The cultivation of wheat, barley, oats or rye continues to be the backbone of extensive crops in Spain, and their profitability depends largely on keeping weed pressure under control.
Among the most problematic grasses are vallico (Lolium spp.), wild oats (Avena spp.) and bromus (Bromus spp.). In broadleaf, species such as poppy (Papaver rhoeas), sagebrush (Sinapis arvensis), sowthistle, camomile and veronica are still present season after season. In areas such as the Duero basin, Chenopodium, Datura or Setaria have been added, and in Andalusia resistance to glyphosate has already been documented in Hordeum and Bromus, which reinforces the need for more diversified approaches.
Strategies based on rotation, preemergence and effective combinations.
Integrated management is the most robust approach in winter cereals. Pre-emergence plays an essential role in the containment of grasses: active substances such as pendimethalin, metribuzin or prosulfocarb show high efficacy when applied with adequate moisture. In postemergence, solutions such as fenoxaprop, clodinafop or pinoxaden allow acting on grasses already established, while for dicotyledons sulfonylureas, auxins (2,4-D, MCPA) or combinations with
Weed resistance
Spain is among the European countries with the highest presence of resistant biotypes in winter cereals. In Aragon and Catalonia, Lolium rigidum shows multiple resistances, while Papaver rhoeas combines metabolic and hormonal herbicide resistances in areas of the Ebro Valley. In view of this situation, management programs should integrate fallow land treated with herbicides of different modes of action, surface tillage and delayed sowing to avoid nascence peaks. It is also essential to respect the recommended doses, evaluate the efficacy after each intervention and replace any active material that loses effectiveness.
Normativa Europea y presión regulatoria
This problem is compounded by regulatory pressure. The European Green Pact and the future CAP are moving towards a significant reduction in the use of phytosanitary products, with the Community objective of reducing them by 50% by 2030. The withdrawal of numerous substances makes it necessary to redesign strategies and increase the combination of techniques: dose adjustment, fractionation of treatments, use of non-chemical methods and taking advantage of the most sensitive phenological windows.
Impacto del cambio climático en la dinámica de malas hierbas
Mild winters and irregular springs are altering weed emergence and persistence. Staggered germination makes it difficult to set the optimum time for treatment, and episodes of intense heat reduce the efficacy of some herbicides by accelerating their internal degradation. These conditions make it necessary to monitor more closely and adjust programs according to the actual meteorology of each season, prioritizing interventions when weeds are actively growing.
A future marked by precision and integration
New technologies are already part of herbicide management: sensors, satellite images, artificial intelligence and robotic systems capable of localized action. At the same time, bioherbicides and advanced formulations such as microencapsulation and intelligent adjuvants are being researched. All this is leading to a data-driven model, with less dependence on chemistry alone and more integrated, precise and sustainable management.
