Socioecological comparison of resistance management for transgenic Bt crops among four countries

In agriculture, one of the most used technologies in the field for pest management and control is the use of Bt crops, which are genetically modified plants that express Bt insecticidal proteins. Bacillus thuringiensis. However, in addition to the high evolutionary capacity of pests, there is high selection pressure due to the continuous expression of the protein, which may favor the rapid evolution of resistance. This is why it is important to adopt Insect Resistance Management (MRI) strategies so as not to put the sustainability of this technology at risk. Given this, several countries have developed governance systems to help preserve the public benefits that the use of Bt crops provide.

To preserve/extend the durability of this technology and delay the evolution of pest resistance, it is essential to cultivate non-Bt refuge areas, associated with other agricultural practices (crop rotation, application window, rotation of modes of action, among others). others). Effective refuge areas “provide” susceptible insects for mating with the rare resistant individuals that may survive in the Bt crop area, resulting in progeny susceptible to Bt, when the Bt crop expresses the protein(s) in high dose.

However, management of pest susceptibility to Bt crops is undertaken across the world in a variety of ways and with varying degrees of success depending on the context. Remembering that the way producers adopt Integrated Pest Management (IPM) practices can influence the evolution of resistance and vulnerability of crops to damage caused by pests.

Thus, a study published in the journal Ambio carried out a detailed and comparative analysis of the influence of ecological and socioeconomic factors on resistance management in Australia, Brazil, India and the United States with the aim of understanding the types of policies and strategies that have the greatest (or lower) probability of generating good results in different scenarios.

In Australia, the OGTR (“Office of the Gene Technology Regulator”) is the body that assesses the risks of technology to human and environmental health and safety and issues mitigation plans, including licensing conditions. Resistance management is carried out between the registrant (responsible for auditing planting dates, refuges and destruction of crop residues at the end of the season), APVMA (Australian Pesticides and Veterinary Medicines Authority) and TIMS (Transgenic and Insect Management Strategies ), committee of industry experts. Before registration, OGTR considers the registrant's information. Following registration, the registrant is responsible for working with TIMS to annually provide evidence to APVMA that resistance is being managed effectively, including: user awareness and compliance with the Resistance Management Plan (RMP); PGR effectiveness, including monitoring changes in susceptibility to Bt toxins in target pests; and proposed changes to the PGR to mitigate emerging resistance risks. Cotton RDC (Research and Development Corporation) works with Cotton Australia to identify research needs, solicit research proposals from academic researchers and government agencies, and undertake projects directly with experts. A dedicated extension team, jointly supported by Cotton Australia, Cotton RDC and the national cotton seed distribution company (CSD), interacts with researchers to develop and promote resistance management strategies for private growers and consultants. The registrant also works extensively with stakeholders to promote the implementation of MRI.

In Brazil, the CNTBio (National Technical Biosafety Commission) is responsible for evaluating the safety of GMOs for human and animal life, but there are no defined strategies and policies for evaluating or regulating MRI within Bt crops. For testing and registration of Bt technologies, MAPA (Ministry of Agriculture) is responsible for the requirements during the process. There are some movements of producer associations combined with researchers and industry in response to problems related to resistance in the country. IRAC Brasil also stands out, which works constantly to provide management recommendations, as well as the holders of the technology. In 2018, MAPA recommended the use of refuge areas in Bt crops and requested additional information on the use of refuges from registrants.

In India, the GEAC (Genetic Engineering Appraisal Committee) is responsible for the registration of Bt crops and requires the use of refuge in cotton cultivation, and during seed distribution, authorized companies must provide non-Bt seeds along with Bt. However, adoption of refuge use in the country is low, due to increased complexity in production and the acquisition of Bt seeds from unauthorized suppliers.

The United States (USA), through the EPA (Environmental Protection Agency), requires registrants or authorized companies to sign contracts with producers to establish refuge areas, and those producers who do not comply with what is established have their contracts terminated. EPA is also responsible for the requirements to be adopted before and after registration, and whenever the agency requests information from the registrant, it is provided directly or can be obtained through the registrant's funding of academic research or with government organizations. There is also extensive work on the part of the registrant to implement management strategies with producers, associations, consultants and seed distributors.

Australia and the USA stand out when it comes to implementing Bt crop refuge areas and resistance management. Based on requirements imposed for the registration and use of technology, these countries are advancing in resistance management initiatives, contrasting with Brazil and India, which require greater commitment to establishing these actions.

As a way to boost adoption of MRI, the authors of the work suggest an approach through a system where the adoption of good practices related to the use of Bt and the implementation of refuge areas is rewarded, and “punishes” those who neglect or oppose it. to such practices. In this system, producers, for example, are directly encouraged through subsidies, discounts on the acquisition of seeds for refuge, among others. When the producer does not correctly perform the MRI, he or she may face higher taxes on the purchase of Bt seeds and ineligibility for crop insurance, for example.

However, it is not only the producer who must be included in this system. It also covers technology suppliers, research and extension and the government. This ensures that the entire production sphere is involved and committed to working with MRI within Bt cultures.

When adopting MRI incentive strategies, it is necessary to consider the reality of each location, as these strategies are often linked to financial costs, which are often not borne by small producers, or even require resources that are unavailable within some realities. . The use of shared refuges is one of the ways to expand and make management more accessible.

MRI in Bt crops is not a simple task with a single model to be followed. It must be constructed taking into account the context of agricultural production. It is noted that those actions that are placed as requirements are adhered to more easily than those that are voluntary or optional. It is important that the country's government is committed to building policies that incorporate greater solidity in management.

Four activities must be highlighted as fundamental principles for the proper functioning of the MRI. They are: 1) awareness among producers about the relevance of resistance; 2) monitor whether the measures adopted by producers are in compliance; 3) monitor the increase in resistance; 4) implementation of corrective actions, giving priority to their execution before resistance occurs. The satisfactory execution of these activities is linked to a robust MRI system, which must increasingly rely on active governance, understanding needs and proposing executable solutions.

Sources:

1. IRAC-BR

2. Carrie`re, Y. et al. Governing evolution: A socioecological comparison of resistance management for insecticidal transgenic Bt crops among four countries. Ambio, v. 49, no. 1, p. 1-16, 21 Mar. 2019.