“…the Agronomic Recommendation document is a fundamental instrument in the practice of agronomy…”
Luis Eduardo Pacifici Rangel is a member of the Sustainable Agriculture Advisory Board – CCAS, former general coordinator of pesticides and related products, former director of plant health, and former secretary of agricultural defense.
Luis Rangel, member of CCAS
The Federal Council of Engineering and Agronomy of Brazil – Confea published Resolution No. 1149 of 03/28/2025, which establishes guidelines for the prescription, use and inspection of Official Agronomic Recommendations. This is a fundamental step towards ensuring the safety and traceability of phytosanitary control in Brazil.
The official Agronomic Recommendation document was created in 1974, during the 2nd Meeting of Agronomists of the State of Rio Grande do Sul, promoted by the State’s Agronomy Society. The origin of this document is undoubtedly inspired by the medical prescription, which has a history based on the professional’s responsibility to diagnose and treat health conditions based on specialized knowledge. When issuing a prescription, doctors use technical criteria, the patient’s history and clinical experience, going through a process that has been formalized over the years and is now under the exclusive competence of medical professionals, regulated by professional councils.
Similarly, the Agronomic Recommendation document is a fundamental instrument in the practice of agronomy, especially in the recommendation of pesticides. The agronomist must have in-depth knowledge in epidemiology, mechanisms of action of pesticides over pests and diseases, as well as knowledge of environmental influences, ensuring the safety of pesticide use. The Recommendation must be signed by a qualified technical professional and is one of the most important risk management tools, promoting the safe and effective use of chemical products in Brazilian farms.
The Agronomic Recommendation has become mandatory and contains technical guidelines for the correct use of pesticides. It must be issued by a qualified professional, such as an agricultural engineer (agronomist). Provided for by the former Law No. 7802 of July 11th of 1989, it was maintained in the current legislation, Law No. 14785 of December 27th of 2023.
Resolution No. 1149/25, which regulates the issuance of Agronomic Recommendations, establishes standards that must be followed by professionals to ensure the safety and effectiveness of interventions. The agronomist has the prerogative to prescribe products outside the original recommendations that are shown in the leaflet. Based on their experience, agronomists use their technical knowledge to adapt pest management to the specific conditions of each farm. This resolution correctly establishes that the Agronomic Recommendation must be prescribed exclusively by agronomists and forestry engineers.
Agronomists receive comprehensive training, which includes knowledge in phytopathology, entomology, ecology, weed science, as well as Integrated Pest Management. They are trained to identify phytosanitary problems, understand the life cycle of pests, their mechanisms of action and the environmental factors that influence the emergence and proliferation of these pests. This knowledge is essential for making accurate diagnoses and prescribing appropriate treatments, including pesticide products.
The agronomist also takes into account environmental variables, such as climate, soil and biodiversity, which can affect the effectiveness of the treatment and the health of the agricultural ecosystem. This knowledge allows them to make more precise and sustainable recommendations, maximizing pest control and minimizing externalities.
Knowledge of the history of pest occurrence in a given region is a crucial factor for prescribing pesticides. Endemic pests, such as weeds, require continuous and specialized management. The history of each area helps to predict infestation patterns and to plan safer and more effective interventions.
Physicochemical interactions, synergisms and antagonisms between chemical products are critical factors that agronomists need to consider when prescribing pesticide mixtures in the spray tank. These interactions can directly influence the effectiveness of products and the safety of application, affecting pest control and environmental and human health impacts.
Some products may react with each other when mixed, forming precipitates, altering the solution’s pH or degrading active ingredients. Agronomists, with their technical knowledge, must evaluate these interactions to prevent pesticide mixtures from losing effectiveness or causing unwanted damage to crops.
The physical and chemical stability of mixtures are essential factors to ensure that active ingredients maintain their functionality until application in the farms. This includes the solubility of the components and the formation of stable emulsions.
Choosing the right equipment and the right conditions (such as spray nozzles, pressure and spray volume) is essential to maximize product effectiveness and minimize drift and environmental contamination. The agronomist has the technical responsibility of guiding farmers in the selection and maintenance of equipment, as well as adjusting dosages as necessary.
In addition to assessing efficacy and safety, agronomists must also consider current regulations and ensure that the prescription of mixtures meets legal criteria. Issuing an agronomic prescription is an act of technical responsibility, which involves recommending safe and sustainable practices.
Pest behavior varies between species (whether insects, weeds, fungi, bacteria or nematodes) and their target organisms or hosts. Fluctuations in the intensity of infestations will determine different uses in volumes, doses and other application strategies. In such cases, diagnosing the situation remains essential.
Integrated Pest Management is one of the concepts studied in depth by agronomists. This strategy consists of prioritizing progressive forms of intervention that prioritize lower economic and environmental costs, using in-depth knowledge of the ecosystem interactions of crops.
An important public policy implemented by the Brazilian government over the last 10 years has been internationally recognized as the most successful on the planet. It involves regulating the use of pesticides for crops with insufficient phytosanitary support, internationally known as “minor crops”.
Understanding off-label prescription is essential. Secondary pests are naturally controlled by products that already prescribed for crops, and agronomists must use their knowledge to recommend products for neglected pests. Dozens of examples occur annually in Brazil and the new legislation corrects historical idiosyncrasies.
For example: moniliasis of cocoa trees was considered an absent disease in Brazil a few years ago and, according to legislation, pesticide products could not be recommended for use against it. However, the imminent risk of its introduction into Brazil led to the study of contingency strategies with chemical control by using products that are already authorized for other crops and extendable to the pest in question, to be used whenever an infestation happens.
These cases occur daily in tropical Brazilian conditions and new pests can be controlled with the use of authorized substances, considering this autonomy granted by law to the agronomist. Thus, contingencies can be quickly applied, avoiding serious economic damage and prioritizing products that have less toxicity.
Resolution No. 1149/25 also addresses complex issues that have been historically neglected or that are difficult to control, such as online sales and prescriptions and preventive recommendations, which exemplify how we should guide these matters efficiently. For example, the recommendation of products for preventive purposes will only be permitted using technical data, the history of the area and other relevant information, with an emphasis on the practice of Integrated Pest Management.
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