• Basic Information
• Additional Info

Basic Information

• Project No. and Title: NCCC_OLD46 : Development, Optimization, and Delivery of Management Strategies for Corn Rootworms and Other Below-ground Insect Pests of Maize.
• Period Covered: 10/01/2008 to 09/01/2009
• Date of Report: 04/05/2010
• Annual Meeting Dates: 01/27/2010 to 01/29/2010

Participants

Accomplishments

Impacts

1. Multi-year data comparing Variant western corn rootworm trap counts from soybean with first year corn root node-injury and yield response, revealed that growers using the soybean trapping protocol and economic threshold of 5 beetles/trap/day for treatment decision support in first year corn would make a correct decision 75% of the time (treat/no-treat). 17% of fields had damage higher than predicted (treatment should have been applied although scouting indicated pest was below threshold) and 8% of fields had lower than predicted damage (treated when not economically necessary). Economic analysis of these outcomes will determine farmer profitability of scouting-based vs. prophylactic treatment. Information will be used to develop more cost-effective Variant monitoring protocols while retaining reliable treatment decision support.
2. Non-transgenic refuges in rootworm-resistant Bt transgenic corn provide locations for susceptible rootworms to develop without exposure to Bt. The refuge strategy for rootworm-resistant Bt transgenic corn assumes beetles from refuge will enter transgenic corn and mate with potentially-resistant individuals. Observation and collection of mate-seeking and mating WCR adults in refuge blocks and adjacent transgenic corn rows indicated that assumptions about limited pre-mating female movement, male mating activity, and movement rates are not accurate. The contribution of refuge male mating activity is likely not as extensive as assumed based on the WCR literature. The trend toward more integrated refuge designs (in-field refuge strips and seed blends, a.k.a. refuge in a bag) will promote desired movement and pairings between refuge males and transgenic corn females, and slow the development of resistance to Bt transgenic corn.
3. A proposed biofuel/biomass crop, Miscanthus x giganteus, was found to be a host for egg-to-adult development of the most significant U.S. corn pest, the western corn rootworm. If widely planted as a cellulosic ethanol feedstock, Miscanthus x giganteus would be grown in proximity to rotated corn and soybean over a vast area. The pest management consequences of introducing this perennial WCR host into the Corn Belt are unknown. This research result highlighted many unanswered questions about the appropriateness of Miscanthus x giganteus as a biomass crop and drew needed attention to the pest management issues for a crop often depicted as relatively pest-free. Multiple Miscanthus x giganteus growers in Illinois have contacted the authors to collaborate on monitoring that will measure pest and wildlife impacts on new and established biomass plantings and enable realistic estimates of IPM expenses in biomass crops.
4. USDA, ARS-NCARL in Brookings, SD rearing of the WCR colonies from different Corn Belt regions and with different characteristics of resistance is a valuable tool for research into pest management and biology. Use of these colonies has been instrumental in several recent studies. USDA foresight to establish and maintain these colonies is enabling comparative research that has contributed to greater understanding of pest genetic, Bt resistance, population dynamics, and behavior.

Publications