From drift to decision-making, why must European Union testing and regulatory frameworks evolve alongside application technology? Prof Dr Jens Karl Wegener from the Julius Kühn Institute (JKI) – Federal Research Centre for Cultivated Plants raises this question
The assessment and regulation of plant protection product application technologies in Europe are under increasing pressure. On the one hand, application systems are evolving rapidly towards adaptive, sensor-based and data-driven technologies.
On the other hand, testing and regulatory frameworks remain largely rooted in static reference conditions that were developed decades ago. This growing disconnect increasingly limits regulatory systems’ ability to evaluate modern technologies properly and, unintentionally, slows innovation that could contribute to environmental protection, pesticide reduction, and improved application accuracy.
Historically, regulatory evaluation of application technologies has focused on spray drift as a key proxy for environmental risk. Drift measurement methods, reference setups, and classification schemes were designed for conventional boom sprayers operating under relatively stable, homogeneous conditions. At the time, these approaches provided a necessary and robust basis for harmonised risk assessment across Europe.
However, application technology has fundamentally changed. Modern systems use pulse-width modulation, variable-rate application, camera-based plant recognition and, increasingly, autonomous or semi-autonomous platforms. These technologies dynamically adapt spray output in real time based on weed maps, sensor inputs, spatial variability, and decision algorithms.
What is the core challenge?
The core challenge, therefore, is not a lack of regulatory ambition, but a structural mismatch between the dynamic nature of modern application technologies and the static nature of existing testing and evaluation frameworks. Dynamic systems are still assessed using methods designed for static technologies. This leads to ambiguous results, limited comparability and regulatory uncertainty for authorities, manufacturers and farmers alike. In practice, innovative technologies are often disadvantaged simply because they do not fit well into established assessment paradigms, even when they offer clear environmental and agronomic benefits.
Spray drift remains an important element of environmental risk assessment, but it is no longer sufficient as a single dominant indicator. Modern application technologies affect multiple performance dimensions simultaneously. In addition to drift, regulators increasingly require information on application accuracy, pesticide savings, misclassification rates in camera-based systems and digital documentation of application processes. These additional dimensions are essential for a realistic evaluation of modern technologies, yet they are not systematically integrated into existing regulatory frameworks. As a result, the gap between regulatory needs and available testing methodologies continues to widen.
This situation is further complicated by fragmentation across Europe. Small differences in reference conditions – such as nozzle type, spray pressure, boom height or wind speed – can lead to significantly different outcomes when evaluating drift reduction or application performance. National testing schemes and classification systems, therefore, often produce results that are not directly comparable (Wegener, 2025).
Mutual recognition becomes difficult, modelling inputs remain inconsistent and regulatory decision-making relies on conservative assumptions that may not reflect actual field performance. Importantly, this fragmentation is not primarily caused by a lack of standards, but by the absence of coherent upstream scientific harmonisation of test methods, reference systems, data structures and interpretation rules.
Standardisation alone cannot resolve this issue. By design, standards are negotiated compromises between stakeholders and cannot replace scientific harmonisation. Without a scientifically coherent foundation, standardisation risks codifying inconsistencies rather than resolving them. What is needed is a clear sequence: scientific harmonisation first, followed by formal standardisation and regulatory implementation.
European Network for Testing of Agricultural Machinery
Against this background, ENTAM 2.0 (European Network for Testing of Agricultural Machinery) provides one possible response to these challenges. ENTAM is a long-established European network of publicly funded testing and research institutions specialising in agricultural application technology.
ENTAM 2.0 builds on this foundation by explicitly focusing on harmonising test methods, reference conditions, data structures, and interpretation rules across Europe. Its role is pre-regulatory and scientific. ENTAM does not set regulatory requirements or impose mandatory testing. Instead, it develops and validates harmonised methodologies that can serve as a reliable basis for downstream regulatory guidance and formal standardisation processes.
A key principle of this approach is the clear separation of roles within the European system. Scientific harmonisation precedes standardisation. ENTAM provides validated scientific frameworks, which can then be transferred into ISO or CEN processes as a downstream formalisation step. This sequence is essential to ensure that standardisation is based on technical coherence rather than negotiated compromise alone. ENTAM, therefore, does not compete with standardisation bodies; it enables them by providing a scientifically consistent foundation.
The structure of the ENTAM 2.0 Drift Group illustrates this logic in practice. Its workflow follows a transparent sequence from empirical field data collection through the evaluation of new technologies, the development of modelling and conversion factors, and, finally, integration into regulatory contexts. This allows different technological generations to be assessed within a common framework, rather than forcing all systems into a single outdated reference model. Stakeholder and industry involvement is systematically integrated at defined interface points, particularly where feasibility and practical constraints are relevant, while the scientific core of method development remains independent.
Closing remarks
From a regulatory perspective, this approach offers several advantages. Harmonised scientific methods improve comparability across Member States and reduce uncertainty in risk assessment. Consistent data structures facilitate modelling and enable more realistic scenario-based evaluations. Clear interpretation rules enhance legal certainty for authorities and farmers. Most importantly, innovation is no longer penalised simply because it does not fit into legacy testing frameworks.
Although the current focus is on Europe, the underlying challenges are global. Application technologies are developed and marketed internationally, while fragmented testing and classification systems create barriers both within and beyond Europe. Scientific harmonisation, therefore, has relevance far beyond the European Union’s borders and can support international dialogue, technology transfer, and more consistent environmental protection worldwide.
The future of plant protection technology assessment does not lie in adding more rules, but in developing better systems. Modern application technologies require evaluation frameworks that reflect their dynamic nature and real-world performance. Scientific harmonisation is a prerequisite for credible regulation, effective standardisation and sustainable innovation. ENTAM 2.0 represents one European approach to bridging the gap between field performance, regulatory needs and technological progress.
