Olive leaf spot, caused by Venturia oleaginea (Castagne) Rossman & Crous, is a major contributor to significant yield losses in Trás-os-Montes olive groves. The prevention and control of this disease are based almost exclusively on the application of copper-based products, mainly in organic olive groves. However, due to the restrictions of the European Commission limiting the maximum annual quantity of copper to 4kg/ha/year over 7 years (Regulation (EU) 2018/1981), there is an urgent need to find alternative control solutions and strategies.

The European project NOVATERRA, titled “Integrated novel strategies for reducing the use and impact of pesticides, towards sustainable Mediterranean vineyards and olive groves” (H2020-SFS-2018-2020), aims to significantly decrease pesticide usage and its negative impacts. Additionally, the project promotes innovative and sustainable solutions to protect olive groves from diseases.

In 2021, 2022, and 2023, within an olive grove in Terra Quente Transmontana (Mirandela), the effectiveness of two innovative products with low copper content (nanoparticles) against V. oleaginea was assessed. These products, Nanocrop (0.18% w/v copper) and Cuprocitor (5.9% w/v copper) are enhanced by a formulation based on metabolic activators and amino acids of plant origin, stimulating plant resistance mechanisms.

Starting in early March (BBCH 08 and 30), two foliar applications were conducted until more than 50% of the inflorescences opened and leaves were collected weekly to evaluate the products’ effectiveness. The results indicate that Cuprocitor significantly reduces the number of olive leaf spot infections per leaf, while at the same time contributing to the reduction of copper applied to the olive grove.