A New Frontier for Ecotoxicology in Brazil
In the Brazilian agricultural scenario, a silent revolution is underway. As Brazil consolidates its position as one of the world's largest agricultural producers, a crucial dilemma arises: how to increase food production for a population expected to reach nearly 10 billion by 2050, while simultaneously reducing the environmental impact of these activities? The answer may lie in bioinsecticides - products developed from microorganisms or molecules derived from these organisms, which present themselves as promising alternatives to conventional pesticides.
Bioinsecticides offer a more environmentally friendly approach to pest control compared to traditional chemical pesticides.
The bioinsecticide market in Brazil has grown by over 60% in recent years, far exceeding global growth rates 2 .
Bioinsecticides constitute a category of biological products formulated from microorganisms (fungi, viruses, bacteria) or molecules derived from them. Unlike conventional chemical pesticides, these products mimic natural processes of population control, offering more specific mechanisms of action and, in theory, less aggressive to the environment 2 .
| Type | Base | Main Target | Mechanism of Action |
|---|---|---|---|
| Bacterial | Bacillus thuringiensis (Bt) | Larvae of Lepidoptera, Diptera and Coleoptera | Produces crystalline toxins that bind to intestinal epithelial receptors, causing cell lysis and insect death |
| Viral | Baculovirus (e.g., SfMNPV) | Fall armyworm (Spodoptera frugiperda) | Infects and replicates inside insect cells, causing death and releasing new viral particles 3 |
| Fungal | Entomopathogenic fungi | Various insect pests | Penetrate the insect cuticle, colonize internally and produce toxins 2 |
One of the most surprising aspects revealed by recent research is that bioinsecticides can also face the development of resistance by pests - a problem that already seriously affects traditional pesticides. An international study bringing together researchers from Unesp, the UK and Sweden, led by the University of Stirling in Scotland, shows that the use of these microbiological products may encounter natural obstacles capable of compromising their functionality 2 .
In Europe, a bioinsecticide adopted in the early 1990s to combat a moth species that attacks apple trees had to be replaced in the mid-2000s due to resistance development 2 .
Ecotoxicology is the science that studies the fate and effects of chemical substances on living organisms. In the context of bioinsecticides, although they are natural products, the fact that they are applied in an unnatural manner and in concentrated quantities raises questions about their environmental impacts .
ECOTOX-BRASIL plays a fundamental role in stimulating research, training human resources and debate between different spheres of society with the aim of identifying and preventing environmental problems early, especially those related to ecosystem pollution 1 .
Determine the potential adverse effects of bioinsecticides on non-target organisms.
Evaluate the relationship between the concentration of bioinsecticides and the magnitude of effects.
Determine the extent to which non-target organisms are exposed to bioinsecticides.
Integrate information from previous steps to estimate the likelihood of adverse effects.
To understand how scientists assess the environmental safety of bioinsecticides, let's examine a relevant experimental approach for the Brazilian context: a multi-species system for evaluating the infectivity and pathogenicity of microbial pest control agents in non-target aquatic species 4 .
Representative aquatic species from different trophic levels were chosen .
Bioinsecticides based on Bacillus thuringiensis (Bt) were prepared in varied concentrations .
Organisms were exposed to different concentrations for varying periods .
Mortality, infectivity, pathogenicity and sublethal effects were monitored .
| Organism Group | Representative Species | Tested Concentration | Observed Effects | Interpretation |
|---|---|---|---|---|
| Crustaceans | Daphnia magna | Up to 1.5 × 10^6 CFU/mL | No effect on survival or reproduction | Safe for crustaceans at field concentrations |
| Crustaceans | Chirocephalus grubei | 18 ppm (100x field concentration) | 57% mortality | Effect only at very high concentration |
| Mollusks | Biomphalaria glabrata | 1.5 × 10^7 CFU/mL | LC50 of 30 days | Low acute toxicity |
| Fish | Danio rerio and Oreochromis niloticus | 5 × 10^6 CFU/mL | No mortality or adverse effects | Safe for fish |
The data demonstrate that, in general, Bt-based bioinsecticides show low toxicity for most non-target aquatic organisms at concentrations normally used in the field. Significant adverse effects generally only occur at concentrations drastically higher than those recommended for pest control.
Assessing the environmental hazard of bioinsecticides requires a multidisciplinary approach and the use of specialized tools. The table below details some of the main resources and methodologies used by Brazilian researchers in this field:
| Tool/Resource | Function/Application | Example in Brazilian Context |
|---|---|---|
| Multi-Species Systems | Evaluate effects on multiple organisms simultaneously, simulating ecological interactions | Aquatic system with crustaceans, mollusks and fish to test bioinsecticide effects 4 |
| Model Organisms | Serve as biological indicators of toxicity | Daphnia magna (crustacean), Biomphalaria glabrata (mollusk), Danio rerio (fish) |
| Baculovirus Bioassays | Evaluate efficacy and specificity of entomopathogenic viruses | Virumix - bioinsecticide with SfMNPV virus for fall armyworm control 3 |
| Gene Expression Analyses | Detect molecular responses to bioinsecticide exposure | Studies of gene-environment interaction in target and non-target pests 2 |
| Mesocosms | Simulate ecosystems under controlled conditions | Outdoor tanks with aquatic communities to test effects at intermediate scale |
Controlled experiments to determine acute and chronic toxicity under standardized conditions.
Monitoring of real-world applications to assess ecological impacts in agricultural settings.
The assessment of the environmental hazard of bioinsecticides indeed represents a new perspective for ecotoxicology in Brazil. As the country consolidates its position as a global leader in tropical agriculture, the adoption of sustainable technologies becomes imperative.
Studies conducted to date suggest that bioinsecticides present low toxicity and low environmental risk when compared to the concentrations used for pest control purposes .
Developing methods and perspectives appropriate for Brazil's rich biodiversity.
Between academic institutions, productive sector and regulatory bodies.
To prolong bioinsecticide efficacy and minimize resistance development.
Brazilian ecotoxicology thus has a unique opportunity to contribute to more sustainable agriculture, developing methods and perspectives appropriate to our rich biodiversity and our crucial role in global food security.
Bioinsecticide developed from an entomopathogenic virus for fall armyworm control, result of public-private partnership 3 .