The European Food Safety Authority (EFSA) has concluded that the available data on the microbial pesticide active substance Trichoderma asperellum T34 are insufficient to finalise the consumer risk assessment and the environmental risk assessment for non-target aquatic organisms, citing unresolved questions over the production of potentially toxic secondary metabolites. In a conclusion on pesticides dated 31 July 2026, the authority confirmed sufficient fungicidal efficacy for the proposed uses on ornamentals, tomato, sweet pepper, aubergine, cucumber, melon, watermelon, zucchini and pumpkin in permanent greenhouses, but identified data gaps that prevent a full regulatory sign-off.
The peer review, conducted under Commission Implementing Regulation (EU) No 844/2012 as amended by Regulation (EU) No 2020/103, covers the renewal of approval for T. asperellum T34, an application submitted by Biocontrol Technologies S.L. The rapporteur Member State Sweden and co-rapporteur Italy provided the initial evaluation in a renewal assessment report received by EFSA on 20 March 2024, with EFSA distributing it for consultation on 16 May 2024 and forwarding comments to the European Commission on 15 July 2024. During the process, the applicant formally withdrew support for the 'Xilon' formulation via a statement dated 31 January 2025 and a letter dated 6 May 2026, while maintaining support for the active substance and the 'T34 Biocontrol WP' formulation, rendering the Xilon assessments obsolete.
EFSA's conclusion, approved on 30 June 2026, lists several areas where the risk assessment cannot be finalised. In mammalian toxicology, the evidence was not considered sufficient to exclude the production of metabolites of toxicological concern. For residues, data gaps were identified on the occurrence of emodin, a metabolite of potential concern, including its potential in-situ production under the representative use conditions. Regarding environmental fate, T. asperellum T34 is expected to persist and multiply in soil at concentrations considerably higher than natural background levels after repeated applications, and current information is insufficient to determine whether the strain produces metabolites of potential concern and the resulting environmental exposure. The ecotoxicological risk assessment for non-target aquatic organisms exposed to these secondary metabolites could not be finalised either.
The conclusion also notes that insufficient data were submitted to draw a conclusion about the production and toxicity of secondary metabolites of potential concern, and that the three different MPCA-AM materials are produced and purified with methods that differ in critical aspects, so it cannot be guaranteed they will be identical in metabolite content. No issues were identified that could not be finalised regarding identity, biological properties, physical and technical properties of the formulation, or analytical methods.
The findings carry direct implications for the applicant, Biocontrol Technologies S.L., which faces the prospect of additional data requirements to secure renewal of approval for the active substance. For growers of the affected crops, the outcome determines continued access to a biological fungicide option, though the identified data gaps do not yet trigger a withdrawal of approval. EU regulators, including the European Commission and Member State authorities, will use the conclusion to decide on the renewal, potentially imposing conditions or requesting further studies. The unresolved questions around metabolite toxicity and environmental persistence also bear on consumer safety and aquatic ecosystem protection, underscoring the trade-off between enabling a biological control tool and ensuring adequate safeguards against unknown risks.