance of natural enemies in regulating European corn borer populations.


(2006): Make available to public via a website site-specific analyses of the economics of Bt corn.

(2007): Publish paper on the genetics of European corn borer voltinism.

(2007): Publish papers on the yield-loss model for southwestern corn borer.

(2008): Publish field protocols for evaluating non-target effects of transgenic corn.

(2009): Publish European corn borer linkage map.

(2009): Publish paper characterizing the genetic structure of European corn borer populations.

(0):): Publish updated edition of the NCR-327 publication European Corn Borer Ecology and Management.

(0):): The spatial relationship between economic value of Bt corn for European corn borer and corn rootworm will be modeled and quantified as a guide for growers.

Projected Participation

View Appendix E: Participation

Outreach Plan

Members of the committee are involved in field demonstrations and outreach efforts related to the sustainable management of lepidopteran pests of corn. In general, they recommend IPM approaches that exploit as many strategies for suppressing pest levels as possible to avoid growers' reliance on any one practice, tactic, chemical or seed technology. Many committee members interact on a regular basis with farmers, farm radio broadcasters, government agency personnel, and other agricultural professionals regarding IRM requirements associated with transgenic Bt-corn hybrids. They also interact with directors of state corn grower association boards to communicate science-based information on biotechnology issues. In addition to helping farmers and the public understand IRM programs, committee members with extension appointments will provide guidance about how transgenic crops and IRM programs fit into a larger field corn IPM program. Specifically, how growers should make informed decisions about the management of corn insect pests. An interactive website also will be established that will allow growers to assess the value of Bt corn at the county level.

Traditional face-to-face extension meetings and educational programs conducted by Extension entomologists will be held with producers, industry, consultants, and regulators to discuss findings, and share information, questions and ideas to enhance policy and regulatory decisions compatible with the economic, environmental, health and social needs of both the agricultural and non-agricultural communities. Feedback from growers will be used to help direct research activities of the committee. Newsletters, traditional extension materials such as fact sheets, Web pages, videos, interactive CD training modules, scientific publications, IPM adoption surveys and focus groups, and position statements will be used to disseminate information to the agricultural and public sectors. The popular NC-205 publication "European Corn Borer: Ecology and Management" will be updated with new information, particularly research related to insect resistance management and Bt corn.


The project will be administered by a technical committee consisting of all participants of the project and all are eligible for office, regardless of sponsoring agency affiliation or the number of members per SAES. An executive committee will consist of the chairperson, secretary, and the administrative advisor. The executive committee will conduct business between meetings. Subcommittees may be named by the chair as needed for specific assignments such as developing new project outlines for continuing the project, to prepare publications, or other assignments. An annual meeting of the full technical committee will be held to summarize and critically evaluate progress, analyze results, and plan future activities, reports, and publications. The chair, in consultation with the technical committee and with the concurrence of the administrative advisor notifies the technical committee members of the time and place of meetings, prepares the agenda, and presides at meetings of the technical committee and executive committee. The administrative advisor authorizes the meeting 90-120 days in advance. The chair prepares or supervises preparation of the annual report of the project. The secretary prepares minutes of the annual meeting and forwards them to the administrative advisory who distributes them to the regional research office, the CSREES liaison person, technical committee members, all North Central AES directors, and directors of other participating states. Procedures outlined in the manual for Cooperative Regional Research (revised 1992) will be followed.

Literature Cited

Acciarri, N., G. Vitelli, S. Arpaia, G. Mennella, F. Sunseri, and G. Rotino. 2000. Transgenic resistance to the Colorado potato beetle in Bt-expressing eggplant fields. Hortscience 35: 722-725.

Agricultural Biotechnology Stewardship Technical Committee. 2003. Insect resistance management Compliance Assurance Program: Backgrounder. public_policy/ PDF/CAPbackgrounder.pdf.

Al-Deeb, M., and G. Wilde. 2003. Effect of Bt corn expressing the Cry3Bb1 toxin for corn rootworm control on aboveground nontarget arthropods. Environ. Entomol. 32: 1164-1170.

Al-Deeb, M., G. Wilde, J. Blair, and T. Todd. 2003. Effect of Bt corn for corn rootworm control on nontarget soil microarthropods and nematodes. Environ. Entomol. 32: 859-865.

Anderson, P. L., R. L. Hellmich, M. K. Sears, D. V. Sumerford, L. C. Lewis. 2004. Effects of Cry1Ab-expressing corn anthers on monarch butterfly larvae. Environ. Entomol. 33: 1109-1115.

Buttel, Merrill, Chen, Goldberg, and Hurley (Submitted). Bt Corn Grower Compliance With Insect Resistance Management Requirements.

Calvin, D. D. 1995. Economic benefits of transgenic corn hybrids for European corn borer management in the United States. A report to Monsanto Company.

Castro, B. A., T. J. Riley, B. R. Leonard, and J. Baldwin. 2004. Borers galore: Emerging pest in Louisiana corn, grain sorghum and rice. Louis. Agric. 47:4-6.

Dively, G. P., J. J. Linduska, and M. Ross. 1999. Timing of insecticide applications for dusky sap beetle and lepidopteran survivors of Bt sweet corn, pp. 22-25. In Proceedings, Mid-Atlantic Vegetable Workers Conference, Newark, DE, October 1998.

Dively, G. P., R. Rose, M. K.  Sears, R. L. Hellmich, D. E. Stanley-Horn, J. M. Russo, D. D. Calvin, P. L. Anderson.  2004. Effects on monarch butterfly larvae (Lepidoptera: Danaidae) after continuous exposure to Cry1Ab-expressing corn during anthesis.  Environ. Entomol. 33: 1116-1125.

Dogan, E. B., R. E. Berry, G. L. Reed, and P. A. Rossignol. 1996. Biological parameters of convergent lady beetle (Coleoptera: Coccinellidae) feeding on aphids (Homoptera: Aphididae) on transgenic potato. J. Econ. Entomol. 89: 1105-1108.

Donegan, K. K., D. L. Schaller, J. K Stone, L. M. Ganio, G. Reed, P. B. Hamm, and R. J. Seidler. 1996. Microbial populations, fungal species diversity and plant pathogen levels in field plots of potato plants expressing the Bacillus thuringiensis var.tenebrionis endotoxin. Transgenic Res. 5: 25-35.

Elmore, R. W., F. Roeth, L. Nelson, C. Shapiro, R. Klein, S. Knezevic, and A. Martin. 2001. Glyphosate-resistant soybean cultivar yields compared with sister lines. Agron. J. 93:408-412.

Gould, F. 1988a. Evolution biology and genetically engineered crops. BioScience 38: 26-33.

Gould, F. 1988b. Genetic engineering, integrated pest management and the evolution of pests. Trends Ecol. Evol. 3/TIBTECH 6: S15-S19.

Gould, F. 1989. Ecological-genetic approaches for the design of genetically engineered crops, pp. 146151. In D. W. Roberts and R. Granados [eds.], Proceedings, Biotechnology, Biological Pesticides and Novel Plant-Pest Resistance for Insect Pest Management. Boyce Thompson Institute Conference, July 1988. Boyce Thompson Institute Publications, Ithaca, New York.

Gould, F., G. G. Kennedy and M. T. Johnson. 1991. Effects of natural enemies on the rate of herbivore adaptation to resistant host plants. Entomol. Exp. & Appl. 58: 1-14.

Hellmich, R. L., B. D. Siegfried, M. K. Sears, D. E. Stanley-Horn, H. R. Mattila, T. Spencer, G. K. Bidne,  M. J. Daniels, and L. C. Lewis. 2001. Monarch larvae sensitivity to Bacillus thuringiensis purified proteins and pollen. Proc. Natl. Acad. Sci. USA 98:11925-11930.

Hueth, D., and U. Regev. 1974. Optimal agricultural pest management with increasing pest resistance. Am. J. Agric. Econ. 56: 543-552.

Hunt, T. E. 1999. Dispersal and behavior of adult European corn borer in and around corn. Ph.D. dissertation, University of Nebraska-Lincoln.

Hurley, T.M., B.A. Babcock, and R. L. Hellmich. 2001. Bt crops and insect resistance: An economic assessment of refuges. J. Agr. & Res. Econ. 26: 176-194.

Hurley, T. M., S. Secchi, B. A. Babcock and R. L. Hellmich. 2002. Managing the risk of European corn borer resistance to Bt corn. Environ. Res. Econ. 22: 537-558.

Hurley, T. M., P. D. Mitchell, and M. E. Rice. 2004. Risk and the value of Bt corn. Amer. J. Agric. Econ. 86:345-358.

Hutchison, W.D., E.C. Burkness, B. Jensen, R. Leonard, T.L. Rabaey, R. Koch, R.A. Weinzierl, E. Cullen and J.L. Wedberg. 2004. Pyrethroid resistance to corn earworm in Midwestern U.S. sweet corn: comparisons with trends in southern states. North Central Branch, Entomological Society of America meeting; Kansas City, MO, March 2004. [Abstract].

Hyde, J., M. A. Martin, P. V. Preckel, and C. R. Edwards, 1998. The economics of Bt corn: adoption implications. Purdue Univ. Coop. Ext. Serv. Publ. ID-219, West Lafayette, IN.

Hyde, J., M. A. Martin, P. V. Preckel, and C. R. Edwards. 1999. The economics of Bt corn: Valuing protection from the European corn borer. Rev. Agric. Econ. 21:442-454.

Hyde, J., M. A. Martin, P. V. Preckel, L. L. Buschman, C. R. Edwards, P. E. Sloderbeck, and R. A. Higgins. 2003. The value of Bt corn in southwest Kansas: A Monte Carlo simulation approach. J. Agric. Resour. Econ. 28:15-33.

Jaffe, G. 2003. Planting trouble: Are farmers squandering Bt corn technology? Center for Science in the Public Interest, Washington, DC.

Jasinski, J., J. Eisley, C. Young, J. Kovach, and H. Willson. 2003. Select nontarget arthropod abundance in transgenic and nontransgenic field crops in Ohio. Environ. Entomol.32: 407-413.

Losey, J. E, L. S. Rayor, and M. E. Carter. 1999. Transgenic pollen harms monarch larvae. Nature (Lond) 399: 214.

Mason, C. E., M. E. Rice, D. D. Calvin, J. W. Van Duyn, W. B. Showers, W. D. Hutchinson, J. F. Witkowski, R. A. Higgins, D. W. Onstad, and G. P. Dively. 1996. European corn borer ecology and management. North Central Region Ext. Publ. 327, Iowa State University, Ames.

Mitchell, P. D., T. M. Hurley, B. A. Babcock, and R. L. Hellmich. 2002. Insuring the stewardship of Bt corn: A carrot versus a stick. J. Agric. Resour. Econ. 27:390-405.

Morrison, W. P., D. E. Mock, J. D. Stone, and J. Whitworth. 1977. A bibliography of the southwestern corn borer, Diatraea grandiosella Dyar. Bull. Ent. Soc. Amer. 23, 185-190.

Musser, F. R. and A. M. Shelton. 2003. Bt sweet corn and selective insecticides: their impacts on sweet corn pests and predators. J. Econ. Entomol. 96: 71-80.

National Corn Growers Association. 2003. Survey shows corn growers good stewards of Bt technology. News Direct from the Stalk, November 13.

Oberhauser, K. S., M. Prysby, H. R. Mattila, D. E. Stanley-Horn, M. K. Sears, G. Dively, E. Olson, J. M. Pleasants, W. -K. F. Lam, and R. L. Hellmich. 2001. Temporal and spatial overlap between monarch larvae and corn pollen. Proc. Natl. Acad. Sci. USA 98:11913-11918.

Oleson, J. and J. Tollefson. 2001. Node-Injury Scale.

Onstad, D. W., and J. V. Maddox. 1989. Modeling the effects of the microsporidium, Nosema pyrausta, on the population dynamics of the insect, Ostrinia nubilalis. J. Invertebr. Pathol. 53: 410-421.

Onstad, D. W., and E. A. Kornkven. 1999. Persistence of natural enemies of weeds and insect pests in heterogeneous environments, pp. 349-367. In B. A. Hawkins and H. V. Cornell [eds.], Theoretical approaches to biological control. Chapman Hall, London.

Onstad, D. W., and C. A. Guse. 1999. Economic analysis of the use of transgenic crops and nontransgenic refuges for management of European corn borer (Lepidoptera: Pyralidae). J. Econ. Entomol. 92:1256-1265.

Onstad, D. W., C. A. Guse, P. Porter, L. L. Buschman, R. A. Higgins, P. E. Sloderbeck, F. B. Peairs, and G. B. Cronholm. 2002. Modeling the development of resistance by stalk-boring Lepidoptera (Crambidae) in areas with transgenic corn and frequent insecticide use. J. Econ. Entomol. 95:1033-1043.

Orr, D. B., and D. A. Landis. 1997. Oviposition of European corn borer (Lepidoptera: Pyralidae) and impact of natural enemy populations in transgenic versus isogenic corn. J. Econ. Entomol. 90: 905-909.

Ostlie, K. R., W. D. Hutchinson, and R. L. Hellmich. 1997. Bt-corn and European corn borer: strategies for long-term success of innovative technology. North Central Region Publ. NCR-602. University of Minnesota, St. Paul.

Pilcher, C. D. J. J. Obrycki, M. E. Rice, and L. C. Lewis. 1997. Preimaginal development, survival, and field abundance of insect predators on transgenic Bacillus thuringiensis corn. Environ. Entomol. 26: 446-454.

Pleasants, J. M., R. L. Hellmich, G. Dively, M. K. Sears, D. E. Stanley-Horn, H. R. Mattila, J. E. Foster, P. L. Clark, and G. D. Jones. 2001. Corn pollen deposition on milkweeds in and near cornfields. Proc. Natl. Acad. Sci. USA 98:11919-11924.

Qureshi, J. A. 2003. Dispersal of marked and feral adult European and southwestern corn borers and its impact on Bt corn resistance management. Dissertation submitted to Dept. Entomol. Kansas State Univ. 205 pp.

Reed, G., A. Jensen, J. Riebe, G. Head, and J. Duan. 2001. Transgenic Bt potato and conventional insecticides for Colorado potato beetle management: comparative efficacy and non-target impacts. Entomologia Experimentalis Et Applicata 100: 89-100.

Regev, Uri, Andrew P. Gutierrez, and Gershon Feder. 1976. Pests as a common property resource: a case study of alfalfa weevil control. Am. J. Agric. Econ.: 186-197.

Regev, Uri, Haim Shalit, and A. P. Gutierrez. 1983. On the optimal allocation of pesticides with increasing resistance: the case of the alfalfa weevil. J. Environ. Econ. Manage. 10: 86-100.

Riddick, E. W., and P. Barbosa. 1998. Impact of Cry3A-intoxicated Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) and pollen on consumption, development, and fecundity of Coleomegilla maculata (Coleoptera: Coccinellidae). Ann. Entomol. Soc. Am. 91: 303-307.

Riddick, E. W., G. Dively and P. Barbosa. 2000. Season-long abundance of generalist predators in transgenic versus nontransgenic potato fields. J. Entomol. Sci. 35: 349-359.

Rogers, E. 1995. Diffusion of Innovations. (4th edition) New York, Free Press.

Schuler, T. H., G. M. Poppy, B. R. Kerry, and I. Denholm. 1999. Potential side effects of insect-resistant transgenic plants on arthropod natural enemies. Trends Biotechnol. 17: 210-216.

Sears, M. K., R. L. Hellmich,  B. D. Siegfried, J. M. Pleasants, D. E. Stanley-Horn, K. S. Oberhauser,  and G. P. Dively. 2001. Impact of Bt corn pollen on monarch butterfly populations: A Risk Assessment. Proc. Natl. Acad. Sci. USA 98:11937-11942.

Shelton, A. M., J. D. Tang, R. T. Roush, T. D. Metz and E. D. Earle. 2000. Field tests on managing resistance to Bt-engineered plants. Nature-Biotech 18: 339-342.

Showers, W. B 1999. Black cutworm, pp. 68-70. In K. L. Steffey, M. E. Rice, J. All, D. A. Andow, M. E. Gray, and J. W. Van Duyn [eds.], Handbook of corn insects. Entomological Society of America, Lanham, MD.

Showers, W. B., L. V. Kaster, and P. G. Mulder. 1983. Corn seedling growth stage and black cutworm (Lepidoptera: Noctuidae) damage. Environ. Ent. 12:241-244.

Sims, S. R. 1995. Bacillus thuringiensis var. kurstaki [CryIA (C)] protein expressed in transgenic cotton: effects on beneficial and other non-target insects. Southwest. Entomol. 20: 493-500.

Stanley-Horn, G. P. Dively, R. L. Hellmich, H. R. Mattila, M. K. Sears, R. Rose, L. C. H. Jesse, J. E. Losey, J. J. Obrycki and L. C. Lewis. 2001. Assessing the impact of Cry1Ab-expressing corn pollen on monarch butterfly larvae in field studies. Proc. Natl. Acad. Sci. USA 98:11931-11936.

Tabashnik, B. E., Y. Carriere, T. J. Dennehy, S. Morin, M.S. Sisterson, R. T. Roush, A. M. Shelton and J. Z. Zhao. 2003. Insect resistance to transgenic Bt crops: lesson from the laboratory and field. J. Econ. Entomol. 96:1031-1038.

Tang, J. D., H. L. Collins, T. D. Metz, E. D. Earle, J. Zhao, R. T. Roush and A. M. Shelton. 2001. Greenhouse tests on resistance management of Bt transgenic plants using refuge strategies. J. Econ. Entomol. 94:240-247.

Taylor, C. Robert, and J. C. Headley. 1975. Insecticide resistance and the evaluation of control strategies for an insect population. Can. Entomol. 107: 237-242.

USEPA 2000. Biopesticides registration action document: Revised risks and benefits sections: Bacillus thuringiensis plant pesticides. U.S. EPA Office of Pesticide Programs Washington.

USEPA 2001. FIFRA Scientific Advisory Panel Meeting Minutes, October 18, 2000, Bt plant-pesticides risk and benefit assessments. Arlington, VA.

Whitworth, F. J., F. L. Poston, S. M. Welch, and D. D. Calvin. 1984. Quantification of southwestern corn borer feeding and its impact on corn yield. Southwest. Entomol. 9: 308-318.

Wiedenmann, R. N., and J. W. Smith, Jr. 1997. Attributes of natural enemies in ephemeral crop habitats. Biol. Control 10: 16-22.

Wiseman, B. R. 1999. Corn earworm, pp. 5961. In K. L. Steffey, M. E. Rice, J. All, D. A. Andow, M. E. Gray, and J. W. Van Duyn [eds.], Handbook of corn insects. Entomological Society of America, Lanham, MD.

Yu, L., R. E. Berry, and B. A. Croft. 1997. Effects of Bacillus thuringiensis toxins in transgenic cotton and potato on Folsomia candida (Collembola: Isotomidae) and Oppia nitens (Acari: Orbatidae). J. Econ. Entomol. 90: 113-118.

Zhao, J., J. Cao, Y. Li, H. L. Collins, R. T. Roush, E. D. Earle and A. M. Shelton. 2003. Plants expressing two Bacillus thuringiensis toxins delay insect resistance compared to single toxins used sequentially or in a mosaic. NatureBiotech 21: 1493-7.


Land Grant Participating States/Institutions


Non Land Grant Participating States/Institutions

Log Out ?

Are you sure you want to log out?

Press No if you want to continue work. Press Yes to logout current user.

Report a Bug
Report a Bug

Describe your bug clearly, including the steps you used to create it.