Definition of Insect Resistance Management (IRM)
- IRM involves strategies to delay or reduce the development of insect resistance.
- Specifically targets the Asian Corn Borer (ACB) resistance to Bt corn.
- Combines high dose genetic expression of Bt toxin and refuges to manage resistance.
Science-Based IRM Approach: High Dose and Refuge
- High dose ensures over 99% effectiveness against ACB.
- Refuge serves as a breeding ground for susceptible insects that dilute resistance genes.
- Refuge types:
- Structured: purposely planted non-Bt areas.
- Unstructured: naturally occurring non-Bt plants in diverse farming systems.
- Due to prevalent small farms and low Bt adoption, unstructured refuge suffices initially.
- At high adoption levels, combined structured and unstructured refuges are required.
Current IRM Strategy (Prior to Revision)
- Implementation of an unstructured refuge strategy.
- Regulated sales cap of 95% Bt corn in a defined production area.
- Part of originally approved 5-year permit conditions for Bt Corn MON 810.
Revisions in IRM Industry Requirements
- Introduction of a mandatory structured refuge (80% Bt : 20% non-Bt) in "bag-in-a-bag" seed packs when:
- Bt corn adoption reaches 80% in clusters of 200 hectares or more.
- Two years have passed since this IRM strategy's implementation.
- Mandatory resistance monitoring in coordination with DA's IRM Program Management Team.
- Comprehensive stakeholder education programs championed alongside DA.
Required Collaborative Studies
- Baseline population susceptibility to Bt.
- Biology and alternate host preferences of the Asian Corn Borer.
- Integrated Pest Management (IPM) approaches.
- Biodiversity and insect management in agro-ecosystems.
- Completion within two years post-issuance of the memorandum.
- Pilot testing of the 80% Bt : 20% non-Bt bag-in-a-bag to evaluate practical implementation.
Role and Responsibilities of the Department of Agriculture (DA)
- Active oversight in enforcing IRM compliance.
- Supports research studies related to resistance management.
- Educates stakeholders and builds capacity within DA agencies.
Periodic Review and Revalidation
- Regular reassessment of IRM strategy after every major cropping season (February and September).
- Reviews consider new scientific data, completed studies, and other Bt crop approvals.
- Ensures continuous adequacy of IRM strategies against resistance development.
Effectivity
- The Memorandum Circular took effect immediately upon issuance on December 23, 2003.