Study reveals economic impact of drift on vineyards.

1The impacts caused by hormonal herbicide drift on viticulture in Rio Grande do Sul will be the focus of a debate to be held on June 17th in Dom Pedrito. On that occasion, a groundbreaking study analyzing the economic dimension of the problem in the state will be presented, a topic that has been mobilizing producers, organizations, and researchers due to its effects on productivity, investments, and the development of wine-growing regions.

Conducted by Consevitis-RS, through Collaboration Agreement FPE 4837/2022 with the Secretariat of Agriculture, Livestock, Sustainable Production and Irrigation (Seapi), the research was carried out by the Engineering School-Company Foundation of the Federal University of Rio Grande do Sul (Feeng). Technical coordination involved Professor Leonardo Cury da Silva, Dr. Jorge Viel, and Professor Shana Sabbado Flores.

The study evaluated official records of drift occurrences made available by Seapi between 2018 and 2024, in addition to interviews with producers and technical agents, a specialized bibliographic review, cartographic analyses, georeferencing, and economic projections. The data indicate more than 400 confirmed cases of hormonal herbicide drift in Rio Grande do Sul between 2018 and 2025, with an average of 57 occurrences per year.

Estimates indicate productivity losses between 20% and 55% in the affected areas, potentially exceeding 80% in some regions. Estimates suggest that approximately 700 hectares of vineyards were directly affected by drift occurrences during the analyzed period. This number, however, may be even higher, as the study was based on official records and consulted sources, making it impossible to measure the total number of cases that occurred in the state.

In the most impacted regions, the phenomenon affects over 4 hectares of vineyards spread across approximately 45 municipalities in Rio Grande do Sul.

Hormonal herbicides, also called auxin herbicides or auxin mimics, are widely used to control weeds in extensive agricultural systems. Among the best-known active ingredients are 2,4-D, dicamba, picloram, and fluroxypyr.

The effects go beyond immediate production losses. 

According to researchers, the effects of drift go beyond immediate production losses. The economic assessment considers the reduction in production volume, the additional costs related to plant management and recovery, and the need for vineyard renewal. Among the most recurring impacts are flower abortion, reduced fruit set, vegetative deformities, and weakening of the plants.

The analysis identified occurrences in important producing regions of the state, including Campanha Gaúcha, the Central Region, Serra do Sudeste, Campos de Cima da Serra, Planalto, Missões, and, more specifically, Serra Gaúcha. The highest concentration of records occurs in areas where viticulture coexists with extensive agricultural systems that use hormonal herbicides.

According to Professor Shana Sabbado Flores, the results demonstrate that the problem has taken on implications that go beyond the productive sphere. “The results indicate that drift is no longer perceived by producers as a one-off event and has come to be considered a permanent risk factor. This has direct repercussions on investments, expansion of the activity, and prospects for the development of viticulture in different regions of Rio Grande do Sul,” she states.

According to the researcher, the study represents an important advance in understanding the phenomenon on a territorial scale. “This study represents a milestone for the viticulture of Rio Grande do Sul by bringing together, for the first time, an integrated analysis of the impacts of hormonal herbicide drift on a territorial scale. In addition to quantifying and projecting the impacts, the work delivers a monitoring methodology that can be used and improved in the coming years, creating a consistent basis for monitoring the phenomenon and for building technical and institutional solutions,” she emphasizes.

This work stems from the understanding that the sustainability of agriculture in Rio Grande do Sul depends on the balanced coexistence of different production systems. In this context, the research seeks to contribute to the development of solutions that allow for the simultaneous development of the various agricultural chains present in the State, without compromising the competitiveness and growth potential of viticulture.

Results will be presented in Dom Pedrito.

The full results of the study will be presented during the event, which is open to the public and aimed at producers, technicians, students, researchers, and other interested parties. Following the presentation, there will be time for interviews with the researchers and representatives of the entities involved. The research will subsequently be available on the Consevitis-RS Viticultural Observatory website.