The mechanisms of action of biological control:

Much of the evidence cited in this article comes from work carried out on one specific strain, which helps illustrate how a mechanism-of-action dossier is built.

Strain T34 of Trichoderma asperellum was isolated in 2002 from a compost with natural suppressiveness to Fusarium oxysporum, out of more than two hundred strains evaluated. Its identification was completed at molecular level using the ITS region and the genetic markers tef1, rpb2 and acl1. FRAC classifies it in group BM02, microbial biological control agents with multiple mechanisms of action.

For this strain, the processes described throughout this series are backed by published documentation: the effect on Fusarium wilt and water use in carnation (Sant et al., 2010); the efficacy against Phytophthora capsici in pepper (Segarra et al., 2013); the suppression of Rhizoctonia solani in cucumber seedlings in combination with agricultural waste compost (Trillas et al., 2006); the characterization of the induced resistance signaling pathway (Segarra et al., 2009); the induction of systemic resistance against the nematode Meloidogyne incognita in tomato (Pocurull et al., 2020); and the series of studies on mineral nutrition presented in the second module. Its ability to parasitize hyphae of Didymella and sclerotia of Sclerotinia.

One feature of this dossier deserves emphasis, beyond the sheer number of publications: much of it comes from groups outside the company and has been published in peer-reviewed journals. The work on the ISR signaling pathway was co-authored with Corné Pieterse’s laboratory in Utrecht, an international benchmark in induced resistance; the Meloidogyne work, with the nematology group at the Universitat Politècnica de Catalunya and the Centre de Regulació Genòmica. That external traceability is what sets a verifiable description of mechanisms apart from a generic attribution to the genus Trichoderma.

Biocontrol Technologies, a spin-off of the Universitat de Barcelona, develops and markets this strain under the name T34 Biocontrol, which is authorized as a plant protection product in seventeen European Union countries and in other international markets such as Canada and the United States. Ongoing work with research centers is what makes it possible to substantiate this description of mechanisms.

Authorized uses, rates and crops vary from country to country and are set out on the label and in the corresponding plant protection product registration in each territory. Any application decision should be based on that documentation and, where appropriate, on the advice of a crop advisor.