As its name suggests, these products do not penetrate into the tissues of plants, but its presence about them that prevents the fungus to develop. These compounds are not curative and preventive.

Most are multiple-action, as they interfere with the central metabolic processes of fungi affecting the production of energy or ATP, or undocked breathing inhibiting the oxidative foforilación of fungi.

Within this group include the following compounds:

• Aromatic Compounds
• Derived from Mercury
• Copper derivatives
• Sulfur derivatives
• Dicarboximide
• Dinitrophenol
• Quinones

These products are traslocations through the tissues of the plant, which means that its effect is not reduced by rain after they are applied. Most are of specific action, and many operate interrupting the biosynthetic machinery of the cell, depriving the fungus of substances needed for their growth.

A problem that has arisen with these compounds is the resistance that can acquire the treaty bodies with them, a phenomenon that can arise as a mutation. However, ownership is not a systemic requirement for the development of resistance, as several protectant fungicides such as Dodin, Fentin acetate and Glicofene, have faced the same problem.

Within the systemic fungal compounds include the following:

• Acilaninas and Fenilamidas
• Organophosphate
• Benzimidazoles
• Pyrimidine
• Antibiotics
• Imidazoles
• Morpholines
• Oxantinas
• Triazoles