NCR046: Development, Optimization and Delivery of Management Strategies for Corn Rootworms
- Duration:
- October 01, 2001 to September 30, 2006
- Administrative Advisor(s):
-
Steven G. Pueppke
(MICL)
- Research
- NIFA Reps:
-
Robert M. Nowierski
H. J. Meyer
Statement of Issue(s) and Justification:
The western corn rootworm, Diabrotica virgifera virgifera LeConte, and the northern corn rootworm, D. barberi Smith and Lawrence, are the most serious insect pests attacking corn in North America. With the movement of the Mexican corn rootworm, D. virgifera zeae Krysan and Smith, into Texas, corn from the Rocky Mountains to the Atlantic Ocean and from Texas into southern Canada is attacked by this complex. Because the pest is distributed throughout most of North America's corn producing areas, it transcends production systems and crop-use patterns. The insect infests irrigated corn in the west and dry-land production systems further east; it infests corn that will be used for on-farm feed as grain or silage as well as grain that will be sold for off-farm use as food, feed, and industrial manufacturing. The diverse geographies, environments, and production systems this insect is established in make it appropriate to coordinate research throughout its range.The original corn rootworm Multistate Research Coordinating Committee was approved in 1964 as a NCR project and the committee has operated continuously since then. The intent of the project was to "study, on a regional basis, the biology of the corn rootworm complex in relation to current and projected cultural practices and to identify vulnerabilities of the pests that could be used as control measures benefiting farmers in the North Central Region." At that time the northern corn rootworm was an economic pest in the central Corn Belt and the western corn rootworm had just began its spread out of Kansas and Nebraska. In 1964 the western had moved into South Dakota, southern Minnesota, and was established in the western half of Iowa. The "official" membership of the earlier research coordinating committees came from the 12 north central state agricultural experiment stations and the USDA-ARS Northern Plains Insect Research Laboratory. As the western corn rootworm spread, scientists from the newly infested corn-growing states and countries, i.e., Canada, began attending the committee's meetings as "associate" members. This proposed renewal of the corn rootworm Multistate Research Coordinating Committee contains internal and external linkages to resources from nearly all areas and corn production systems in North America currently infested by the pest complex.
As stated previously, the original intent of the previous committees was to study the biology of the corn rootworm complex to identify vulnerabilities of the pests that could be used as control measures. Understanding the host/pest interaction led to the promotion of crop rotation as a reliable and safe control option and the release ofrootworm-tolerant corn inbreds. Pooling data across states generated management decision guidelines and chemical tools. Examples of tangible results that were achieved and delivered to growers because of regional coordination include: the understanding of how the repeated use ofcarbamate insecticides on some soils can result in an enhanced rate of degradation that eliminates their effectiveness in those fields; by combining data across states, a large enough database under differing environments and production systems was generated to demonstrate that the rate at which many insecticides are used could be reduced and effective control still achieved at a lower cost to the grower; and the concept of controlling adult corn rootworms with reduced rates of insecticides before they lay eggs was refined and demonstrated across Midwest corn production systems.
Advances to date have not eliminated the need for regional coordination of corn rootworm research because of changes in corn rootworm biology, pest management technologies, and regulatory issues. Crop rotation will no longer guarantee corn rootworm control. A variety of the northern corn rootworm has been selected for in parts of SD, NE, MN, IL, and IA that has a two-year lifecycle and is adapted to annual rotation of corn with another crop. In eastern Illinois and western Indiana a strain of the western corn rootworm has evolved that oviposits in soybeans, making it a pest of rotated corn. This strain has been spreading into Michigan, Ohio, and has been found in eastern Iowa. New classes of insecticides are being introduced by industry that may be able to prevent larval injury by merely coating the corn seed with them. Before they can be recommended to state extension specialists and agricultural product vendors, a large public database across production systems and environments must be generated to demonstrate their effectiveness. The western corn rootworm is again developing resistance to insecticides used in Nebraska. A coordinated monitoring program is needed to determine if the genes for resistance are spreading throughout the rootworm population and how this might effect integrated management strategies. The seed industry is on the verge of releasing genetically modified corn varieties that are resistant to rootworms. To ensure that these products of biotechnology are environmentally benign and that resistance to the proteins deployed will not develop, the combined expertise of the technical committee will be needed to evaluate environmental impacts and to design and test resistance management strategies that are compatible with production practices throughout the corn producing region.
Objectives
- Systematically design and implement research on rootworm mating, dispersal, survival, and host range across environments and production systems to understand gene flow in the landscape for the design of insecticide and transgenic resistance management plans and the spread of pest strains that differ behaviorally. These research needs may be identified by and used in resistance-management computer simulation models.
- Coordinate regional research on the impact of new corn rootworm management technologies, such as transgenic varieties and new classes of insecticide chemistry, on non-target organisms and environmental quality.
- Produce a Corn Rootworm Management Guide that collates current management knowledge for this pest complex across regional production systems and make it publicly available through both a brochure and a web publication.
- Publish a statement that draws on published research and the expertise of the committee that lists considerations that must be addressed in an Insect Resistance Management program before transgenic varieties are released.
- Coordinate the monitoring of insecticide resistance and develop a regional strategy that can be used to stop or delay the spread of resistance.
- Continue to evaluate the efficacy of conventional insecticides in various crop production systems, assist in the development of new chemical tools and modes of delivery, and calculate the impact on corn production of the failure to reregister existing insecticides.
Procedures and Activities
Expected Outcomes and Impacts:
- Through committee discussions and with the help of simulation models, identify data needs and design and coordinate regional research to provide this missing information for the design and deployment of management strategies.
- Publish and maintain (revise) a Corn Rootworm Management Guide that provides practitioners with a thorough, but relevant and understandable description of corn rootworms and their management.
- Publish public statements concerning the appropriateness, methods of deployment, and environmental safety of new corn rootworm management strategies such as transgenic varieties and treatment of corn seeds with insecticides.
- Propose, plan, and officiate symposia and research presentations at national and regional professional meetings.
