La Rioja suspends the herbicide prosulfocarb in winter cereals

The Department of Agriculture, Livestock, Rural Affairs and Environment of La Rioja has approved Order AGM/45/2026, dated September 3, which temporarily suspends the application of plant protection products containing the active substance prosulfocarb in winter cereal crops during the 2026/2027 agricultural campaign. The regulation, published in the Official Gazette of La Rioja number 172, dated September 8, 2026, will be in effect from its entry into force until December 1, 2026, in the municipalities and polygons listed in its Annex I.

The measure is a response to the detection of prosulfocarb residues in olives intended for oil production. Although the use of this active substance is not authorized in olive groves, inspections have confirmed that its use is widespread in Riojan cereal-growing areas for the control of adventitious plants of the genus Lolium, which can lead to contamination of olives through long-distance drift.

Regulatory Framework and Background

The order is based on Law 43/2002, of November 20, on Plant Health, whose article 32.2 allows autonomous communities to propose restrictions when there are founded reasons of risk to human health, animal health, or the environment. It is also supported by Royal Decree 1311/2012, of September 14, which enables the competent administration to apply the precautionary principle by limiting the use of phytosanitary products in specific areas or circumstances.

Since the 2022/2023 campaign, La Rioja has been publishing orders that temporarily limit the use of products formulated with prosulfocarb in areas with problems or with organic olive groves. Controls carried out on olives and oils throughout these campaigns have shown a reduction in contamination with residues of this substance.

Scope of the Restriction

In the municipalities and polygons of Annex I, the suspension affects the entire territory unless a specific delimitation is indicated. In the remaining regions, municipalities, and areas, a minimum distance of 100 meters from unharvested olive plantations must be maintained during the same dates.

From December 1, products containing prosulfocarb may be used under the conditions and limitations of the data sheets of the Registry of Plant Protection Products of the Ministry of Agriculture, Fisheries and Food, which include maximum values for forward speed, treatment boom height, and wind speed, as well as the obligation to use drift-reduction nozzles.

Among the affected municipalities are, among others:

• Logroño, Haro, Calahorra, Arnedo, Alfaro, Autol, Nájera, Santo Domingo de la Calzada, and Villamediana de Iregua.
• Bañares, Briones, Cihuri, Fonzaleche, Grañón, and Nájera, with delimitation by specific SIGPAC polygons.

Control, recommendations, and sanctions

The General Directorate of Agriculture and Livestock will develop a Specific Control Plan that will include sampling for residue analysis in cereal plots and the inspection of farm records in holdings with the highest risk of drift contamination.

The order also establishes recommendations to minimize risks:

• Strive to use herbicides or management techniques as alternatives to prosulfocarb.
• Delay cereal sowing in olive grove environments until after the olive harvest.
• Begin the olive harvest before the appropriate time for herbicide treatment.
• Keep equipment calibrated and check the functioning of the nozzles before each campaign.
• Use sprayers with boom stabilization systems on irregular terrain.

Non-compliance with Article 1 will be subject to the regime of infractions and sanctions under Title IV of Law 43/2002 on Plant Health. The order, signed by counselor Noemí Manzanos Martínez, will take effect throughout the 2026/2027 agricultural campaign, in an attempt to reconcile the protection of Riojan olive groves with cereal farming activity.

Source: Official Gazette of La Rioja, no. 172, September 8, 2026, section I. General Provisions, pp. 15373-15377 (official reference: BOR-A-20260908-I–75).