Welsh onion (processed extract)

Allium fistulosum, commonly known as Welsh onion, when processed into extracts or essential oils, is classified as a natural biopesticide. Its active ingredients, primarily sulfur-containing compounds like allicin and various sulfides, serve as potent agents for plant protection, making it an excellent candidate for integrated and organic farming systems.

The mechanism of action relies on both fumigant and contact properties. The volatile phytoncides released by the extract interfere with the metabolic processes of pathogenic fungi and exert a repellent or insecticidal effect on pests by damaging their cuticle or disrupting their nervous system functions.

These formulations are effectively applied to a variety of vegetable, berry, and ornamental crops. They are particularly successful in managing populations of aphids and spider mites, while also suppressing the growth of powdery mildew and various soil-borne or foliar rot pathogens that thrive in humid environments.

Application requires strict adherence to concentration guidelines. The highest efficacy is achieved during evening applications or under overcast conditions, as direct exposure to intense ultraviolet light and high temperatures can accelerate the degradation of active volatile compounds, thereby reducing the duration of protection.

Despite being a natural substance, caution should be exercised when handling concentrated forms to avoid irritation of the eyes or respiratory tract. The product is considered environmentally friendly, leaves no toxic residues in the harvest, and generally allows for immediate harvesting after the application period is complete.