Fuente: WIPO "tomato" The present invention relates to a product with anti-oomycete properties to control diseases in silviculture, agriculture and aquaponics. The product comprises 1% by weight of tannic acid and 1% by weight of chitosan, which, when combined by mixing in a solution with 1% acetic acid and synthesised in a temperature range between 50 and 70°C, produce a liquid with a strong anti-oomycete effect with slow and progressive water-solubility, ensuring that the product continues to release product in aqueous solution for at least 48 hours. This product has been successfully tested in both laboratory and real environments for treating salmon affected by SAPROLEGNIA, Quercus trees and pepper plants affected by PHYTOPHTHORA, and crayfish affected by APHANOMYCES ASTACI. All this experimentation does not limit the scope of use of the product in other oomycete prevention, treatment and control applications.