Agrobacterium radiobacter strain K84

Agrobacterium radiobacter strain K84 is a beneficial soil bacterium used as a biological control agent to protect plants from pathogenic strains of Agrobacterium.

The primary mechanism of action involves the production of agrocin 84, a bacteriocin that selectively inhibits the growth of the pathogen Agrobacterium tumefaciens.

By colonizing the rhizosphere and the wound sites of the root system, the K84 strain outcompetes harmful bacteria for nutrient sources and physical attachment spaces.

The bacterium forms a robust biofilm on root tissues, which acts as a protective shield against the infection of crown gall, a disease characterized by tumor-like galls.

This biological control method is highly specific and environmentally friendly, targeting only the pathogen while maintaining the natural balance of the soil microbiota.

The strain is primarily used for the prevention of crown gall disease in a wide variety of fruit, nut, and ornamental plant species.

It is widely applied in orchards to protect stone fruits such as peaches, cherries, apricots, and plums from infection during the planting stage.

Pome fruits, including apples and pears, also benefit from treatment with K84 to prevent root system damage caused by agrobacterium pathogens.

Ornamental growers use this biological agent to protect roses and various nursery trees from galls that interfere with nutrient uptake.

• Stone fruits (cherries, peaches, plums)
• Pome fruits (apples, pears)
• Grapevines
• Ornamental shrubs and nursery stock

The most effective application method involves dipping the bare roots of seedlings into a suspension of the K84 culture before transplantation into the field.

It is essential to ensure that all root surfaces, especially areas with pruning wounds or transplant damage, are thoroughly covered by the preparation.

Applications should be performed immediately before planting to maximize the establishment of the beneficial bacteria on the root surface.

The concentration of the product should strictly follow the manufacturer's guidelines to ensure the population density of the bacteria is sufficient for effective protection.

The prepared suspension must be kept cool and shielded from direct sunlight to maintain the high viability of the live biological component.

The treatment is strictly preventive; it will not eradicate or reduce existing galls or tumors that are already present on the plant root system.

Compatibility with chemical pesticides should be verified, as some antimicrobial compounds may inadvertently kill the beneficial K84 strain.

Soil pH levels should be monitored, as extreme acidity or alkalinity can inhibit the growth and survival of the bacteria in the soil environment.

Low soil temperatures may slow down the establishment and colonization process, potentially reducing the early-stage effectiveness of the biological treatment.

Only use certified commercial formulations of the K84 strain to ensure the genetic purity and efficacy of the biological agent applied to the crops.