Onion extract

Onion extract (Allium cepa) belongs to the group of natural biopesticides widely used in organic farming. Its efficacy is derived from phytoncides, allicin, and various sulfur-containing organic compounds that possess antiseptic properties.

The mechanism of action is primarily based on a pronounced repellent effect. Volatile phytoncides disrupt the chemoreception of pests, preventing them from locating host plants by their scent.

In addition to its repellent impact, the extract exhibits fungicidal properties, suppressing the development of pathogenic microflora on the surface of leaves and stems of cultivated plants.

The active substances in the preparation can slightly improve the local immunity of plants by stimulating the production of defense proteins and enzymes in response to stress factors.

The extract decomposes rapidly in the environment without accumulating in produce or soil, making it a safe component for integrated pest management systems.

Onion extract-based products are most effective against a wide range of insect pests that are sensitive to specific scents.

Specifically, they are used against aphids, spider mites, psyllids, and certain species of caterpillars that damage vegetable and fruit crops.

The preparation also demonstrates inhibitory activity against pathogens causing powdery mildew, bacterial leaf spot, and rot during the early stages of infection development.

It is successfully utilized for protecting cabbage, cucumbers, tomatoes, strawberries, and ornamental flower crops in both open-field and greenhouse conditions.

It should be noted that onion extract does not possess high contact insecticidal power, which is why it works best as a preventive protection measure.

Application rates depend on the concentration of the active substance in the commercial product and the method of its preparation (aqueous infusion or concentrated extract).

Treatments are typically carried out by spraying plants during morning or evening hours to avoid rapid evaporation of volatile substances under direct sunlight.

The frequency of application is 7–10 days, depending on the intensity of pest flight and weather conditions that favor the development of diseases.

It is recommended to add a small amount of an adjuvant (spreader-sticker) to the solution to improve the retention of active substances on the leaf surface.

The total number of applications per season is not limited, as the product is environmentally safe and does not have a long pre-harvest interval.

The main limitation is the dependence of efficacy on weather conditions; high humidity or heavy rainfall can rapidly wash the preparation off the plant surface.

The product is ineffective at high pest population densities when a rapid "knock-down" effect from conventional chemical insecticides is required.

Avoid applying concentrated extract to tender young shoots and flowers, as this can cause phytotoxicity due to the high content of active acids.

Onion extract products should be stored in a cool, dark place, as active components degrade rapidly when exposed to light and heat.

Despite its natural origin, it is recommended to perform a phytotoxicity test on a limited area of plants before large-scale application.