Bacillus thuringiensis subsp. Aizawai strain GC-91

The active substance is a spore-forming soil bacterium that synthesizes highly specific endotoxins during fermentation. These crystalline protein inclusions (delta-endotoxins) exhibit potent intestinal toxicity specifically toward the larvae of certain insect species.

Once spores and crystals are ingested by the pest, the alkaline environment of the insect's midgut activates the pro-toxins. These active proteins bind to specific receptors on the gut epithelium, resulting in the formation of pores in cell membranes.

As a result of the gut wall damage, the insect experiences intestinal paralysis, and feeding stops within just a few hours after ingestion of the product.

The second stage of action involves the loss of intestinal barrier integrity, allowing bacterial spores and gut contents to enter the insect's hemolymph, which triggers rapid bacterial multiplication and septicemia.

Pest mortality occurs within 2 to 5 days, depending on the insect species, its developmental stage, ambient temperature, and the dose ingested from the treated leaf surface.

This strain belongs to a group of biological insecticides with a narrow spectrum of action. The primary targets are larvae of Lepidoptera pests, including high-risk species that may exhibit resistance to other bacterial strains.

The product is effective against various species of cutworms, leafrollers, moths, webworms, and certain caterpillars that damage fruit crops, as well as vegetables grown in both open and protected environments.

Due to the high specificity of its endotoxins, strain GC-91 is frequently utilized in integrated pest management (IPM) programs, as it does not adversely affect entomophages, pollinators, or other beneficial insects.

This biopesticide is particularly valuable for pest control near harvest time due to its minimal pre-harvest interval and the absence of toxic residue accumulation in the final crop product.

For maximum effectiveness, it is critical to ensure uniform coverage of the leaf surface, as the product's action is strictly contact-stomach, requiring the pest to ingest the active ingredient.

Application rates for the product vary depending on pest population density, the phenological stage of the crop, and the method of application. It is recommended to perform treatments during early larval development (early instars), as these stages are most susceptible to the toxin.

Spraying should be conducted during evening or morning hours to avoid direct exposure to intense ultraviolet radiation, which can inactivate the protein components of the product on the leaf surface.

The frequency of treatments is determined by the agro-technical situation; however, to prevent the development of resistance, it is recommended to rotate the use of this bioinsecticide with products of different chemical classes.

The use of adjuvants significantly enhances the product's performance by ensuring the active ingredient remains on the leaves even in the event of moderate rainfall, which is vital for long-season crop protection.

The optimal temperature range for the product's activity is between +15°C and +30°C. At lower temperatures, insect metabolism slows down, reducing the rate of treated mass consumption and, consequently, the effectiveness of the treatment.

A primary limitation is the dependence of effectiveness on solar radiation: direct exposure to UV rays degrades the protein crystals, meaning the residual protective period in the open field usually does not exceed 5–7 days.

The product does not possess systemic activity and cannot penetrate plant tissues, making it ineffective against pests that live inside stems or fruits unless they come into direct contact with the product.

It is necessary to avoid mixing the tank solution with products that have strong bactericidal or alkaline reactions, as this may kill the spores and lead to a loss of insecticidal properties.

During concentrate storage, it is essential to maintain a temperature below +25°C to preserve the viability of bacterial spores and the stability of the endotoxins.

While the product is safe for humans and warm-blooded animals, standard personal protective equipment for the respiratory tract and skin should be used when handling highly concentrated solutions.