What is Beauveria bassiana 203?

Beauveria bassiana is a fungus that controls insects in nature. It also survives by decomposing dead plant matter in soils throughout much of the world. Recent studies indicate it also interacts with plants, activating their defenses and transporting nutrients.¹

Beauveria bassiana 203 (Bb203), approved by the EU for bioinsecticidal use against pests, is Symborg’s strain of choice for the best biological pest control in agricultural, forestry, and ornamental crops.¹


How does Beauveria bassiana 203 work?

After inoculation with Beauveria bassiana 203:

  1. Spores of this fungus come in contact with the skin (cuticle) of susceptible insects, and they germinate.

  2. Then, they adhere and secrete substances that degrade the cuticle, allowing them to penetrate the insect.

  3. Once the fungus is inside the insect, it multiplies, consuming the insect's nutrients. As a result, the insect dies from starvation, toxins produced by the fungus, and/or invasion of all its organs.

  4. Finally, the fungus emerges to the surface and produces more spores, helping it disperse Bb203 to the other insects.² ³


Practical case: Red palm weevil (Rhynchophorus ferrugineus) control

The following shows an approved test on Canary Island date palm trees, carried out in Elche (Alicante, Spain) in an area where the red palm weevil is present. Canary date palm trees with a 1-meter stipe were studied under field conditions.
A dose of 1200-1800 g/tree was applied 3 times per year.

Number of treated plants: 401.
Number of untreated plants: 588.
Date of the first application of the product: 1/5/2011.
Date of the the second application of the product: 5/1/2011.
Date of the the third application of the product: 9/6/2011.

Result: after three applications, the treated palms showed an 82% decrease in the red palm weevil population.


Does Beauveria bassiana 203 have other applications?

Beauveria bassiana 203 has been found to be highly effective against a number of pests of agricultural interest.

Thus, we are working to develop additional applications and formulations of this new active substance, adapted to different farm, crop, and pest management practices.


  1. (Behie y Bidochka 2014 y Gómez-Vidal y col. 2009).
  2. Behie, S. W., &Bidochka, M. J. (2014). Ubiquity of insect-derived nitrogen transfer to plants by endophytic insect-pathogenic fungi: an additional branch of the soil nitrogen cycle. Applied and environmentalmicrobiology80(5), 1553-60.
  3. Gómez-Vidal, Sonia & Salinas, Jesús & Tena, Manuel &Lopez-Llorca, Luis. (2009). Proteomic analysis of date palm (Phoenix dactylifera L.) responses to endophytic colonization by entomopathogenic fungi. Electrophoresis. 30. 2996-3005. 10.1002/elps.200900192.