Purpureocillium lilacinum strain PL 11

Purpureocillium lilacinum strain PL 11 is a highly effective biological control agent based on spores of an entomopathogenic fungus. This microorganism is a natural enemy of a wide range of harmful soil-dwelling organisms, specializing in the suppression of their life cycle.

The fungus acts by actively parasitizing the eggs, larvae, and adults of pathogenic nematodes. Fungal hyphae penetrate the cuticle of the pest, utilizing it as a source of nutrition, which leads to the death of the host organism.

During its life cycle, strain PL 11 secretes specific enzymes, such as chitinases and proteases. These substances break down the chitin-rich shells of nematode eggs, rendering them non-viable and preventing the further multiplication of the pest within the soil profile.

The preparation promotes the colonization of the plant rhizosphere, creating a protective barrier around the root system. The continuous presence of the fungus in the root zone ensures long-term control of nematode populations throughout the entire growing season.

Beyond direct parasitism, the fungus provides a stimulating effect on plant development. The metabolic products of strain PL 11 positively influence nutrient uptake, allowing the crop to recover faster from root damage caused by stressors.

The primary use of this strain is for the biological control of root-knot, stem, and foliar nematodes affecting agricultural crops. It is an indispensable tool for protecting vegetable, berry, and ornamental plants in both open-field and greenhouse conditions.

The product is effective against a wide list of species, including:

• Meloidogyne spp. (root-knot nematodes);
• Heterodera spp. (cyst-forming nematodes);
• Pratylenchus spp. (lesion nematodes).

Application of the product significantly reduces crop losses caused by gall formation on roots. The damage caused by these organisms often leads to chlorosis, stunted growth, and plant death, making nematode control a critical phase in crop protection.

The fungus is active in various soil types; however, maximum efficiency is achieved under moderate moisture and temperature conditions that favor mycelial development. It is safe for beneficial insects, earthworms, and humans, allowing its use in organic farming practices.

This bio-preparation can be used both as a preventive measure and during periods when high pest pressure is detected. Due to its eco-friendly nature, it fits perfectly into integrated plant protection systems, replacing harsh chemical fumigants.

Application rates depend on the degree of soil infestation and the crop being grown. Typically, the application is carried out through irrigation or drip systems, ensuring even distribution of fungal spores in the area where the main roots are located.

For pre-planting soil preparation, application as an aqueous suspension with mandatory incorporation into the top layer of the soil is recommended. This provides starter protection for young seedlings, which are most vulnerable to nematode attacks in the early growth stages.

During the growing season, the frequency of treatments is determined by the agronomic plan. In high-infection conditions, the interval between applications is reduced to 14–20 days to maintain a sufficient concentration of fungal spores in the rhizosphere.

An important condition for efficiency is maintaining soil moisture at 60–80% of field capacity. In dry soil, mycelium development slows down, reducing the speed of pest suppression.

It is recommended to avoid using the product simultaneously with systemic chemical fungicides. If a fungicidal treatment is required, a time interval of at least 7–10 days before or after the bio-preparation application should be strictly observed.

Purpureocillium lilacinum is sensitive to extreme temperature fluctuations and ultraviolet radiation. Therefore, the working solution should be stored and used in a place protected from direct sunlight, and application should be performed during morning or evening hours.

The product is incompatible with powerful disinfectants and aggressive mineral fertilizers that may inhibit spore activity. The use of tank mixtures must be consistent with the manufacturer's guidelines to avoid microbial antagonism.

When working with biological plant protection products, basic personal protective equipment must be worn. Although the fungus is not pathogenic to humans, avoid contact of the concentrate with mucous membranes and inhalation of dust.

Storage of the product requires specific conditions, excluding overheating or freezing. The use of an expired product or violation of storage conditions leads to a loss of spore viability, rendering the treatment economically ineffective.

Agronomists should note that bio-preparations act more slowly than chemical counterparts. Achieving maximum effect requires a systematic approach aimed at creating a stable biological balance in the soil.