Lecithins

Lecithins belong to a group of natural phospholipids obtained mainly from soybeans or sunflowers. In agronomy, they are classified as biological contact fungicides.

The mechanism of action is based on the physical effect on pathogens. Lecithins create a thin protective lipid film on the leaf surface, which prevents fungal spore germination.

The substance disrupts the integrity of the cell membranes of fungal microorganisms. This leads to the dehydration of the mycelium and terminates its development on the plant surface.

Lecithins also possess the ability to strengthen the natural immunity of the crop. They contribute to the thickening of the leaf cuticle, making it difficult for pathogens to penetrate plant tissues.

Lecithin-based products are completely biodegradable. They do not accumulate in the soil or produce, which makes them ideal for organic farming systems.

These substances are primarily used to combat fungal diseases from the true powdery mildew family (Erysiphaceae).

They effectively suppress late blight on solanaceous crops, especially in greenhouse conditions. Lecithins are also used to control scab on fruit trees.

The preparations show activity against gray mold (Botrytis cinerea) on berry bushes and vineyards. They can also be applied to suppress a complex of leaf spot diseases.

Lecithins do not have systemic action; therefore, it is advisable to use them at the early stages of disease onset or as a preventive treatment.

They are often included in tank mixtures to improve adhesion and ensure better distribution of other active ingredients across the leaf blade.

Application rates for lecithins depend on the level of infection and the crop type. Typically, the working solution concentration ranges from 0.5 to 2 percent.

Treatments are carried out at 7–10 day intervals depending on weather conditions and disease pressure. In case of frequent rainfall, the frequency of treatments can be increased.

A crucial requirement is thorough spraying of all parts of the plant, including the underside of the leaves, where fungal spores are most often localized.

It is recommended to apply lecithins during morning or evening hours to avoid rapid drying of the working solution under the influence of direct sunlight.

To achieve maximum effect, it is recommended to start the protection program before visual signs of disease appear, using the product as a barrier method.

Lecithins have a limited residual protective effect due to washing off by precipitation. This requires repeated applications after every significant rainfall.

They are ineffective against bacterial infections and pests. In cases of strong epiphytotic development of a disease, lecithins may not provide an adequate level of control.

Strict adherence to the manufacturer's recommendations regarding mixing is necessary. Lecithins may be incompatible with some highly alkaline products or adjuvants.

The products are practically non-toxic to humans and bees, allowing for applications during the flowering period, although direct contact with mucous membranes should be avoided.

Products should be stored in a cool, light-protected place, as high temperatures and light can cause the lipids to undergo oxidation processes.